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Shot

Firing Apparatus. BRITISH DESIGN.

BRITISH MANUFACTURE. PIT

SINKING PLANTS.

WIRES. CABLE REELS.

Send

for

List

No.

15.

JOHNDAVIS" SON (Derby). Ltd,DERBY. "

Telegrams:

Telegrams"

"BLASTING

DAVIS

SERRIDGE

DERBY."

Telephone,

240.

JUNCTION."

Established

1873,

TieElectric RegisteredTrade

Marks.

CINDERFORD,

B TRADE

SO.

I*

GLOUCESTERSHIRE.

MARK

MANUFACTURERS

OF

ELECTRIC

...

AND

HIGH

TENSION For

Confining ourselves an experience of superior to any on the with

LISTS

FUSES

with

use

LOW-

entirelyto

the

35 years, market.

over

ON

Explosives.

All

we

manufacture can

of Electric Fuses, and

guarantee

to

supply

an

article

STERLING" Electric

BLASTING

MACHINES DYNAMO

or

MAGNETO,

HIGH

OR

LOW TENSION.

Firing 2

to

8O

for

Shots. JVo.

J4it,

"Shot-

Firingby Electricity/' full

containing and

Price.*.

MANUFACTURED BY THE

Teiepnone Sterling " Electric Co., Ltd., 200, UPPER

THAMES

LONDON, Works-DAGENHAM,

ST,, E.C ESSEX.

QUICK

DELIVERY

at .

DURABLE

.

OF

.

.

and EFFICIENT

CABLES,

TRAILING SHOT-FIRING

CABLES,

TELEPHONE ARE

CABLES, ON

OBTAINABLE

APPLICATION We

For

PRICES

LOW

are

ACTUAL

TO MANUFACI

COLLIERIES

or

US.

URERS.

QUARRIES.

WITH

High-InsulationResistance, PerfectlyNon-Hygroscopic, Great Dielectric Strength, Unaffected by Acids, Do not Crack, Long Lengths, Flexible,Light*

MINING

SWITCHQEAR, LAMPS,

JOHNSON

ARC

"c.

" PHILLIPS, Ltd.,

VICTORIA

CHARLTON, Established

WORKS,

S.O., KENT. 1875.

SafetyFuse.

Bennett

BRAND.

CROWN

ttfiflE

For

all

of

kinds MADE

ONLY

BENNETT,

WM.

Blasting.

BY

SONS FUSE

ROSKEAR

CO.

"

WORKS

CORNWALL

CAMBORNE,

108, BtSHOPSGATE

OFFICE:

BLASTING

Trices

and

Samples

,

,

.

LONDON

Ltd.

STREET, application.

on

CARTRIDGE

TOOLS.

E.G.

CASES.

E. C. THEEPAM, L^ DUDLEY. Q:::

REGD.

SCRAPERS.

AND

RAMMERS

CASES.

DETONATOR MAGAZINE

LOCKS,

NOTICES, LIGHTNING

SHOES, "c.

CONDUCTORS,

MINES.

ELECTRICITYJN the

-^S[)

\~

v.

//

:^rr:

in Mining and Regulationsconcerningthe Use of Electricity of Cases compulsory ihat directiojs for the effective Treatment Apparent Death from Electric Shock be conspicuouslyplacedin certain prescribed

UNDER Operations, new

Rules

it is

of

positionsin the Mines. A Set of these DIRECTIONS,

with

accompanied by PRECAUTIONS Electric

Current, and

TRIG

WIRES

"THE

ELECTRICIAN"

can

Paper,

17 in.

by

12

for

$ in. 4d.

showing the

adopted

Dealing

to Prevent

with

cation, appli-

method

of

Danger

from

the

BROKEN

ELEC

COMPANY,

LIMITED,

from

PRINTING SALISBUKY

On

to be

INSTRUCTIONS be obtained

Illustrations

AND COUKT,

each, 3/6

doz.

PUBLISHING LONDON, On

ENGLAND.

Card, 17 in. by 12i in. 8d.

Carriage paid in each

case.

each, 6/6

doz.

THE

Detonator Electric Compound Is

the

Most

Reliable

ELECTR/C

COMPOUND

H/GH

Made.

TENS/ ON

(ACTUAL

COMPOUND

ELECT/?/CPOWD"#

(ACTUAL.SIZE)

COMPOUND ELECTWC Low

TENS/ON DsroN/iTOft /V?7

(ACTUAL SIZE)

The Secures

Complete The

Detonation

The

Complete

Blasting Explosives.

in

made

Detonator

Immunity

from

Mis-Fires.

Detonators

Electric

Compound Are

of all

Electric

Compound Ensures

Detonator

Electric

Compound

High

or

Low

Tensions.

The British Electric Detonator LIMITED,

43, CASTLE

NORTHERN

PUBLISHING

STREET,

CO.,

5,

ELSWICK

LIVERPOOL.

COURT,

NEWCASTLE.

Co.,

EXPLOSIVES (Best Quality Only.)

"

*S"5^t3"*t

GELIGNITE,

/jLy^

\M(^^K^\

GELATINE

BLASTING

/Egf P

H

DYNAMITE,

DYNAMITE,

,ji i^si^^v

GELATINE,

*^iyi"^"^Q

BLASTING

COMPRESSED

V"mfmj^"

POWDER.

CHEDDITE

"

A

H'Sa

Contains Exude.

PELLETS.

Explosive of Great Itending Power. not Freeze or Does no Nitro-Glycerine. .

.

.

EXPLOSIVES

PERMITTED

Hard

Rl PPITE"

A

Explosive for

of Ammonia

Nitrate

EXCELLITE"

Coal and

High Explosivefor

Stone. Pit

Sinking,Ripping, Work. Colliery

Driving and General * "

W~^

"^v

w^

"B"^

T

m.

v

w

BOBBINITE. The

Best Coal

f~m^

"

^

9*

No Detonator

Required.

carried Getter,as provedby experiments

by

H.M.

of Inspectors

out

Mines.

PERMITTED PELLET.

Largest

Sale

of any

CURTIS'S 3,

Permitted

"

HARVEY, STREET,

GRACECHURCH

Local Depot-ALBERT

Explosive for Coal Getting.

CHAMBERS,

CARDIFF-

LONDON,

Ltd., E.G.

ConnollyBros.,Ltd BLACKLEY,-

"

MANCHESTER. Makers

of

PATENT

.

.

ENAMEL

INSULATED

SHOT-FIRING AND

Detonator

-

Connecting

Wires. FOR

Telephone,

5

SAMPLES

Lydbroati.

AND

Telegrams:

ELECTRICAL

LYVBROOK."

,fMITH

"

CO., AND

WIRE

MANUFACTURERS,

CABLE

GLOUCESTERSHIRE.

LYDBROOK,

IN

THE

VULCANIZED

GUTTA-PERCHA, BITUMEN TO

"

INDIA

RUBBER,

INSULATIONS,

AND

OTHER

ANY

CONSTRUCTION.

Prices

OF

MANUFACTURE

CABLES,

SHOT-FIRING

Samples

"

SMITH

H. W.

-

PRICES.

on

application.

-

CRESCENT COAL The work.

" ROCK

handiest and In

a

PRILLS.

best Shot

two=ft. seam

hole Drill for coal face

of these machines

one

60 holes 4 ft*deepper shift. Power

will drill

about required,

2 H*P.

H 2 " M

u M

u, u-

Made

for direct-currentor Also

When

sending

for

3-phasecurrent. Any voltage, compressed-air driving.

inquiries work

SOLE

tor

give

to

be

"full

particulars

of

done.

MAKERS:"

A. HIRST

"

Crescent Works, Meadow

CRESCENT

LT^

SON, Lane, DEWSBURY.

COAL

CUTTERS.

'

The

f

" IrTsftKlten "f Mioipg; JJ

E\ectfica\Enioeere.

*

adsuncernern 'rt" aj^

of e

rr?nncrch

m

eucb

Membership"^ofDenioall Mning Electrical Encrincere nine ,

and

Officials c

world.

16

Colliery

Srancbce

may ^ mining;dielnc^

A to

eetublie"bed

ir; any

valuableweekly journal

i

every

Further

The

member.

will jrrfarmaVfon

Inefituliiop of Minipcr

Eledricci\ Enoloeere?, BanK

Chcimbere

Derby. Errand.

"

^

THE

GUIDE:

SHOT-FIBER'S

16lastingantr

PracticalJJtamtal 0n

"pnbiutian of IHastxng J

BY

WM. PRESIDENT

FELLOW MEMBER

OF

ALL

OF

MINING

ENGINEERS; MANAGERS.

COLLIERY

OF

ASSOCIATION

NATIONAL

THE

OF

ENGINEERS;

ELECTRICAL

OF

:

;

SOCIETY

GEOLOGICAL

THE

INSTITUTION

THE

OF

MEMBER MEMBER

OF

INSTITUTION

THE

ENGINEERS

ELECTRICAL

MINING

OF

INSTITUTION

THE

OF

MAURICE,

RESERVED.

RIGHTS

LONDON:

"THE

AND

PRINTING

ELECTRICIAN"

COMPANY

PUBLISHING

LIMITED, SALISBURY NEW JAPAN INDIA

YORK : :

:

Z. P.

The

D.

Maruya

Van "

COURT,

FLEET

E.G.

Co., 23, Murray

Nostrand

Co., 14,

STREET,

Nihonbashi

Tori

Street.

Sanchome,

Spink " Co., Calcutta. Higgiubotham " Co., Madras.

Thacker,

And

all Booksellers

at

Home

and

Abroad.

Tokyo.

LONDON

:

PRINTED BY

GEORGE

TUCKER,

SALISBURY COURT.

FLEET

STREET, E.C

.

INTRODUCTION.

In

of

service

the

at

SHOT-FIRER'S

the

GUIDE

explosives

in

users

mines

simple, practical explanations concerning types and

methods that

precautions

of are

stage of

Every instances

frequently

firingin fiery and the

most

It is

the

methods

that

by

thus

annual failure

to

In

Great

caused

On dies

Britain

than

by

the as

lives

with

which

comprehend

killed

500

of

more

her

3,000

accidents

;

most

of

in the

result

of

shot-

light of

be

in

of modern lessen

to

as

cials, offi-

involved

use

done

exacts

mine

the

the

price

of

laws. 106

mine

the

past have

persons

is

person

have

explosions 10

of the

injured

injured

use

of

same

and

over

explosives. day

every

week

been

In the

years.

been

injuries each

his

risks

skilful

will

arising out

one

the

the

Nature

alone

average,

the

which

familiarise

to

with

others

by shot-firingduring

period

the

in detail

question

is considered

ignition, something

toll

and

is described

of accident

seeking

shot-firing,and

of

approved

safety.

secure

important

very

mines

dusty

shot-lighters and underground

quarries

inquiries.

recent

hoped

varieties

of the

j and

occur

and

the most

to

blasting operation

given

are

in order

place

to

handling blasting apparatus

necessary

a

is made

attempt

an

and

one

the

throughout

year.

Few

of

these

casualties

For

occurrences.

result S.F.G

of

inexperience

partake

or

of

the

of

most

the

nature

part

thoughtlessness,

they and

of

foreseeable un-

the

are

form A

a

INTRODUCTION.

IV.

in

powerful argument who

known

are

which

upon

they

"

of

standard

the

of

employment of the

knowledge

men

duties

engaged.

are

sufficient

provisional,and

be

of

sufficient

to possess

definition

The

favour

of

"

knowledge

dependent

proficiencyin

must

the

on

the

sarily neces-

current

class

of

tainable at-

workmen

concerned. least

At

of

that

he

in

is desirable

that at

or,

such

series of

this

book.

At

as

they during they

a

they

questions as

shot-firer

that

mine

is also

of

years

only

a

during

vague

which

the

is able

miners officials,

the

of

quarrymen of the

rials mate-

development

facilities.

of

it

ficate, certi-

p. 154

on

and

enormous

inarticulate

operations

to

person

deputy,

a

appears

educational and

can

some satisfactorily

answer

considers

one

candidate

under-manager's

an

to

dition con-

shot-firer

competent

a

not

percentages

Regulations,and

rule, singularlylittle knowledge

recent

run

able

least, be

use, when

have

acquirement, a

hold

he should

present time

the

possess,

If the

mine.

a

or

minute

he is probably d'etre,

raison

fire shots

to this

the Official

knows

explain their to

addition

essential

an

positionof deputy

abilityto accurately detect

''gas."*If,in

show

to the

has

stress

to become

likelysoon

appointment

is the

"this of

laid is

been

hitherto

which

qualificationupon

one

idea

of

Generally, the

priming, stemming

risks and

firinga charge. In coal mines, where to

be

of the

that

probable

risks of

by specialconditions,

accentuated

important

the normal

individual

every

and *

should

possibleconsequences See

Appendices

I. and

II.

blastingare it is be

liable

exceptionally

fully cognisant of his every

act.

IN

VI.

A

considerable

safety

carried

of H.M.

to

of

the

explosives

and

him

electros

of current

to

the

and

from

to

the

works Nobel

these

of

Dr.

particulars

for purposes

Torkard,

Books Office

Official

Publications

of His

Schwartz

and

other who

to

their

Majesty's

pleasure and makers have

his M. of

kindly

specialities

of illustration.

Notts.

a

seek.

Von

relative

on

constantly

are

with

Company

an

desire

Home

records

shot-firing apparatus with

Blue

H.M.

Controller

also

views

Author's

read

to

care

freely

form

expert

the

not

been

they

WM.

Hucknall

Great

Bobbinite

have

Explosives

of

Author

The the

of

use

due

are

to

and

supplied

that

of

on

because

does

of all who

make

to

Office.

indebtedness

and

disposal

acknowledgments

Bichel,

Medical

Association

inquiries which

Mines

permission

Stationery

that

valuable

of

Departments at

H.

America,

experiments

Explosives

partly

public

a

of the

knowledge

For

of

partly

and

explosives

before

bring

placing

Inspectors

up-to-date exposition

use

Henry

of

Committee

Departmental

contribution,

admirable the

of the

Report

under

laid

the

on

British

valuable

Mining

added,

Altofts.

at

those

and

the

by

out

the

to

the

Dr.

as

Institute

Mining

Address

been

bearing

mines

dusty

Coal

also

work

recent

Sheffield, and

at

being

Britain

the

Presidential

Association

The

before

Paper

Snell's

are

such

to

has

matter

new

shot-firingin fieryand

of

Payne's Dr.

of

amount

references

including

UCT10N.

TROD

MAURICE.

JACKHAMMER for

Adapted

of

style

any

bit.

Designedto give

IN COST

ECONOMY OF

UPKEEP, and

-

to

-

have Fast Drilling Capacity.

.

SUITABLE

FOR

.

SINKING,

DRIVING,

BLOCK

HOLEING,

"

TRENCH

WORK.

0.

G [SOU-IP 165,Queen Victoria Street, EC." LONDON,

"

EXPLOSIVES EXPLOSIVE.

PERMITTED

%

CORNISH

P " s

"

This to

explosive has

Write

lor

HIGH

"S

"

the market, owing coal. in either stone or

equal

no

for adaptability

its

"

use

of

List

POWDER

on

Testimonials.

EXPLOSIVES.

Gelatine Dynamite,Gelignite, Non-FreezingGelignite, Dynamite,BlastingGelatine. Factory"

NATIONAL EXPLOSIVES SS: HAYLE, Head

CORNWALL

Office : 14,QUEEN

Electric PATENT and

use

do

firingfrom not

exhaust

superior

STREET,

Shot

DYNAMO

For

Time

VICTORIA

to

4 to the any

LONDON, EC.

Firing. EXPLODERS.

80 shots

simultaneously. strength of these exploders,which type yet produced.

arc

Cables,Fuses,Galvanometers and allAccessories. Write

for Lists

to"

FLEMING " 31, Robertson

Street,

Address:"" Telegraphic

DYNAMITE

CO., GLASGOW. GLASGOW."

TABLE

OF

CONTENTS.

I." EXPLOSIVES.

CHAPTER

I.

PAET

PAGES

1-10

EXPLOSIVES

Coal

of Iron.

Result

the

Explosion

Gas.

Gases.

Explosives

of

of

Nitro-

Nitrate

and

of

their

Quarries.

and

Oxidising Body.

the

Bobbinite

Explosives.

and

Detonation. Fuse.

Preparation Permitted

of

Fuse

"

"

Explosives.

Permitted

Detonator

of "

for

Fuses. "

Head.

Priming.

"

of

Selection

Fuses.

"

tonators. De"

Safety Igniter. "

Electrical

"

"

tance. Resis-

and

Low-

tors. Detona-

Fuse

Electric

"

by

Detonators.

High-tension

"

Action

Delayed

Cases.

APPARATUS.

11.-BLASTING

CHAPTER

for

Charge

and

Detonants

Fulminates.

"

Mines.

Firing

Fuse

"

Non-

Bickford

Cartridge.

Fuse

of

Fuse.

by

Detonants

Fuse.

Wires.

Ignition

"

Explosion

Combustion,

"

Fuse.

Primer

Electric

tension

British

II.

Composition

Igniter Electric

"

of

Standard

"

Fuses.

Bickford

Ignition

"

according in

Explosives

11-31

Noii-Detonants. "

powder. Gun-

"

FUSES

AND

Detonants

of

teristics Charac-

"

classified

of

"

Characteristics

Mixtures.

Explosives

"

tics Characteris-

"

Mixtures.

Mechanical

of

sion Expan-

"

Committee.

"

Nitro-Glycerine

PART DETONATORS

Air.

Glycerine Explosives.

Identification

"

of

Element

Consumption

Ingredients.

"

and

by

Permitted "

and

Coal

tion Combus-

"

Oxidation

Gas

Non-Detonating

List

"

Pressure.

and

Combination.

of

Nitrate

Ammonium

of

Mines

Mixture

Classified

Characteristics of

of

Combustible

"

as

Ammonium

Temperature

Energy

"

Explosion

"

of

to

of

I.

PART

3359

EXPLODERS

between

Dynamo

Exploder." "

Rack-bar

Exploders.

of

Classification

and

Sterling Machines.

"

Magneto

Magneto Pocket "

Exploders.

Exploders."

Exploder." Dry

Batteries

"

Difference

Helsby Magneto

Dynamo

Exploders.

Exploders. "

mulators, Accu-

viii

TABLE

CONTENTS.

OF

PART WIRES

II.

Conductors

and

60-68

Insulators.

Resistances.

Tables

"

Conductors

"

mate Conductivity. ApproxiCircuits. Shot-firing Uncoilingand CoilingWires. of

"

for

for Conductors. Specifications and Jointing InsulatingWires. "

"

PAGES

CABLES

AND

"

Permanent

"

PAKT

Joints.

III.

TESTING

69

Testing Explosivesfor use Test of Safety." The "The

Austrian

Test.

"

in

Fiery and

Woolwich

The

Mines.

Dusty

Test," and

Belgian

Test.

Tests.

German

Testing Effective

lute Abso-

"

French

The

78

"

Testing Electric

Strength of Detonators. Appliances for Fuse Testing. High-tension Fuse and and Precautions. Testing. Risks Testing Magneto Davis Roburite Tester. Dynamo Exploders. Exploder Co.'s Exploder Tester." meter. Testing Dry Cell Exploders." VoltCables plete Comfor and Testing Leakage. Continuity Circuit Testing."" Earthed Wires. Fuses.

"

"

"

"

"

"

"

"

"

"

CHAPTER PRACTICAL

III.

APPLICATIONS

79107

to Coal Mines. Preparationsfor Blasting,with SpecialReference Shot Holes. Drilling Preparingand Stemming the Charge. nators Different Kinds of Stemming. Methods of Securing Detoto Cartridges. Danger of Bunching Cartridges. Position of Primer Cartridge. Connecting the FiringLine. Precautions after Firing. Missbefore Firing. Precautions fires. Double Detonation. Hang Fires. Gunpowder Class nections Conwith Getters. Coal Permitted compared Explosivesas for Simultaneous Firing. Shot- firing in Frozen Ground." Drift. Driving a Stone Blasting in Quarries. Blastingin Shafts and Headings. "

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

CHAPTER

PAKT RISKS

IMMEDIATELY

Accidents

ACCIDENTS,

IV." BLASTING

CAUSED

Classified.

I. BY

109-124

EXPLOSIVE

THE

Handling Explosives. Directions for the Weather. of Explosives in Cold use Periodical of Accidents with Recurrence Nitro-Glycerine dents. AcciFrozen Detonator Explosives. Thawing Explosives. Risk of working with Naked Lights. Accidents in Stemming and Accidents Fire. to through Preparing Bunching Cartridges. Accidents through Boring into when Unexploded Charges. Accidents Firing. Accidents Accidents Wires. through use of Electric Signalling through allowingUnexploded Charges to leave the Mine. "

Accidents

in

"

"

"

"

"

"

"

"

"

"

"

"

"

PART ACCIDENTS

RESULTING

ix.

CONTENTS.

OF

TABLE

FROM

II.

PAGES

IGNITION

THE

OF

FLAMMABLE IN125-157

ATMOSPHERES become

Explosive. Ignition of Gases by Temperatures at which Blasting Materials Explode. Range of Inflammability of Gases. for Dust Dust Explosions. Reason becoming Inflammable. of Dust Occurrence tutes ConstiOcclusion. Explosions. What of Dust in a Mine. a Dangerous Amount Degree of render Coal perature to Dust Fineness requisite Explosive. Temof Ignition.of Coal Dust. Quantity of Firedamp Inflammable to produce an Atmosphere in the necessary of Investigaof Coal Dust. Dr. Payne's Summary Presence tions. plosives Selection of ExGas. Ignitionof Coal Dust without The for use in Dangerous Atmospheres. Relation Influence of Dust of Ventilation to the Watering Danger. of Explosions in South Reciirrence Wales Coal Dust. on of Dust. Methods for the Removal Coalfield. proposed of Deposition of Dust. Rate Preparation of a Dustless Zone. Altofts The Safeguard? Nystagmus. Experiments. ledge KnowShotand from firing. Qualities against Explosions and

Gases

How

Vapours

Flame.

than

otherwise

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

"

should

Shot-firer

Competent

a

Possess.

CHAPTER LAWS

REGULATIONS

AND

USE

AND

The

OF

V.

RELATING

STORAGE

THE

TO

EXPLOSIVES

159176

Explosives Act, 1875." The Quarries Act, 1894." The Coal Mines Regulation Acts, 1887 to 1896. SpecialRules for the Installation and Use of Electricity in Mines. SpecialRules in North in for Ore Mines Wales. Coal Mines Explosives Collier^ Bye-laws. Orders. "

"

"

"

APPENDICES, 1. SUMMARY FROM

THE

SECOND

COMMISSION 2. COMMENTS OF

ON

ON

GAS

3. BRITISH

OF

COAL

4. EXAMINATION

FIRING INDEX..

THE

DUST

SHOT-FIRING

ON

REPORT

OF

ROYAL

THE

MINES

177-178

TESTING

LAMP,

GARFORTH

REPORT

SUBJECT

CONCLUSIONS

MAIN

OF

ROYAL

DESCRIPTION

AND

FROM

SECOND

THE

COMMISSION

ON

MINES

EXPERIMENTS

QUESTIONS

RELATING

179-182 183-186

TO

SHOT187-195

197-208

LIST

xii.

39 40 41 42 43"44

II."

CHAPTER

FIG.

ILLUSTRATIONS.

OF

PART

Exploder SterlingDynamo Sterling50-Shot Exploder SterlingExploder, showing Spring Catch for FiringHandle. Spring-controlled Gearing Dynamo Exploder with Automatic of using Sterling Exploders Methods .

46

Section

47

Wood's

Cell

Primary

through

44

Davis

49

Accumulator

45 40

51

Shot-firer, with

52

Charging Apparatus

58

II.

PART

BlastingCircuits and Bad Good Joint-making and InsulatingWires Splicing Conductors

44

50

Safety Firing Key Safety Key

and

.

48

Dry Cell

Obach

Dry Battery Pocket

48

52

43

.

Elementary

51

continued.

of

Mechanism

45

50

I."

64

for

67 68

"

PART 53

Showing Shunted

54

Low-tension

55

Low-tension

Exploder Exploder

56

Low-reading

Voltmeter

57

Combined

III.

of Low-

Bridge

Tester Tester

tension

Fuse

72

pattern) (Roburite Co.'s pattern)

75

(Davis

76 and

Galvanometer

CHAPTER

Dry

Cell

77

III.

63

Stemming a BlastingCharge Holes in Cartridges Peg for Boring Detonator Methods of attachingDetonators to Cartridges Position Correct of the Stemming a Charge (showing Cartridge) Connecting FiringLine to Sh" "t Wi res Fuse with Severed Bridge Diagram of Low-tension

64

Cable

58 59 60 61

62

65 66 67

68, 69 71

72 73

Reel

75 76

78

82 Primer 83 87 89

106 Firingin Quarry of Connecting Series of Shots for Firing Methods 107 Pan Nobel's Warming Ill Cause of Shot-firing Accidents " 70 Diagrams illustrating 118,120 Photo of SafetyLamp Flame, showing Gas Cap, facing page 152 Safety Lamp facing-page 152 in Motion Safety Lamp facingpage 152

Series

"

"

"

View

of Interior

"

II.

"

from Break CollectingSample of Gas Gas Testing Sample of The Garf orth Firedamp Detector Lamp

in Roof

181

"

APPENDIX 77

81

82

102

APPENDIX 74

75

181 182

III.

of

Gallery at Altofts Diagrams illustrating Experiments at

184

Altofts

186

PART

I.

EXPLOSIVES. Result

the

Explosion

Coal-Gas,

of

1.

p.

Gases,

p.

An

Committee,

Gunpowder, to

by

Explain,

"

List

Quarries,

and

Mines

1

p.

All

that

namely,

readily

burn

The

air.

form

water

combination

given

out, A

heat. S.P.G.

(H20). so

sufficient

there

piece of

In

both

great

that

iron

raise if

and

an

the

exposed

coal

the

the

hydrogen

burning the

an

when

and

coal-gas in these of

oxygen to

"

light

seen

form

a

the gas

combines the

bodies

to

of

energy heat

of

amount

enormous

is

and

present

reactions

"

chemistry

forcibly

oxygen

to

causes

heat

place

the

these

subject

two

on

and

p. 10.

There

elements

are

with

to

manual

Wood

British

produced.

pressure.

most

according in

the is

8.

p.

Explosives,

to

affinity for

great

(C02)

to

is

Mixtures,

Explosives

Permitted

takes

place.

a

dioxide

is

this

combines

carbon

carbon

called

and

takes

have

which

substances

of

7.

p.

Mixtures,

Explosion

action

chemical

Explosives,

classified

introduction

elementary

every

Bobbinite

Glycerine

Mechanical

and

and

Explosives,

Explosives

an

Expansion

the

Glycerine

Nitro-

of

Iron,

Element

by

explosive properties

air, because

in

and

temperature

combustion

ordinary

Nitro-

Consumption

of

generally evolved,

are

Combustible

of

of

2.

p.

Ammonium-Nitrate

how

of

when

of

Identification

their

in

axiom

important

10.

p.

owe

result

the

as

Classified

Permitted

9.

p.

Explosives,

explosives

namely,

of

way

.

of

a

Non-detonating

of

9.

Ingredients,

their

of

Air,

of

Combustion

Oxidation

1.

and

Ammonium-Nitrate

Characteristics

8.

Explosives

Characteristics

of

Characteristics p.

p.

1.

p.

p.

Coal-Gas

consists

Characteristics

4-7.

pp.

Explosive

3.

p.

of

3.

Pressure,

Combination,

of

Mixture

Body,

Oxidising

an

of

2.

and

Temperature

Energy

Explosion

1.

p.

of

to

atmosphere

a

is

white

slowly B

2

SHOT-FIRER'S

THE

rusts, the oxygen

of the

air

GUIDE.

combining with

it to

form

oxide

In

doing this a certain quantity of heat is formed ; but the rustinggoes on so slowly that the amount of heat is inappreciable to the senses. If we expeditethis action by heating the iron and plunging it into oxygen gas, rusting takes place so rapidlythat the iron actually combination or of iron, or

rust.

fire and

catches

burns.

In the latter

the heat

case

is

given out

intense,and is easily

takes place so rapidly. recognised,because the combination combination It is a proved law that when takes placebetween of heat is given out if the amount bodies,exactlythe same to accomplishthe process takes a few seconds or takes years result.

same

called oxide

substance

elements

we

turn

and

escapes

a

of heat

"

the iron

with

the

air,no

the

For

gaseous.

room

a

tain cer-

cause

;

the

gas

combination

of gas and air fire and burns.

match, for instance

taking place. by applyinga light, On removing the

the gas does

"

not

go

coal-gasin burning, combining with the oxygen of the air,gives out so much heat that each successive portionof gas issuingfrom the jetis raised the gas burns steadily, to the point of ignition. In this case out, but

continues

owing

the

to

burn, because

solid

producesa

however,

can,

coal-gasin

of

the mixture

up

We

jet

immediately catches

the gas source

on

mixes

warm

of iron.

and

combine, the products being

to

instance, we If

of the oxygen

combination

The

to

gradual mixing

the

air of

a

room,

on

to

even

and

of the gas

If,however, the tap be turned with

the

so

and

air.

the gas

small

an

allowed

extent

to mix

10 per

as

and a lightbe then introduced,a violent (ofthe coal-gas), explosionwill take place,owing to the whole of the combustible mixture combining,not slowly,but almost instantaneously.

cent,

As

a

result,the

windows

blown

room

may

This

out.

be wrecked

increase

of pressure

effect of temperature, for it is well known heated

are

form

and

the

is due

that when than

they expand, gases expanding more

and

doors to

the

substances any

other

of matter.

Explosion

be, therefore, caused

may

combustion, and,

as

a

generalrule,it

may

by intenselyrapid be

stated

that

all

3

EXPLOSIVES.

their

explosivesowe

explosiveforce to the generation of pressure, caused by rapiddecomposition, combination of certain or elements, the productsformed being largelyexpanded by the

heat

evolved,the destructive effect being regulatedby the time

taken

in

producing the change of state. All ordinaryexplosives consist of two tible parts the combuselements and the oxidising body. Carbon and hydrogen, either free or combined in certain compounds, generallyform the combustible combined with other part,and oxygen, loosely "

elements,

in

as

the carbon

the

nitrates and

chlorates,is added

to

burn

and

hydrogen to form carbon dioxide and steam at a high temperature. (W. J. Orsman, F.I.C.,in a lecture before the National Association of Colliery Managers, England.) up

2.

How

"

If

would

you Combustion

explain

the

and

difference

tween be-

Detonation?

explosiveis ignitedsimply by a spark or flame, a small portionof the explosivemixture is kindled in the first instance,and for a periodit is called simply progressivecombustion in the neighbouring ; this produces a slightpressure layers of gases, and of course naturallyheats them ; and, by the time the progressive combustion reaches these more highlyand at a higher temperature, the rate of compressed gases, an

combustion

is accelerated

until at

last it ends

But in the case of being formed. the initiation or a detonatingsource, explosive, is set up more wave rapidly,and the series take placein au infinitely shorter time.

3."

How

are

In the

valuable

Bobbinite

.

a

a

true

detonating

of this of

sive explo-

operations

Report of the Departmental Committee which

are

as

plosion ex-

classified?

(Cd, 3,423, 1907) explosivesare

principal groups, 1

Explosives

in

under

divided

on

into five

:

"

Nitro-glycerine : explosives (a) Low per cent, nitro-glycerine (b) Medium per cent, nitro-glycerine. (c) High per cent, nitro-glycerine. (d) Gelatines. B2

4

SSOT-FIRStiS

THE

2. Ammonium

4. 5.

Gunpowder.

Of these

1, 2 and 3

groups

(SeeQ. 12,

Chief

the

are

detonants,or high explosives.

Characteristics

of the

First

Glycerine Group?

Nitro-

or

are

explosives.

11.)

p.

What

The

explosives.

and ammonium-nitrate Nitro-glycerine Non-detonating mechanical mixtures.

3.

4."

nitrate

GUIDE.

chief characteristics of this group

depend on the presence ingredientbeing a liquidnecessitates

This nitro-glycerine. will retain it in the substance which the employment of some cartridgeas a sponge retains water, or else the presence of an it so that it ceases to be a liquid. ingredientwhich will gelatinise A prominent characteristic of this group is that they are of

relativelyeasy

detonate

to

under

normal

conditions,since

is relatively sensitive. Unfortunately it becomes nitro-glycerine solid at temperatures well above that of the freezingpoint of in this state the cartridgesare, generally water, and when sensitive to rough treatment, but less easy to speaking,more

explode with

a

Hence, after

detonator.

spellof

a

cold weather

the number

of accidents

explosionsduring the chargingof a shot- hole when removing debris strikingunexploded cartridges

due

to

increased.

In the past

arisen from

the

employment

cartridgesto

the

a

considerable of

them

restore

number

due

or

is

to

largely

of fatalities have

for warming improper means condition (seepp. to a plastic

111-113).

explosivesof this group are readilyinflammable, and when burnt, instead of being detonated, they give off generally, largequantitiesof highlypoisonousgases. Sub-group(a),Low per cent. Nitro-Glycerincs." All

Low

per

cent.

Nitro-

Glycerines.

This

sub-group

group.

The

25

cent,

per

absorbed added

a

or

nitrate,or

oxygen

barium),thus

may

be termed

the Carbonite

which nitro-glycerine, of the

total

forms

about

weight, is generally

by wood-meal, and to this mixture is nitrate of potascarrier (generally sium

forming,as

it were,

a

mixture

of nitro-

5

EXPLOSIVES.

glycerinewith introduced

as

be

intended

were

between

for

in coal

use

down

by

slow

very

and

where

so

danger

to

was

speak, diluted

to

or

cool

gunpowder, these explosives speed of detonation and are

comparatively low

a

possess

a

were

a

mines

apprehended from fire-damp. The nitre-glycerine having been,

tamed

carbonites

highly shattering non-detonatinggunpowder,

dynamite, and the

as

The

gunpowder.

compromise

a

explosive,such and

wood-meal

a

suitable for coal-getting than any alleged,therefore,to be more other detonatingexplosive. and They have successfullypassed both the Woolwich Belgian tests (see pp. 70 and 71) and are considered on the Continent be among the safest of all explosivesused in to The

mines.

gassy

is

Frameries

charge limite (seep. 133) of carbonite 900

over

in addition

those

to

They have

grammes.

inherent

in the

at

tages, certain disadvanthe chief of

group,

tively they are bulky and thus entail the use of relalargechargesand a relativelylargediameter of bore-hole. This sub-group is also generally regarded as being more than the other explosivesof the nitro-glycerine liable even noxious to cause fumes, consistinglargely of the group is that

which

inflammable

gas

carbon-monoxide.

Sub-group (b), Medium

Glycerines. This

per

"

sives which

Nitro-

cent.

in which

Glycerines,

from

they have

present the

35

to

been

not

48 of the total

much

of 44 per

Frameries

12 is 650

be taken

cent,

of wood

(seepp.

Normanite,

9

On

as

a

type.

per

cent,

-meal.

Its

at

It consists

of sodium

phate, sul-

charge Limite

at

grammes.

Occasionallya small percentage

explosiveswith

in this country.

been

44 nitro-glycerine,

per

is nitro-glycerine weight. Up to the

employed for some successfullypassed the Belgian tests

have

of

cent,

and

List

used

strong carbonites,

of

percentage

Grisoutirie 11. may

Frameries.

Nitro-

sub-group consists of explo-

Continent, however, they have

little time, and

cent.

per

be termed

may

the

Medium

this

of nitro-cotton

ingredientpresent

and

but their

10) use

under

the

appear

names

is restricted.

on

of

is

added, and

the Permitted

Dragonite and

6

THE

SHOT-FIRER'S

GUIDE.

High per cent. Nitro- Glycerines, Sub-group(c), This sub-groupis represented High per cent. by dynamite, which consists of 75 per cent, of nitro-glycerine Nitroabsorbed by 25 per cent, of kieselguhr. Glycerines, It was the first nitro-glycerine practically explosiveused on a largescale and its chief characteristic is it" from its high velocityof detonation, great shattering power, arising "

which It will

is

not

nearly three times

great

as

either the Woolwich

pass

Sub group

that of carbonite.

as

the Continental

or

tests.

(d),Gelatines. In this sub-groupthe nitro-glycerine is gelatinised by nitro-cotton,and all the explosivesin it can be recognisedby their somewhat cluded Injelly-like appearances. in sub-group (d) are such explosives as blasting The Bobbinite Committee "c. gelatine, Gelignite, placethem in this order to show the process of evolution. tine, Blastinggelathe most powerfulexplosiveused commercially,consists of nitro-glycerine and nitro-cotton only. This composition for various reasons requiredto be tamed down, and hence it diluted with carbonaceous materials and oxygen-bearing was such salts, these

wood-meal

as

additions

Woolwich

added, and

a

10

per

largeamount

in this form

nitrate

known

required to

less than

contains

and

it is well it

test not

purpose

which

"

and

as

the Continental

Gelignite. To tamed, and

be further cent,

of oxalate of

of water under

Arkite, "c., it passed the Woolwich pass

potassium, and with

of

the

pass

the

for this

of ammonium,

wa" crystallisation,

of

names

Storvite,

ever, It will not, how-

test.

test,chargesof 50 grammes

almost

invariably causingignitions. From a blastingpoint of view the chief feature in the Gelatines is their great local shattering effect,though, as we modified by shall subsequentlyshow, this can be successfully skilful use,

and

shot holes without To the

sum

up

the

also

the

great

fact that risk of

a

they

be

can

used

in

wet

miss-fire.

characteristics of the

nitro-glycerine group,

advantagesmay be said generallyto be : 1. Ready detonation under normal conditions. enables them to be squeezedinto 2. Plasticity, which it up. bore-hole,completelyfilling be used in wet holes. 3. In the case of the gelatines, can "

a

8

SHOT-FIRER'S

THE

6."

Describe

the

Third

GUIDE.

Ammonium-Nitrate

or

and

Nitro-Glycerine Group. The

introduced

AmmoniumNitrate

explosivesin

Nitro-Glycerine Group.

of wood-meal of nitrate of ammonium.

been

the

gettingover

is mixed

with

about

84 per cent,

explosiveswill detonate

These

fairly

is frozen, but they have nitro-glycerine has waterproof cartridges.Great difficulty

in

up

of

been

the

when

be made

to

the view

with

have

group

in detonatingammonium-nitrate exdifficulty plosives. Generally speaking, about 8 per in 8 per cent, absorbed cent, of nitro-glycerine

and

freelyeven

this

suitable

experienced in providing a

method

of waterproofing

the

cartridges. into use These comparatively explosiveshave only come in recentlyin this country, but they have been manufactured

Germany

for

Those

which

to

some

years.

are

the Permitted

on

pass the Continental

test,but

as

probably fail

List would

somewhat

similar

explosives

have

in assigned to them charge Unities of 500 grammes Germany, it is probable that, with slightmodifications,the the to pass British-made explosive could be manufactured

Continental 7."

What

test.

are

Group"

the

Characteristics

Non-detonating

of

the

Mechanical

Fourth tures Mix-

?

The Non detonants.

now

The

first is in two

manufactured.

shortlywith

are

Amasite,

Aphosite, Bobbinite, and Virite. used

not

of this class only explosives

Bobbinite.

It

or

a

new

three

explosive:

the second

collieries and

is

the last is

remains, therefore, only to deal very

This

explosivem its action resembles gunpowder, and is consequentlypopularwith miners who have been accustomed to blast with gunpowder. Like that explosive, it requiresto be efficiently temped to obtain good results. Bobbinite consists of a high-gradegunpowder containing but little sulphur,mixed and pressed with starch and paraffin wax into a pelletwhich is coated with paraffin wax.

EXPLOSIVES.

The

method

employed

of

for the

Continental

the

its manufacture

is very

similar

production of gunpowder.

tests,as when

to

that

It will not

pass

it does not

unstemmed

explode

properly. 8 "Describe

the

The

characteristic

of Group explosives

Gunpowder,

explosion,which for work

A

where

further

fact that

an

as

of

Explosives

?

gunpowder and the their low velocity of

of 4 is

renders

them

suitable

very

slow

heaving action is required. from the advantage in use for coal-getting accrues tion overchargedhole is not penalisedby the produca

of slack to the turns

Class

Gunpowder

to an

extent

same

as

with

a

detonant

disadvantagewhen there is a overchargedhole is a distinct a

risk of

firedamp, igniting of danger.

source

will not pass either the Continental

Gunpowder

ever, this,how-

;

Woolwich

or

tests.

9."

Give

the

List

(July 3, 1909) classified

Explosives GROUP

I. "

Sub-group(a),Carbonites

according

Kynite. Kynite Condensed.

Carbonite.

Nobel

Clydite.

Oaklite

No.

1.

Kolax.

Oaklite

No.

2.

Carbonite.

Sub-group(5),StrongCarbonites Dragonite.

Cornish

Arkite.

Dominite.

Celtite. Ciiffite.

Fracturite.

Powder.

Haylite

B.

Ammonite.

Powder.

Pit-ite.

Tutol. Victorite.

Normanite.

,

Albionite.

Ammonal

Phoenix

:

Extra-carbonite.

Ammonal.

gredients. In-

their

NITROGLYCERINES.

Catnbrite.

GROUP

to

:

Britonite.

Sub-group(c),Gelatines

Permitted

of

II. "

Bippite. Eusselite.

No.

Samsonite 1.

Stow-ite.

AMMONIUM-CITRATES. Odite.

St. Helen's

Permonite.

Koburite

Permonite

II.

Powder. No.

3.

Thunderite.

Amvis.

Kipping Ammonal.

Titanite.

Bellite

Bellite

Titanite No. 1. Westfalite No. 1. Westfalite No. 2. Withnell Powder.

No. 1. Colliery Steelite. Good Luck.

Curtisite.

Minite.

Electronite.

Negro Powder.

Faveraham

No.

Dahmenite

3.

A. Powder.

10

SHOT-FIRER'S

THE

III"

GROUP

AMMONIUM-NITRATE

Abbcite.

Monobel

Excellite.

Permitite.

IV.

GROUP

GUIDE.

Eexite.

Powder.

Nobel

NON-DETONATING

"

NITROGLYCERINE.

AND

MIXTURES.

MECHANICAL

Bobbinite.

Aphosite.

Powder

Ammonia

Virite.

Amasite.

Give

10."

Table

a

Explosives during

the

showing British

in

Year

How

would

Mines

of

Quarries

and

1908. Table

11."

Consumption

the

I.

identify

you

a

plosive Ex-

Permitted

? Since

is conditional

FIG.

it to be a

crown

1907, the

the 1st of March,

a

1.

"

on

each

COMPULSORY

the letter P

of

a

sive permittedexplo-

cartridgebearing a

MARK

ON

permittedexplosive. with

use

A

The

EXPLOSIVE.

PERMITTED

marking

in the centre,

as

showing

mark

is the outline of

shown

in

Fig. 1.

and p.

Fuse,

p.

Bickford

12.

Ignition

Detonators, p.

14.

p.

and

High-Tension Electric

Fuses,

"

Fuse p.

it takes

for

a

materials

some

slowly, producing In with

other

yet

and

is called

depends

on

the

another,

stage

is

the

the

is

no

bordering

on

that

"

p.

28.

is,

with

takes

of

the

with

such

solid

matter

produced by

combustion

menon pheno-

into one

gases,

explosive from

passing

series to

into

explosive

an

it is converted

form

place

ordinary extra-

This

sharp dividing-linebetween

simple

time

explosion.

occurs

force

classes

the

is released

energy

of energy

called

which

in

very

CQmbustion.

is called

change

The

vary

be

explode.

to

conversion

different

the

of

will

non-detonant

practically instantaneous.

rapidity

21.

Detonant

a

chemical

which

detonation.

and, since there and

that

vapours

combustion

is then

materials

other

Cases,

explosives

transformation

and

p.

19.

Selection

25.

Detonator

a

that

accumulated

the

rapidity

rapidity gases

of

change

materials

greater

In

a

and

detonant

given weight the

p.

Priming,

between

recognised

rapidity

trical Elec-

Head,

Fuse

p.

Safety

p. 17.

?

a

is

27.

p.

Detonators,

for

p. 20.

Wires,

p. 13.

Bickford

Mines,

19.

p.

Fuse

Fuses,

Firing

by

Fulminates,

15.

p.

Fuses,

difference

it

their

which

21.

p.

between

when

in

Electric

Action

the

difference

much

In

Low-Tension

for

tion, Detona-

and

Non-detonants

Charge

of

Fuse,

Non-detonant

a

understood

Fuse

13.

p.

Cartridge,

Electric

19.

Delayed

is

and

Composition

Igniter

of

Ignition by Fuse,

Primer

Detonators,

26.

What

The

of

p.

12.

Detonants

Permitted

16.

Resistance,

12.

of

Explosion

Combustion,

p.

Standard

14.

p.

Fuse,

Preparation

Igniter,

p. 11.

Non-detonants,

11.

FUSES.

AND

DETONATORS Detonants

II.

PART

L"

CHAPTER

a

stage

of

a

true

detonation. In

(a)

practice, however,

those

which

are

blasting agents

exploded

can

be

divided

by simple ignition and

into

(b) those

12

SHOT-FIRER'S

THE

which

be

requireto

called non-detonants

13."

What to

detonation.

exploded by and

GUIDE.

The

are

the latter detonants.

is

Safety Fuse, and how Firing of Non-detonants

the

former

Non-detonants, of which

is it

applied

?

class

gunpowder and Bobbinite are the principal representatives, igniteon the simple application of sufficient heat, usuallythrough the medium of a fuse,consisting of a cord,taped or otherwise covered, containinga core of fine gunpowder. Safety fuse, the invention of William Bickford, of Tuckingmill, Cornwall, was designed by the inventor to obviate the various dangers inseparablefrom the use Germans of and other stillused but happily obsolescent methods of conveying fire to a blastingcharge. "

"

Numerous

by

and

the inventor's

patent, which

since 1831, the year

successors

resulted

have

qualitiesof fuse, adapted modern

blasting. followingTable

The

of

have

important improvements

safetyfuse Table

in

the

illustrates

of the

introduction

all the

to

been

original different

requirements of

various

of the

some

of

effected

descriptions principal

used.

now

Bickford'*Safety Fuse.

II."

Maker's

Description.

Number.

1

Small

4

Ked

8

Tape

9

13 15

Purpose.

fuse

fuse sump

fuse

For

immediate

For

use

in

For

use

in wet

For

use

For

use

in very in water

For

use

in 300

For

use

in wet

....

Double

tape sump fuse Gutta-percha fuse Double gutta-percha .

.

use

in

and

damp

dry ground close

places

ground wet ground ft. water

fuse 23

White

tape fuse

' .

.

.

.

and

exportation White

double

tape

For

fuse 25

To

Patent

fire a

use

fuse colliery

charge by

obliquely and

means

inserted

To .

.

very wet in hot

convey fire or

into

and

close warm

close

a

for

climates

places, and

for

climates

emitting sparks laterallyduring combustion fire without

of fuse,a suitable

through

places,and

hole

length is cut

in the

centre

off

of the

AND

DETONATORS

Fig. 2. been placed in the carefullytamped, and

is added, the whole

combustible

The the

cord and

end

which

bore-hole a

required

the

primer

lightappliedto

ultimatelysends reversed

is shown

and

it were,

ignitedburns along the

thus

core

object of reversingthe end its

prevent

so

out

the

burns

fuse

the

at

be stated that

approximate speed

margin of time should atmosphericor other causes.

The

seconds,

for variations

from

2.

Fired

by

Fuse

Ignition

?

ordinarilybe exploded by simple receive an must extremely violent shock such as produced by another explosionof the most rapid

detonants

ignition,but

only be

can

Detonants

are

the

ordinaryBickford

of 1 ft. in 30

be allowed

FIG.

How

from

cartridge, Fig. 2. (The of the fuse is to form a wedge, as accidental withdrawal during the

some

"

spurt of flame

a

inside of

the

in

operationof stemming.) As a guide to safety, it may

14.

the

extremity of the fuse.

free

but

When

in

shown

as primer cartridge, weight of charge has

13

FUSES.

cannot

kind, namely, detonation. This

is obtained

initial detonation

by

the

extremely explosivesalts called Fulminates,which fulminic

from for

which

which

is

is used

This

or

the chemical nitro-acetonitrite, The

CH2(N03)CK for

are

blastingpurposes

best

known

is mercuric

and

has the chemical

compound

when

heated

when

brought into

to

is

sulphuric and

with

an

one

It

on

mercury

It

explodes

HgoCsNoOo.

360"F., when

contact

the

fulminate.

extraordinarily unstable.

about

it is in explosive.

formula

derived formula

and

by the action of alcohol and nitric acid

is obtained nitrate

acid

of certain

use

scratched electric

nitric acids.

When

by

spark,or

a

pin, and with

centrated con-

thoroughlywet

14

In the

chlorate

tube, closed

copper effect

solid

a

shown

in

at

pieceof Fig. 3.

shown

one

This is called

III.

aluminium

the top of the

appears

1

in

in section

appear

Nobel

detonators

is

for Detonators.

is mixed

with

pressedon

or

Tetryldetonator,as used

new

Co.,is made of Tetra-nitro methyl aniline. illustration showing a group of detonators (actual size) in

Fig. 4.

prepare

a

tool special

a as

explosionof

coil,either with shown

in

8

7

(Actual Size.)

4."DETONATORS.

fuse for the

6

5

3A4

3

from obliquely

of the

to form

as

Eoburite

FIG.

cut

powder

fulminate,while the

2

To

Mixture

Standard

"

solid-drawn

a

3.

in Table

III.

fulminate

detonator.

a

compositionof charge for

Sometimes

An

would

which

fulminate

standard

Table

by The

quantity of

potash) is put into end, in such a manner

of

FIG.

The

GUIDE.

small

applicationa practical

(mixed with

as

SHOT-FIRER'S

THE

a

Fig. 5-

a

detonant

sharp knife

or

a

piece is

by

means

16

SHOT-FIBER'S

THE

the

of

use

of

causes

defective,inferior, or

unpleasantfumes

detonation The

of the

primer

in the

and

prepared is stemmed

so

PRACTICAL

the

to

are

fruitful

only partial

fired

explained

as

p. 80.

7.

Fuse

used

be

in

Fiery

?

In all coal mines within

and

APPLICATIONS,

Safety

can

Mines

detonators

explosive.

chapteron

How

damp

frequentlylead

FIG.

15."

GUIDE.

in which

inflammable

has been

found

quantityas to be indicative of danger, only "permittedexplosives may be used, and if requiredto be exploded by safetyfuse,the only permissible is by a "permitted of ignition means (otherthan electrical) previous three

months

gas

in such

"

igniterfuse" of the kind manufactured Smith iron

Co.

"

Bickford's

steel,closed

or

at

igniterfuse one

end, and

by the

firm of Bickford,

consists of

a

tube

containing a

of tinned

mixture

of

Chlorate

Potassium

and Wool

Glass

bulb

Fuse

Sugar

containing

SulphuricAcid FIG.

fuse is

Fig. 9.

"

SECTION

THROUGH

BICKFORD'S

IGNITKB

FUSE.

potassium and sugar pressedinto a pellet,in close sealed glasscapsulecontainingconcentrated with a hermetically sulphuricacid. A section through such an igniter in view of the same shown in Fig. 8, and a perspective

chlorate contact

s.

of

DETONATORS

AND

17

FUSES.

The

ignitionof the fuse is effected by breaking the glass into contact capsuleand so allowingthe sulphuricacid to come with A

the chlorate of

potash.

powerful oxidising agent known

very

(C102)is

thus

produced,and

when

of such

generated in

PRESS

.

9.

chlorine

peroxide

the presence

LIGHTER

FUSE

FIG.

as

"

VIEW

PERSPECTIVE

substance

HERE

IGNITER

BICKFORD'S

the

oxidation

is

FUSE.

vigorousthat the sugar takes fire. An igniterfuse of this description may be used as a substitute for open flame ignition anywhere except in which the Coal Mines Order applies. in placesto Explosives Only a permittedigniterfuse may be used in those places the Coal Mines Order applies. The essential difference where between an igniterfuse and a permitted igniterfuse is in the requirementthat the latter class must be of specialqualityand be suppliedpermanently attached to its igniter. must the fuse (No. 25, Table II.,p. 12) must consist Specifically, of gunpowder in weight not exceeding 6 grammes of a core per 1'09 traversed metre yards), (0*21 oz. (avoir.)per by two threads and enclosed by : (1) a layer of jute yarn ; (2) a layerof jute yarn laid in the contrary direction; a

as

sugar

so

"

(3) a layer of tape ; (4)

a

(5) a

layerof tape laid layer of jute yarn

in the contrary direction ; secured

BICKFORD'S

outer

suitable varnish

;

FUSE

FIG.

three

a

PERMITTED

IGNITER

the

by

10.

layers being speciallytreated

with

a

fire-

proofingcomposition. This

fuse must

securelyattached S.F.G.

be

fitted into

thereto, and

the open

the

end

of the

jointcemented

by

igniter, tape

a

C

18

SIIOT-FIRER'S

THE

bearing the

"Crown"

and

the

GUIDE.

letter "P."

The

permitted

in Fig. 10. seen igniterfuse presents the appearance It is further provided that the permitted igniterfuse shall be fired only with the implement suppliedby the manufacturer and accordingto the instructions enclosed in each package. The implement referred to, namely, Bickford's patent nippers,

is shown

in

FIG.

when

the

serve

also

and

Figs. 11

11.

12.

BICKFORD'S

"

They

are

PATENT

so

constructed

that,

NIPPERS.

the nippers longitudinally, will close exactlyon the rightspot to be pressedfor firing.The lightercould be fired with any nippers,but the inexperienced operator might not always squeeze at the exact pointwith the which ensured laythe use of Bickford's patent nippers, accuracy has lighter

as

a

gauge

FIG.

The

chamber

and

"

of the the

inserted

cannot

BICKFORD'S

fail.

PATENT

NIPPERS.

nippers entirelysurrounds

and

encloses

lighterin which the ignitiontakes place, of a spark reaching thus effectually preventingthe possibility the outer atmosphere. The slots in the handles are for use and serve the purpose of closing with ordinaryigniters the open end of the lightertube around the fuse before firing. that

portionof

12.

been

DETONATORS

16."

virtue

By

Fuses For

the

of

be

AND

what

19

FUSES.

.electrical

ignited

property

can

?

of

securinggreater safetyto workers in mines and in the conduct of blastingoperations trical generallyelecmethods of explodingcharges have been developed and In these methods are extensively used. advantage is very taken of the fact that a wire of a given diameter will only carry If this quantity safelya definite quantity of electric current. purpose

is exceeded known

the wire

and resistance,

as

it.

suppliedto

be

will

which one

end

be

and

which

joinedby

a

pieces of wire

length will become mixture with which ignitible are

to

very

the

carry

incandescent it may

connected

and in

be with

taken

are

the extremities

given current, and short length of wire

consequently unable

of the wires

if sufficient current

a

this short

free ends

be melted

even

may

If,therefore,two

safelycarry is

hot, by virtue of the property

becomes

much

thinner

current,

same

set

fire to any

contact

when

suitable

a

at

the

source

of

electrical energy.

17."

What

Electric

an

consists

electric fuse

An

which

are

FIG.

descent

on

This

or

with

a

paper

in contact

one

is

end

ing pair of conduct-

a

by

a

thinner

wire

capable of becoming

or

incan-

13.

through it of a suitable electric current, compositionbeing either inflammable itself or

an

inflammable

which fuse-head, in

?

the passage

the said wire in contact

Fuse

of essentially

joined at chemical compositionwhich wires

a

is

tube with

inflammable

mixture.

mixture, togetherwith the part called the

produce ignition,is generallycontained which about 1^ in. long and Jin. in diameter in Fig. 13. a cartridge appears as shown is to

C2

20

SHOT-FlREtiS

THE

There

18."

two

are

There

are

varieties of each classes

The

?

denned

classes of electric fuses, and

distinct

two

Fuse

Electric

of

systems are they

How

ignition.

GUIDE.

many

class. known

commonly

are

as

HIGH-TENSION

and

LOW-

and are perhaps best defined by respectively, the wire connects reference to the ignitingmedium, which terminals within the fuse tube or casing. fuse is one having its terminal wires bridged A HIGH-TENSION high by a combustible and conductive composition of relatively electrical resistance,as indicated diagrammaticallyin Fig. 14.

fuses

TENSION

A

connected, as in contact

and

fuse is

LOW-TENSION in

Fig. 15,

with

a

having its

one

terminals

being

the connection

metallically

surrounded

by

mixture.

combustible

Priming

FIG.

14."

FUSE.

HIGH-TENSION

Priming

FIG.

19-"

How

does

15."

LOW-TBNSION

Ignition

case

manner

of :

in

occur

Fuse, (b) Low-tension In the

FUSE.

Fuse

heat

Electrical energy

at

the

is,owing to the fusehead) bridgingcomposition, converted cannot

dissipatewith

temperature rises also be

may

and

initiates the

With and

the

so

?

high-tension fuses,ignitionoccurs

the

of the

(a) High-tension

to the

fuse terminals

nically, (tech-

insufficient conductivity into heat energy.

The

sufficient

rapidity,therefore the ignitionof the bridge (which

point of

priming);

in the following

the

latter then

bursts

into

flame

required explosion.

low tension

fuses the wire

heated, bridge is similarly

ignitesthe priming with which

it is in contact.

What

20." An fuse

is

Detonator?

Electric

an

21

FUSES.

AND

TORS

DETONA

electricdetonator consists of the combination

detonator of

as

HIGH

either

be

(which may

of

electric

an

with

LOW-TENSION)

or

a

described,and presents the generalappearance

above

Fig. 16.

FIG.

16."

ELECTRIC

DETONATOR

FUSE.

(Figs.14 and 15, though only intended to show diagrammaticallythe difference between High-Tension and Low-Tension fuses,may

21."

also be taken

Describe

sectional

as

the

of

some

diagrams

Electric

E.D.

(Electric Detonator)

used

in

British A

of

electric detonators.)

and

Fuses

generally

Fuses

mines.

high-tensionE.D. fuse is shown sectionallyin Fig. 17. To prepare this type of fuse the connecting wires W, consistingof two No. 24 S.W.G. tinned copper wires,separately insulated and then braided together, bared for a length are well-known

of about

1

in.,the bared wires being then laid

in grooves

wooden

at

side of

each

plug, PL. this plug to

around

of

make

longer than

A form

small

cylindrical stripis rolled paper T, rather a cylinder, a

its support, and

of

outside

an

nator approximating to that of the detoA charge of priming,P, is put tube.

diameter

in

with

contact

thin membrane

place by

a

means.

The

a

F, the

prevent withdrawal FIG.

17.

HIGH-TENSION

shown

outer

tube

of the

is sealed with

the end

or

other

held

in

suitable

completed fuse is then placedin containingthe requiredweight of

detonator

fulminate

ends, and

the wire

is indented

fuse,and

to

finally

waterproof cement

as

at C.

DETONATOR FUSE.

In the

speciallow-tension

detonator

made

22

by

SHOT-PIRER'S

THE

the

Cotton wires

copper

Powder

(Ltd.)two No. through a wooden

Co.

threaded

are

Fig. 18, which

GUIDE.

has been

in

shown

plug,as

in varnish.

soaked

and

drilled to gauge

tinned

S.W.G.

22

and shown in the illustration, as projectslightly, are joined by a platino-iridiumbridge two mils (0-002in.) diameter. This bridgeis enclosed in nitrated cotton, no other priming being used. The fuse is put into the detonator until the priming just The

ends

touches suitable The

fulminate, and

the

is then

fixed

positionwith

in

waterproof cement. Lancashire ExplosivesCo. (Ltd.)produce in the

fuse

detonator

design of which

great

compound

a

is taken

care

a

to

which are a constant of miss-fires, source precludethe possibility in this construction is The fusehead of danger and expense. of wood, through which two separate passages Z are bored in such a (Fig.19),and through which the wires are drawn Indie-Platinum Cement

Wire

Wood

0-002" dia.

FIG.

18."

No.

Cotton

Gun

Plug

Copper

Priming 7 L.T.

Shell

DETONATOR.

that

The ends of the into contact. they cannot come wires terminating in the internal powder-chamber C are passedthrougha perforateddisc of non-conductingmaterial, G, and securelyriveted,forming two copper heads, as shown at F, manner

The when

fusehead

is formed

as

inserted

into

detonator

the

priming compositionand millimetres.

four of the

under

B.

pressure

offeringthe A

coat

of

the insulated

in elevation the

the fulminate This

tends

(Fig.20),so

distance

between

is constant, to

ensure

the

that the

being precisely projection

priming composition direct on to the The priming E in these fuseheads is moulded into the shape of a nipple,the apex of which,

flash from

fulminate

shown

least

the

resistance,ensures

a

central

fire.

varnish,D, protects the priming composition,and wires Y

are

twisted

(asshown

in

Figs.19

and

20)

24

THE

GUIDE.

liS

divisions,or, in other words, of

in two

in the middle

is blocked

which with

SHOT-FIRE

end

tube, the

metallic

a

wall,homogeneous

of the tube

(Fig.2 IB) contains

a

charge of priming

the ends of compositionin which are embedded bridged by a very thin platinum wire, as shown

FIG.

SECTION

22."

is made

These

fuses

machine-made

course

of manufacture.

are

TIRMANN

THROUGH

fuse-head

The

through

way

itself.

the tube

One

by

a

fast in the

Great

the conductors in

Fig. 21

A.

FUSE.

casingby sulphur cement.

and

are

tested

is taken

care

times

three

to make

in

the fuse

tate bridgesof perfectlyequal electrical resistance,so as to facilitheir application to simultaneous firingin great numbers. made with iron and sometimes with copper They are sometimes

FIG. 23.

"

EXPLOSION

OF

TIRMANN

A

FUSE.

conductors, either pattern being insulated,of to the

wires

nature

1 metre

Tirmann same

fuse

of the work

it is intended.

suitably

With

iron

(3ft.3^ in. approx.)long,the total resistance of is 1 ohm.

length the

coned slightly

for which

course,

resistance

inside

Using

a

is reduced

(seeFig. 22)

to

conductor

copper

by half. hold

a

The

of the

free end

detonator

a

is

tightly

DE

without

further

detonator

A ND

A TORS

TON

'manipulation. The

instead

of within

fuse

in other

it,as

25

FUSES.

being put

the

over

patterns, eliminates

the risk of

the platinum exploding the cap by friction. When wire bridgein this patent fuse becomes incandescent through the passage of an electric current the explosionof the priming

caused, bursts the metal wall which

so

parts and action of

of

shot from

a

into two

the cap

through the tube with the pistol. Fig. 23 illustrates the manner

projects a fire a

divides

stream

firing. An

development of the paste form of priming is interesting This firm, that employed by the Koburite ExplosivesCo. (Ltd.). instead of using a granulated priming, dips the fuse-head (which may be either high or low tension)into a conductive and

inflammable

terminal

wires

compositionwhich adheres and dries on the like the tip of a lucifer match. By the adopMetal

Card Stripwith Connections

on

each

Foil

Solid Fuse

side

Priming

\Solder connecting

Cement

with Metal

Wires

FIG.

tion of this method circuit is

24.

of construction

which

the metal

spacing of

the

automaticallyadjusted by to

on

Detonator

Foil

foil is

the thickness

broken

the

board of the card-

pasted. Fig. 24

shows

this

type of fuse in section. 22."

What

Fuse

are

or

Detonator

Wires

?

conductingwires or leads which serve nication of completing electrical commupurpose

The Fuse

Wires,

the

the

between head of

are

copper

sometimes

made

brass

wire.

or

of tinned The

firingcable and the fuse-

iron, but

size is

more

usually No.

frequently 22

I.W.G.

(Imperialwire gauge),and the lengthvaries from 8 in. to according to requirements. The most commonly used lengthsfor mining purposes from

36

in.,increasing b}'additions

of 6 in. to 5 ft.

45

ft.,

range

26

THE

Fuse

should

wires

always be they are to

bore-hole in which to make

necessary

SHOT-FIREliS

and joints,

GUIDE.

few

a

be

inches

the

longer than

used, otherwise

this introduces

be

it may

risk of miss-fires

(seep. 96). On

the

other

hand, the

42 in." that is to say,

would

to

mean,

month,

6 in. of wire

23.

Is

there

and Fuse

at

6s. per

Low-tension

wires

leakage of either wire

current

longer than is using

instead

necessary

of "

5,000 shots per

say

"18, taking the

of

cost

an

of

one

wire

to

?

ignition

insulating material

with from

High-tension

between

systems

covered

are

wires

1,000 fuses.

choice

any

48 in. fuse

6 in.

of about

waste

extra

"

of wires

colliery company

a

annual

an

of

use

the

to

vent pre-

other,or from

intended for (seePart III.,p. 77). When in dry ground, a simple wrapping, consisting of two layers use of cotton yarn saturated with an insulating compound, is amply sufficient. For blastingin damp ground or under water indiarubber or gutta-perchacovered wires are necessary. At the present time custom is, perhaps, Selection fairlyequallydivided between the use of high to

earth

and

of Fuses.

low-tension

fuses.

treme generallywhere exclimatic changes are not to be looked for,high-tension fuses give most results. For group firing"in satisfactory fuses are parallel"they are to be preferred. Low-tension

In Great

better for obtain this

a

firing"in

more

type.

Canada

and

series"

Britain, and

(seep. 107),because

it is easier to

exactlyuniform electrical resistance in fuses of throughout They are in almost universal use the United

States,and this system is

to

be

mended recom-

long storage or long transport is necessary, countries. in tropical and specially for use definite infor an in good condition Low-tension fuses remain period,if stored in a dry place,and their efficiency be verified at any time by testingwith a galvanometer. can not generallyapplicable This is a great advantage,and one fuses. OF TESTING, see p. 71.) to high-tension (For METHODS wherever

DETONATORS

24."

What

Delayed-action Fuses, Purpose are they used? are

what In

headings,shaft sinkings

measure

cross

similar

and

work, great and

Delayed

of

economy

Fuses.

of

number

a

of shots of which

stages. Many

most

quent in subse-

upon

chapters. simplestand yet practicalmethods be

to

appear which

are

some

in

those

the Bickford

fuse,

cording graduated in length ac-

the

to

desired

rotation of in

is used firing, trical conjunctionwith elecigniters.Messrs.

Bickford, Smith

supply

for this purpose time

mann

a

fuse

Tirstructed con-

as substantially

above

described

(p. 24,

Fig. 22). It also is made

strong

metal

from

a

N

capsule

divided

into two

but

partition(Fig.

the

25) which is

the

much middle

parts,

divides them

stronger. In of this wall

plosions ex-

in

ing of attain-

vised, de-

been

and

The

methods

delayed

and

have

touched

occur

instantaneous

ignition action

the

tions combina-

various of

time

explosivesis gained by simultaneously igniting

Action

successive

27

FUSES,

AND

"

1

I

and

for

"28

is

THE

a

On

connects

Bickford

attached

a

fuse

electric fuse

firingan

capsule bursts, and Bickford of

GUIDE.

very fine hole which of

core

SHOT-FIREIiS

fuse.

allows

Bickford

centimetre

one

the

priming with

the

to

the

end

other

powder

of the fuse.

of this type the wall of the

metal

free

the

development of gas from gutta-perchafuse burns at the

(0-4 in. approx.)

data the time interval between

second.

per

successive shots

rate

From be

can

this

adjusted

desired.

as

Mr.

Bigg-Wither, of the Koburite Co., has designed an igniterof similar character,which is illustrated in Fig. 26. In this pattern "Venus"

long brass tubes,into iord

fuse to make

fuse is

taped

which

are

fuses

fitted

are

the space

between

made

up

in extra

varying lengths of Bick-

delay-actionfuses.

up

over

with adhesive

low-tension

For

the

wet

arrows

waterproof tape of the kind used for

work

each

(seeFig. 26) joint-making

by electricians.

25."

Describe and

Many

of

of

Packing

Detonators.

Carrying

accidents

Methods

Safety

some

a

more

or

less serious

nature

having

occurred

defect in the method

of

one

owing to want of system or other conveying electric detonator fuses from

attention

has

been

directed

towards

the

placeto another, provision of safe

for

packing and carrying. The Lancashire ExplosivesCo. have registereda system of packing electric detonators which is both simple and practical.

arrangements

The

detonators

neighbour,in in Fig. 27. The

cardboard

a

interior view.

continuation

packed in tens, each

are

the

of

When of

the

previouslyslotted

box the

one

separate from

box, details of which

is ten

external

partitionedas detonator paper

are

shown

fuses

are

covering,which

its

indicated

in the

tional sec-

inserted,a has

been

punched to admit the connectingwires, is fitted over them The and gummed to the side of the box. on is suitablylabelled for registration by the storekeeper, cover and as

the shown

and

complete package when ready in the sketch (Fig.28).

for

deliveryappears

29'

FUSES.

AND

DETONATORS

packed in this styleno further precaution, to comply beyond the provision of a suitable locked case be to with Eules (see p. 174), would necessary. appear carried are (in mines) in small tin Ordinarily detonators of of which the covers are firmlysecured by means canisters, With

detonators

HIGH TENSION E.D. FUZES. No.

Detonator*.

T

\Virfi

Datco/Iuue Shot No.

ThU

Box

-B

.Vouiw

.'

of Pay

Empty No.

,

Firer'i

rttd

of Shall find 8y"t*m

o(

P.ckloi

Section

at

FIG.

is

R"p"Mre"l.

A.B.

padlock. Such a having wires of say a

doubled available. eontents

and

FIG.

27.

canister may 36 in. in

intertwined

so

length. as

Consequently,when of the

case

must

hold

to

from The

5 to

wires

fit into

one

be withdrawn

is

28.

the

10 are

detonators

frequently

limited

required,the in order

to

space

entire

separate it

TEE

SHOT-FIBJSKS

FIG. 29."

FIGS. 30 and

31.

"

LEATHBR AND

THE

XL

DETONATOR

DETONATOR FOLDED

GUIDE.

CASE,

RESPECTIVELY.

CASE

BY

THEEDAM,

UNFOLDED

\

PART

I.

EXPLODERS. "dlassification of Exploders, p. 34. between

a Dynamo Exploder, p. 35.

Magneto DYNAMO

p. 37.

EXPLODERS,

Current,

Exploder,

Dynamo

Exploder

DRY

MAGNETO

BATTERIES,

p. 34.

ence Differ-

Exploder,

p. 34.

Helsby

SterlingMagneto Back-Bar

Exploder,

Machines,

E.M.F.,

p.

Field

Laminated

Nobel's

35-36.

Induced

Three-Post

Exploders, and

Magnets

Production

pp. 47-53.

pp.

37-41.

pp.

41.

Sterling Dynamo

p. 41. with

EXPLODERS,

Magneto

a

Superimposed

p. 37.

Back-Bar

p. 43.

and

pp.

42-47.

Armature,

of Current

Chemical

by

of Elementary Primary Cell, p. 48. Nomenclature Polarisation p. 49. Dry Cell, p. 50. Exciting and

Be action, p. 47.

Cells, p.

48.

Depolarising Mixtures, Cells, pp. 51-52.

Working,

in

56.

p.

available In

the

machine tried for

50.

Facts

pp.

54-58.

p.

55.

Casings Davis

p. 51.

for Guidance

Conditions

Electrical

for

Dry

Pocket

in Selection

Formation

Mains, Polarity Pole-findingPapers, p. 58. of

Process for

and

Successful

p. 56.

Charging

p. 57.

Electrical

What

p. 52.

Secondary Cell,

a

Accumulators,

"

Safety Key,

Cell, p.

Safety Disc,

Patent

Accumulators,

Cells, p. 53.

Beactions

26.

Wood's

Firer, with

Shot of

Obach

p. 50.

for the

Appliances purpose

of

and

Methods

Exploding

are

Fuses

?

early days of the electrical industry almost every device capableof producing an electric current was or the purpose of explodingmines or blastingrock.

Frictional

machines, induction

secondary cells

and

of energy

are

coils,all kinds of primary and

have at one magneto-inductionmachines service. Modern ever, time or another done practical practice,howof (1) Magneto and dynamo confines itself to the use and (3) Current cells, exploders,(2) "Dry" or accumulator of employing the latter mains. from power Safety methods source

S.F.G.

described

in the author's

Electric

Blasting D

34

THE

Apparatus mines

27."

causingpremature

explosionby leakagecurrent.

Types

many

Current Current

Current

induction

into three

Induction

(a) In

which

current

a

lyingoutside

Types (6)and (c)include

28.

"

be divided

is induced

in coils of

.

coil-wound

armature

is rotated

between

the

1 armature

in

an

modern

is rotated

between

the

ordinarydynamo.

Type (a),although examples are

in

explodersmay

types :

polesof a permanent magnet (c)In which a coil-wound polesof an electromagnet as

now

ploder Ex-

surrounding the poles of a permanent magnet by suddenly detachingtherefrom a

soft iron armature

as

Induction

wire

Exploders.

which

of

there?

are

dismissed

G UIDE.

Explosives,althoughthe application of it in of the ever-present possiencouraged, on account bility

How

(") In

'$

T-FIRER

and

is not of

SHO

still used

abroad, may

be

practice.

all mechanically operated

exploders

general use.

Describe

the

Operating

Construction

Magneto

and

Method

of

Exploders.

Magneto Exploders. Type (b)embraces the class of magneto exploders, examplesof which are to be found in probablyevery British colliery where electric shot-firing is practised. A magneto armature of an exploder consists essentially revolvingbetween the poles of a set of permanent magnets. The main difference between a dynamo and a magneto exploder lies in the fact that the former has electromagnets, soft i.e., iron or mild steel wound with insulated wire, through which electric current an passes and magnetisesthe iron ; whilst the "

latter has hardened

steel permanent

magnets, without field coils.

Fig. 32 illustrates the type of magneto exploderwhich has been in generaluse for many years. It is built up of a series of horseshoe magnets joined togetherby soft-iron polarextensions, magneticfieldof whichashuttle-woundarmatureisrotated. A high armature speedis attained by suitablyarrangedtoothed Current is producedby rapidlyrevolvingthe handle wheels. in the

35

EXPLODERS.

attached internal

to the main or

drivingwheel and firingcircuit by pressinga

FIG.

placed convenientlynear shown The made

in the external

view

pattern from which

by

the

is transmitted

button.

The

to the

latter is

32.

terminals

of the

firingline,aa

of the apparatus. the illustration

the British Insulated

FIG.

"

Helsby

32) (Fig.

Cables

is taken

is

(Ltd.).

33.

In the

recentlydevelopedand now extensivelyused Sterling patent magneto exploder(Fig.33) mechanical energy is transD2

36

THE

mitted

to the

SIIO

*S

T-F1RER

G UIDE.

through suitable speed-increasing gear, detachable half of correctly, -twist, a by a singletwist,or, more By a cleverlycontrived trip device the T-shaped handle. thrown of gear of the twisting wheels out at the end are armature,

and

movement,

the

continues

armature

FIG.

The

momentum.

the

contact

stop ;

armature

firingcircuit is then

oak

box,

as

by its

own

until the handle

automatically, and, passes

strikes

with

the

throughthe

explodesthe charge.

mechanism

metal-cased smaller

is open

made

FIG.

an

rotate

34.

stillrevolvingfreely, the current

firingline and

The

to

of the in

35.

Sterlingmachine

Fig. 34,

or

a

metal

case,

pattern has the advantage of

patterns, and

is

suitable

more

countries,since it is not liable

to

shrink

is encased

either in

in

Fig. 35. being lighter,in as

for and

use

in

The the

tropical

split. The

two-

37

EXPLODERS.

shot

in oak, (high-tensionor low-tension)measures, brass 4f in. x 2| in. X 4f in. and weighs 3f Ib. In nickel-plated it measures case 3f in. x 2J in. x 3f in.,and weighs 8 Ib. size

17, 1906, Explosivesin Coal Mines Order of December Rule 2 (/)requires that every electrical firingapparatus shall handle be provided with a removable or safety plug,or push button, which shall not be placed in positionor operated until The

the shot is requiredto be released handle

as

soon

safety plug shall

or

custody of

at

fired.

The

all times

remain

in the

the shot-firer whilst

29. -Describe

of

These the

Dynamo Exploders,

Method

and

Bar

Rack

of

of which

armatures

ploders. Ex-

revolved

be

can

miniature,

in

rotary crank, a pull-overlever, or

a

struction Con-

Dynamo

Type

dynamos practically

are

personal

duty.

on

Principles

the

or

removable

been

has

shot

a

as

shall be removed

fired,and which

by

vertical

a

geared direct,or into a train of with the armature wheels in contact spindle. They are the efficient and reliable exploders extant and, the weight most by recently improved immensely reduced having been of design,the smaller sizes are methods bility comparable for portarack

explodersof

with

and

Figs.36

figuresthat

It will be noted

machine.

key circuit-breaking

the

; this

modification

the

end

field magnet

brought to

and the

armature

current

of

a

a

dynamo

the

breaking of

generatedin

through the air through a derived

at

the

the

the

circuit

coils to be

an

older

is also

bar

shown

I, as

fact that

well-known

small

the top

rod, H,

may

point of saturation, and that, when

is at its maximum, induced

It is

(Fig.37).

view

rack

of

causes

be

with

the

the

quickly

the current the entire

discharged,either

point of rupture of the current,

circuit connected

to

always kept

be

easily accessible for cleaning. A

providedfor guiding and steadying the in

of the

by reference

placedin

is

that it may

in order

made

pattern has been

type.

sectionallythe construction

containing case

of the wooden

dry and

other

any

illustrate

37

rack-bar

well-known these

bar,

terminals

or

of the

38

SHOT-FIRER'S

THE

field-magnet.In is taken

of this is

the

exploder under

knowledge, and effective than

more

GUIDE.

a

consideration, advantage

also of the fact that uniform

lerated acce-

an

rotation of the

ture arma-

in

of

The mechanism bringingabout magnetic saturation. rack-bar exploder is as follows : A field magnet, J (Figs.

a

and

36

37), is formed

with

soft-iron

P, secured to pole-pieces, a with a predetermined yoke, in the usual way, and wound The quantity of insulated copper wire. polar extremities bored out to receive a Siemens are H-type armature. Upon the end of the armature shaft b is placed a commutator, h,

FIGS.

which

36

is touched

pairof

commutator

secured

to, but

end

37."

AND

"RACK

BAR"

DYNAMO

EXPLODER.

diametricallyopposite

on

springs (not

from, the

insulated

of the armature

shown

in

yoke. the

shaft, between

by

surfaces

a

the

illustration), Upon the opposite

armature

yoke, is placed a pinion,d, provided with a series of teeth,w, on its inner face. These are adapted to engage

and

the

ratchet similar

the end of the on oppositelyarranged teeth, formed Between the pinion and the yoke there is placed armature. but

a

spiralspring that

engagement

with

tends

the

to

ratchet

press

teeth

the n

former

of the

forward armature.

into A

40

THE

SHO

T- FIRER

's

G UIDE.

41

EXPLODERS.

field

winding,

Very

little current

the

increases

field magnets

and

The

the

rack

armature

bar

travel.

spring key screw

c

and

s

the

at

the

that

At

the

the circuit of that

direct

external the

the

from

circuit

the

owing

through

so

and

magnet

external

the

therein,and

bringing

charge.

dynamo

could

the

and, whereas

not

through

pass

of the

it to do

readilyenables

higher

much

great resistance

the

to

when

obtained

is very

broken

working;

superimposed E.M.F.

the

reached,

field

pass

normal

in

the

strikes the

p

is

the

included

manner

between

current

superimposedE.M.F.

the

generated

current

fuse

ance resist-

excites

pin

from to

electromagnetis

an

to, the

maximum

current

ignitingthe

is well known,

than

the

to

ward limit of its down-

the extreme

is forced

explosionof

in this

the electrical connection

induced

windings

circuit,thus As

breaks

owing

approximately

or

"

yoke.

high

the

descends, and

referred

point

instant

extra

armature

about

the

and

saturation

to

just before the bar reaches

"

circuit

produced

current

and

screw

electrical pressure

firingline.

rapidly as

contact

along the external

passes

comparativelylow of the

so

plates,key,

screws,

latter, as

soon

as

so

the

the short-circuit is broken.

of

connecting cables when

to

be fired is shown.

in

series,two

considerable

a

For

firinga

with

and

for submarine

that connected at

its outer

fuses

end

with

a

bared

should

terminal

;

joiningthe

covered

afterwards

be used

be connected

portion of the wire

together,the jointbeing

of fuses

should

leading wires

the middle

with

of which

firinga largenumber

For

work, three

of fuses

number

moderate

terminal,and the other with

the middle

either of the side terminals.

of fuses have

number

only be used, one

need

leadingwires

be connected

must

method

three-postrack-bar exploder(Fig.38) the

In Nobel's

with

lating insu-

tape. In

Firing

with

handle

firingwith must

and

be then

Rack-bar

come,

Exploder.

possible. These when

both

hands

rack-bar

the

pulled up forced

as

down

operationsare are

used

exploder,the far as

best

as

it will

quickly

as

performed

together.

42

SHOT-FIRER'S

THE

30.

"Describe

the

GUIDE.

Sterling

Type

of

Dynamo

Exploder. The

type of exploder,which

dynamo as

lends

complete

a

itself

series-wound

its construction

by

large current

at

fired,because

the whole

to

be

may

scribed brieflyde-

dynamo in miniature, the productionof a fairly

fore, comparativelylow pressure, and is,therespecially adaptedfor firinglow-tension fuses. In dynamo machines the magnets are freshlyexcited every time a shot is

field

a

ture generatedin the armathrough the field magnet windings. Thus, the passes and are not affected magnets always retain their strength,

is the

by vibration, as In

dynamo

strikes the

being in series,to will not

firingdevice

is necessary,

close

dynamo

free to flow out

exploderof

and

convenient

The

armature

of the

reason

With

windings the

coils,otherwise The

current.

automatic

the stop.

strikes

The

is

current

to the line and

on

any

closed.

type, therefore,operates by opening

the "handle

greatlyincreased current explainedin connection An

by

ploders. ex-

circuit is open

is then

short-circuit the

or

of magneto

magnets

stop, and

generate sufficient

in the

the circuit when

the

exploders the

magneto

explodersit

machine

with

case

with shot-firing

until the handle

then

of the current

is obtained

with

kind

explode the charge. A by this method as already

the mechanism

be

must

of

a

rack-bar

ploder. ex-

simple in operation,light

capable of withstanding neglectand perature. rough usage, and be unaffected by damp or variation of temThese essentials have been met in the Sterling electric blasting machines to a degree hitherto unapproached by any explodereither of English or Continental manufacture. a

to

field wires

specialenamel

renders

the

magnets

and

thin

carry,

wire

covering by

iron

prevents the formation excitation

are

of

the

insulated

of

eddy

laminated

currents

at the terminals

The

moisture.

type, built

and

This

ensures

with

which

process,

securelybolted together.

of the field magnets, and

output

are

entirelynew

an

quite impervious to

armature

stampings of

in these machines

field up

of

method instant

creased consequentlya greatlyin-

of the machine.

43

EXPLODERS.

The

parts

held in

are

to the

The

case. "

BD

positionby

liable to be put out

not

"

in

apparatus is self-contained

smallest

type, and

It is assembled

the of

in the

framing and

own

The

case.

Sterlingmachine

cases

to

the

as

no

fore, is,there-

machine

operationby warping

indicated,as

is

its

or

is known

injury as

the

construction,in Fig. 39. small

in

shown

magnets

It will,however, fire three shots through Figs.34 and 35. 150yds. of copper cable,as against two shots for the magneto dimensions. exploder of the same

in

Another

series,of which

Fig. 40,

differ from

FIG.

city.

39.

They

A

when

to fire from

about

into which

spring.

in

not

base of the block a

EXPLODER

6

The

the a

this type, which

action

shaking will remember

the cause

to detach

This

use.

stem

small

range

in

is not

of the

knob of

is

in the

adopted for fixing

consists handle

found

of

is

a

small curved

passed.

At

the

recessed,pressedupwards by

this knob

is to

hold

the

handle

tion does it perform this funcefficiently of handle is placed in the block no amount

securely in place,and that when

capa-

TYPE.

shots and

50

to

"

BD

"

machines, is the ingenious method

the handle block

DYNAMO

and

14lb.

6 Ib. to

feature

novel

smaller

made

are

weight from

one

STEELING

"

generalconstruction another only in their size

is shown

the

so

it to fall out.

the handle

and

The

shot-firer will doubtless

put it into his pocket when

44

he is above

SHOT-FIltER'S

THE

preparing to is shown

in

fire

a

charge.

GUIDE.

The

spring catch

described

Fig.41, which, however, represents

another

*^fc

FIG.

40.

FlG.

41.

type, with and

"

"

ANOTHER

AXOTHEB

FORM

automatic

medium-sized

FORM

OF

OF

STERLING

STEEL'

NG

DYNAMO

DYNAMO

EXPLODER.

EXPLODER.

gearing. spring-controlled

machines

are

operated by

a

The

small

simple

half-

45

EXPLODERS.

twist of the

handle, but

is found difficulty

as

the size of the

increases,

machine

owing to the appreciable of strength amount to give it the sharp twist necessary essential to fire the shots successfully. In the larger size, of operationis slightlydifferent. stead Intherefore,the method of a sharp twist, the handle is slowly revolved in the direction of the arrow until brought to a stop after half a turn has been made. The hand is then slippedfrom the handle, and

the armature

internal

FIG.

the the

in

(acting under

spring)is

42.

"

THE

caused

"GF"

handle

operatingthe

to

TYPE

positionof rest of its own most perfectresults,even

the

revolve

OF

a

rapidlyuntil it

STERLING

accord. with

of

pressure

DYNAMO

This

unskilled

powerful comes

to

EXPLODER.

operation ensures

manipulation,as

firingis rendered quite automatic by the action of the spring. The 15-shot size weighs 81b. The type (Fig. 42) is designed for the Sterling "GF" heaviest blastingoperationsand will fire from 70 to 80 shots the act of

in

series

attachment

simultaneously. It is fitted with for the

comprisesthe

a

safety firing

preventionof premature explosions.This used in the powerfulinternal springmechanism

46

SHOT-FIRER'S

THE

GUIDE.

15-shot

type, but instead of its being set free at the end of the stroke,it is wound further,and is up until it will go no then held in positionautomatically all is by a pawl. When the key is changed ready for firing, rightof the winding hole, and given of the

springto This

31."

the

actuate

5 in. x

43."

hole, at the

turn slight

in the direction

a

the

pawl,

in the most

aluminium

cast

and

allows

efficient

alloy case,

the

manner.

measures

6f in.,and weighs 16| Ib.

FIG.

TYPE.

POCKET

Describe

releases

mechanism

in

machine,

6| in. x

FIG.

This

arrow.

into another

"

WOOD-CASED

TYPE.

Firing with

of

Methods

the

44.

Sterling

Exploders. fire'with the pockettype hold the machine With in Fig. 43. shown the left hand as

To

Firing ^ith Sterling Exploders,

in

socket, and give it At

the stop, when force may With

ground

about

a

a

half-turn

firingkey

sharp twist the

contact

able Consider-

be used

injuring the mechanism.

wood-cased

tilt it to

a

type place the machine

convenient

angle,as

shown

right.

will strike

instantlyexplode.

without

into the

to the

the shots should

the smaller and

insert the

right hand

the

in

on

the

Fig. 44.

48

SHOT-FIRER'S

THE

GUIDE.

sulphuricacid. The liquidin which the couple is immersed is It is absolutely called the electrolyte. essential to the production the that shall be capable of (1)acting of a current electrolyte chemicallyon

of the metals

of the

couple,(2)conductingthe current, and (3)being decomposed during the action of the cell. the two metallic stripsare connected When outside the liquid rent *bya pieceof copper wire, chemical action takes place,and curis said to flow from the stripat which the chemical action is most energeticto that at which activityis least displayed. If a singlecell,such as here described, is set up, it will be observed "on

one

bubbles

that many

the copper

strip;

hence

of gas appear on the zinc,and few it is conventional to say that the

FIG.

flow is in the direction

45.

from

the

positive(+ ) to the negative (-) strip. Adhering, for sake of simplicity, to this convention, let it be supposed

the

-current

current

continues

to

flow in the

stripto its terminal,thence

of zinc to copper,

same

through the

or

direction,up the

connecting wire

that

copper

zinc,

to

pointwhere it is assumed to start. As the binding this the copper stripis +" and that on the zinc strip on screw terminal is on leads to the apparent anomaly that the positive the positive and the negative terminal the negativestrip, on and

so

to the

"

,

strip. If, however, it is noted flows

from

the

that

inside

positiveplate (zinc)to

whilst outside the cell current .(copper),

the

the

flows

cell current

negative plate from the positive

49

EXPLODERS.

terminal

(copper)to

this littlepecunegativeterminal (zinc), liarity

the

of batteries at

in the nomenclature

clear.

becomes

once

Referringagain to the rudimentary cell,it is found that the bubbles of gas (which,if collected and tested,would prove from the zinc to the copper have to be pure hydrogen) passing a tendency to stick to the latter plate. This tendency is,for detrimental the working of the cell. In the to two reasons, first place,the bubbles of hydrogen form a film of insulation, which acts as a counter the internal resistance force,increasing thus reducing the available electromotive of the cell, and force. electromotive force is set Secondly,a further counter up owing to the fact that hydrogen has an opposite electrical in other words, is electropositive, fore to zinc,and therepolarity, tends to send a current from itself againstthe working of the cell. This gaseous action on the platesof voltaic current The thousand-and-one modifications cellsis called polarisation. construction primary-battery

in

devised

the

with

in

absence

reaction a

most

part, been

particular objectof overcoming this

defect in the transformation Chemical

have, for the

must

of chemical

into electrical energy. take placebefore current be procan duced

primary battery,and

of moisture

inherent

this is

as

impossiblein the

absolutelydry cell is unattainable.

an

The

should not, therefore, be taken in its literal dry cell, expression, sense, but rather as a generictitle for all those cells in which and which the exciting mixture is pasty instead of being fluid, sealed

are

at the

In

top with

general, the

mixtures depolarising is

bitumen,

are,

other

or

convenient

composition of the so

concerned, similar

far

as

the

mere

paration. pre-

excitingand production of

to those

employed in a common Leclanche but by varying either (orboth) the mechanical cell, of ingredients and proportions construction different makers claim specialmerits for their particular form of cell. Some further improved by the addition of novel depomakes are larising current

agents. 34."

Describe

the

Fig. 46 represents and

consists of S.F.G.

a

zinc

Construction a

vertical section

A, cylinder,

fixed

of

a

Dry

Cell.

through an Obach cell an on base, insulating E

50

SHOT-FIRER'S

THE

GUIDE.

rod, (7,surrounded

B, and containinga central carbon

by

centric con-

and exciting mixtures, covered with granudepolarising lated cork or equivalent material for preventing escape of moisture ; the cork being sealed in with a layerof bituminous In the

cement.

cylindercemented to Surrounding a carbon rod, 6',is a

A, is illustration,

a

zinc

base, B. prepared-asphalt of about 50 or 60 per cent, mixture, D, consisting depolarising of manganese bago. peroxide and about 40 or 50 per cent, of plumThis is mixed with a gum-tragacanthto the condition of

a

FIG.

a

paste,which

thick

the form

of

a

latter is

hollow

squeezed out column. cylindrical from

this column

of

an

annular

die in

placedin the cell and centred within the upwardly projecting ring b of the base C beingpreviously B the carbon placedwithin it. The annular the depolariser and the zinc is filled in with an space between excitingmixture. E, consistingof about 80 to 90 per cent, of calcium sulphateand 10 to 20 per cent, of vegetablemeal, made A

into

suitable

46.

a

lengthcut

thin paste with

a

is

solution of ammonium

chloride.

The

layer Gr consists of cork, sawdust, or other moisture absorbent, K being the black sealing-compoundthrough which is fixed a small glasstube, -L,to allow the escape of gases.

51

EXPLODEES.

It is

where desirable,

dry cells are used, that they should be enclosed in some kind of casingin order to minimise to liability make accidental contact with the firing line. When used in an unprotectedcondition the negative ( ) connection is also liable to touch the positive ( + ) terminal,as shown in the figureby dotted lines. This,of course, destroysthe cell. In the absence of special of protectionthe negative wire should be cut means off short and bent down, as illustrated at aj, Fig. 46. "

35."

Describe with

One

Dry

It consists of

terminals

Wood's

"

a

of which

DRY

there

BATTERY

the

the

EXPLODER

cable shot-firing

batteries

is

The

SAFETY

that

for

use

safetyarrangements is that shown in leather case, 0, containing dry cells, to

patent safetydisc.

FIG. 47.

Attachments

Cells.

of the best known

Fig.47. the

Safety

some

an

attachment

latter is

IN

CASK,

known

designed to

WITH

WOOD'S

as

ensure

PATENT

Disc.

shall be

totallydisconnected

immediately after the shot has been

from

fired.

In

figurereferred to, the safelydisc A has a brass terminal plateon one side in electrical connection with one pole of the battery through one of the wires in the flexible twin-conductor the

B.

On

the

other

side of the

safety disc is

a

brass

terminal

the centre of that plateis Underneath convex. plate,slightly with the other pole of the a brass pin in electrical connection batterythrough one of the wires in the flexible twin-conductor, To completethe circuit the convex B. plateis pressedinwards until it touches the brass pin. E2

52

SllOT-FIRER'S

THE

This

device

GUIDE.

adopted owing to a placing the through a man

occurred

wires

of

a

having

twin

cable

sides of the disc of the pattern

againstboth each

in which

fatal accident

was

issued, originally He was showing a

in direct contact.

platewas

holding a primed Roburite in his hand, and all connections completed) how to cartridge fire the shot, and thoughtlessly placed the wires againsteach standingbeside

man

him

(who

was

side of the disc. Messrs. on

pressure

It action

48.

will

be

"

DAVIS

POCKET

seen

that

of

the

free

the

safetydisc.

about

the The

a

Davis

shot-firer to meet

and

cable

complete the

have

the demand

WITH

necessitates circuit.

SAFETY

KEY.

and

operator is necessary into

electrical has

weighs less

Son

device,which

predetermined

apparatus

2,500 shots,and

Messrs.

this

SHOT-FIRBB,

part of the

the end

adopted

side of the disc to

one

FIG.

on

then

Wood

a

than

deliberate to

connection

bring with

shot-firing capacityof 21b.

recentlydesigned a dry battery for

a

portable form specially

apparatus. This battery is contained

in

an

aluminium

case

of of

EXPLODERS.

the

form

shown

in

o

To

comply with the rule of dry battery exploders in mines an regulatingthe use is ingeniouslyarranged detachable press-buttonor firing-key dental provided, which is calculated to render impossible an acciof the fuse. too hasty ignition or At many collieries one, two three dry cells are grouped or side outlid. The together in a pinewood box with screw-down and

+

bolted

wires

"

through

Fig.

respectivelyjoined

are

side of the

one

by the addition of Messrs. tension a

Nobel

sets dry-cell

of

of reference

Give

36."

of

in Table

for

Data

handle

a

slingstrap.

or

with

use

their low-

belt carrying military-pattern

dry cells.

Explosivesin Coal with a firing-key.

number

a

pleted exploder com-

Mines

the

be fitted

must

Particulars

with

comply

a

small

two

and

terminals

two

to

the

battery for

consists of

with

pouch

In order to

belt

and

case,

key firing

a

supply a

fuses which

leather

48.

cells

dry

are

given

for

Order,

nience conve-

IV.

in

Guidance

Selection

the

of

Cells. The

followingfacts

of cells to the

same

The

for

serve

may

guidance in

E.M.F. is any given conditions : The of size. for all cells of the same type, irrespective work

E.M.F.

under

of

number

any

The

E.M.F.

that of

one

the number

of cells

the number

of shots that it will fire before

smaller

therefore

the

the

joined. The

so

cell the

of line and

fuse.

available

permitsof a greater number of firing a lesser number or What

is

Battery, and In

the

early part

largerthe

of

multipliedby

cell the

exhaustion

greater ensues.

resistance,and

Joining cells in series of shots being fired simultaneously,

size of

over

how of

number

tance overcoming the resis-

for

a

a

cell.

longer or lighterline.

Accumulator,

an

cell

parallelis

is practically Joining cells in parallel

equivalentto increasingthe

37."

of any

greater its internal

less energy

in

joined

cells

of

equal to that of one cell only. cells joinedin series is equal to

The

the selection

the

does

it

nineteenth

or

produce

Secondary Current

century, the

?

French

Prof. Gautherot, whilst engaged in decomposingaciduphysicist

54

SHOT-FIRER'S

THE

GUIDE.

a

^

"D

o.2

to

t.

to

"

0)

C

a "

on

03

"U

lljll

JS S

O

O

Ct

O

O

*p

09

O

O

"O

9* "O

"5

"0

ioG"OOO"0^ "0

r-

CO

(M

(^

CT

iS

70

"C

/,

M

"OCCrH

o

6

0)

'

|| ||

""

"

.

I

S"S^2

.^~5 -M

.1

I

2

I .5 3

!

"

-0

"M

0

C-

-n

xxxxxxxxxxxx

" ^

-oo^

^'""'^'^fl

"

=

rt

^

fe

t 1 xxxxxxxxxxxx

I

X

X

X

x

(

2 S

"

""

9 "

"H

" ^ g

"o

s

s

56

1 UE

SHO

JS

T- FIBER

G UIDE.

oxidised platesare in this manner continually as they are chargedand discharged.

and

38.

Shot-firing?

Are

"

Accumulators

Accumulator

cells have

cells

more

are

damaged cases. of upkeep add

for

far been

so

used for shot- firing "

shot-firingbattery must withstand mulator perhapsan occasional fall. Portable accu-

and

rough treatment

not

used

A

great extent.

to any

much

deoxidised

"

less of

or

of

Leakage

necessityenclosed in easily-

acid,corrosion of terminals and

to the difficultiesin the way

cost

of their

adoption. Size for size an accumulator will fire a considerably greater of shots than a dry battery, and if suitably number designedfor the purpose in view such exploders should prove very serviceable. 39.

What

is necessary to ensure the Cells ? satisfactory working of Accumulator

"

attention

cell should be tested daily, Every secondaryshot-firing by of an means If accurately-calibrated low-readingvoltmeter. the

P.D.

its

at

terminals

lower,the cell should

or

is

be

shown

set aside

be

to

for

volts

1'85

charging. To

this

end the

removed and each compartment of are ebonite-plugs the batteryis filledwith sulphuricacid,diluted with water to The proper a specific gravityof 1-175 to 1180. strengthis ascertained by means of a hydrometer: that of Beaume, for example,would read 22 degs.to correspondwith the abovenamed

specific gravity.

It is importantthat the

of the mains be ascertained polarity before placing for a chargein the wrong direction a cellin circuit, will ruin the plates ifnot discovered and remedied very quickly.* *

There

direct-readingindicator

A

mains.

"

indicates the mail

that the apparatus

as

is

similar make

the

to a

tongue, and other.

"ach

litmus

test,

a

a

a

are

bright,and

which and

turmeric from

extremities

papers

show

a

after

using

conditions

are

the

in

a

negative

restored,so

use.

sent

are

fitted with

chemically-preparedstrips,known

of

use

and

knobs, immersed

small

two

are

always ready for the

glasstube, capped

test,the normal

strip is torn

the wire Some

After

involves

third method

pole-finding papers,

To

on

small

a

knobs

using both

purple.

becomes

of

Within

end.

at each

liquid. Before

A

may "

negative

pole tester consists

terminal

end

"'

be

8.

Another a

"

positive or

polarityof electrical obtained,in which a pointer dial when simply joined across

of ascertaining the

several methods

are

out

books the

in the

form

of small

used in chemical

book, damped

books

laboratories.

on slightly

1 in. distant

applied to it,about brightred mark at the negative

the from

contact.

57

EXPLODERS.

Chargingis continued of

until the If the

vigorous effervescence.

admit

hydrometer, the

small

a

ascertained

with

electrolyte appears cell is of

state

that instrument.

A

in

state

a

design that will of charge may be best dischargedcell may have a

acid

densityof 1*150 (itshould not be allowed to fall below while during charging the density will gradually rise, this), an

until when

limit of 1 '200, fullycharged it reaches a maximum it is If, as is usually the case with accumulator shot-firers, impracticableto make a hydrometer test, the voltage should be ascertained,remembering that a newly-charged cell (ofany higher than the type except lithanode)gives a voltage O5 normal. This, however, graduallyfalls off,leavingthe normal voltage of 2 to 2-1 after the first discharge. It is desirable that all secondary cells should receive a good in a fortnight, charge at least once even though they may have remained idle in the interim. Cells are injuredby being partially charged and then exhausted, but overchargingdoes harm. Indeed occasional charge prolonged for several no an hours after the electrolyte boil is advantageous, to appears provided, of course, that the proper current- density is not exceeded.

If

of the hand

applying the back there is any perceptiblewarmth, indication that the charging current

this may

40."

suitable

on

Describe

is too

Apparatus

an

to

a

cell

taken

be

as

case

an

heavy.

charging

for

Accumulators. Messrs.

shown

charging set

in

from

direct-current

others

a

mark

brown

Fig. 49

mains

where

consequent mistakes in the following manner

will

To

an

free extremities

to

respectively, for

a

and brown.

few that

If

moments

another the

now a

(of two

current

strip attached

to

have

voltage.

any

by

wire

one

to

lamp

designed the charge motor-ignitioncells Co.

It

is, of

course,

Confusion and positivewire. if polarity be ascertained avoided, however,

lead,previously scraped bright incandescent

to

touched be

:

of

of

the

"

Everett, Edgcumbe

all

leading over.

used

kind

the

cleaned lead

the

from

the

attach

two

a

short

installation) and

strip and

leaden

main

attach

Next on

a

the

strip wires

join

opposite main

strips are held in dilute sulphuricacid through the lamp and the liquid,

will pass the

positive main

(Vide experiment described

on

next

will

page

.)

be

observed

to

turn

58

SHOT-FIREtiS

THE

GUIDE.

to secondary-cell exploders,there being no equallyapplicable

difference between and

protectingcases The

one

contact

apparatus consists of

reading

flexible connections, "c., in handle

for

or

5 amperes

closed walnut

a

direction electric

any

preferred, with carrying as

box

travelling.

How

49.

of

Electric

American Scientific First method

: :

?

recentlygiven

were

the

in

"

Dissolve

sodium

pint of water, in which quantity of potassium iodide

"

starch the water

must

in this solution

and

size ;

prepared

Wires)

following methods

two

(for testing the

Pole-finding Papers

are

Polarity The

2J

to

FIG.

41."

with

connection

of

matter

keys. two lamp holders,current

indicator,adaptor for making ammeter lightfitting,

except in the

the other

and

be

dry by 2

also and

heated. it.

in sulphate,a teaspoonful,

Cut

dissolve

about

of starch.

To

Soak

the

same

dissolve the

white

it into

blottingpaper venient stripsof any con-

in. is suitable. | in. Keep the paper in a dry place such as a tin box or a glass bottle. To use, moisten a it, nearer strip and place the two poles upon together or farther apart according to the voltage of the dark A current. the positive pole. at spot will appear Second of

common

method

:

Dissolve

alcohol.

15

Dissolve

in " grainsof phenol-phthalein also 20

grainsof

sodium

oz.

sulphate

59

EXPLODERS.

in

4

and

of

oz.

drain

second

off

It

those

to

that

note

an

8

on

red

it

spot

solution

first soak

treat

A

~

On

a

high-voltage

a

will

lamp

c.p.

about

lamp

c.p.

120

Afterwards

method.

first

volts,

240

ampere.

to

it the

in

the

in

same

the

at

appears

low-voltage

32

a

that

circuit

volts"

the

will

passed

currents

be

^

is

to

ampere,

about

lamp

c.p.

"

from

say,

about

pass

and

ampere,

supply,

say,

approximately

from

100 double

given.

It for

useful

to 16

the

the

Then

liquid.

it.

dry

in

paper

pole.

is

200

blotting

superfluous

and

in

as

negative

|

the

solution

manner

a

Soak

water.

should hour

one

hours,

be

or

to

remembered is

2

that

equivalent

amperes

for

to

half

a

current

a

an

of

current

hour,

of and

1

J so

ampere ampere on.

flowing for

two

CHAPTER

CONNECTING

WIRES

Conductors

and of

p.

for

Resistance

and

for

Insulating

Explain

the

Uncoiling p.

Different

the

Substances

p.

tions Specifica-

Wires,

65.

p.

Joints,

68.

p.

Conductor,

the

Resistance with

compared

as

with

compared

terms

show

and

showing

62-5.

Permanent

of

ing descend-

Table

Coiling

and

66-7.

meaning

Insulator, Resistance, of

61.

p.

Shot-firicg Circuits,

"Wires,

in

Substances

Different

63.

p.

Substances

showing Resistance,

of

Conductors

Conductors,

Jointing 42."

61.

61.

CIRCUITS.

FIRING

Tables

p.

II.

SHOT

60.

p.

Conductivity,

Approximate

Copper,

FOR

Insulators,

order

the

PAKT

IL"

Copper. In and

order the

place

to

it

operator

safe

a

is

communication iron

wires

distance

the

used

were

for

this

frictional

exploders

Europe

where

wire

frequently" employed.

is

wire

copper

obtainable

readily will

this

widely it is

be in

an

when

relative

in

of

(which

is

a

conveying substance

conveying Y.

an

an

indicates

conductivity,

a

electric

current)

few

substances

commencing

is the

with

the

kind for

reason

metals

electricity,

vary

and

is

only in

one

is

The substance

a

insulator

an

conditions of

descending known

as

or,

conductivities.

ordinary

best

brass

only

The

(which

under

used

that

current)

of

parts

ments blasting equip-

conducting

conductor

"

be

covering.

electric

trical elec-

Formerly

those

to

and

different

have

incapable

a

in

it is remembered of

of

means

space.

modern

suitable

powers

fact, between

all

insulated

a

while

continue

In

most

usually expressed, they

capable

Table

the

with

apparent

their

difference,

of

is

intervening

purpose,

blasting charge

a

establish

to

necessary

across

between

"

degree. order

conductor

of of

and

electricity"silver

"

insulator)" dry air

best known

(thatis,the

Silver.

Copper.

Bodies

Aluminium.

Linen.

Gold.

Cotton

Silk.

Gas-coke.

Hemp. Mahogany.

Resin.

Charcoal.

Pine.

Graphite.

Rosewood.

Shellac. Ebonite.

metals.

Strong

earth.

Moist

The

ores.

qualityof of

passage

given

wire

a

Glass.

Marble.

Dry

cross-section is

this it is seen

substituted

VI."

for copper

and resistance,

the

Substances

be increased

:

if any the

other

with

metal

Resistance

in Table of Different

1 2

Zinc

3"

(pressed)

Platinum

5

Phosphor-bronze

5}

Iron

6 silver

(Cu4, Ni2, Znl) (Pt33, Ag66) Platinum iridium (Pt80, Ir20) Manganin (Cu70, Mnl2, Ni4) Platinoid (German silver + 1 or 2 Mercury Arc-light carbon Pure

Bohemian

13J

16}

silver

at

water

18" 26 per cent, of

tungsten)

27J 59

4,400

18"C

2-3billions.

glass

40 trillions.

Ebonite

187

ftutta-percha

300

The

lower part of Table VI.

resistance

termed

between

insulators.

VI.

Copper.

Copper

Platinum

(except

relative resistances~"of

Aluminium

German

of the

by decreasingthe diameter

Approximate compared

in

to directlyproportional

being approximatelyshown

Showing

the

it opposes

that resistance may

It is also increased

different substances

in

of which

air.

to the sectional area inversely proportional

conductor.

Table

Paraffin.

vitae.

Teak.

by increasingthe length or

be silver)

'

Gutta-percha.

conductor,in virtue

of uniform

conductor.'"From

of

Wool.

electric current, is called its

an

length,and

either

a

Porcelain.

of animals.

Lignum

acids.

Metallic

the

Oils.

Water.

Other

any

Insulators.

Conductors.

Partial

Conductors.

:"

V.

Table Good

conductor

known

the worst

ending with

61

CIRCUITS.

SHOT-FIRING

FOR

WIRES

COXXECTIXG

A

any

serves

of the

to show

metals

"

the vast difference and

the

substances

pieseof gutta-percha,for example, offers

62

SlIOT-FIRER'S

THE

trillion times

300

much

as

oppositionto the passage of a equal length and cross-section.

pieceof copper of outcome The practical

as

GUIDE.

a

of the fact that

current

latively good conductor has a resmall resistance and a good insulator a relatively great resistance is found in the facility with which an easy path may thereby be providedfor the electric current, and be surrounded

with

insulation

43."

Describe

to prevent

for

wires,

of

or

small cable.

The

and flexibility

"or

circuits shot-firing

number

a

of

wires

latter type have

lessened

consequent

or

and

rock

wire, and

rough

other

is in

earth.

able suit-

composed of single togetherto form a advantage of greater

to rupture liability

in the

uncoiling of the firingline. blows

from

piecesof

better than

much

treatment

coal

solid

a

decidedly preferable for

respect

every

are

the

cable will also withstand

stranded

leakageto

Conductors

twisted

necessarilyfrequent coilingand A

loss by

Shot-firing.

for

Conductors

minimise

or

"Cables

some

a

all

blastingcircuits. These

wires, whether

solid

stranded,are

or

lated, variouslyinsu-

ozokerite,indiarubber cotton, jute, paraffin,

percha being the materials For

convenience circuit

complete a side

by side

as

twin Jiable.

a

in

a

are

If

over

set

one

all in such of strands

a

manner

are

wires

laid

conductor, and

then

covered

all,a concentric cable

circuits

of 10 varieties of cable

given explanationsrefer : are

in

Table

a

then

to

enclosed

and spirally

circular twin

around spirally

inner

Details

and

twisted

are

to form

as

covering an over

wires necessary

strong braiding,the double wire being known

In other patterns, insulated braided

gutta-

for the purpose.

chieflyemployed

manipulationthe two frequentlyinsulated

of

and

braided

cable.

insulation

the

otherwise

or

is formed.

suitable specially

VII.,

to

which

for

the

blasting following

"

Column

I. indicates the size of wire

to

the

legal 3/22

specimen, e.y.t is marked (sometimes written 3*22),meaning a three-stranded cable of wire gauge which each wire is No. 22 standard (S.W.G. or L.S.G., Legal Standard Gauge, or I.S.G.,Imperial Standard standard

wire

gauge.

No.

according

1

"64

SHOT-FIREtiS

THE

GUIDE.

Gauge). Similarly,4/25 impliesfour stranded together. Column

II. contains

"classesof work. rubber

FIG. 50."

wherever

a

1 to 6 have

are

well

highly insulated

.allyby

for

adapted for heavy

insulation. the

FOR

It

BLASTING

cable

of

an

suited

use

vulcanised or places,

CIRCUITS.

No.

but high-tensionblasting, work

as

outer

the

wires

to various

in wet

is necessary.

others

with

5

is

a

is not similar

mechanicstrengthened wire armouring. galvanised

is,however, sometimes

addition

S.W.G.

gutta-perchaor

suitable for

most

CONDUCTORS

high-classcable, suitable so

25

details of insulations

Nos.

coatings,and

No.

CONNECTING

No.

FOR

WIRES

SHOT-FIRING

65

CIRCUITS.

of a low-tension firing cable which has givesparticulars and economical for all underground proved most satisfactory A cable of this kind, though heavier than those more work. and it commonly used, possesses greater wearing capabilities, 7

is not

liable

so

short-circuit

to

covering. No.

singleouter

unit

as

a

twin

wire

enclosed

has the specification

8

in

same

a

ductivity con-

length,and is the pattern commonly employed with low-tension exploders. No. 9 is a concentric cable the conductors in which are composed of very fine wires. it exceptionallyflexible and well adapted for This makes No. 10 has two No. 22 working off a small reel or drum. wires separatelyinsulated standard wire gauge and then per

of

braided

over

all.

It is suitable for

dynamo

exploder,but

is

with any

use

obviouslynot

durable

so

on

the others

as

in the table.

enumerated

III. in the

Column

of

dimensions

drum

a

table

gives diameters to hold

necessary

a

from

which

the

given lengthof wire

may be ascertained. IV. indicates the resistance per double Column the resistance per yard out and return, or the 2

magneto

yard

that

"

is,

resistance per

yds. of singlecable. V. and

Columns the number Column

VI.

show

the

yards per pound

of VII.

weight

of cable

gives the metrical

shown

44."

the

figuresin

preceding table correspondingwith

to in the

Fig. 50, the uppermost cable

in

1 in the list.

Explain the and Taking

of Paying Proper Method Cable." Up a Shot-firing

Unless

Uncoiling and Coiling Shotfiling Wires,

a

separatetwo on P.F.O.

the

or

Out

"

a

received

firer has

shot

he is scarcely ever instructions, coil of wire in

a

workmanlike

commonly be observed 50 yard lengthof twin

will or

them

respectively.

equivalentof

Illustrations of the wires referred

No.

and

yard

VI.

Column

are

double

per

three coils at

a

time

with

to

seen

to handle

He

manner.

take up

cable in the

special

one

his 40

hand,

other,and drop

ground. F

66

THE

When

but,

line is

the

pulled the ringsmay not, the line closes

than

often

more

If the kink

'$ GUIDE.

SHOT-FIRER

spiralout straight, on

itself and

forms

a

is noticed

by the shot firer,he will give the it out, regardless line a vigorous pullto straighten of the fact is precisely that which a man that his method would adopt if he were requiredto break a wire with his hands. The damage caused to a shot-firing wire by this thoughtless kink.

is certain to result in breaks

treatment

these breaks without

occur

out

clockwise forward

to the

as

the other

because

cable in the proper way

a

will take it.

the hand

hand, which

taking the

the end

at

At

the

continues

hand

one on

the

point

a

end

of the the

nearest

end is first turned tied.

2 ft. diameter, and

made

coilingof

The

the line

formed

it is rotated

the

instead

of from

45."

Show

How

be

Properly When

Wires.

relied upon

not

conductivityis

forward

body by nately alter-

walks

away

and

leaves

a

ring of about

tying is important, for

18 in.

if the

loose and make

it,the operator meanwhile

direction of the shot hole.

Insulating

far

the first ring impossible. When as alreadydescribed, but towards

in the

and

into

the end will work

secure

has been

Joining and

rotated

hand

the motion, each

(to

other's

To coil a line one

first circle is not

fast

and

"

body

can

spindle)as

"

the proper

may

then

is made

position. As the cable falls to the ground the operator from it backwards, if he can convenientlydo so before him. out the line lyingstraight or

they

by testingor carefully feelingalong the line.

the coil is seized

movement

later, and

or

and insulation,

wires),the coil gripped by wheel a (as though it were

fuse

the

troublesome

more

apparent injury

only be found To pay

all the

are

sooner

Why

Joints

advancing

in Wires

should

Made. a

shot-firer who

has

not

acquired

is elementary electrical information requestedto join two piecesof -wire together he almost invariablydoes it as illustrated in Fig. 51 (A). Wires so joinedcan probably be. to pull apart, but the question of electrical It would be possible for entirelyoverlooked. any

CONNECTING

wires

two

WIRES

thus

touching one

SHOT-FIRING

looped togetherto

another,and

would

contact

FOR

if

even

obviouslybe

very

lie

the

on

the amount

ground without

tightlystrained

the

area

of

small.

Every joint increases the resistance of reduces

67

CIRCUITS.

of current

a

line and

available

quently conse-

at the

battery

the ior firing

charge. A joint on wire must a be sound both current-carrying On all sizes generallyused for mechanically and electrically. a joint is made shot-firing by laying the bare ends across one in

.another

the

position of

wire is then

Each

turned

widely opened pair of scissors.

a

less than

not

six times

over

the other

partlydone in Fig.51(B)and completed in Fig.52. It is important to remember that the wire ends must be -cleaned and rubbed bright with emery cloth before being twisted together,and that they should not be nicked by the knife when paring off insulation. "one,

seen

as

"

"

FIG. 51.

46."

Describe and

When in an

and and

a

making old

How

Joint

a

jointis intended up

a

new

Soldered

to

be permanent, as, for

line from

short but be

example,

undamaged piecesof

made

as

above, soldered,

soft solder should be used soldering, geneous. jointthoroughlypermeated with it and made homoIt should be cleanlyfinished and free from sharp

then insulated.

In

points either of wire ends insurance

be

Insulated.

cable,the junctionmust

the

should

and

other

or

solder.

electrical rules to

It is contrary to all fire use

any

flux for

joint-

making except resin,or resin dissolved in methylatedspirit. Joints are very easilysoldered, providing care is taken to rub all the wires with glassor emery as paper until they are F2

68

bright

they

as

using

by to

insulate

joint

a

knife

Take

The

splice

then

must

the

of

use

wire

covered;

match),

be

made

is

fingers

fatal

slight

side

of

the

in the

free

indiarubber

the

wrap the

rubber

(with

opposite

direction,

joint

from

which

is

spirit

a

it

joint fibres.

and,

strip

warming

"

one

from

splice,

until

overlap

after

and

52

with

the

making

for

joint,

Fig.

by

one

"

tapered

the

of

wrapping

same

and

in

as

rubber

pure

prepared

an

coverings,

required

clean

with

then,

return, the

and

side

one

the

away

distance

of

lenght

a

the

at

pliers.

insulation

from

off

The

cut

the

for

the

leave

and

made.

vulcanised

tape,

sharp

round

of

pairs

GUIDE.

soldering.

braiding,

and

be

can

two

easy

To

a

SHOT-FIXER'S

THE

thus

mencing com-

spirally reached

lamp ending

started.

Strands

Copper Twisted

and

Soldered

f

the

After

layers layer

layer

of

splice

adhesive

covering covering,

or

tape all in

the

is

strip should

1

on,

laid

be

rubber

exposed

addition,

wound

in.

at

each

independent

two

all, the

over

on

and

strip, end

of

the

the

lower

upper

braiding.

or

II."

CHAPTER

PART

III.

TESTING.

Tisting

for

Explosives

Test The

French

and

Test,

German 71.

p. p.

Testing Tester, Cell

47.

74.

Roburite p.

Wires,

that

p.

is

Stations

Fiery

or

Dusty

of

Blasting

Dry

Testing

tinuity Con-

for

77-

p.

the

Absolute

any

and

others

than

are

means

the

from

more

? countries

in various such

"safety"

as

plosives Ex-

use

Mines,

in

Safer

Agents

established

classed

Is there

Exploder

to

what

separating

been

are

73.

p.

Testing,

Places

are

testing explosives and

tests

Testing,

Cables

Circuit

Atmospheres,

for

have

Fuse

75.

p.

Dangerous

Explosives

safe

Detonators,

Davis

Testing

Complete

it

Explosive

less

76.

that

some

provided

74-5.

p.

Belgian

Precautions,

Tester,

p.

76-7.

for

70.

p.

p. 78.

Admitting

"

Voltmeter,

Leakage,

"

and

Exploders, Exploder

of

Strength

Risks

Test, The

70,

p.

Appliances

73.

p.

Co.'s

75.

71.

p.

Absolute

Safety

Test,

Effective

69-71.

p.

(Woolwich)

Austrian

Fuses,

Dynamo

in

48.

Testing

and

Exploders,

purpose

71.

Magneto p.

in

The

Fuses,

Earthed

"

English

High-Tension

and "

p.

Mines,

Dusty

70.

Electric

Testing

72.

The

p.

Tests,

and

Fiery

p. 69.

Safety,

of

in

use

as

for the

certain

pass

scribed pre-

"permitted" explosives.

or

Test

of

Safety

for

plosives Ex-

? No. will have

It be

than

the

of these

users

really claimed

be

gunpowder

far

The

to

safer

explosives are the

dangerous

true

unless

the

have

facts

used

of with

explosive

an

H.M. be

is that

they

strongly

too

are

less

ignitionof firedamp ('safety,'as

caused under the

some

all conditions, case,

certain

and

applied users

that

definite

they

which

Inspectors

(permitted) explosives that

misnomer

explosives) seems

to

as

get

it cannot

"

for them

so

to

all conditions.

that

frequently reported

is concerned.

these

impossible

present

absolutely safe under

on

can

is at

to

to

all that

dangerous coal dust

permitted

imagine

in total are

pressed im-

that

tion opposi-

absolutely

precautions."

There

70

SHOT-FIRER'S

THE

is not

permittedlist at some time or other caused an explosion of testingstation when fired without stemming. singleexplosiveon

a

49."

What

Method

Safety The

is

which

of

practised

Testing England

in

"

which

has not

the gas

the

at

for

Explosives ?

the Woolwich, test as generallyknown the conditions reproducing,so far as is practicable,

obtain into

cannon

Each

in actual work.

stemmed

in order If 20

the test.

to

it

Is

Gas

a

Whatever

Yes.

51.

What

"

for

of

in

conditions

the

fired into the

are

Safety

Mixture

Town

error

is the

sample

Gas

a

of plosive ex-

in

a

on

Safety

the side of

safety

and ignition, dangerous gas than is-

more

Method

French

of Coal-

sensitive to

more

are

an

?

be is

may

"Fire"

to formed

Supply

there

coal gas mixtures therefore the test is made in mines.

coal-gasand air. dry clay,this selection having

any

Test

because

found

steel

"

in

from

a

conditions as to weight specified the explosiveis then causing ignition, the permitted list."

Fair

Explosive

fired from

certain

placed on a

are

uniformity

charges of

stemming, without

50."

shots of

with

secure

mixture, under entitled to be

The

explosivemixture

an

charge is

made

and

"

English,more

consists in

been

the

GUIDE.

of

testing

plosives Ex-

?

the temperature calculating mitted produced by the explosionof each explosivewhich is subfor testing and passing it for use in mines if the The

method

French

temperature does 52."

Explain

not

the for

In Austria a

lead

block

the and

consists in

exceed

a

certain

point.

Method

Austrian

of

plosives testing Ex-

Safety.

cartridgeto surrounded

placed on atmosphere

be tested is

by

an

is drawn

from

the top of of between

working: of the mixture the remainder and purified, being air. colliery is then detonated, and if there is an ignition The cartridge the weight of the charge is reduced mixture of the inflammable 7

and

8

per

cent,

of

pit

gas which

a

72

SHOT-FIRER'S

THE

the

supposed advantageis assumed.

than

one

defective

On

there

fuse per thousand

is

ascertained

answering to

actual

an

The

appliancesrequired for comprise : (1) A suitable source

the

The

This while

53."

SHOWING

OF

CONNECTING

IN

FUSE

be

be

Thus,

means.

the

test.

must

can

of

so

constituted sufficient its

tion. igni-

readilyattained, a

latitude weak

very

in

cell,

incapable of firinga fuse, may

be

detector

SHORT-CIRCUITING

BY

itseif

end

injury

explosion

allowingconsiderable

choice of FIG.

(3) adequate

operator from

fuse under

of

means

incapableof sending through a fuse to cause

current

fuse

a

Fig. 53,

to

be

to

as

that

(2)some

untoward

apparatus

well be

testingfuses

flow, and

protection of the detonator

of

purpose

of current,

by

more

sample.

indicatingcurrent caused

is frequently

by testing.

evidence necessarily be seen by reference

not

it will fire may has been drawn from

importance as is probably not

issued,and it may be

cannot

one

test a continuity

which

much

so

the average

that the defect in that That

of

GUIDE.

WIRES

HEAD.

but

galvanometer which interposes triflingadditional resistance in the

circuit ; or,

the other

on

hand,

any

form

.of

be shot-firingcell may employed in connection with a high-resistancegalvanometer or voltmeter offeringopposition sufficient to reduce the batbelow fuse an a intensityat which tery current might ignite. It should will must

the

be remembered

explode a either be

fuse. run

testingcircuit.

that any

primary eel! in good order Consequently,the batteryused for testing

down, A

or

a

resistance

simple method

of

must

be

inserted

in

testingfuses without

galvanometer is to joineach one (or a group if preferred)in series with a singleLeclanche cell and a long-distance electric Vibration of the bell hammer bell, or a telephone receiver. or buzzing in the telephone indicates electrical continuity. a

absence Conversely,

of sound

is

an

indication of rupture

some-

73

TESTING.

in the

where

circuit,and

bridge,providedthat to

be taken

may

all other

to

defective fuse

imply a

parts of the circuit

are

known

be intact. A

magneto for

to

necessary

used

a

for

stitute is often used as a subtelephone (bellcircuit) exploder,and it is,therefore,scarcely high-tension observe

that

such

instrument

an

should

not

be

testing.

ease be tested with comparative fuses may high-tension current neto a through them from a low-tension magby circuiting exploder in series with a suitable galvanometer. The key should be temporarilyfastened down, and exploder firing-

Some

the handle

turned

slowly when

making

a

test.

fuses are not so readilytested, and may, high-tension in some require apparatus not usually available at a cases, colliery. As a rule,althoughthe conductivityof the bridging Other

of a long, often be ascertained by means "compositionmay the testingof high-tensionfuses distance magneto-telephone, is not considered practical. In all fuse-testingoperations personal protectionagainst is imperativelynecesthe possibleexplosionof a detonator .sary.

|

It is sometimes .so

as

to

pass

but

prevent,

only

claimed a

that if

minute

a

current

testingcircuit is arranged there

is

no

although careful choice of apparatus it cannot

absolutelyassure

immunity

danger may

from

of

tion, igni-

do much

to

accidental

explosion. flaw in a fuse bridge, A slight which, it should be remembered, a rise of in- iQ diameter, might easilycause is usually only TiyV o temperature to ignition point with considerablyless current than

is

normally requiredto

Every detonator

under

test

fire the fuse.

should

be

suspended freelyin an in a specialiron box

pipe about 3 in. in diameter, or .arrangedfor the purpose. where further precautionof placing other detonators The dentally possiblybe struck by fragments from a fuse accithey cannot iron

exploded should also be observed. detonators has The Author exploded disconnected -distance of 4J in. from the one purposelyfired.

at

a

74

SI10T-FIRER'S

THE

56."

GUIDE.

the Faults which to Explain Show are Exploders Liable, and be

may

Testing

troubles with

occur

Mechanical

are

Exploders.

casual

causes

in

and

the

such

time

as

of

case

and

contacts

of insulation

exploders,

similar

ruptures,

the

principal fail through loss of are

in the

coils.

armature

The

latter may arise through imperfectdesign,or it may from the storage of the exploderin a damp place. Messrs.

John

introduced

tester, which

shot-firers.

manner

consists

of

carried

in

enclosed

54."

EXPLODER

a

in

side

one

FIG.

a

a

have

exploder

of

requirements

intended

to

Fig. 54 almost

in itself sufficient information the

result

Son

"

fulfilsall the

instrument

an

by

Davis

simple form

a

on

seen

worn-out

or

dynamo

Magneto-explodersmay

of

time

to

be

can

Displaced

electrical circuit

breakdown

or

from

may

examination.

in the partial,

magnetism

they

mechanicallyoperated exploders

terminals, oxidised

of failure.

that

usuallytrivial

brushes

complete or

how

Remedied? The

loosened

Mechanical

be

used

conveys to

cate indi-

application.It specialincandescent lamp, suitable lamp-holder, and of its

a

small

which

case

glassdisc

stout

diameter, mounted

in

a

has

2 in.

about

bezil.

o"

Wires

TESTER.

from with

two

with

contact

the

lamp

terminals brass-plate

pair of

wires

from

connected

are

arranged

to make

tively respec-

wedge-

the

exploderthat is to be tested. To make a test, the exploder wires are wedged on the indicator terminals,the firing-key is pressedand the handle rotated at normal speed. Satisfactory working condition isshown of the lamp, as seen by incandescence through the disc in front

a

of the

instrument.

These

testers

be

may

used

to

ascertain the

strengthof either continuous or alternating current, high-tensionor low-tension generators; but, it need

scarcelybe observed, the every

machine.

To

ensure

same

instrument

is not

the reliability,

to applicable

makers

should

be

75

TESTING.

advised

as

the kind

to

of

exploderwith

which

it is intended

to-

be used.

supplied by the Eoburite Company consists small polishedboard fitted with terminals and a resistance in Fig. 55. in the styleshown The

tester

The

machine

end

one

to

of the

the terminals for

as

The

jointsand

FIG. 55.

57."

the

at

oppositeend

firinga charge.

usual

"

is connected

and

If it is in

coil should

have

BESISTANCE

How

COIL

is the

CONDITION

Condition

of

by

simple applicationof

of the cell to those movement

An

Battery

Ascertained

?

that bhe normal

E.M.F.

dry

cell 1'5

that of

needle

or

accurately-calibrated

pair of wires

voltmeter

for bad

added, all other chemical

oi" an

means

of the instrument

of the

a

from

the

of

a

volts,

terminals

gives visible indication, over

scale,as

a

to

the

available.

pressure

accumulator

re-charging. A 1 volt should

a

be

that of

to

EXPLODEKS.

L.T.

Dry

Shot-firing Set

low-readingvoltmeter. Knowing singlesecondary cell is 2 volts and

exact

equal

OF

a

to

the fuse bursts.

resistance

a

TESTING

FOB

best tested

generators, are

at

exploderoperated

order

good

and, it might Dry-cellexploders,

by

the

firingline and fuse plus a margin to allow of loss of power. similar possible sources

Accumulator

the

terminals

to the

a

coil

board, a fuse (not a detonator fuse)is joined

resistance

the

tested

be

of

cell

dry

showing

cell

be discarded.

less than

giving a

voltmeter

1'85

volts

requires

deflection below

76

SHOT-PIKER'S

THE

GUIDE.

of cells coupled together in series, testinga number the pointer should indicate a pressure equal to that of a of cells in the group. singlecell multipliedby the number When

A very cells is

represented in Fig. 56.

5f in. by

5 in.

provided

with

by

3 in.

is 3 volts

it

be fitted with

internal

It has

either side

on

a

simple

of

Describe

Methods for

(b) Leakage Wire

between

The

Testing

Firing

Lines.

in other

a

required

working conditions.

56.

between

safe distance

usual

The If

is

showing the actual

Testing (a) Continuity

cables

scale and

zero.

of

and

measures

mirror.

central

attachment

resistance of the cell under

''Cables"

and

a

dry

or

instrument

perfectlyeven

a

FIG.

58."

This

knife-edgedpointer and

a

range can

of cell tester for accumulators

compact form

Wires,

Shot

-firing Circuit,

of

(c) Leakage

Earth. used

for the purpose

between

of

the operator

placing and

the

explosivecharge are liable to be injured by fallingdebris,rough handling,lying in water ways.

Sometimes

a

wire

may

break

inside

the

TESTING.

insulation,either the

the result of

as

blow

a

or

probably by

more

of kinks.

out frequentstraightening

Again, the insulation may be abraded, in which case would be leakage to earth, supposing the faultyspot to moist ground. A

would

test

(a) To (b) To

wire

each

from

two

of Circuit,

ing the

If the

Fig. 57.

can

be tested

broken,

a

or

shows

Absence that

the

of

ment, move-

wire

is

firingline are joinedto testingset as above and

the

partlyso.

FIG.

If two terminals

between

oppositeends each

Wires.

of

other

a

and

a

are

left free from

with

galvanometer

the

The

the wires. for it to

considerable

57.

ends of

Leakage

between

of

galvanometer and dry battery,ascircuit is good the fact is indicated

irregular one,

very

touch-

the terminals

on

by deflection of the galvanometerneedle. or

the

by joining

line togetherand firing

extremities

other

combined

a

in

of the

ends

Continuity

between

earth.

to

Continuity of circuit

shown

on

"

continuityof the circuit. of leakage either the amount

determine or

:

lie

the

ascertain

wires

two

be made

there

be

contact

the

with

ground, deflection of needle indicates leakage the

leakage would, however, need to be proved by the use of a dry-battery

tester.

It is advisable obtainable of

to

lines. firing

make A

wherever use

proper

of them

for

galvanometerdoes

insulation

testingsets

determiningthe not

measure

are

condition

either pressure

78

THE

it

current,

or

absence

of

SHO

merely

join the

Wire

By wires

been

repeating reversed

ascertained.

the

the

the the

of

presence

test

other

"earthed" with

condition

"

to

or

positions of

the

other

and

free

one

con-

Deflection the

on

explanation of

and

free

earth."

earth

leaving

tester

one

leakage (for

the

the

to

of

extremity

main

a

cable

each

indicates

pointer

purposely

between

leakage

end

one

necting

Earth,

not

detect

opposite

the has

VIDE.

flow.

current

Leakage

and

G

indicate

to

serves

To

between

*S

T-FIRER

can

"

be

tvhich

wire

see

and

of

p.

76).

earthed

similarly

"

80

SHOT-FIREH'S

THE

GUIDE.

explosives containingnitro-glycerine (v.p. 4) this action is very liable to cause disaster,owing to the explosionof particlesof exuded nitro-glycerine by friction againstthe sides of the hole. And

where

gunpowder (v.p. 8) is used sufficient heat be developedby the contact of particlesof grit or stone may to produce ignition. It

even

is,therefore,important that

when to

they

the A

become

so

worn

to

as

drills should

fail of

be

not

used

clearance

giving easy

charge.

might be carried and applied to the pointsof each "bit" before drillinga hole, as of guarding a means againstthe danger referred to. Holes should be well scraped out and,if damp, dried as far as may be practicable. The maxi mum rendingeffect, apart from the influence of other conditions, test

gauge

-

is obtained The

when

maximum

the

charge exactlyfits the

effect

it is often necessary violent

to

its action

in

is,however,

not

make

an

than

of

use

the

shot hole.

always desirable,since explosivewhich of the

nature

material

is more to

be

blasted in itself requires. force

comparable explosions to follow to powerful hammer a

"

as

a

whole

between And

may

the

out

"

blows.

Permitted

be said to lie in

gunpowder as

with

Gunpowder, it is well known, exerts that of a wedge, while dynamite the analogy are more closelyallied

and

Permitted

explosives(v. p. 9) graduated range of effect

a

dynamite. class tends

to

be

used

almost

sively exclu-

for coal

mining,it is often found advantageousto reduce the tendency towards in some local pulverisation. way Many practical pitmen claim that less damage is done to coal of considerably smaller diameter than the by using cartridges shot

hole,thus allowinga portionof the initial explosiveenergy

to be lost

Monobel

by expansion. Fig. 58 cartridgefin. diameter The

manner

of

shows in

a

the

applicationof

a

IJin. hole.

attachinga fuse

or

detonator

charge varies in different localities. It is the instances of defective Stemming probable that many Charge. ignitionoccur through neglectto bringa fuse detonator into sufficiently effective contact or in appearance with the primer cartridge.Many explosives are

Preparing

and

to

a

not

unlike

sawdust,and

81

APPLICATIONS.

PRACTICAL

a

inserted,may detonator,if carelessly

of the mixture, or may, indeed, only touch a few loose particles hecome detached during the operationof stemming. entirely To ensure complete the

of

detonation

charge the

whole

tonator de-

should not be the size

smaller than

the

specified by of the

makers

sive, explo-

it should be

and

buried in and entirely

broughtinto the closest contact with the possible explosive. The

Lancashire

plosives Ex-

Co.

the

recognise importanceof this

pointby sendingout a special 59) peg (Fig. to be used for boring detonator

holes

in

It will be cartridges, observed

that the peg

stead chisel-shapedinof beingpointed.

is

This enables the shotfirerto bore

a

size of

exact

and

a

nator, deto-

with

pointed stick

leave the

a

end ; whereas

square a

hole the

an

may

air space in

charge beyond

the detonator. The maiks it S.F.Q,

foregoingrewill have made

evident

that Q

a

82

THE

detonator

be

must

inserted

in such

a

SHOT-FIRER'S

GUIDE.

securelyattached

to

that there

manner

its be

can

and cartridge, the

not

slightest sible pos-

risk of its withdrawal

during the subsequentoperationof stemming. In some explosivesspecialprovisionis made for the preventionof mishaps of this kind. Tonite, being a solid has a suitable opening for the insertion compressed explosive, of a detonator left during the moulding process.

FIG.

The

outer

with

brass

a

round

twisted

after the

man

59.

waterproofed covering is fitted round binding wire, the free ends of which for the

the conductors in

shown

her

may

devices of this kind

be put in at the

back, and secured An

alternative

illustrates a round

by

a

be

securityof the detonator,

end

60.

is

not

are

of

half hitch

method

detonator

the neck

rear

can

Fig. 60 (A).

Fia.

Where

its neck

a

provided,a detonator

the cartridge, as

indicated

in

wires turned

Fig. 60(B).

provided in Fig. 60(c), which and secured pushed into a cartridge

by string.

PRACTICAL

Explosivesof are

the metallic-cased

variety,such as Ammonite, end of the casingand boring

primed by cuttingoff the neck

the whole

hole

deep to ensure sufficiently as being buried in the explosive, a

In wet

holes extra

by using a littletar

care or

83

APPLICATIONS.

must

of the

shown

in

Fig. 61.

be taken

to

ensure

grease round

the neck

a

of the

detonator

tightjoint

cartridge.

FIG. 61.

cartridgesto the requiredweight ready for charging, at a time, to the back of a borehole with one are gentlypressed, In ramming chargesinto a shot-hole there a wooden rammer. must danger,and it cannot be too strongly always be some urged that this operationshould be carried out with the least possibleexercise of force. When

84

SHOT-FIRER'S

THE

Great

should

care

be taken

to avoid

i.e., tying two Danger

otherwise

of

"Bunching" Cartridges,

GUIDE.

or

jamming

"bunching,"

or

cartridgestogether,or

more

insertingseveral

the

at

H.M.

Inspectorsof Explosivesdrew

some

years

to

ago

the

time.

same

attention

desirabilityof using

hole, cartridgeof a suitable diameter for the boreand the necessity for inserting only one cartridgetherein "It is reasonable to conjecture," at a time. says a report relative to certain accidents due to the neglectof these precautions, between the "that either the rammer got jammed and cartridges

the sides of the

stuck cartridges used the

aci

oss

either to withdraw and cartridges,

smearing of explosion. The

the

obvious

hole,or that

the borehole, and the wooden

this force,

that

acting

remedy (inaddition forcible handlingof

or

on

hard

both

of the

force had or

rammer

the

explosive on

one

to

be

to press down

(probably)a

thin

rock, caused

the

to the

rigorousavoidance the rammer) is to use of anything like tridges carwhich a reasonablyand moderatelyeasy fitfor the are at a time." and only to push home one cartridge borehole, The primer cartridge, viz.,that containingthe detonator,is inserted last of all,and the charge is then stemmed, lightly at first with about 6 in. of loose stemming, and afterwards harder (seeFigs.58 and 61). This consists in filling up a shot-hole above the charge of explosives, in order to oppose a Stemming or 41

Tamping.

resistance to the gaseous in the

direction

of the

productsof explosion borehole.

Failure to

carry this out

of the stemming. properlyresults in the ejection In other words, it produces that wasteful and, in fiery or dusty mines, most dangerous effect" a blown out shot. It will be noticed in the section on SafetyRegulationsthat certain materials are prohibitedfor stemming. conditionally Certain specified are tools,moreover, required,particularsof section (v.p. 169). which will be found in the same The most generallyused stemming consists of plastic clay, which

is first rolled into short

insertion in the hole,

When

plugs and in firing

rammed

stone

gently after the boringsmade

PRACTICAL

by

the drill

85

APPLICATIONS.

frequentlyemployed. The French on Explosives,after conducting experiments with the conclusion clay stemmings, leaned towards gave

better results in to

Committee

are

oppose

greater resistance

blowing out, which, in the

practice. The

case

is

of course, of

Capt. Desborough,

a

sand than

and

sand

sand

that

sidered stemming was conplasticsubstances to

of considerable

factor

portance im-

fieryand dusty mines.

Testing Station, has carried out gain of experiments to show the economic thoroughly tamping charges,and presentedthe results of his experience in the Annual Report of H M. Inspectorsof Explosives for the

unstemmed, with the "

and the

twice

as

cotton.

noted

Office

Equal charges,according to this and ballistic pendulum, both stemmed weightof charge" viz.,100 grammes

same

results

following average

It will be

Home

1907.

year

fired at the

report, were

the

of

that

the

were

obtained

:

"

relative loss of effect is

with

explosivesthan great with the gelatinised In

earlier series of

an

nitrate

experimentswith

explosiveit was found that the loss absence of tamping was even greater than the gelatinised explosivesabove mentioned.

an

than

more

of effect due was

gun-

ammonium

the

to

case

the with

to the minimum as quantity investigations of stemming necessary to produce the complete explosionof ascertained that, after a certain length of the explosiveit was stemming (between two and three times the length of the

In the

course

charge)had

been

of

well rammed

home, the addition of

a

further

augmentation to the swing. quantity caused no perceptible most probably due to This, Capt. Desborough explains,was confined to the fact that the explosivewas alreadysufficiently which was the production of the maximum ensure energy capableof being generatedby the active chemical changes of

86

SHOT-FIRER'S

THE

the

explosion,and

would

the

the

for the purpose,

stemming

energy.

length of stemming the material employed

requisiteminimum

accordingto

vary

added

consequently any

increase the muzzle

not

As, however, must

that

GUIDE.

of

nature

probably also accordingto the nature of the only saferule to followin practice the explosive, is to use as much stemming as possible and to make sure that it is well rammed. that an now Having regard to the probability, recognised, fore explosiveforms different decomposition products,and theredifferent explosionphenomena, when fired under varying conditions

and

the

of pressure,

operationsof shot with regard to the quantityof explosiveused the sufficiency of stemming, should receive more has hitherto

been

What

60."

considered

in

mines,

charge and

a

attention

than

necessary.

Precautions

are

Stemming

or

firers in

a

ming Ram-

when

Necessary Charge ?

Inspectorsof Explosives have frequentlyobserved in Reports that in ramming charges into a borehole there be too strongly danger,and it cannot always be some

H.M. their must

urged that the operationshould possibleexercise of force. The class

this

allowed that

to use

the

clearance

thing

of

to

accident

is to

drills which

diameter

of the

with

even

a

is that

ensure

borehole,as if it does the

care

of

the

much such

preventing

men

are

not

worn,

and

also

as

to

give good

drill. The worn important slightly shall not stick in the the cartridge

the

which

become

cartridgeis

miner

force to get it to the bottom After

that

ensure

have

method

best

the least

with

carried out

be

should

quite certain

is

cient suffi-

of the hole. be

devoted

pointswhich require attention the cartridges (i.e., tying two or

other

to use

are

to to (i.)

the

the drills,

avoid

ing bunch-

wise togetheror otherof the use time), (ii.) insertingseveral at the same glycerine the thorough softeningof all nitrowooden (iii.) rammers,

explosivesbefore

three

use.

however, the use of precautions, undue force may sion always cause an accident. A generalimpresto exist that,at any rate in the case of gunpowder, seems Even

with

all the

above

88

SHOT-FIRER'S

THE

trate

a

looped joint,which of

means

GUIDE.

is incorrect

conductingelectric

and

ineffective

as

a

(v. also p. 91). When

current

the

the cable or firing made line jointshave been satisfactorily be paid out to a place of safety(v.Rules in Chapter V.). must The method of coiling and uncoilingcables has been proper alreadydescribed.* The firing line must ahcays be paid out FROM the shot-hole the place of safety, where TO the exploder (unless it is a belt or pocketbattery)has been previouslydeposited.

Having reached into effect such under

which

the

desired

shelter,the shot-firer carries

and precautionsas inspections he

be

may

the

specialrules and

working (v.Chapter V.)

his

the free extremities judgment demand ; then he connects line to the exploder,and fires the charge. of the firing NOTE. If the shot-firer has occasion to leave the firing line,even momentarily,after having paid it out, he must take the exploder with him. the shot-firer should immediately After a shot has been fired, both ends of the cable from disconnect the exploder,free it own

"

from

any

chance

debris which

have

may

fallen upon

it,and coil

it up. This

should

instruction

followed

be

when

even

a

miss-fire

has occurred.

61." -How

Charge

a

may

Where

lapseon

the part of

a

man

have

electric

new

to

been

is shot-firing

firingis introduced apparatus.

low-tension

only they

then

brought about by

arise

for the first time The

kind

the duties than

Difficulties often

in materials.

ill-assorted

likelyto

more

are

shot-

practiceof

established,failures of any happen at rare intervals,and even

Shots.

defect

Fire?

well

Miss-Fire

some

the

Miss

where

owing

electric

to the

system

to any

use

may,

of for

example,be adopted. A dry cell is obtained,along with 30yds. wire. 40 yds. of shot-firing or Perhaps a thin singlestrand After firingcomparatively wire, say No. 22 S W.G., is used. *

Chap. II,

Part II.,p. 35.

89

APPLICATIONS

PRACTICAL

and the fact is becomes impossible, ignition frequentlylost sightof that the greater part of the energy of the cell has baen used up in overcoming the resistance of the line. (Thispointis further developed in the followingpages.) shots further

few

noticed

It is often

referred to, there

frequent complaintsas

are

"

that caps,"

rule the fault may In

the

for

report

that

general

a

as

.

the

of

1905,

tric Elec-

to be elsewhere.

safelyassumed

be

of

to the number

detonators.

is to oay, electric fuses or well made fuses are, however, now so

bad

already

the conditions

too, that, under

.

Inspector of

Chief

(comprisingthe counties of Bedford, Berks, Buckingham, Cambridge, Derby, Hertford, Huntingdon,Leicester,Middlesex, Northampton, Nottingham, Mines

Midland

for the

Oxford, Rutland

Warwick), Mr. A. H. Stokes gives the shots fired (in his district) as 2,305,591, or and

total number

of

162,904

than

more

fire shots

are

cent., and

:

district

in the year

percentage of miss-

The

1902.

tension 0'42 per cent.,low tension 0'23 per

High

gunpowder

0*25

The

cent.

per

is thus

shots that

assumed

by

the

0-3

per

cent., it shots

gunpowder

And

only

a

small

of

fraction

fired

are

traceable all but

traced

to

defects

to a

very

one

or

in fuses few

the

other

or

this

even

percentage of failures will,as

small

being

of tape fuse.

means

In

trical percentage of miss-fired elec-

averge

a

rule,be

explosives.

failure may

of

the

be

following

FIG. 63. causes

DIAGRAM

OF

:

"

~.

-

In LOW-TENSION

SEVERED

WITH

BRIDGE.

the

FUSE nave

may

sary to

.

,

.

exPloder" the fallen below

overcome

.

.

.

electrical pressure ,

that

intensityneces-

the resistance of the circuit.

tance, firingcable may offer too great resisowing to (a)badly-madejointsor (6)defective insulation, arisingeither from mechanical injury,absorptionof moisture The

or

of too

use

In

a

fine gauge

low-tension

wires.

fuse, (a) the bridge may

be

Fig. 63 ; (6) the bridge may be shunted, as (p. 72); (c) there may be insufficient priming,or

in

severed, as in

Fig.

the

53

latter

90

SIIOT-FIRER'S

THE

GUIDE.

incandesce the bridge would case damp, in which without causingignition (d) if fuses are tested before ; and firinga defective bridge may then give way without firing. In high-tension fuses,the wires in the fuse heads (a)may may

be

make

contact

with

each

other,thus passinga

decomposingthe priming ; (b)they may good

resistance

is

In either the

if a charge be variety,

in wet

of

be

manipulation,in tamping and

result in missed

abraded

to

overnightin a wet hole, be destroyed. Consequently, wires should be placed fired immediately after

stemmed.

Accidents

shots,thus

tamping, (a)the

Whilst

may

covered guttapercha

holes,unless the shot is

havingbeen may

left

insulation of the fuse wires but

sufficiently

the

too

none

make

without

priming,in which case the electrical ploder. high for an ordinary high-tensionex-

with

contact

not

current

:

"

insulation

short-circuited.

connectingup, be

liable to occur especially in anthracite mines, where the particles of coal are sharpedged and hard, and may easilycut the wires during the operationof of,say, stemming. On testingsuch a circuit in situ,by means a Hold en firingapparatus or rack -bar or Manet exploder,the indicator would show continuityand lead one that to suppose the fuse was in good order.

(b) A

and

wire may

then, upon

been

have

tamping, the operator causes

and

give way

(c)The

This

of the fuse wires may

is

inserted in the shot-hole kinked

strain

put upon

the weakened

;

the wires

pointto

perienced by an inexout straighten

inside the insulation.

wires

may

be

partly carried

into the

hole

by

an

tamping rod ; they are pulledout again thus bringingabout result (a)or (6). forcibly, (d) Manipulative accident (c) may result in the detonator the cartridge, the fuse from the from or being withdrawn detonator. (This may be entirelyobviated by insertingthe then detonator in the cartridge, doubling back the wires alongsidethe primer aad making a half hitch with them round the same. The detonator end of the primer leads into advance

stroke

the shot hole.

of the

(SetB, Fig. 60, p. 82).

PR

A OTIC

(e) Splicingfuse wires in hole, and

he

so

He

91

TIONS.

shut-hole.

a

36 in. wires.

with, say,

caps

A PPLICA

A L

(A miner

occasion

has

to bore

piecesof old fuse wire

twists

will have

to

on

48 in.

a

the new,

lays the jointsside by side,and proceedswith his stemming. The fireman comes along,applieshis exploder,and " wonders why it won't go off" !) In connectingthe fuse and the exploder,(a) the jointsbetween line may the fuse and the firing be dirtyor covered with tallow grease. (They should be rubbed brightbetween thumb with a pinch of coal or shale dust, before splicing.) and finger, of jointingmay be mechanicallybut not (b) The manner electrically good. (Seepp. 67 and 87.) been have (c) The joints,though properly made, may with each other, whilst inadvertentlybrought into contact reelingoff cable. (d) The firingline may have been kinked and afterwards forciblystraightenedout, thus breaking a wire. exploderends

(e)The ;

the

as

firingline

binding terminals

ing requireclean-

may

studs

contact

or

on

exploderitself.

62."

What

Double

hangs

is

fire

a

"

The

or

detonator

may

when

occur

a

fuse in

may

fail to

of the

Can

In view

an

?

shot

a

detonator,or the

detonate,but succeed

charge. Then, accordingto developed by the gases would

63."

a

placeof

the

remainder

"

Detonation

detonation.

insertion of

weak

Double

partlymisses or form, in fact, of delayed ignition. A damp badly mixed explosiveare the two principal

of double

causes

"

detonation

detonator

a

also the

may

of the

Sarrau's be

theory,the

sufficient to

Electrically-Ignited Shot

of the fact that four

pressure

explode the

injuredat

pitsinkers

Simderland

were

colliery owing

known

Under

the

Quarries Act

"

If

a

?

recently reported

explosionof a blastingcharge,it cannot that electrically ignitedcharges can. and

a

Fire

Hang

been

fire.

igniting

explosive. (Seealso Question 63, following.)

to have

hang

in

of

use

shot has

to the

be

too

do

at

pected unex-

well times

apparently

92

SHOT-FIREtiS

THE

missed the

fire,no

used," and from

the

shall be allowed

person

half

lapse of

GUIDE.

to

hour, except where

an

in coal mines

has electricity

electrical miss-fire is

an

regulationas

it until after

near

go

the

to

caution

fixingof

been

exempted boards

or

fences. The

North

Staffordshire

misses fire,no at least

the

shall return

person

hour

one

;

authorised

SpecialRule providesthat to it

taking the battery with that

thus

in

Cannock

Chase.

measure

It is not

unusual

in

for

in

one

fuses,though it detonator

simultaneous

or

it may

half

a

that the

kept

heated

warm

rises to the

for

or

the

during

occur

of

use

able suit-

a

ensuring the electric

in the

detonator

dirt

or

of

passage

fuse

seconds the

a

wet

latter has

The

before

priming. Or

defects in the fuse, such

priming,or by

through

the The

be

broken

and

springcontacts

on

general

might

only justsufficient

bridge.

several

in

whereas

in the circuit

resistance

explodeafter

retardation

The

produced if the exploderwere

insufficient

of

of shots.

exploderhandle,

point of ignitionof

by

element

an

towards

will sometimes

instance,to loss of magnetism.

be caused

may

approximation to

that the

way

will suffice.

turn

permittingthe to

always

explosive. A damp

shot

a

wires,bad joints, or grease

energy

fire and

the

fire.

increased

by

in

electrically ignitedtime

ignition, may in the

occur

prolonged turning of less than

is

of

use

battery and

danger. of simultaneously-fired

nearer

a

number

any

retarded

It is well known

be

group

long

a

go

ignitionof

might readilyhang

would

of

also be admitted

must

would

or Hang-fire,

detonator

lie in the

hang

not

there consequently

perfect safetywould

return

may

rules rather favour

do

group-firing.Probably

person

similar rule is in force

These

a

lapseof

by electricity,

cable of the

source

a

prove

shots to miss, and

caused

A

electrically ignitedshots

some

danger

him."

fired

are

competent

or

immediately,after disconnectingthe

idea

until after the

if,however, the shots

shot-firer

and Shropshire

"

if a shot

minals, ter-

electrical

then

to

be

temperature same

effect

under-powered,owing, might delayed ignition as

badly mixed, damp,

charge.

PRACTICAL

93

APPLICATIONS.

Capt. Desborough (Annual Report for 1905, p. 137) states that he had electrical hang-fires when firing experimental shots with

three

different

greatest duration the

between the

With

several

found

he

be

to

that the detonator

had

The

This

by

was

no

to

seconds

explosionof

in

charge was

fired,but had

when

overcome

carbonite

collieryin

a

tracted, ex-

failed

this connection

In

cartridgeof

a

shot-hole

a

a

Capt. found

was

South

Wales.

the first instance of the kind, and

means

seemed

caused

in

that

the

the

was difficulty

employed.

was

50

of

explosiveshe subsequently had when

mentions

burning

and

case,

stronger detonator

Desborough

of about

detonator

in each

explode the charge.

to

the

all these

miss-fires,and

explosives,that

interval

involvingan

explosionof

charge.

nitrate

ammonium

lie in the

of

use

faulty or

a

the

insufficiently

powerfuldetonator." The Annual also records electric fire

to

Report three

found

of these

one

from

the

no

doubt,

The

time

cable and After

the

the

made Volf.

says

The

happened an

of

France

a

the Transactions

that the accidents

only

the

others minutes.

that in

assumed

was

first

became The

each filledwith

was

a

borehole

exploded by

the

It

There case

was

is practically of

hang-

of

the

five minutes.

safety explosives, Collieries and

were

report by Mr. L.

a

translation

phenomenon of double detonation, retarded ignition or hang-fire.

It

of

St. Etienne

from

a

about

and investigation

appeared in

Mining Engineers,show

at

was

then

was

disconnection

the

charge was

into

followingnotes

report, which the

the

made

were

tested.

exploded.

the report, that this

explosionof

subjectof

and

1906

with

occurred

attempts

leads

elapsing between

accidents

several

two

cases

shot then

introduction

the

hang-firehas

detonator

to be all right. The

fire.

a

electrically (high tension); the cable

shot

disconnected

of Explosivesfor Inspectors

in which

cases

firing.In

a

of H.M.

of Mr.

Volf

s

of the Institution of were

which

attributed is another

to

phase

charged with cartridges, detonator, and

that

the

ignitedafter an interval of a few seconds or followingaccident proved this : Three holes,

3J oz. (100 grammes)

of

were qrisounitc-couche,

94

SHOT-FIRER'S

THE

coal,and ignitedby 0-052

in the

bored

distinct reports

goingaway, deduced

was

stillsmoking

the workmen

as

exploded and injured

exploded twice.

a

to which

the

products are

exposed during such

nitrate of

ammonia,

air,and give out nitric oxide, but if they are

they instantlydecompose,

raised.

Both

"

burn

igniteand

instead

varies

also

with

a

a

the

closed

closed

hindered

be

of the

detonator

a

space

and

high

at

charge is at

the

is the

pressure. once

verted con-

ignitionbe defective,the charge of exploding; it is then said to

its

the small

grisounite upon

ignitedin

produced by

nitric oxide.

givesoff

cook," and

charge

if the

But

into gas. may

ing blast-

other

and

forming a trace of changes immediately into

of gas

rapid that the whole

so

are

reaction

The

by ignitionin

that

as

tion. reac-

without

process

free evolution

if the

second

same

first slow

The

nitric oxide.

pressure

theory

containingnitrates,decompose graduallyin

materials

the

The

decompositionof a blastingcharge is not singlechemical reaction, but depends on the

Dynamite, guncotton,

space

were

that the

was

pressure

heard, and,

; it appeared to have

result of

the

were

shot which

a

of them

one

nators (1J grammes) deto-

oz.

three fuses.

and Three

GUIDE.

The

of

explosivepower

a

depends, in

composition,and

that quantity of nitro-napthalin

it

contains.

charge begins to burn,

If the

by

the gases

given off

the Karwin

Mine

(Austria)20

series.

The

(by means

of

Tirmann

was

second

first and

low-tension

fire the

15 seconds

of the shots

4 ft. deep, and

six others.

each

were

bored

and

fired

series

having

been

fired

dynamo exploder)from when

after the first.

It

produced

gone

off.

a

heard, and the workman

was

remaining holes

had

report, but all had

holes

second

ft.,a loud report

proceedingto

tell which

or

a

of 260

ensued, about

caused

explosionand ignitethe

produce an

may

in three

distance

increasingpressure

after the other.

cartridgesone At

the

was

a

second

impossibleto

the first,and

The

report

boreholes

which were

the

about

five contained, besides the firing cartridge,

96

SHOT-FIRER'S

THE

through the

current

force set

available be

may

circuit is less than

the

at

GUIDE.

terminals

expected

to

of

the

the

electromotive

battery;

perform its work

in

hence

this

efficient

an

manner.

It need

scarcelybe said,however,

maximum various

This

internal

indeed, if the

resistance

the terminals of

the

when

margin

this alone cell,

remembered

this

small

using very is

of power

so

cell

first

be

place,

considered.

lasts;rapidly,

And,

increased

as

force at

the cell incapable

types of explodershave be taken

requiresto

machines.

In the

a

into

largersizes

the internal great that in practice

ignored.) The firing line,again,may cuts from flying piecesof rock resistance

cell to

render

may

that all

resistance,and

definite internal

the

less effective electromotive

means

of the

firinga fuse. (Itshould be

account

of the

to obtain

compensate for

to

In

gradually so long as the exploder is heavilyworked.

increases

internal

resistance.

resistance

in order

be made

must

of increased

sources

is the

there

allowance

economy,

that

be

can

be

expected to

receive

frequent or coal,thus necessitating splices to the resistance; or jointsthat may or may not add seriously accordingas they are proparlyor improperlymade. of making a jointin small wires or strands The best method An has been explained (seep. 66). injured cable should, of be sent

course,

it is

but

order

of the mine

out

frequentlynecessary

that the round

of

a

for

repairsas make

to

district may

soon

possible,

as

splicesin completed without

temporary be

delay. Another

of failure

source

to instruct blasters is that of

needful

off

a

foot

or

jointshave

If two

each other. cut

againstwhich

of

so

wire

one

on

it has

making to be

each

found

splices opposite

two

made,

been

it is better to

piece.

bringingthe long and short wires of oppositecables each the jointswill be separatedfrom togetherand splicing, Then,

other

on

by insulation.

It may becomes wires may

further be noted saturated be

so

with

much

that if the insulation

of

a

firing-line

water, the resistance between reduced

as

to

providean

easier

the two

path for

then,

would

as

fuse.

fail to go

of course,

matter

a

of failure in the

sources

the

through the bridge of

than

the current

97

APPLICATIONS.

PRACTICAL

firingline

The

latter

Other

off.

will doubtless

gous analo-

readily

suggest themselves. that

fuses,it is found

to the

Passing now

they

of

are

what some-

widely varying resistance ; from which it follows that a battery and line admirably adapted for the ignitionof one utterlyuseless with another

be

of fuse may

make

bridges are variouslymade and and iridio-platinum, platinum-silver, range fuse

Low-tension

0'3 ohm

about

resistance from

desirable that

ample margin of

an

in the

power

platinum,

in electrical as

it is

unknown,

fuse is

is often the case, the resistance of the

of

Hence, when,

ohms.

T65

to

pattern.

explodershould

always be available.

Permitted

do

How

65."

class

Explosives Some

Coal

Getters

experiments,which

recent

Bobbinite

with

compare

as

Committee,

of

Explosives

the

powder Gun-

Permitted

other ?

carried

were

out

for the

generallyacceptedbelief stillthe best explosives for

the

go to prove

gunpowder and its allies are producing strong coals, not only because these non-detonants the whole get the coal with less production of small, but on that

coal

because

least amount to

the

These

cracked,

got is not

of

in conveyance disintegration

or

and

from

suffers the

the coal face

consumer.

Table which

shattered

so

VIII.

were were

Whitwood

shows

in the

made the

generalresult of the experiments, of widely varying nature. four seams

the

Stanley Main

"

"

at

seam

Collieries,Normanton,

the Don

in South

Pedro

Yorkshire

Pit, ;

"

at seam Moorgreen Colliery,Eastwood, Deep Hard Black Vein seam Nottinghamshire; the Bydelog or "

"

the Victoria

Ebbw Colliery,

"

"

Nine

Feet

in the Swansea S.F.Q.

"

or

Big

Coal

Vein

"

"

Vale, in Monmouthshiro "

seam

at

; and

the in at

the

YstradgynlaisColliery

Field. H

98

THE

R'S

SHOT-FIRE

GUIDE.

"

co

02

.a HS" 1-H

3

VI

.3

^

w i"

*

bo

.3

I

" o

O

o

o

o

co

o

'"H

cL

"""*

PJ

""'

PJ

^

CO 'N "M

"o

o

^H

CO1^ CO

^

-" .

'

CO

^00

o

o

PH

PH

""1 ^"

""

11 P

"

"p 55

A OTIC

PR

BLASTING

A L

IN

A P PLICA

PIT

99

TIONS.

SHAFTS

AND

STONE

HEADINGS.

66.

What

"

of Electric Advantages Sinkings and Headings ?

Shaft

in

Firing

the

are

electric current

Ignitionby

ought to be the only permissible of firing means blastingchargesin shaft sinkingand tunnelling operations. For rock blastingand all tunnellingwork, shot-firing by sides beis acknowledged to be the most economical electricity Moreover, in being safer than any other system. such places as shafts and ventilation tunnels, where may defective,it is usual

be

wait

to

blast to several

perhaps

allow blasts

smoke

half

and

made

are

under

the

old

hour

an

fumes

to

dailymuch

system more

or

clear away,

valuable

time

men for workafter and is

each when

thereby

lost. Smaller

rock when fired simultaneously chargeswill liftmore than would if the holes were fired by electricity greater ones independentlywith tape safetyfuse. It has also been proved that

the

of work

accomplished with a less number of holes where is employed than electricity would be required if the chargeswere fired singlywith tape amount

same

can

be

fuse. is more advantage of electric firing evident,as, if the holes are not simultaneously exploded,there of a smouldering fuse lying dormant is but little possibility and unexpected,* and, consequently,less exploding when of danger in approaching the charge to ascertain the cause In

of

case

a

miss-fire the

miss- fire. Given and

a

code of

rules,as

protection againstthoughtlessness

ignorance of the risks involved,it should,by the

electrical methods, made

a

for the

and

enforced

for any

of

assuming that adequate provisionis observance

accident *

use

See

to

of the

rules,be almost

occur.

"Hangfires," p.

91.

H2

possible im-

100

SHOT-FIRER'S

THE

67."

State

the

Series

Advantages

and

in

System;

High

and

the

Disadvantages how Firing; Show

Resistance and

of

shown

in

the

the

give

Low-Tension

for simultaneous

as parallel,

In

the

each

Fuses

and

Parallel

calculate

GUIDE.

of to

Circuit

for

Resistance

of

Puses.

ignitionmay

be

joined in series,or

Fig. 66.

series system, wherein

line and

fuse

wires

all

are

the total external resistance of the coupled consecutively, of the separate resistances nal circuit is equal to the sum (exterresistance RZ-t-(R/xN)) ; where R" is resistance of line, =

resistance of

E/

In

fuse,and N the number

one

the

the

circuit may be the ladder sides and

parallelsystem ladder, the line forming fuse

compared each

to

a

detonator

stave.

a

total external

The

It is thus

of fuses.

The

resistance

resistance

of

fuses

varies

is very

(R/-f-N). inverselyas the +

variable,and

be

may

upwards. L.T.

a

H.T.

the other

fuse,on

rarelyexceeds

generalrule

a

resistance

of H.T.

and

0-7 ohm,

about

the

50 ohms

anything from The

resistance in this system is El

that

seen

number

As

of fuses in series.

fuses

hand, is usually

1'5 ohms.

fired in

are

and parallel

L.T.

fuses in series. is usual as firingin parallel,

in

ignitionfrom lighting mains, a bad fuse simply misses fire while the rest explode. the other hand, a defective fuse usually In a series circuit, on the entire blast to miss fire,though the system has the causes When

advantage that If

a

fault

great number

a

50, the best way

the

68.

be

can

fired is limited

How

are

Shaft In

the

Sherwood

the shot-holes

were

fired,say,

more

than

them

only by

the current

available and

the mains.

Shot-Holes

Sinking

to be

in groups of about 20 in in parallel. In this way the number

groups

carryingcapacityof "

easilylocated.

of fuses have

is to arrange

series,and jointhe that

be

can

arranged

in

a

modern

?

England),all Collierysinking(Mansfield, from a centre line : set out systematically "

PRACTICAL

Six inner

holes, 6 ft. deep and

sumper

drilled in

circle of 4ft.

a

6 ft. deep and

2 in. in

101

APPLICATIONS.

and

radius;

16

outer

drilled in

diameter,were

diameter,

2 in. in

were

holes,

sumper

circle of about

a

9 ft. radius.

Tne

whole

of these inner and

outer

holes

sumper

fired

were

and togetherby electricity, Then

the debris cleared away. side holes,6ft. deep and l^in. in diameter, were

24

drilled at

These

left the shaft-side

together,and dressingwas The

of 11 ft.

radius

a

done

by

no quite clean,and practically

pick. sinking only through

drilled in The

a

the

as

ground

inches

69."

of rock

ft. radius ; and

2 in. in

diameter, were

6Jfb. deep and The

rocks

were

when

finished diameter

were

of the shaft

1903-4.)

should

Frozen

through

Sinking

countered, en-

l^in. in diameter

Precautions

Shot-firing

taken

hard

by hand

off

Fryar, Trans. I.M.E., Vol. XXVI.,

(J.W.

What

dressed

were

where

soft ; and

was

in the limestone.

20ft.

was

4J

circle of 10 ft. radius.

side holes drilled

circle of

a

holes, 7ft. deep and

sumper

remaining 16

when

drilled in

diameter, were

outer

(magnesian

holes,7 ft. deep and

In the softer coal-measures, five sumper

10

this

22^ ft. per week.

was limestone)

2 in. in

all fired

were

the

of

rate

average

side holes

be

Ground

?

plosives freezingprocess at Dawdon Collieryexused to blast through the limestone,the natural were intensified by the frost. Great care hardness of which was the quanin placingtha shot-holes and regulating was required, tity of explosiveused, to prevent any breakage of the freezing tubes surrounding the shaft and so cause a leakage of brine,

In

the

sinkingby

might damage the ice-wall. The followingshot-firing were regulations (a) Black compressed powder must be

which

(6) Sumping Not

holes

than

more

primer,may be

fired

holes may

not

must

be

12 in.

used

be of

in any

and by electricity, be fired at

one

adopted : used than

"

for all shots. 50 in.

deep powder, including tht,

more

hole. not

time.

The more

shots than

must

three

102

THE

(c) Connect

SHO

40 in.

shaft,and

holes must

Not

primer, may

the centre

shearing-backof

rock

shot-holes

were

The

(E,Seymour Wood,

Trans.

is Electrical at

Charges Exploder

the

Electrical connection the

surface from

the sump

may

be

the

shaft

or

the

to

and

the

jointmaking wire

one

great

large

a

of

amount

straightdown.

566.)

p.

made of

Surface

between Shaft

a

The

to

?

bottom

of

point a

a

lower

and

shaft

a

end

few

of the

and lators insu-

on

yards above cable

being

injury by flyingdebris,a separate length of

the

to be

upon

connection

fired.

This

between

method

the shaft

necessitates It is"

sinking of the shaft progresses.

therefore,often considered insulated

than

more

by suspending bare wires

mouthing

charges as

degrees

I.M.E., Vol. XXXIL,

the

twin flexible cable is used to make wires

The

freezingeither by using a soda or 10 percent, of washing

Bottom

the

shaft bottom.

liable specially

1 7 to 20

cluding in-

64.

between

made

hole.

of drilling

a

Connection

at

powder,

from

FIG.

the

the

also entailed

kept

than

more

in any

angleof

an

than

time.

one

solution of 6 per cent, of caustic

How

6 in. of

dress the shaft-sides

to

not

of the shaft. Not

be fired at

of shot-holes, and

placed nearer

be used

precedingregulationsnecessitated

number

70."

be

than

more

be drilled at

shot may

soda.

G VIDE.

the side of the

the

The

*S

not

deep.

towards

Eli

side holes must

or

1 2 in. to

T-FIR

a

to preferable

drum

situated

carry at

a

the

length of surface

twin

of the

SHOT-FIRER'S

THE

relative

the straight, positionthroughout

(4)No

shot shall be fired within

drift ;

shall be

and

by mark, same

all loose stone

and hand

GUIDE.

(5)Price supplied at the

by

to

include

cost

rate

of tUd.

per Ib. ;

in drift and

drift shall

back

shall fire

(6) Contractors

keep

to

by

will be

selves them-

(8) The

filled into tubs ;

be

sides,

or

shall be dressed

shall set sufficient timber

(7) All stones to of anything except

the

length of

which explosives,

of

safe ; appearance

whole

1 ft.of the roof

shots

affected

;

all shots

the

in the

line to be

centre

in the face of the

solid stone

(9)The drift shall be driven continuously from 10 p.m. Sunday till 12 noon the succeedingSaturday; (10) Contractors will be supplied on with power drill and gear all drills and picksbeing sharpened by the company; (11) A priceper yard for drivingthe drift in

immediatelyterminate

the

contract

;

"

accordance in

a "

with and

proper The

drift

all the above

conditions,the drift

workmanlike

manner,

let to five

was

"c.

at the

men

priceof

plus the then existingpercentage, which Refuge holes,5 ft. by 5 ft. by 3 ft.,were and

were

the

full distance

let

complete at of 158

yardage driven fortnight. The maximum yds. of drift and

of shifts worked average

wage

over

who fillers,

eighthours. the drill and

or

driven

4f months, the

being 8*3, or 16-6 yds. per yardage in any one fortnightwas

one

paid

were

a

made

of

fixed wage

of the five

prepared and

method

weeks,

was

yds.

20

"

above, paid a fixed The

19

every

drift

cent.

per

refuge hole. The average number was 16, and the per fortnightper contractor ing the whole time of drivingwas not includ-

Out

filled the stones

"

yds. in

made

yard

per

27^

was

The

35s.

per week

average

20

6d. each.

32s.

be driven

to

in the wage

men

in the

6d. per

and night shift,

shift of

drift,three worked

holes,while the

fired the

at the

working

12s.

"

were,

as

two

fillers

mentioned

of 5s. per shift.

rate

the drift

was

similar to that

usually

exceptionthat all holes drilled by machine, the face being sometimes fired right were and sometimes worked and back-end,accordingas across sump the conditions suggested. Sumping, covering and flanking holes were employed and placedaccordingto the judgment of employed

the

with

hand

contractors, who

with drilling,

took

the

advantage

of

the

bedding

and

A CTICAL

PR

cleavageplanesof 13

for each round.

favourable

under

of hole

as

hours, clearing10 ft.of drift. In follows

as

were

6 ft.,drilled in 16'5

h. 11

58

drill

11

58'5

drill up Started 3rd drill

12

0

12

0'75

..?

2nd

3rd

ditions con-

drill up 4th drill

12

2

Started

12

3'o

4th

drill up

12

5

Total

time

min.

m.

57

1st drill up Started 2nd

different

drilled 6 ft. 11

drilling

Started

actual instances

"

metal

2nd

two

of

:

nodules with ironstone hole in mild blue metal was

1st hole in blue

and

filled away

stones

holes under

two occupied in drilling

times

of 24 lineal ft.

complete rounds

two

as

many

rule,

spent in settingup

fired and the drilled, occasionally

were

in the 24 the

while drill,

a

drilled were length, in four accomplished

at the rate

or conditions,

As

in

sometimes

was

hour, includingall time

per

taking down holes

This work

holes.

placingtheir

in

5 ft. to 6 ft. each

holes,of from

to 16

hours

the stone

1 05

TIONS.

APPLICA

\,

_.

jlmin-

8 min. ...

"The

valve Ingersoll-Sergeant auxiliary rock-drill of the D 24 type, diameter of drills 2 J in. to 2 in. Drills used in soft ground were of chisel section,while in hard drill used

ground, where a

rose

were

or

ironstone bit

star

tempered

were

the

laid up

an

nodules used. from

dull red

a

drill

to

were

in water

edge through to necessary

was

a

supposed

The to

a

100

of best tool steel drills,

peacock

to

body.

blue

430

strokes cubic

drills

at the

drill

the

cutting were

3 in. diameter

pipes of

with

110

at the

Three

12 in. air main

drill,running

consume

The

Air

flexible hose for connection

diameter.

encountered,drills with

in the

6 ft. hole.

drift from

the

a

were

being

per

bottom, 1 in. in

minute, is

ft. of free

air per

Saxonite,with high-tension explosiveused was detonators. The cost 2,271 lb.,which quantity used was 10s. 4d., equal to 12s. 2'6d. per yard of drift; 2,076 "96. used, making the total detonators,costing"10 15s. 9d.,were for explosive and detonators "107. 6s. Id., equal to cost 13s. 7d. per yard. The quantity of explosiveper average hole was 1 '09 lb. The greatest quantityof explosiveused in minute.

The

106

drift,equal

cost

of 21s.

for both

a

FIG.

3d. per

65."

one,

attached

to

a

make mains.

detonators, for

260

yard,

or

twin

1*35 Ib. per

yard for explosive, or

EXAMPLE

bare the

OF

yds.

shot, at of 23s.

cost

iron

wires

timbering

or

between

the

may

should

be

either be

or, if the

BLASTING

SIMULTANEOUS

flexible insulated

connection

a

14

a

2d.

detonators."

in headings, "c., shot-firing coil each time they are wanted

long

case

25 Ib. per

GUIDE.

for

from

out

to

explosiveand

Wires

a

350 Ib. with

fortnightwas

one

of

SHOT-FIRER'S

THE

IN

carried

fuse

is used wires

insulators

In the latter

in the and

headingis

SKRIKS.

on

side of the road. wire

paid

the

head-end

to

permanent

72.

Give

"

an

Illustration in

Blasting

of

this

Simultaneous and

Quarry

a

of

107

APPLICATIONS.

PRACTICAL

indicate

the

vantages Ad-

Method.

Quarry ivork it is generallyagreed that

In

Series

substantial

a

firing, saving of explosivesis to be obtained by simultaneous since each shot helps its neighbour and there is no binding / end of the line of holes. This advantage except at the extreme is further

of different exercise

and

similar ways

may

be

of work

by usingexplosives

different parts of the

strengthsin

the

A

in certain kinds

increased

hole.

same

of individual

judgment and experiencein this qualityand quantity of stone obtained

the

considerablyincreased.

method

is shown

of

simultaneous

quarrying by Fig. 65.

in

blastingin

_

.

in

Series

FIG.

73."

series

Parallel"

4 in _

2

By

66.

Give

"

METHOD

Methods

Simultaneous Various series and

FUSES

Illustration

an

Parallel

CONNECTING

OF

methods are parallel

of

FOR

FIRING.

GROUP

showing Connecting

Series Fuses

and for

Firing. of

connecting fuses for group

shown

in

Fig. 66

above.

firingin

CHAPTER

IV.

^"Jfff"\!tt\!gfSM^\XM""!/%

'499y?/9y?

BLASTING

ACCIDENTS. PAET

IMMEDIATELY

RISKS

for the

Directions

112.

of

Thawing with

and

Working Preparing

Cartridges, p. p.

117.

Lights,

Fire,

Accidents

Signalling Wires, of

as

under

higher order

are

the

by

the

of

p. 123.

mines

may

be

in the

explosive,and

ignitionby

part, owing

the part of those

engaged

the

to

in

explosiveof

ledge of know-

want

blastingoperations,

subsequent development

of their

be said, too, that the latter,the risks classed

often caused

these risks there

they

caused

most

might

Mine,

explosivesin

arise,for the

will appear

(2),are

the

atmosphere.

on

in

through Use of through Allowing

Accidents

Accidents

inflammable

skill

It

Accidents

f or Risk

"

resultingfrom

and

116.

Pot

p. 114-115.

:

(2) Those

former

Russbach

The

112.

leave

to

of

use

immediately

The

causes.

p.

(1) Those

an

Nitro-glycerineExplosives,

119.

121.

Unexploded Charges

into

odical Peri-

p. 111.

Accidents

firing,p.

followingthe

Weather,

110.

Stemming through "Bunching" through boring into Unexploded Charges,

p.

when

EXPLOSIVE.

Accidents,

p.

116.

Portions

risks

with

Detonator

Accidents

117.

broadly divided

whom

Naked

to

in Cold

Explosives, p.

p. 112.

Electric

The

a

Accidents

THE

Handling Explosives, p.

in

Explosives

Frozen

Thawing Dynamite, of

Accidents

of

use

Recurrence p.

BY

CAUSED

Classified, p. 110.

Accidents

I.

in the

knowledge

may

be

brought

a

is

same

requisitefor

little more

about.

way,

excuse

though the

as

perhaps

prevention of

for the person

by

110

THE

It has been

who

given before

"

acting as

than

rather

desired

be

greatlyto

have who

generallyemployed

are

that the statement

is

that

men

compelled to acquirethat competence understand the necessityor have not

blastingaccidents

as indicating they do

the

of

for which

74."

the

may

Explosives

by

Explosives.

and

lessen the

to

accounts

frequency of

these

for convenience sub-heads

mg

by explosivesmay

caused

accidents

be

grouped

under

Handling Explosives.

whilst

(c) Accidents

when

Firing.

(d) Accidents

after

Firingor attempting to

Describe

the

in

in

Preparing to

and

of

Sources

the

subjectto part of

low

users

Fire.

Fire.

Accidents

Explosives.

handling

Handling Explosives."A

in countries

neglecton

Stemming

Main

occur

(a) Accidents

the follow-

:"

(6) Accidents

which

by

Classified?

broadly

be

caused

Accidents

in

is the

of

sense

of prevention,

means

(a) Accidents

accidents

do

commonly recurringtype and,

various

The

Accidents

75."

legally

occurrences.

How

caused

it is

they either

sufficient

not

causes principal

will,it is hoped, help unfortunate

of fact

be

obtain. to voluntarily responsibility in this chapter contain The questions and answers of many

shot-

as

one

occupied should

so

no

know

personalexpressionof opinion,and

mere

a

whole, of

"

explosives. Those

to

firers will be the first to agree

the

shot-firers

competent

who

men

the Coal Mines

90 per cent., if not

at all as

knowledge

of the type of

most

in evidence

that sitting,

now

are

theoretical

GUIDE.

asserted

Commission, those

SHOT-FIRER'S

fruitful

cause

of

atmospherictemperature to

soften

nitro-glycerine All

them to render plasticand fit for use. as so explosives as pointedout in Messrs. Nobel's explosives, nitro-glycerine become handsomely prepared Book of High Explosives," "

112

be

It may allowed do

not

been

added

show

so

much

once

and

killed and

hot

on

induce

those

tendency

while

fires and in over plates, in authorityto see that

to

been

it

Has

76."

observed

almost

The

of the year.

steadilyincrease from decrease again in May. What

thaw

thaw

been

explosivesin should

workpeople are

perly pro-

approved methods

the shot-firers themselves breeds

contempt.

that

Accidents occur

the

with quently fre-

more

than

year

at

them

of accidents

November

in

a

warming

has been

till February

of the kind

pan

cold

during the

the safest consider you Frozen Explosives?

do

thawing To

have

persons

entirelyoccur

number

to

77."

their

of

time

one

accidents

These

months

have

?

another Yes.

which

other similar ways

Explosives

Nitroglycerine at

80

to the most

as

handlingdangerous material, and which of that familiarity beware

of

nitro-glycerine

those

as

attempting to

frequentlyinformed

and

freeze

to

been

never

subsequentlythawed.

wounded

123

have

solidification of the

by

of the fact that since 1871

Knowledge

ovens,

hard

become

GUIDE.

explosiveswhich

that

to

frozen

-FIBERS

SHOT

THE

and

found then

of

method

suppliedby

the

A proper warming pan consists explosivesmanufacturers. of a double vessel similar to that used for the puressentially pose of cooking oatmeal porridge. The explosiveis put into the

inner

The

pan

of

compartment not

must one

thawing The one

Russbach

hot

the

is shown

an

average

in

Russbach

poured other

into the outer. tion illustra-

An

way.

Fig.67, on previouspage. Pot

for

softening

or

Dynamite. pot consists of

into the other, with double

material,and

water

in any

be heated

of these pans

Describe

78."

and

provided with

two

vessels,fitting cylindrical

walls,lined with non-conducting a

double-lined

cover.

To

temperature in the pots of, say, 122"F.

tain mainfor 10

EISKS

IMMEDIATELY

CAUSED

THE

BY

hours, the inner vessel is plunged for

kept

water

and

the

to

ago

of its interior.

vessel, and

15 minutes

boilingwater,

in

end

of five hours

and

at the end

8 to 9 Ib. of

air

was

dynamite

a

time

The

could next

Accidents

Material

Frozen

53-6"F.

and

for

be

the

ture tempera-

vessel tested

was

of

described,

as

in three

softened

or

four hours.

than

may

At

87-8"F. ;

The

previouslyheated

if

5J Ib. during the

other

What

cold.

very

at

placingit

102"F. respectively

were

capacity,and

four hours, and

79."

they

After

of the walls

of the interior 105-8"F.

of 10 hours, 62-6"F. and

of the outer in.

into

the temperature of the walls when

107-6"F., and

was

cubic

the temperature

measure

of the empty

305

minutes

20

placed inside the other vessel, number of experimentswere made

replaced. A

cover

withdrawn

or

the boil,dried,

on

five years

about

15

113

EXPLOSIVE.

caused

those

handling

in

occur

by

Explosives. Another

kind

of accident

in

handlingis reportedin Explosives,from which

the 1905

of Heport of H.M. Inspectorsof many the examples followingare also taken. A contractor, having prepared the charge and fixed the detonator, is said to have jointwith the fuse by cutting attempted to make a water-tight off a pieceof the explosive(Blasting Gelatine)and applying a the cartridge caught fire the lightedmatch to melt it. When it by graspingit in his hand, deceased attempted to extinguish

whereupon

it

exploded.

Fifty-seven accidents

are

reported to

have

been

caused

during 1905 by explosivesbeing ignitedby a naked flame or and in every case of blastingoperations, spark in the course the explosiveinvolved. but two gunpowder was killed and 63 injuredby these accidents, Three persons were due in many to nonconformity with which the cases, were, usual irom

regulationenjoiningthe removal of the cap before preparinga charge.

Numerous of S.F.G.

a

accidents detonator

in

also a

occur

the candle

in connection

charge, and

with

also in the

or

lamp

the insertion

practiceof I

114

"

THE

SHOT-FIRERS

socketing,"which

be concentrated Others

of

end

enlargingthe

consists

arisen

have

extremely sensitive is

There mine

instance

an

one

A "

knowledge of

of

detonator

a

end

circuit.

manner following

other

the

be

bad

a

assuming

that

thought, the resistance The

test

circuit

the

completed

through

through

one

the

coils and

hightion deflec-

no

inferred to

repeat the test, and,

faulty,applied,as

low the

mon, com-

and

Unfortunately for

fingers. Another

low-resistance

a

to

reallywas before.

as

galvanometer lost two

man

essayed

the detonator same

low

therefore

was

wa"

galvanometer

terminals,

respectivelyto

:

their

of them

cap," justtested, gave

onlooker

An

one.

introduced

One

cell and

three

galvanometer needle, and

the

on

"

certain

A

coils.

resistance

had

liery col-

a

together in

were

through a dry

attached

two

at

recentlybeen

officials

latter instrument

The

tube"

fingers.

had shot-firing

detonators

and

cap

of the

a

exploded, and the

course

cabin," engaged in writingtheir reports.

testingelectric

detonator.

a

official shot-firer in

stuff in the "

the

to

as

propertiesof fulminate

an

in the

underground

of

number

of

stuff

occurred

electric

where

violent

"the "

three

and

eye

accident

Another

of

want

recorded

proceeded to extract by the aid of a pin. The officiallost

to

and

then

charges for

powder charge to

a

the electric fuse from

withdrew

who

enable

to

small

of the hole.

owing

nature

of

use

is the essential component

which

of mercury,

in the

borehole,

a

the back

at

GUIDE.

instead

of the "

detonator

operator tested

galvanometer, and,

him

he he

highoff."

went

detonator

a

cautious

in his

dry cell supposed to be almost exhausted. He, too, neglectedthe important precautionof placingthe

way,

used

detonator

a

in

and, testing,

Eleven

had

or

otherwise "

chanced

bridge

accidents

of these

cases

only their

own

to

way

be somewhat

piece of

of this character it

the

before weaker

capsule

copper

dangerous

follyto

blame

in

occurred

probable that

seems

of the

fullyaware

a

of harm's

out

in his eye.

embedded

became

were

its

as

"

usual, it exploded, and

than

three

iron tube

an

nature

for their

the

1905.

In

injuredpersons

of the

article,and

injuries.

RISKS

IMMEDIATELY

In two

had

that

115

EXPLOSIVE.

that

suppose

the

injured

idea of the

any

probably

was

to

reason

no

THE

danger they incurred,while in six it may be assumed, from the fact that a lightwas applied, the injuredperson was that they are explosive, but aware

persons cases

there is

cases

BY

CAUSED

80."

Detail

There

that

unaware

further

some

detonator

22

were

they were

Accidents.

Detonator

accidents

examples will, it is hoped, serve of detonators

dangerouslyso.

in 1906.

The

tiveness sensi-

indicate the extreme

to

the great risk involved

and

following

in unskilful

handling. 1. A

with

received

boy

others, had of

been

Glasgow a boy

it exploded and found

He

blew

off two

the act

of

replacingit,at

detonator

a

at

a

pit in

the

,

with

a

pin when

fingers. At Hett, Durham, in

the

a

box time

same

and

foldingup

clay pitin Flint cause,

a

man

was

for his

He

a

man's

hand, and

cuttingoff the it

pipe when

end

of

a

at

a

in

quarry

detonator

some

plained unex-

Derbyshire

to make

a

ferrule

exploded.

a

pieceof

fuse

was

beinginserted

boy picked up a detonator scrapingat the compositionwith

in it. in

A

At

a

detonator detonator

when

so

it exploded,and

exploded in

a

man's

Glasgow

the butt end

injuredhis hand Warwickshire a man colliery

it exploded,and

a

exploded,from

detonator

was

nator in Lanarkshire was man a extractingthe detocolliery it exploded,and from the primer of a missed shot, when detonator Easter Jaw Colliery, a exploded when a Stirling,

At

at

in

a

man

the wire,

it

a

a

he said, in

was,

exploded,seriously injuringhis right hand. probably pullingat the wires. At

bourhood neigh-

righthand.

detonator

a

which,

it exploded

the fire and

fingersof his

pickingat

was

box

a

put it on

loose electric detonator

a

when

stolen from

lose several

to

schoolfellow

a

Linlithgow.

causinghim At

from

and of

a

that it had to be was

merely

was

match

when

amputated.

pickingdirt

out

of

a

quarry in Gloucestershire a pocket while he was drilling at

a

hole. 12

116

SHOT-FIBERS

THE

specially risky

Is it not

81."

in

Lights Yes, such

proximity

procedure

in every

in many

82.

due

cases,

years

it not

were

and

deaths

generallycaused

is

use

either

fact

a

which

or

the

usual

lamp

from

during

and

ing prepar-

for the evidence in

1905

such

accidents caused

of accident

type

of

means

by thoughtlessnessor

of premature

cases

in

(seeChap. III.,p. 86, for

43 persons

of electrical

occur

annually assembled

39

Another

liable to

are

might easilyescape

regardingthe exploding apparatus producedby it.

Several

with

occurred

of accidents

injuryto

the

resultingfrom

be

have

number

precautionarymeasures).

to

accidents, which

of the candle

stemming

Yet official publications. seven

these

whilst

considerable

observation

or

nonconformity

to

removal

tamping charges

whilst

flame

in 1906

Fire.

to any

a

Accidents

how

recent

That

caused

were

naked

defective

a

preparinga charge.

before

State

"

accidents

injuredby

were

enjoiningthe regulations the cap

possession of

but two.

case

Seventy-sixpersons were,

Naked

Explosives?

the

argues

with

spark in the blastingoperations,gunpowder being the explosive

of

involved

to work

to

intelligence.No less than 70 by explosivesbeing ignitedby course

GUIDE.

and

ignition. It want

is

of knowledge

the effects liable

been

ignitionhave

is that

caused

by the

insulated shot-firing cable. The latter is defectively damaged in dailyuse by falling fragments of stone necessarily

use

of

or

coal.

at

the

the

a

wires of

Both

point and

same

twin cable may

lose their insulation

in contact, thus

come

short-circuiting

pected, charge having failed to explode,the line,if susis examined, the exploder,say of the dry batterytype,

line.

A

left in circuit.

being meanwhile removed,

and

Instances extent.

a

the shot

of this kind

Eight

resultingin

"

short

"

is found

and

exploded in doing so. might

accidents

three deaths

The

be related to

in electric and

injuryto

an

almost

firingoccurred five persons.

indefinite in

1905,

RISKS

by

It should

be

exploder when

who

man

allowed

Accidents "

1. At

The into

the wires to the

which

have

Durham

a

shot-hole

chambered

by

23 Ib. of

The

a

severely.

The

A

them

in bundles

cause

them

ing bunch-

"

been

cartridges been

recharged with was

pan

vided, pro-

of the accident

cause "

injured.

hole had

warming

three

"

bunched

was

cartridges^

injured.

persons

charging a

14 ft.

hole, using a of them

charge exploded,injuringone

bunching

of three

"

the

cartridgesby lying

four, a practicewhich

or

stick in the hole and

to

had

The

were

were

men

that to be

one

three

three

The

proper

Three

"

The

nected con-

frozen.

injuredmen

rammer.

charge of

rammer.

of the

in Fife.

quarry

three

wooden

been

killed and

final

a

used.

jamming

have

may

to be

never

exploder.

person

wooden

a

been

not

are

operation.

the shot-hole,and

is at

previous shot, and

a

had the

probably 2. At

One

gelatinedynamite.

but

which

with

the

avoided

through the practiceof

ramming

was

been

"

quarry.

deceased

a

occurred

Cartridges:

have

working placeis the only

last leaves the

to connect

might

carrying out

anyone

117

EXPLOSIVE.

THE

rule that the wires

invariable

an

to the

the

of

systematic method

more

a

BY

five of these accidents

less than

No

CAUSED

IMMEDIATELY

likelyto

friction in

undue

create

so

is

charging. 3. At

rammed

home

through Boring

Figs. 68 in 1900

a

first

rippingshot

and

made

bunched

home

with

killed and

one

together,and

in the

stuck

into

a

bore-hole. wooden

jured. in-

whilst

The

men

The

rammer.

Unexploded Charges :

illustrate two

69

and

in Lancashire

In the

they

person

probably frozen.

was gelignite

Accidents

been

to force them

endeavoured

One

Kinross.

cartridgeshad

Three

being

in colliery

a

fatal accidents

several

a

which

occurred

collieries.

(Fig.68), a collier drilled ;

"

fireman

attempts

charged the to fire

by

a

hole in the roof for

hole with 8 electric

oz.

of

amvis,

battery,without

118

THE

success.

He

shot and

that

it 8

told the two

the

the old one, hole

second

one killing

and

man

stallmen

drill another

they must

9 in. from

or

As

then

GUIDE.

SHOT-FIRERS

and

of the failure to fire the

hole, takingcare

not

to drill into the old hole.

being drilled

was

the

charge exploded,

seriously injuringanother.

SECTION

AT

to have

Examination

A.B.

PLAN

FIG.

69.

"

FATAL

ACCIDENT

BY

MAY

proved

that the second

that the hole drill had inches of

was

removed

so

hole

directed some

and explosive,

EXPLOSIVES

LIXNYSHAW

COLLIERY,

31, 1900.

was

only 5J

in. from

that it entered

of the then

AT

the old hole ; the

clay stemming,

struck

the first hole,

the detonator.

two

or

three

120

eight years

Some

of

evidence

as

a

incredible

almost

an

is instanced

and country colliery,

north

necessityfor

the

of

accident

an

will be

ventilation

second with

end, placedthemselves

the head

his back

to

door

the

opened his

explosionand

of the

VENTILATION

door

accordingto

Through neglector recently killed

at

dead.

over

70.

omission

that all Persons

to see

different Durham

connectingthe cable to had firer,thinkingthe man was

At

in colliery

a

testingthe cut

the

off

a

portionof

Through

some

end

the detonator taken

cover,

Northumberland

cable it

further

the

heard

he

safe positions before completing the Firing Circuit. were

the

DOORS

FIG.

2.

rolled

son

a

standing

man,

young

the moment

at

with

wire

safetybehind

the door, fired the shot and,

father's statement, the sound

The

shown.

as

for

and Two-

rock.

through a heading or tunnel driven in the the line father and son, having connected

charge,in

plan

a

seen

sections men,

in those

caution

extreme

shot-firing.In Fig. 70

in

engaged

ago

in

happened

nature

GUIDE.

SUOT-FIRERS

THE

was

found

to

the cable and

of the

cable

the detonator

make

the test the

leads,and

sent

men

Each

the shot-

exploded the charge. missed

fire,and The

of

purpose

shot-firer

a

latter connected

the shot-firer

the charge exploded,killing

on

to short-circuit

the hewer

(for the

on

leads,when

be defective.

the misunderstanding,

with

collieries.

shot

a

Two

"

in

are

re-test). it up

attempting to

hewer.

CAUSED

IMMEDIATELY

At

Durham

a

leads, the hewer

the

up

causingthe At

whilst colliery,

shot to

mine

One

time.

same

shot

a

man

missed

A

the

to

to hold

cable

in

the wires apart at the

the fact that his comrade It is difficult to say inevitable 3.

be

which

in

midland

a

colliery. the wires

between

that in

so joints,

produced through

his

of the two

with

contact

rightanglesoff

distant, perhaps,80

a

man work-

paying

off

tent inadver-

an

main

road

at

removing

the

of the cable

or

ago

time

same

pected unex-

ing drift branch-

stone

a

An

"

In the head

end,

pay

out

that

the

the

the latter towards workmen

working

were

On

face.

gaged en-

the

junction of the roads the portionof this act

bare

some

passed

was

end

a

over

set

a

either the two

of

and

one

completed

way

signalling battery,and as causingthe death of one of vicinity

Wires.

ft.,a shot-firer joinedthe fuse wires

their tools from

in

in

haulage road.

possiblya

the other

Signal

main

firingline remaining uncoiled iron electric signalwires. In

Another

the

deserved

most

men

years

arrival of the officialat the

place in

wires at the shot-hole.

some

100

or

Electric

firingline,and proceeded to in

the

his

to

punishment.

Through

at

the

shot attached

will strike the reader

holdingthe

was

occurred fatality

the

injured.

his line,requestedanother

charge and

was

pull. Having paid out sufficient length to place himself of he immediately fired the shot, forgetful safe position,

a

to

another

the connection

short-circuit would

no

the cable

shot wires to the cable

of which

cause

shot-firer,having made

connected

current,

killed.

was

being particularly stupid,occurred

as

of

a

couplingthe

accident, the

Another

the

on

batteryfor testingcable

killed and

from

charge exploded and he

the

connecting

was

fired while

of the

was

battery. On

low-tension

turned

was

use

shot-firer left the cable

A

mistake

by

being attached, through the at the

shot-firer

explode.

Staffordshire

a

the

121

EXPLOSIVE.

THE

BY

free ends

uninsulated

an

the circuit the

consequence of the workmen

of bare

through

charge

ploded, ex-

remaining in

the shot.

accident, the

cause

wires, occurred signalling

of which at

the

was

Worsley

traced Mesnes

to

the

use

Colliery,

122

THE

with

fatal results to two

1904) It

Inspectorof extraordinary.

were

steep tunnel, and This

proceeded

Mines

circumstances

for the

of the

one

LiverpoolDistrict,

prepared at

were

deceased, who

was

he left at the top of the tunnel, and to

charge and

this work

he

(vide

the face the appointed

there, bringinghis firing battery with

shot-firer, came him.

The

three drill holes

appeared that

a

GUIDE.

workmen.

of the

Eeport

of

SHOT-FIPERS

the three holes,and

stem

heard

was

going down, pleted having com-

to

shall I fire first?"

say" Which

there was violent explosion. The a Immediately afterwards evidence it clear that the shotgiven at the inquest made wires to fire the shot, forgetting, or lighterused the signalling attached to or not appreciatingthe fact that the wires were in circuit with an eight-cell battery. An eight-cell battery(say,8 or 9 volts)is not normallystrong enough to fire a detonator such as was used here, but when a bell is in the circuit and it is called in the instant

By

Report,

means

;

bell rang

was

a

breach

did not

beingattached

third

1908. 4.

out of the fatalityarising at

a

near colliery

shot, then instantly this accident

In

there

deceased whilst

use

of

Wakefield

teach

Experiencecannot

if men

shot-lighter couplingup to

serious a

reason

accidents

have

shot-firer and misses

will be work

accident

exchanged

and

his machine. is the result.

One

waits

Workmen.

man

workmen. goes

shot

least

At

"

to

and

charge for

A

seek

by the machine.

misunderstood The

learn.

through misunderstanding

fellow

a

fire.

failure whilst the other

arisen

signalwires for shotso recentlyas April,

wont

Through misunderstandings between

between

to

to the

off.

went

by

that the wires should

was

SpecialRules in that the his firing batterywith him

have

to fire the shot

quiteeasy

an

(i.e.,electric

detonators

necessary

the shot

as

"

of

occurred firing

some

and

or,

charge.

A

20

was

each other after

the

the

all that

induced,

breaking current for in switchingoff a motor.

extra

an

that it was

,

touch

"

there is an

givinga spark,as is the case experimenting with dummy

fuses) Mr. Hall found this

this is rung,

the Some

p.

of

signals

the operator starts

unexpectedlygoes

(See also 2,

cause

120.)

off and

an

RISKS

IMMEDIATELY

5.

the

Through

"(See

116.)

p.

83."

State

how

Firing The

the

to

fire,or had

been

believingthat

that it had

in the Midland

inspectiondistrict

mines

charge in

fired.

until about

passed unnoticed

occurred

years

ago.

somehow

or

other it is

fortnightafterwards, when

a

exploded spontaneously

have

some

roof failed to fire,and

rock

missed

shot had

the

have

miners

where

cases

heading

this

under

and, it is believed, unexplained accident

curious

said to

after

occurred

classed

or hang-fires,

or ignited,

(Seepp. 91-5.)

"

Fire.

to

accidents

of the

shot-hole

not

Hang Fire." have

attempting

be the result of

to

returned

A

"

Accidents

or

majority

appear

123

EXPLOSIVE.

THE

Cable. Insulated Shot-firing of defectively

use

Through Delayed Ignitionor

6.

A

BY

CAUSED

and

brought

the

down

rock. similar

A

charge which exploded while

A

of the

ground Has

84."

a

caused

Yes,

been

much

workman

was

had a

supposed

was

Charge

charge fired

a

an

in

at

by

caused

have

to

neighbouringshot Pressure

wires. the

explosion.

Mine

part of the

?

mine)

(ina Cumberland injured

level and

and

through

blown

vertical hole

upper

a

attachingthe

in another

a

collieryin Glamorgan.

a

shaken

ever

injury

through into

blew

is recorded

occurrence

youth standing

a

there. At

deflected road

from

connect

to

the

to

Northumberland

collieryin

a

its proper with

headways than

it ; he

direction,and

owing

special and to

neglecting in The and

blown-down

look

injuryto

hewer

drivinga

was

other

serious for

a firing

on

been

was

closer

shot it blew

side.

Danger traces

of

is there

in

Explosive

Coal?

unexploded charge may

cause

the

on

a

the deflection he

thought,and

through, injuringa deputy 85. "What

to

had

headways

a

find its way

the occupants and

into

damage

a

privatehouse,

to the

property.

124

SHOT-FJRERS

THE

Two

such

shovelful

small

minutes

few which and coals the

destroyed

delivered

with

husband

grate,

the

in

his

other,

out

by

the

in

The

had

present

coal. been

issued in

a

slightly

Undoubtedly

coal

work

was

the

from

that

a

burnt

from

colliery allowing is

a

in

was

explosive.

use

kitchen

the coals the

blasting which

explosives punishable

the

by

dropped

of

a

the

by

this

burning

of

house

explosive

in

children

colliery

the

to

would

The

four

the

warned

out

been

presence

of

manager

was

sent

the

had

A

fireplace,

whether

occurred

noise.

hissing

the

some

brusher

pit

explosion

injuring

cause

it

a

kitchen.

done

ascertain

whether

her in

evidently to

a

of

put

woman

a

slightly

were

was

as

fire

was

husband

or

one,

occurred

damage

some

violent

a

preceded

thrown

the

coal

the

on

impossible

the

who

dross

There

was

In

1906.

explosion

her

water.

it

but

and

;

and

hot

and

in

violent

a

woman

coal

In

coals

later

was

the

occurred

cases

of

GUIDE.

were

occupier, explosive coal

the

to

offence.

be

BLASTING

ACCIDENTS.

CHAPTER

ACCIDENTS

PART

IV."

RESULTING

FROM

INFLAMMABLE

The

Risk

How

Gases

and

in

Mine,

Coal-dust

Coal-dust

without

Selection

of

Charge

Gas,

Explosives

Limite,

Coalfield,

p.

Damp

p.

and p.

for

Watering

on

and

of

Dust,

of

Relation

Ventilation, p. 151. "

Most p.

Dr.

Possess,

154.

of

to

the

of

Selection

149.

Snellon

Defective

Safeguards and

a

Eyesight

against

Knowledge

by

the

a

in

Competent

of

Mines,

of

of

ing Prevent-

Table

Showing

in

Midland

the of

deposition

Zone,

p.

148.

from

Deputies, from

The

Excessive

149.

Blast

Explosions

of

Rate

p.

of

133.

Wales

Methods

Means

143.

Danger,

Dust

a

144.

p.

p.

of

132.

Influence

Fatalities

Dustless

Dust

as

p.

1905, of

Dust

141-148.

Watering

to

p,

South

138-141.

pp.

pp.

Explosion

1872

Coal,

Summary

Dangerous

District,

the

Preparation

Qualities p.

Midland

from

Ventilation p

142-3.

Ignition

by Explosions

Payne's

Experiments, Dust,

in

Life

Dr. of

mable Inflam-

an

Atmospheres,

of

134.

of pp.

Cause

Important 154.

Altofts

in

Explosions

Loss

Occurrence

135.

bored

Dangerous of

p.

146.

p.

in

Coal-dust,

131.

p.

of Render

to

of

produce

to

Dust

Amount

Ignition

Coal-dust,

Shot

Use

Coal-dust,

District

Inspection

for

Average

the

in

Explosions

p.

of

Holes

Recurrence

Coal-dust,

number

131.

Removal

the

of

Presence

of

Requisite

Necessary

Annual

The

135-146.

Proposed

the

133.

134.

Investigations, pp.

the

Fineness

Gases,

becoming

Dust

Dangerous

Temperature

Firedamp

in

Atmosphere

131.

ing Blastof

Occurrence

a

Gases

which

at

for

129.

p.

of

Ignition

Inflammability

Reason

of

Degree

p. of

Quantity

Range

Constitutes

130.

p.

126.

p.

of

128.

p.

What

Explosive,

131.

OF

Atmospheres.

Temperatures

Occlusion,

129.

p.

a

p.

129.

127*

p.

127.

Explosions, p.

Explosions,

Explosive,

Flame,

Explode,

Inflammable,

Dust

become

by

Dust

128.

Fire

IGNITION

ATMOSPHERES.

Vapours than

Materials

p.

THE

of Ignition by Explosives of Inflammable

Otherwise

p.

II.

Shot

Shot-firer

an

pp.

sion, Explo151-3.

Firing, should

126

THE

86.

How

"

do

Gases

Explosive Gases

and

in

mixed

mixture

and

general

with

air

is in definite

Combustible

and

gases

or

just sufficient

oxygen

combustion differs for each How

87."

Every

more

of

by

to the

increase

an

accelerate

the

This outside a

two

;

on

the

and

dimensions

which side

one

on

the

of the

plane of combustion

moves

and

;

intimate

thus

of the

two

and

substance

for instance

limit of

the

connection

"

is

has

placed

explosivemixture

an

at produces ignition

reaction.

the centre, and

divides the

are

other

two

of heat, which

amount

match

progresses

from proceedssuperficially

"

towards

combustion

combustion, The

combustion

"

of the mixture

parts

outer

reaction

i.e.,incites chemical

contact,

reaction

plane of

a

"

gas

:

reaction

highly

a

"

air,the flame of that substance

point of

Vapour

or

smallest,is accompanied

in the

the

in

burning substance

and

of gas

plete com-

quantity

explosionof

the chemical

as

;

with the extreme

in contact

this

Gas

a

the

mutually helpful,until the entire mass been heated and chemicallyconverted. a

contains

for the

"

followingmanner

reaction,even

together,both

When

when

explosion

an

mixed

are

present, and

of sufficient oxygen

helps to

advance

nor

Explosion

by the liberation of heat in turn

only

?

chemical

it is followed

furnish

they

less

vapour

proceeds in the

vapour

then

vapour.

the

does

and

cannot

which

neither

"

or

gas

In the presence or

become

actuallyexplosive

not

are

oxygen,

vapours

of the

proceed

Vapours

proportions.

ignitionunless the air with

on

GUIDE.

?

vapours

except when the

SIIOT-FIREKS

parts from

thereby forms mixture

the gaseous

highly heated

is the vary

into

products

still imconsumed in

the

gas.

proportionas

the consumed

to the

of

the

sumed imcon-

portion. The each

velocityat gaseous

the mixture

which

this

plane

advances

mixture, and depends both and

on

the pressure

to

on

which

is different for

the

compositionof

it is

subjected,the

12S

THE

90."

Discuss

SHOT-FIRERS

the

different

produce

Gases

with

minimum

the

quantity of

be

can

or

gas

(air)is

oxygen

exceeded

within

the

to

necessary

and,

case,

certain

mixture

01

by simple contact

vapour

differs in every

which

beyond

maximum,

any

This amount

flame.

Explosibility Vapours.

and

explosionof

an

of

range

certain minimum

A

GUIDE.

moreover,

limits up

to

becomes

again

a

inex-

plosive. The

each

for

narrow,

vice

and

vapours

the latter

exhibitinga of

margin

these gases

such

explosiverange

is

narrow

have

as

of

range

wide

a

explosibility owing

range,

of explosionexistingin possibilities

behaviour

coal gas

air become

and

percentages of

Explosive 8

per

attain the

of the

followinglimits

:

"

Inexplosive at

at

23

cent

cent,

per

and

over.

82 "

"

be well for

hibited ex-

respectively.Mixtures

3

Acetylene

in this respect is

when explosiveand inexplosive

gas in the mixture

gas

It may

limits differs

case.

by acetyleneand

Coal

maximum

versa.

antithetical particularly

A

and

if small, the

;

dangerous than

the increased

to

vapour

and

far less

are

and

gas

Gases

the minimum

between

range

colliery managers

to bear this in mind

when

of usingacetylenesafetylamps. consideringthe desirability

91."

What

is

It has Dust

already been

of gas

case

Explosions,

Explosion?

Dust

a

is the

explained that

explosionsan of air

presence

or

in the

essential condition in

oxygen

a

certain

proportion. A

gas

the

any

air

vapour

nevertheless, become

or

out explosivewith-

(or,indeed, any) air

powdered

fine dust, which

place of or

may,

of sufficient

presence

as

of gas

vapour

it contain

should

the

or

substance

in

a

state

or

oxygen

of suspension

latter then

oxygen.

with air and

The

partly or wholly takes explosionof such a mixture

dust is termed

a

dust

explosion.

IGNITION

92."

INFLAMMABLE

OF

chief

is the

What

129

ATMOSPHERES.

for

reason

Dust

ing becom-

Inflammable? chief

The

occlusion

for this

reason

atmospheric oxygen,

of

sponge.

carbon

monoxide

vapours

like

act

these

93."

What

Occlusion

dust

material, which

atmosphere

ignites hydrocarbons

of

the

remaining air

ignitedand exploded by

is the power

one

the

volume

Gases so

area

of

the flame

absorbinggases. varies

exposed,and

gas.

boxwood freshly-ignited

thus occluded

that chemical

solids of

of the surface

of ammonia,

90 volumes

absorb

possessedby

of solid and

the kind

Thus,

are

10 of oxygen

brought into

actions will go

and very

which

on

charcoal

intimate

would

"

part of methane

for the most

lump coal,continues especially

time.

During

occludes

to

and

tact, con-

take

not

oxygen

in

"

How

Dust

the

weight of the coal cent, in lignite. do

Dust

explosionsoccur

in the

S.F.G.

case

of

the

position comsists con-

fresh coal, for

some

methane

attain up

to

coal 5 per

of anthracite,and

occur

up

?

stages : The

and the explosionof particles, formed gaseous products. These two phases follow in such form one operation. practically dust

may

Explosions in two

The

giveoff this gas

liberation

quantitieswhich

of the

10 per

94.

after

or

"

ethane.

to

will

1J of hydrogen.

admixture. place on mere Freshly raised coal is charged with fire-damp the of which varies in different pits,but in all cases

cent,

an

Occlusion?

is

depends largelyon

and

an

burning dust.

of the

with

is

which vapour,

that furnishes with

which

explosivemixture,

It

or

gas inflammable highly

or

gases

dust

with

Laden

particlesform a with great rapidity, forming an and

other

or

of particles

present, by the minute absorbent

of dust is the ready inflammability

the

ignitionof the and readyresulting

rapid

succession

as

K

to

130

kind

Any

of dust

simplestflame, The

explosionof warming,

motion

of

the

dust

other

sparks.

considerablyfacilitated by of

a

warm

a

liminary pre-

Violent

gas.

contribute

their

to

shock, percussionor friction

the other hand, the

the

ignitedby

production of sparks can

cause

never

explosions.

dust

What

"

constitutes in

Dust

35 cubic

and

dangerous

a

that

as

little as

it is

dust than

the

more

its

on

of coal dust

oz.

fineness

the

these volatile matters

of the

of subdivision

in the coal dust has

matter

per

explosion,

an

of division

to fineness

and inflammability,

with which

ease

In addition

weight.

centage of volatile

influence

question of

a

|

productionof

ft. of air will suffice for the

that

of

amount

Mine?

a

has shown

Experiment

the

or

be

can

particleswill also

dust

unaccompanied by

per

is

air

the

the introduction

or

explosion; but, on

95.

floatingin

by electric

or

GUIDE.

SHOT-FIREKS

THE

important

an

also

same

the

appliesto

disengagedunder

are

the influence of heat. The

Commission

Minerale

the investigate

to

floatingcoal-dust 111

is evident

from

dioxide

proportionfurnishingcarbon a

of 15-5

pressure

the pressure of

of 8-9

of coal-dust

amount

monoxide

is

on

of air

firedamp and

is double

produced, the

taining con-

in the (i.e.,

combustion) develops

the above

air.

Even

when

the

figure,so that carbon

generated amounts

pressure

with

the combustion

atmospheres produced by of

mixture

a

as ignition, compared

atmospheres on

explosivemixture

an

the fact that

of dust per cubic metre

grammes

explosionshave

of coal-dust

causes

1'Industrie

de

great danger of explosionpresentedby

the

that

pointed out

Societe

the

appointed by

to

6-7

atmospheres. 96.

What

"

a

Dr. mine

Coal-dust H.

Henry dust

of

Degree

as

a

fineness

suffices

render

to

Explosive?

Payne

in

a

valuable

factor in coal mine

paper

on

the

read explosions,

subjectof

at the June

(1908) meeting of the Coal Mining Institute of America, that

only coal

dust which

will pass

through a

No.

100

states

screen

is

IGNITION

capable

of

OF

initial

INFLAMMABLE

131

ATMOSPHERES.

primary explosion,although secondary explosionsmay be propagated indefinitely by the largersizes. Such fine dust, after having been subjectedto ordinaryatmospheric air for onlya few hours, becomes largelydecomposed and

exists of

as

bubble

a

or

of constituent

carbon undisintegrated known

are

and

ash.

as

gases

whose

film is

which, impurities,

Such

dust, when

composed

after

bustion com-

suspended in

a

is susceptible homogeneous cloud with a moderate air velocity, of ignition either through shock, compression, sufficient heat or to inaugurate combustion, and the result will be classified combustion

explosion, depending upon its supply of oxygen and the space ignited, takes place. as

97."

At

what

Prof. Henri

356"F.

inflammation Dr. has

What

in

has

dust heated

produce

"

a

"

the spontaneous

in

an

experimentsin

air-bath at

of

which

he

temperature of

a

the

of

presence

will

Firedamp

Inflammable

an

of the former

to

and

112

suffice

Atmosphere ?

Coal-dust

Is

it

Gas)

possible with

a

of the latter,becomes

temperature, when

dry coal-dust,such as that in dry coalmines." 99.

described

quantity

ordinarypressure

at

on

of ignition

so Galloway proved experimentally, long ago as 1876 mixture of firedamp and air in the proportionof one

Prof.

volume

Coal-dust

(140"C.)

to

that

bustion com-

of coal.

ignitedcoal

98."

which

that the temperature of

(180"C.)in his work

Bedson Phillips

284"F.

does

Temperature

Fayol showed

was

within

of dust

?

ignite coal-dust

the volume

or

which

charged with

is to be found

ignite Coal-dust Explosive permitted to

explosionwhich

occurred

inflammable fine

the roadways

on

(without ?

Wingate Grange Colliery, Wingate on October 14, 1906, originatedfrom flame due to a charge of geloxite ledgeof being fired on a projecting Yes.

The

at

K2

132

covered

rock, probably

by in

explosionoccurred

The

been

never

caused

100.

ignitionof

an

What

"

generallyagreed

is

clean

to

have

to

been

from

apprehended

be

Shot-holes

out

had

gas

air.

and

to

coal-dust.

airway, where

intake

coal-dust

danger

failure

main

a

and

of grease

mixture

a

it is

found, and

by

GUIDE.

SHOT-FIRERS

THE

in

bored

Coal? There

is

nearlyalways

holes bored the

in coal, the amount

coal, the inclination

the hardness

depending on

of the

left in

of coal-dust

certain amount

a

hole, and

the

of

bestowed

care

cleaningit out.

on

According to

the conclusions

in coal and

is certain smaller

ignited.

in the

extent

carbon

of the

the Commission

ramming

danger

firedamp present

is also

present

complete detonation,

mix

of probability

to

a

the carbon

detonation

of

and

ducing pro-

ignitionof

be

the

cartridgesso

the contents

hard

101."

coal dust

with

is it that

How

dangerous or

It has

Dust been

provided they

to

than

used

envelopes and

be abandoned,

be increased.

the

presence

are

more

of

Gas

in

that

all known

explosives,

ignite sufficiently largequantities, coal-dust.

It is

solelyin regard

dangerous quantitythat they differ from one difference,as M. Bichel points out in "New

to the limit of the

This

in

practice

others?

explode both pit-gasand

another.

the

Explosives

some use

break

to

should

should

conclusively proved are

of dust ; that the as

cause,

ing in the stand-

that shot- holes bored

cleared carefully

this

from arising

accidents

that the size of the detonators

and

any

the

cause

may

the thereby facilitating

recommend

coal should

and

case

temperature

monoxide,

blasting

damp.

In view

of

This

of

case

present increasingthe fire

these conditions

the mixture, in which be

to

of

the contents

with coal-dust in shot-holes bored

mixed

that miss-fires under

of deflagration

sion Commis-

by the French

that

drawn

were

become

cartridges may

carried out

tests

some

IGNITION

Methods

of

students

ought whilst

5

gelatinedynamite mixture

different

length

dynamite

1

of carbonite

fails to

explosivesdepends duration

and

between

No.

or

mining For

ample, ex-

powder, blastinggelatine, sufficient to fire a

are

given

for example,of firedamp and coal-dust,the explosion,

of

1 ,000 grammes of

of black

all

considerable.

possess),is,however,

grammes

which

work

Testing Explosives" (a to

133

ATMOSPHERES.

INFLAMMABLE

OF

detonation

The relative

it. ignite

time

duration

and

(viz.,ratio

ratio

flame, afterflame

of

of detonation,

their rate

on

safety

beyond it),and

of flame

temperature. M.

Bichel

follows

as

Thus

:

"

showing that

the least safe

but

flame

that

of

safer

of all "

the

range

as

safe

safe !"

times

safer

regardstemperature.

as

the time

explosivesdoes

of afterflame

length

to

as

of flame, 100

explosivesoutlasts

degree than in the contrary The

duration

to

as

times safer than

time, 5-6 times safer

ratio,and twice

to afterflame

The

explosiveis four

the safest

to detonation

as

of flame, 36 times as

the least safe

explosiveswith

the safest

compares

of detonation, in

so

less

much

a

case.

therefore

appears

be

to

the

mining deter-

factor in the

ignitionof firedamp. generalsafetyexplosivesshould show

In

of detonation, and

given as

pressure

the

minimum

a

of

none

;

detrimental

effect of

by the others, however

102.

What

"

"

One recent

is

Charge

of the most researches

for every

the

should

"

cannot

of flame at

certain be

of

limits,

of

the

Expression

?

fixinga

given explosive. It

a

balanced counter-

important practicalpointsbrought is that

rate

favourable.

meaning

Limite

exceed

of them

one

minimum

duration

lengthand

these

a

definite maximum

has been

out

by

charge

proved experimentally

134

SHOT-FIBERS

THE

that there is for each will

GUIDE.

a explosive

certain

maximum

which ivcight

failto ignitean ordinarily Victor

M.

1903, termed

103.

a

this maximum

What

"

in

Watteyn,

atmosphere. explosive valuable Paper read in Berlin

by

in

weight the charge limite.

is the

annual

average of

Explosions

Coal-

and

Firedamp

Life

of

Loss

dust?

Taking

the three decades

periodduring which the number

much

of persons

Kingdom)

increased

the

"

ending

with

104.

To

"

427,017

from

60

1904,

133,306,485

the

It is said,on is due

mainly

in the

majority of

to

been

decade

a

"

opened, and United

the output

232,411,784

to

loss of life from

statute

explosionsin

the

174, and in the third

lives.

is this

what

have

ending 1904

681,683, and

to

256, in the second

was

and

employed underground (in the

annual

average

first decade

deeper mines

from

of coal also increased tons

beginning1875

attributed

Improvement

hand, that the diminution

one

the fact that coal mines

?

in loss of life

gunpowder has been prohibited by the Explosives in Coal Mines

Orders. On

to the increased

the

and rules

"

No. the from men cause

South

effective ventilation

of

of the

generaland special explosives.

Explosion 1902

period

a

risks until the

for example, coalfield,

and explosions,

was

had

of

tivity inac-

ceased?

beginningof

1905

remarkably

free

since

lost their lives at

explosionsat

the

from

September 3,

Wales

has been

use

assume

you that

:

that

explosives improvement being

safetylamps, more

the detailed

Would

From

of

use

effect

no

rigidenforcement

more

to relating

105.

opinionis stronglyheld

little or

had

has legislation due

the

the other hand

small. Gowerton

May 25, 1901, when seventy-eight Senghenydd, the loss of life from this

Yet

in the first half of 1905

and

Clydach

Vale

and

there

were

Wattstown,

136

THE

depending

the

upon

and

high explosive local,due strictly

be

chief

6. The

dust

nevertheless material

dioxide

under

8.

largean

amount

at the site of

will

assisted

called

of such

9. When

formed

travels

toward

a

air,must most

follows the

course

monoxide

to carbon

will be found

gation. propa-

in the coke

by the depositof red hot cinders,

and

the

to testifying

bustion. incompletecom-

explosionmay, and generallydoes, distil so is impossible of gas that complete combustion

local

an

combustion,

at

ing vary-

temperature greatly

a

sufficient oxygen

present,

intervals,whereexplosionsat irregular oxygen

is available, such for

passages

rock

have

side

as

tracks

occurred, and

explosion,either primary

dead

generatedby

end its

of

entry

an

expansion and

almost

incredible

rise in temperature,

various

hydrocarbons from

even

are

at or

quently fre-

heat

or

secondary,

or

passage,

momentum

the causes

sufficient to

pression coman

distil the

and the ribs of the coal itself,

potentialfar

supplementingit with

a

through radiation

expansion.

and

dust, in

of gas and

mass

areas."

flame

such

this

condition

a

falls of roof "

of

oxygen

extinctive,and prohibitsfurther

junctionsof airways, widened cavities where

supply of

of the carbon

adequate atmospheric

ever

that

the intake

by

when

were pointof ignition

develop into

monoxide,

airwaysfurnishingthe

or

and this distillation,

of the

excess

dust,

explosion may

is greater than

its continuous

feed, and

to

stages of ignitionand in

is free from

explosionis carbon

combustion

the air wave,

initial

The

dust

conversion

splashing,or crusts, by

a

receives

the air

Evidence

carried

coolingeffects of

of

place.

the walls.

which

renders

the mine

takes

to the

follow those entries

airways,the

return

combustion

the

explosion,while

upon

ignited,its supply

the intake.

by feedingtoward 7. A

which

explosion,

or

effect is obtained, and

which

and

methane,

combustion

as

of dust

within

product of

expansion

whose

volume

the space

"

"

GUIDE.

and gas alone is ignited,

5. Where a

-FIBERS

results will be classified

4. Such

oxygen,

SHOT

in

excess

of its losses

of liability

10. The

combustible, i.e.,the divided

matter

is

the

by

of

sum

explosive,the distinctively of methane

amount

its percentage

quotient of

the

that

is

of volatile volatile

of

percentages

the conditions

coal dust alone, under

While

11.

explosion increases

to

fixed carbon.

and

matter

dust

its percentage of volatile matter

directlywith

almost

coal

any

137

ATMOSPHERES.

INFLAMMABLE

OF

IGNITION

of

presence

enumerated, smallest

the

even

to materiallythe susceptibility

augments

ignition. 12. On that

no

its gaseous

"

of air,it is highlyprobable elasticity

speed

with

which

to far distant

be extended

products,may

of the

explosion,through

dust

a

attained

been

conception has yet

proper

incredible

almost

a

of the great

account

portionsof

the force of initial expansion,properlycalled the

mine, under

percussivetheory." 13.

explosionin

to

in barometric

Changes

far

so

of settling

a

small

quantitiesof

gas

of air than

when

into the

if it is

even

ventilatingcurrent in

concentrated

granted that

A

14.

such

is falling,

such

but

;

a

place.

one

low

a

from

diffused in the

when

allows

barometer

greater occlusion,it also allows easier ventilation of such

liability

of methane

safer infinitely

are

affect the

the barometer

possibleaccumulation

any

in the roof rock

Moreover,

they allow,when

as

dome

current

only

pressure

sion for the diffu-

occlusion.

mine

may

until the air current

be over-ventilated

velocitythat it stirs up dust, ignitionwhich might take place and a

would

and

otherwise

has

feed any

slight

die out.

(See'

Q. 1U.) The

15.

air

difference in the amount

punchers or

electric chain

depending machine

man,

class,creates 16.

show

The that

that of

the nature

on

that it cannot dust

more

results of the

loose connection.

a

machines

is

be said that

than

from

cloud

so

slightand

of the coal and

by either so

able, vari-

the skill of the

either machine,

as

a

the other.

experiments with

danger

stirring up

of real dust made

electric of dust

electric

wiring is

from

a

ignitionof no

broken

dust

greater than air

pipe or

a

138

THE

Coal dust cannot

17.

used

method

results, but

GUIDE.

SHOT-FIRERS

be made

wet, in the usual

by SuperintendentButler then

even

it is

"

is not

While

the

an

careful

most

infinitesimal

an

it is

detrimental. positively

18.

the

prevention,"and

of

ounce

is indicative of the best

hypotheticalif

system of wateringis not merely

The

sense.

portion of the it

questionwhether

open

(See Q, 107.)

th" abolition of all explosives, recommended as

Belgian authorities,appears

by

and

impracticable in this country,* yet the greatest field of investigation lies along that line, and only those explosivescarefully now to be uniformly prepared, by well-known tested, and known should be used. and responsible manufacturers 107.

the Explain Experiments

"

evidence

on

the

in mines

(2) the

;

to

means

in

Mines

on

dust

to

sittingtook

now

prevent such

prevent the extension

of

towards

of

(1) the part

fosteringexplosions explosions; and (3) such explosions. In

of the failure of the Commission

consequence

Dust

during the earlypart

engendering and

means

Coal

Altofts.

year,! their inquiries being directed coal dust

obtain

to

mous unani-

expressionof opinion from witnesses as to the efficacy methods the numerous suggested for allayingexplosions,

of it

at

Royal Commission the subjectof coal

played by the

of

Objects

British

The

this

unnecessary

decided

was

to

institute

experiments in

settle if to this

Mr.

G. Garforth, chairman

W.

Colliery Co., Atkinson

Ltd.,

Mr.

of Messrs.

dimensions

and a

Pope

"

concluded

character

*

maintained U.S.

America.

that

Mr.

W.

at

an

H.

for South

for the

Royal Commission. an

installation of

carrying out extended period,

for

necessary over

regard

Pearson's

(H.M. Inspectorof Mines

large scale, and

be erected and

definitely

exist in

Galloway,

Wm.

selected to advise the

advisory committee

experiments on could

Hall

Henry

were LiverpoolDistrict)

the

Prof.

opinion as

to

(H.M. SuperintendingInspector of Mines

Wales) and This

of

possiblesuch differences important problem.

order

an

inclusive cost of t 1908.

"10.000,

IGNITION

and

OF

the Commission

should

be raised

139

ATMOSPHERES.

INFLAMMABLE

accordinglyrecommended

by the Government

and

this

that coal

the

sum

in

owners

equal proportions. For

various

allocate the

to

the

of the necessary

basis,to which It

funds

to

be

September 4, 1908, and September 4, 1908. In view dust

the

of the immense

theory which

has

how coal dust absence

there

could

settingup

to

the

and

28

August

"

Eeview

of information

during the past

opinionsas

"

the

to

dangerous explosionin

a

of

the coal

on

Guardian* Colliery

exist two a

of

experiments,

Coal Trades

accumulated

been

tonnage

a

galleryat Altofts, full

first series of

amount

"it is difficult," says

years,

a

Iron and

"

raise the

to

subscribed.

erect

the

eventually

levy on

a

Guardian" ''Colliery

in the

found

of

and

decided

of

means

all the collieries have

particularsof which, and may

by

ultimatelydecided

was

Britain

of Great

unable

were

this purpose,

requiredfor

sum

Association

Mining

whole

however, the Government

reasons,

25

stand under-

to

abilityof in the

mine

of

fire-damp. Yet there is a considerable body of in spiteof the expert opinion still opposed to this view, even largequantity of experimental evidence in its favour and the reports of the Royal Commissions Austria, all of which It will be these

of the

would

exist in

theory have

be

answer

to what

extent

the

moment

that the scale.

theory of coal-dust explosions.

The

the

blown-out

been

followingcriticisms first place,they state that

made

under

in the most

the

objectionis that stir up

September 4, 1"08,

pp.

quantity of what

excess

we

further were

say,

454-5.

The know

do not

the dust in

explosion. A

experimental gallery,they

The

in

tions condi-

same

dusty mine.

experimentshitherto performed

*

The

offered the

shot may

preceding an

why

reasons

unanimously accepted. In the

even

this latter

to a

examine

experimentsis usuallyfar

normally present

and

England, Germany

ordinaryworking coal-mine.

an

in the

obvious

a

been

experimentshave

of dust used

was

not

experimental evidence.

as

at

have

of this

opponents

none

the

therefore, to interesting,

results

of the

endorse

in

on

a

mine

objection too

should

small be

as

140

THE

SHOT-FIRERS

GUIDE.

and should be from 200 yds. large as an ordinarymine gallery, to 400 yds.in lengthor even longer. Then, again,with regardto of

fire-damp. It has been urged that there absent in many of certaintythat fire-damp was

the absence been

no

Of

previoustests. of

absence

it is difficult to prove

course,

fire-damp,especiallywhen

the gases occluded

on

comparatively easy

to

Prof.

coal dust,

by

Bedson's

recalled.

are

the presence

prove

of any

quantity of fire-damp by the simple process galleryair before each experiment. Quantities for chemical

minute

too

detection

would

the

of

the

complete ments experiit is

But

appreciable testing the

of occluded

scarcelybe

has

of

gas

practical

in connection with colliery workings. significance of the previousexperiments,and notably Although many "

of Mr. H.

those

Hall, had

come

very

taken a

deductions

drawn

was by these objections

of

source

year

every

from

them.

the observance

of coal dust

largeproportion of

a

form

common

20,000,000 shots

some

of

againstthe legitimacy A

the unlikelihood

danger,seeingthat in this country,

to

stillraised

these conditions, objectionswere of the

near

them

being

are

fired

being in

are dry and dusty mines, and yet explosions comparativelyrare. of 1894 made The Royal Commission the obvious reply to "

this

objection.

of circumstances

combination the "

working practical When

we

consider

controllingthem The

In order to set up

main

in

factors, so

of

a

what

an

which

explosionthere must probably rarelyoccurs

as

a

in

mine. these factors are, the difficultiesof

practicalexperiments far

be

knowledge

our

at

becomes

present

obvious. goes,

are

probably the following:

"

"1.

The

chemical

character

of the dust.

physicalcharacter

of the dust.

"

2. The

"

3.

The

quantityof

"

4.

The

distribution

"

5. The

"

6.

"

7. The

"

8.

The

The

nature

dust present and its suspensionin the air, of dust

of the flame

positionof

the shot.

dimensions

of the

condition pressure

of the and

in the

gallery. causingignition.

zones

gallery.

atmosphere as regardstemperature, humidity.

IGNITION

The

"9. "

10.

The volume

the material

that quitepossible

It is,however,

current.

its relation to the volume

of air and

conductivityof the gallery.

141

ATMOSPHERES.

the ventilation

velocityof

Heat

"11.

"

INFLAMMABLE

OF

amongst which yet appreciated,

walls of

forming the

there would

some

of dust.

are

other factors not

be inclined to

place

caused by the initial compressionwaves The have concussion, to which we already alluded above. time factor is also by no means a negligible quantity,especially in connection with the heat conductivity. the

"

heatingeffect due

The

to

primary objectof

considered

the Altofts tests, therefore

be, in the first place,of

to

They have been designedwith the objectionsthat have been carried fail to

out, and

conviction

carry

coal dust

which

a

with

confirmatory character.

specialobject of overcoming made to the experiments previously

the

results

the

already achieved

regard

to

the

cannot

important part of any appreciable an originating

in the absence play,even and even gas, in intensifying

may

quantityof

be

must

explosion." Having

the report in the

accordingto

mentioned,

of which

108."

The

The

Coal Trades

Eeview

"

lars particu-

answer.

have Dust

been

Danger

suggested in

?

danger in mines 1. Watering. 3. Stone

the next

principalremedies

2. Dustless

Iron and

Principal Remedies for allaying the

What

three

"

preventivemeasures, investigate

to

quoted in

are

Mines

is in itself explosive,

conductingthe experimentsnext proceeded,

the committee

above

the fact that coal dust

established

suggestedfor allayingthe

dust

:

are

"

zones.

dust

zones.

first method

is

for,while disliked, generally

it has many

back good points,its effect on the roof of the mine is a great drawinvolve the danger of falls ; and not only does watering treat every of roof, but it is almost impossibleto effectually crevice and

dust-laden

comer

of the mine.

142

THE

SHOT-FIRERS

GUIDE.

it were regard to the second suggested remedy, even dustless zones ful), (which is doubtpossibleto maintain perfectly In

it has stillto be in

effectual preventive

an

explosion.Experiments have shown that a quantityof dust will serve to propagate an explosion,

so

to be efficacious these

be

dustless. practically perfectly There

are

of

cases

small

very

proved that these

remains, then, the

of the stone

dust

would, in any

zones

dust zone,

stone

that is now

zone

requireto

case,

and

it is the effect

attention receiving particular

at Altofts.

The

of

presence

claims, exerts

certain amount

a

of stone

coolinginfluence

a

dust, Mr. Garforth

the blast, and

being atmosphere.

on

on

stirred up also serves to dilute the coal dust in the Being heavy it also offers a decided resistance to the passage

that Prof. explosiveblast. It will be remembered dust the idea many Galloway originated years ago that stone of safety.It has yet to be determined might afford a means of

an

to what

extent

to dilute the coal dust with stone

it is necessary

dust in order to render

it harmless

Courrieres

the recent

; at

certain conditions 46 per cent, of stone dust proved effective. This point, however, will be disaster it was

ascertained

experimentswhich

dealt with in the further

109."

Does

the

air

be doubted

It may

explosions.Mr.

Ash worth

could saturate

steam,

barrier in front of

say,

26

p.

have

a

gas

Mr.

an

oxidation *

See

moisture

explosion. On process

;

Appendix

and

taken no

further

ing except-

of water

vapour,

exercise any deduced

from

or, trolling con-

the

Wingate Grange that air sion againstthe extenprotection at

other

moreover,

III. for

(Transactions

to placea sufficiently

5 per cent,

the

stopping

explosion.Koughly estimated,

Ashworth

was

to

?

of water,

form

no

air-current

over

out

serve

of

means

pointed

193) that

observations hygrometrical

of

an

it may

as

damp, Explosion

cubic ft.,before it could

influence.

with

far

so

place.*

to take

are

moist air is a

dust

to contain

grainsper

saturated

of

has

an

or

Mine

a

whether

I.M.E., Vol. XXXIII.,

air would

of

spread

the

prevent

in

-spraying,

water

make

that under

in

hand, it assisted in the

addition,the explosion

particularsof

later

experiments.

144

THE

either

to

the

Stokes, H.M.

SHOT

FIXERS-GUIDE.

of naked

use

lightsor

Inspectorof Mines, in

attributes the

decrease

in the

defective

lamps.

his report for the year

number

Mr. 1900

of

explosionsnot to but to the watering or to the use of permitted explosives, of safetylamps, these comprising 67 per cent. increased use of lights. of the total number Referringto from

occurred

good

the

period 1888-1892, during which explosionof fire damp, Mr. Stokes says

result cannot

mines, for

many

be due

mines

to

Report, p. 30.) Only one explosionhas

outbursts

been

of

caused

162,904

"cent,

recentlyas

than

gunpowder

were

TABLE

more

so

and

be classed gas

this

1905 the number

in 1902 and bobbinite

This

occur."

fiery, (1900

notwithstanding

of shots fired

was

of the total number

63 per cent,

(44 per

as

the

by gunpowder during

the 34 years referred to in the table, and the fact that

"

:

scarcityof fire-dampin

in the district would

occasionallyenormous

.and

the

death

no

cent,

gunpowder,

19 per

bobbinite). IX.

"

Cause and Showing the Number Inspection District from

in the Midland

of 1872

the

Explosion Fatalities

to 1905.

IGNITION

111.

the

Does

"

of

use

from

Rule

12

it "is

"

of such

Gas

inflame

it cannot

Explosive on watering

Permitted

a

exemption provide that the assumption that

145

ATMOSPHERES.

INFLAMMABLE

OF

or

nature

a

Dust

"

(Gen.

?

(h) (2)).

Inspectorof Mines, in his Report the circumstances on attendingthe explosionwhich occurred Feb. 20, 1908 at Durham, on Washington Glebe Colliery, the generalinterpretation of the on (Cd. 4,183),comments Coal Mines Regulation Acts and Explosives in Coal Mines Orders, and states that a claim of exemption from watering well be, however, that shotIt may be upheld. cannot in this light, firers look upon and do not permittedexplosives such as they would take if using gunpowder. take precautions This would be a veritable playing with fire. I do not altogether share the view held by some of my colleagues, that the in recent decline in explosions due to the years is principally employment of permittedexplosives.I think it is more bably produe to the increased knowledge of the causes of explosions it is insisted and unless that no on generally, explosive be used unless where it that givesoff flame or heat should ever be perfectly safe to fire a gunpowder shot, the use would of Mr. J. B. Atkinson, H.M.

"

permitted explosivesmay than and

of the

become

a

of

source

danger

rather

safety. Safetyshould be sought outside the shot-hole

should only be looked upon, permittedexplosives additional safeguard. In the north of England within as an 16 months four explosionsdue to permittedexplosives have occured, viz., at Wingate Grange Collieryon Oct. 14, 1906, and causing the death of 24 persons ; at due to geloxite, Urpeth Collieryon Dec. 17, 1906, due to westfalite No. 2, Nov. on causingthe loss of four lives ; at Whitehaven Colliery and the 26, 1907, due to saxonite,causingthe loss of five lives,

present

use

case.

England

and

or

This

is

is concerned was

heat

of

flame must

record

worse

than

universal.

The

use

of

attended

far

so

occurred

ever

alwaysbe

dusty mines, but S.P.G.

a

when

as

the North the

use

of

of gunpowder

explosivesthat give off with

believes that with

a

some

risk in gaseous

thorough appreciaL

146

THE

SHOT-FIRER8

tion of the conditions adherence

If the main

small.

very

which

danger may arise the risk may statutory regulations

the

to

under

roads

this risk would

coal-dust

GUIDE.

of mines

usuallybe

and

be made free from

kept

were

confined

to

district,

one

then, having regard to the fact that the danger

and dust

at the

in

state

a

working of

face is so

capable of maintaining

currents

less than

division

fine

very

much

when

coal

from

it is present swift

(accompanied by

and

rigid

a

carryingforward

air-

cloud)

a

,

dry mines in blastingmight be permitted at the face in some the first working of the board-and-pillar system and in long wall workings,with some provisionas to watering or removing different to those

somewhat

dust

with

(Ti)(2),and

the

to

cloud

of a possibility

the

to obviate

as

provisionas

some

in General

Rule

12

plantingof

shots

so

contained

of dust

being raised

from

the floor."

1 12.

"

what

At

is Dust

rate

Henry Hall,I.S.O.,H.M.

as

before

that

pointedout

ground Under-

has

recently*

Inspectorof Mines, useful

any

suggestionscould

of coal dust, so

the treatment

to

on

?

Roadways Mr.

deposited

render

to

as

it

innocuous, it

idea as to absolutelynecessary to obtain some which dust is depositedon underground roadways.

the rate

was

of

experiments carried

some

shown

that

something

inquiry,it

has

dust

carried in eight hours

were

been

in furtherance

out

measurement

carryingthis

dust

for dust it was

and

of the dust

A third method

Annual

ft. per

point the

a

the

gramme,

results show as

that

it travelled

of measurement

quantityof

was

dust

there

above

where

The

of air

aspirator, 0-002,

was

the

on was

the

ments measure-

bellows

depending

result

a

current

minute. with

made

were

general meeting of Edinburgh, September, 1908. *

velocityof

95 cubic

0-0005 These

arrivingat

The

at

J Ib. of coal

that in 3 cubic ft. of air the amount

and

measurement.

of

was

in the air

found

0-001, 0-002

diminution

taken.

was

As

of the

like 11

past the

be made

point of a

gradual

outbye.

adopted,with

depositedon

the Institution

of

the

the

object

floor,sides,

Mining Engineers

at

IGNITION

it

-"c.,as 'Flat

porcelaindishes,of

which

were

main

return.

from

These

(about600

shaft

the

"

the

come

the main

bottom

road

of the

minute

of

dust

a

and

when

12 ft. in width

and

the

of

area

of dust

air, startingwith

J Ib. of dust per ture explosivemix-

an

further

it would

sheet

this 3,000 ft. of

render The

assumed

If it be

clean

a

the floor and

of the shaft and

that

road is requiredto make

the shaft than

day).

velocitywas

to

on

3,000 ft. inbye.

"

near

the

the

So that at least this quantity

require83 ordinary working days to road absolutelydangerous. (Note. will be thicker

down

grammes

the bottom

between

tunnels

that this road averages lineal foot of such

and

the shaft each

passedup

being depositedeach working day

ledgesof

passingthe partlyfrom the

passing up

that is,18 Ib. in six hours.

ft. is

have

tubs

air each

the

on

dust

that at the shaft bottom, where

the

passing in

225

The

is 150 sq. ft.,something like 1147

road

were

of coal

tons

results show

The

the

two

operation for periodsvarying

intake must

partly from

and

of

used, two

intake and

separate days.

two

on

the main

pointson

screens

the main

in

were

current. ventilating

of 1-12 sq. ft.,were

area

an

placedat pointson

8 to 10 hours

two

the

being carried along by

was

147

ATMOSPHERES.

INFLAMMABLE

OF

deposit,of

course,

in.)

Hall Colliery. interesting experiment was made at Garswood The screens the downcast at this colliery are near shaft, and a considerable quantity of dust is made in the process of of which finds its way back into the mine along some screening, An

with

the ventilation.

fitted up

at the bottom

put in the main around is to wash

frame.

Quite With

obviate

a

this,water-sprays have

of the shaft,and

airway

several

are

the dust from considerable

40,000 cubic

also

little distance

a

this frame

which

out.

To

the air

from sprays,

as

air

frame

has been

the shaft ; the

it passes

of dust

amount

ft. of

a

been

ranged ar-

object of

through the

is thus

washed

passing through, 7J

Ib.

of a (weightafter drying)of dry dust was recovered by means tank in 14 hours, and probably as much more settling escaped

collection,which

means

15 Ib. in the 14 hours. .screens

and

partlybe

that the sprays The blown

dust would from

the

washed

down

14 Ib. or

originate partlyat the in the pit shaft. trams L2

148

SHOT-FIRERS

THE

The

total

quantityof

dust

findingits way large,when with one

be very

must

GUIDE.

back

ways to the road-

on

frame

only

much

so

be recovered.

can

These

of accumulation

the rate

go, it

it follows

that

when

the shafts and

before it starts

ventilation

Describe

113."

brushing and

of

of the quantity

have

not

to

amounts

made

been

present

get back

to

any

into

the

poisoningthe

to

duty. of

preparing

Hedley recentlydescribed

M.

A.

method

a

dust

as

the actual facts ;.

roads

ought

far

so

Dust-

a

Zone.

less Mr.

its

ing ordinarywork-

estimate

screens

on

under

further ; but,

the

once

idea of

gettingan

far exceeds

thoroughly clean, to keep them so insuperabledifficulty.Allowing workings from

of

common

depositedday by day

of dust and

be carried much

clear that the

seems

the view

of dust in mines

conditions, should

they

with

experiments,made

effective combination

an

had

watering which

been

employed by

Mr. R. Crombie. He

would

cleared of dust served

as

side, if

on

the road. deemed

It

at such

current ventilating

area

zone

of the

the nature found

roof and

treated

was

that

layerson

wet

to the

distance

from

the roof

great

case

attached

was

of

a

of

as

was-

obstruction

an

strong

the brattice cloth

or

thill would

be carried out

canvas

time

same

the full width

across

by water-sprays

raised, if carried forward

meeting the

water,

to such

current

by

with

an

was

dust

impunity.

the air current,

obstruction, be moistened

floor,whence, with the bottom

fixed,

extent

allow, and

operationof brushing the

the

sides could

at the

weighted by attachingpiecesof

When

roof

seams

in

and, in the

be

edge.

a

be

requiredto

inbye side (or the autbye to be treated, a piece of

offeringtoo ;

should

its lower

to

the dust

dust

the

this

without

canvas

which

the roof timber,

hung

was

necessary,

of air, the

then

On

airway.

edge to

ft. was

300

haulage road,

cloth, thoroughly soaked

along its upper

timber

lengthof

a

airway) of

return

brattice

to the

main

a

intake

an

a

that

assume

as-

it

was

from The

the

light

would, and

on

fall in

dirt it could

be

IGNITION

removed

OF

and filledinto

Possibly

wet

further

It

with

to him

depended

It

acting as

so

114.

"

Is

of the water

possible,

Dust

Donald

this

and

sides

roof

the

one

throughout

required purpose. driven

was

ment treat-

againsta

to the dust and

on

disturbingagent.

connection

in a

Mine

with be

to

the well

too

?

M.

D.

Stuart

in

Explosion (Trans. Inst, M.E., that

better

possiblethat

beingthrown

for

Danger,

ventilated Mr.

give

of water

spray answer

agitatingand

it

even

the

was

the fact that the dust

on

an

completed.

(Mr. Hedley) that the efficacyof this

surface,instead

wet

might along

matters.

continuous

a

operationwas

sheets

brushing operation,would appeared

the

stretched

improve

sheet, treated the

of wet

canvas

149

ATMOSPHERES.

tub when

a

succession

a

results, and would

INFLAMMABLE

had colliery

been

discussingthe Wingate Grange Vol. XXXIII.,

worked

for

pp.

183-4) noted without

40 years

over

of coal-dust and yet an explosionhad explosionor ignition Originatedin coal-dust in the main intake-airwaywhere over .any

26,000 cubic "could have dust

ft. of air

passingper minute,

was

existence.

no

The

from

whether

explosion,or

where

whether

inquiryarose,

possessed explosiveproperties during

immunity

and

the

they

gas

the coal-

40

of

years

of

were

recent

development. The had

effect of air currents

been

been

often

observed, and

largelyabsorbed

mines

both

danger stage It also

was

minute

;

but

here

the

period of

a

coal-dust

might

extend

and over

40

moisture years

;

withdrawal

roads have

must

but

in

some

of moisture

many

years

year

the mine

before

the

reached.

appeared that

ventilated per

in

depositionof

gradual,and

were

sweeping through haulage

by

to

up

a

fan

a

recent

producing 102,000

subsequentlythe

new

fan had

cubic

was

quately ade-

ft. of air

yieldednearly

quantity,namely, 193,478 cubic ft. If this increased intake-airways, quantity of air was taken through the original

twice the

the velocity of the currents

must

have

been

considerablyraised,

150

THE

GUIDE.

SHOT-FIRERS

acceleratingthe absorption of moisture, increasingleakage tubs, and

the

from

One

haulage roads.

the

to

effect of the increased a

of coal dust ; another, the increased after exposure

Prof. P. P. Bedson.

coal-dust

of the explosiveproperties development, and this was

explosion occurred

mines

had

from

70 to 100

with

; but

years

alteration

no

with

worked

been

and

the

by the

of recent

fact that

the

in

explosionfor

from

immunity

his

Both

Collieries.

Timsbury

dimensions

been

circumstances

the ventilation

in the

observed

the ventilation.

similar

found

have

with

changes in

the Camerton

at investigations

been

of coal dust

suggestedthat

might

consistent

after the

(Mr. Stuart) had

He

had

circumstances

These

supply

abundant

sensitiveness

the

would

ventilation

more

air currents, which

to

depositsin

coal-dust

dry intake airways and

be

therefore

adding

largelyincreased

was

intake

of the

airways,

whereupon explosivepropertiesdeveloped in the coal dust extensive in the haulage roads, and distributed explosions occurred. of mines

ventilation

The

had

claimed

principalattention

with limitation of view past legislation, the time

of gas ; but

disastrous

more

even

evident at

a

gases

that while

had

energy

when

come

Considerable

serious the

one

ignitegas

or

danger

main

labour

had

coal-dust

of

were

air-currents

loaded

tubs

at

been

mine, that needed

now

in the

years

many

subjectsof

dust-

would

tighttubs

receivingmuch to

not

the

tion, atten-

coal-dust

overlooked.

velocities of 400

in travelling

time

the whole.

spent for

; the

noxious

same

obtainingexplosivesthat

in mines

have

the

at

the potent relations of air-currents

questionappeared to With

harmless

tions creatingexplosivecondi-

traverse

been

watering haulage roads but

in

arteries of the

point,to

hopelessmission

almost

factor of

considered,since it was

be

to

another

high velocity,would dilute and render with a largemargin of safety,they

only kindlingat

and

now

removal

to dilution and

of air,necessarily travelling largequantities

developed a more throughout

and

had

in

the

to

800

ft. per

oppositedirection

minute, at

equal

of coal-dust along the arteries of the mine, speeds,depositions

152

THE

"

"

this

being due

cap

Snell

has

who

a

his

safety lamps

which

observations

examined,

dangerous One

their

from

see

spinningtoo much," he

Another

had

could

not

lamp

ceased

a

he detected

assumed a

full of blue flame.

large cap

or

he

and

There

moderate

a

were

1 in. cap.

recognisea

be

to

the

gas

cap.

could only see slight,

was

was

the

lamp

The

the whole

could

all,

steadied, and

risingfrom

In another

cap.

was

at

lamp appeared

became

could

for work.

as

cap

recogniseda

the

in

lamp

small

a

unless

marked

very

the nystagmus

when

man

swinging round,"

was

he

see

he

the eyes

the nystagmus

drunken

a

floor he had

a

when

Another, in whom

reeled like

did not

because

cap

collieries,were

he said the

as

cap

his eyes

spin round,

to

Another, in whom

largecap.

"

gas

capacity

"gas cap"

a

see

cap

several who

sized cap

when

positionon

the

full before

was

to

until the

be

lamp

either

saw

they

a

marked,

very

lamp appeared

no

a

safetylamp.

a

present, was

was

another

see

of

detect

"

steadied

all jerkingabout, but

*'

big

a

to their

as

of

practically

test

different

13

of gas

especiallywell-

Snell to

the flame

incapacityto

amount

did not

when

led Dr.

over

cap

prominent

a

the delicate detection

to

"

gas

and

in

from nystagmus suffering

"

recognisethe

but

and

the apparent

such

forms

would,

hindrance

a

Forty-eight miners,

"

in his

deputies

among

opinion that

nystagmus

instances, be

of those

it

"

miners'

of

number

all.

nystagmus

was

These

a

particularlymentioned

Dr.

are

cap."

to

of

presence

of the

sympton marked

time

to

in the air.

of gas

"

dancing

"c

the presence

to

in his address

state

GUIDE.

chieflyresponsiblefor seeing that the pit is dangerous quantitiesof gas. For long he proceeds

free from to

time

from

writings the others

SHOT-FIBERS

only

steadied

had

themselves. The

method

restingthe

steadying the eyes referred to consisted downwards, when by turningthem directly

eyes

oscillations ceased* another "

could

man

moving," *

All

Sheffield

the

of

of

became

or

not

see

but could do

miners

tested

so

were

Royal Infirmary.

a

much small

cap

after the eyes under

treatment

less when were

for

the

marked.

Thus,

the

was

lamp

steadied, and he nystagmus

at

the

The Shot-Firer'sGuide.

FIG. 71.

FIG. 72.

154

THE

Fig. 73 is,of

8HOT-FIRERS

only intended

course,

indistinctness of the

occasioned

to

lamp, and

is .not

what

of representation

is

point raised by

The

the miner

designed to

miners

proportionof all risks.

eliminate

to

individual form far

a

obtain

to

affected is only about

the

are

2. Selection

known

are

of

technical

from

0'5 per

conscientious

have

mine

proved

5. Absolute

118.

"

A

a

their

abilityto

be discovered

can

with

will indicate

safety-lampthat

of the mine

cent,

to

and

Shot-firer

or

shot-firer

or

and trustworthyand self-reliant,

He

should

know Coal

well

the

Mines

Sec

Coal

Orders,

capable of testingfor *

haulageroads,

Information to

fireman

and

Explosivesin

main

Manager. shot-firing regulations.

Qualifications

competent

present in

the

authorityfrom

Fireman

gas is

air.

on prohibitionof shot-firing

written

What a

sufficient

possess

of shot-firing where prohibition

Rigid adherence

6.

who shot-firers,

him

to

132).

of gas.

of 1 per

a

shot-firers of

by

use

cent,

without

to

p.

lamp they use.

*4. Absolute excess

to

proportionis

explosive(seeQ. 101.

of the

Manager

one

this kind

of

cases

a"

Safeguards Shot-firing?

find the smallest percentage of gas that

*3. The

low

so

supposed.

suitable

knowledge, and

the type of

4 per cent.,

important

and intelligent

the

by

been

most

1. Selection of the most

in

it is possiblethat the

Explosions

against

Snell estimates,

affected becomes

so

sufficient data

has hitherto

What

"

Dr.

If, as

the prevalence

to

as

portance, im-

the other hand, it is difficult for

reliable estimate, and

higher than

117.

On

of considerable

prove

mines.

then the percentage of shot-firers

exact

by him.

data is available

in British

of nystagmus

ments move-

an

convey

the

to

as

the apparent

by

actuallyobserved exact

no

idea

give an

to

Dr. Snell may

as especially

the

GUIDE.

should

Mines and

minute

Appendices

be

be be

a

conscientious

good pitman.

Regulation Acts physicallyand

of quantities I. and

?

possess

should

ought

II.

gas.

and wise other-

IGNITION

He

should

him

INFLAMMABLE

OF

at least

know

the

understand

to

155

ATMOSPHERES.

much

as

as electricity

Ohm's

of

meaning

Law

will enable

and

much

as

what is meant chemistry as will enable him to understand by such expressionsas, for instance, chemical combination,'* "

"

He

should

"

and

combustion,"

detonation."

also know

holes, in the

unstemmed mixtures

of the with

Prof.

Galloway

official who

is

through

for regulations

the

has

gas, and

in which

in

take

in the

placewhere

a

shot

as

Commission

Royal

fireman

a

he puts

but in other

(1)Name been

work

yourself?

coursing *

Minutes

to

(6)Have

air

'

mean

of Evidence

ing appoint-

he has sufficient

capacityhas

how ? of the

you

the

was

duties

sidered con-

or

lost much

you

follow, is

"

(5)Are

purpose

the

before

:

(3)In what

long ?

are

before

and

deputy and is one officialsnot only in Staffordshire

of fireman

?

(7)For what

the

present

in evidence

which questions,

(2)Age

(8)What

damp, fire-

candidate.

districts

?

stated

questionsunless

mining

is ventilation, and

What '

series of

the duties

(4)How

?

regularat ?

?

is gas

of the Cannock

that sitting

now

well be commended

may

made

a

series of

to embrace

"

Mines

of the

Williamson's

which

and

have

so,

of explosion

there

generalmanager

on

personalknowledge Mr.

do

to

small

a

is fired unless

Staffordshire,has Rugeley Collieries, the

every

fiery,dry

a

authorised

that

the shot is fired.

S. Williamson,

R.

in

force.

and the man ought to be withdrawn absolutelyimpossiblefor an explosion

it is

place before

Mr.

shot, such

a

certificate

punished,because to

being

being in

opinion*

shot

a

in strict

practicaltrainingin examining for he has passed through that a certificate that the event of anything happening in a place

he has fired that

the

than

of

course

obtained

training ; and

fire

to

in.

coal-dust,fire-damp,or

the time

expressed

appointed

a

of

fire shots

to

generallyotherwise

dusty mine, should, before gone

dangerous

presence

and

two,

accordance

it is

why

of

is it

time

Coal

1887

the

are

you

Mine

man

?

What

names

Committee,

cant appli-

by absenting

arranged ?

(10) Give Bobbinite

sober, and

competent

a

the

p. 29.

Act

(9) does

of

the

15G

different How

appliances in

(13) What is

with

comply

to

blasting where and

wastes

bottom

whilst

how

the

far would

workmen

is used

lamps

to

be used

examine

(20)How

?

of gauge, do ?

you

if

and

Act

in

a

allowed

(25) What

mine

blast ?

mine

ought to be (28) Supposing a body where would

you

after

a

timber

a

of gas

be

and

a

(33) What

precautionsare

stall beginsto

working with

a

where

sider con-

explosive

an

(24)Who

?

it is allowed

of the

allowed

?

the part of the

(30)What

the

from

(29) What

roof ?

petent com-

parts of

distance

faces ?

?

in

take

to

men

blastingis

ought

would

velocity

ought

to

know

do you

(31) How

would

(32)Supposing

weightheavily,what should in drawing timber necessary and

inch

you

(27)What

what

bad

you

it dangerous

what

in

existingin

fired ?

safety

square

lamp

duties

it safe to blast ?

face of work

distance, when

to

before

at blasting,

shot has been

timbering roads

what

a

gas

blasting?

examined

sanction consider

you

with

the

are

?

ought blastingto

for the

necessary

and

would

(22)At what

conditions

(26) What

the roof of

At

the

yieldinginflammable

in connection

man

you

what

precautionsare

preparing to

about

in

give the order for blastingin mines where

to

be done

describe

in mines.

use

examine

broken

was

in the

ought safety

lamps explode,supposingthey are

be

gas

and

name

safest for

(23)Under

mine

there

are

?

in the wastes

consider

you

or

yieldgas gas

(19) How

should

of these apertures

?

the

when

apertures

many

atmosphere ought

go back

?

in

their work,

the Coal Mines and

in

of inflammable

is it to

wastes

allow

is found

employed

lightsto

?

the coal,roof

duty

(21) Give the

do the above

been

so

halo

or

you

gas

(18) Whose

one

the best and

would

(17) When

safetylamp,

a

blue cap

?

?

lamps accordingto

and

the air

of Parliament

a

engaged with

are

ventilate

to

when

(11)

long wall

a

carry

(15)Does

?

bodies

allow naked

you

What

deal with

you

you

(14) What

?

have

you

ventilate

the Act

in mines

case

ventilation.

would

the roof of mines

would

to

does this mean,

is the

of the mine

(16) How mine

with

what

:

such

about

is necessary

requirementsof

met

are

gases

in the flame

seen

the

the

with

(12) How

yds. long ?

500

"

GUIDE.

connection

minute

air per

much

work as

SHOT-FIXERS

THE

sprags

to

you ?

do ?

(34)

be set

or

OF

IGNITION

used

the

on

face

and

sides

of

the

roof

and

dangerous

the

and

of gas

body

a

be

affected

see

workman

every

also

and

to

have

you

describe

make

in each of 1887

to

violate

any

duties

roads a

gauge

be

(46) What

how

Special

used

and

should

Rules

?

they

are

or

return

Coal

Mines

where and

Kules

for

workman

a

punished

be

by the

to

?

your your

competent

in

placed

an

are

commencing

the

main

(54) What

?

inch

expect should

for?

(59) Why

is

it represent

on

you

(57) Where

?

would

relating

would

used

you

and

shafts does

(45)

stall ?

workmen

be

during

relating to

Rules

downcast

gauge

largest,intake

hours,

often

he

could

examined

(56) What

?

water

what

to

(55) What

for ?

pressure the

be

to

doors

upcast

work

(49) Supposing

?

General

the

is it to

is the

Special

the

are

of the

(44) Supposing

Rules

General

the

long previous

placed; the

?

the

many

rise in be

road

working place

regards

sudden

an

?

duty

examination

of

mine

ventilation

?

sort

such

in the

visit each

you

(41) Supposing would

how

charge, how

your

made

me

the

ing fall-

a

(39) What ?

(43) Whose

?

Special Eules,

to

the

between

water

should

of the

and

would

are

they

it ?

gob,

of workmen

(48) What

?

(53) How

as

a

his

has ?

gob

(47) What

(52) How

duties.

man

what

does

how

frequently during

stalls under

me

breaking

thermometer

act

roads

people's lives, what

affect

or

roof

finding

workman

a

waste

do

cleared

(51) Describe

?

work

mine

mine

describe

(50) Now

in the

were

purpose

travelling

other

a

a

to

eight hours

from

and

after

rise of temperature

a

you

stall and ?

they taken what

to

by

would

ten

shift of

Just

Act

the

eight or

working

a

see

in

ceased

fan

what

ceased,

do

yielding gas,

is

of gas

body

a

you

and

mine

a

do

found

own

(40) What

(42) Supposing the mine

his

the

you

places

you

examine

do

risingthermometer

a

?

had

you

working

(38) In

?

barometer

a

of

endangering

barometer is

(36) What

?

(37) Supposing

do

you

(35) How

?

mine

sides

?

the rules, and would

of work

157

ATMOSPHERES.

INFLAMMABLE

with lators regu-

(58) Which ?

"

160

SHOT-

THE

of their

that not

singlerule

a

GUIDE.

ways,

who

within

come

them

is, of

has been

the

authorityof compulsory,

course,

who

anyone

liable to

become

may

in which

strange and unexpected ways occur

8

R

this it is clear to

apart from

but

those

To

compliance with

edicts

these

in other

occupation or

explosiverisks.

F I RE

knows

blastingaccidents drafted

without

the most careful Consequently they demand almost absurdly elementary some Elementary "

attention.

the

definite

and

amongst

working miners,

re-cast

knowledge, and it may

materiallyreduce

and

the

of

development

notable

the

be, and, perhaps,having regard to

to

of scientific

extension

of

"

will appear

often

excellent

cause.

instructions

of the

tardy but still

general intelligence be found

soon

the number

possible to

without

any

tion diminu-

of safety.

119.

Enactments

What

"

the use regulate and Blasting Apparatus ? Quarries (in England)

Explosives and

Mines The

use

and blastingapparatus explosives

of

is regulatedby quarries 1. THE

EXPLOSIVES

2. THE

QUARRIES

4. THE

SPECIAL

ELECTRICITY

IN

5. EXPLOSIVES

ACT,

1894

Act, 1872 and

ACTS, 1887

EEGULATION

RULES

FOR

1875).

INSTALLATION

THE

TO

1896.

AND

USE

OF

MINES, and IN

COAL

ORDERS

MINES

made

by the Secretary of State in pursuance

Coal

Mines

Regulation Act,

What

and

(comprisingcertain provisionsof

time

120."

in mines

1875.

ACT,

MINES

COAL

in

"

the Metalliferous Mines 3. THE

of

of

from sec.

time

to

6 of the

1896.

is the

Object

The

object of

of the

Explosives

Act,

1876?

The

Explosives Act,

1875.

to control veyance

the

Explosives Act, 1875,

keeping,sale,conimportation of explosives for

the manufacture, and

is

legitimatepurposes.

STORAGE

For

AND

the purposes classes

seven

Class

I.

161

EXPLOSIVES.

OF

of the said Act

follows

as

USE

divided

are explosives

into

: "

Class

...Gunpowder

II. ...Nitrate mixture

Fulminate

V

Ammunition

VI

,,

,,

III. ,,

...Nitro-compound

VII

Firework

"

IV. ...Chlorate mixture ,,

121."

Define

the

Seven

Explosives

CLASS The

divided

are

Act,

into

under

which the

plosives Ex-

1875.

L"

GUNPOWDER

"gunpowder"

term

Classes

CLASS

exclusivelygunpowder

means

ordinarilyso called. II.

CLASS The

term

"

nitrate mixture

MIXTURE

CLASS.

"

means

any

other preparation,

gunpowder ordinarilyso called,formed

than

of

mixture any

NITRATE

"

a

nitrate

with

substance

carbonaceous

any

form

nical by the mecha-

of carbon,

mixed

sulphurbe or be not added such preparation whether be or be

with

any

other

CLASS The

"

term

with

possessedof explosiveproperties,

not

whether and

or

to such

not

tion, prepara-

mechanically

non-explosivesubstance.

III,

"

NITRO-COMPOUND

nitro- compound

CLASS.

"

means

chemical

any

pound com-

possessedof explosivepropertiesor capable of combining with metals to form an explosivecompound, which is producedby the chemical action of nitric acid (whether mixed acid)or of a nitrate mixed with sulphuric or not with sulphuric acid upon any carbonaceous substance,whether such mixed with other substances or not. is mechanically The

nitro-compoundclass

has two

divisions

compound

:

"

comprises such explosivesas nitre-glycerine, dynamiteand any chemical compound or mechanically mixed glycerine preparationwhich consists either wholly or partlyof nitroother liquidnitro-compound. of some or Division

I.

162

THE

II.

Division so

SHOT-FIRERS

GUIDE.

comprises such explosivesas

nitrated gun-cotton, cotton gunpowder, Schultz's called,

powder, and any nitro-compound as not comprised in the first division.

CLASS The a

narily gun-cotton, ordi-

* '

term

IV."

CHLORATE

defined

before

MIXTURE means

is

CLASS,

"

chlorate-mixture

which

ing explosivecontain-

any

chlorate. chlorate-mixture

The

Division

partly of

class has two

divisions

:

"

I.

comprisesany chlorate preparationwhich consists of some other liquidnitro-comor nitro-glycerine

pound. which

comprisesany chlorate mixture comprised in the first division.

II.

Division is not

CLASS The

"

V.

FULMINATE

"

CLASS.

"

fulminate

before defined

as

chemical

compound or included in the foregoingclasses mechanical mixture, whether to detonation, is not, which, from its great susceptibility or suitable for employment in percussion caps or other any appliancesfor developing detonation,or which, from its extreme and from its great instability to explosion, sensibility (thatis to say, readiness to undergo decompositionfrom very dangerous. slightexcitingcauses), is especially term

This

means

class consists of two

any

divisions

:

"

I.

comprisessuch compounds as of and preparations silver and of mercury, used in percussioncap* ; and such as are Division

the

these

ot

a

of carbonaceous

mixture

sulphuret,with Division

II.

iodide

of

the

or

of

without

a

matter, and chlorate

with

carbonaceous

any

nitrate

of diazo benzol.

substances,

preparation phosphorus, or

with

or

without

sisting preparationcon-

sulphur, or

with

a

matter.

comprises such substances as nitrogen,fulminating gold

benzol,and the

of

any

of a chlorate with consistingof a mixture of phosphorus compounds, certain descriptions the addition

fulminates

the and

chloride

and

silver,diazo

AND

STORAGE

VI.

CLASS The

term

USE

AMMUNITION

"

"

ammunition

"

means

an

classes when enclosed in foregoing otherwise adapted or preparedso

charge

for

small arms,

163

EXPLOSIVES.

OF

any as

CLASS. of explosive case

contrivance, or

or

form

to

of the

any

cartridgeor

a

other

weapon, or for other fuse for blasting for or

or

cannon,

any

or or to form blasting, any safety to form any tube for firing or to form a or shells, explosives, a percussion fog signal,a shell,a torpedo,a cap, a detonator,

rocket,or other contrivance other than

war

The

term

The such

term

percussioncap

"

"

detonator

strengthand

"

does not

"

means

a

a

include

capsuleor

construction, and

firework. detonator.

a

case

contains

an

which

is of

explosive

fulminate

of the

explosiveclass in such quantitythat the the exexplosionof one capsuleor case will communicate plosion to other like capsules or cases. The term fuse for blasting which a safetyfuse means burns and does not explode,and which does not contain its of ignition, and which is of such strength and conmeans own struction and contains an explosivein such quantitythat the with other burningof such fuse will not communicate laterally "

"

like fuses. The

ammunition

Division

class has three divisions

:

"

I.

: safety comprisesexclusively safety cartridges, railway fog signals, percussioncaps. blasting, Division II. comprisesany ammunition before defined as

fuses for

which

does not

included

contain its

in Division

own

I., such

means

of

and is not ignition,

for small arms, cartridges not safetycartridges which and chargesfor are ; cartridges blastingor other like purposes ; fuses for blastingwhich are which do not not safety fuses ; tubes for firingexplosives of ignition. means cor tain their own Division III. which

con

Division not

ammunition

comprisesany

tains its own

I.,such

as

as

means

detonators

as

before

defined

and is not included in ignition, which are and fuses for blasting,

of

of ignition. safetyfuses, which do contain their own means is of ignition means containingits own By ammunition ammunition

meant

to it

the

or

same

havingan

arrangement,whether

attached

forming part of it,which is adaptedto explodeor by friction or percussion.

fire

M2

104

THE

VII.

CLASS

SHOT-FIRKRS

FIREWORK

"

COMPOSITION

What

122."

the

Mixed

store

licence must

3. The

store

"

by the local authorityin the

tunnel tunnel

explosives.

mixed

or

annually.

be situatecl below

not

quarry,

gunpowder

be renewed

in any

or

mine,

which

must

for

other

or

ground in

mine

any

underground place,in is

work

underground placeany

or

and

of Gunpowder

:

be licensed

must

2. The

quarry,

Mixed

and

Storage

to

as

follows

as

occupiereither

of the

name

as

?

Explosivesare

1. The

Regulations

Gunpowder

principal Regulations

The

FIREWORKS.

principal

of

Explosives

FIREWORK

COMPRISING

MANUFACTURED

storage

to

or

CLASS,

AND

are

OUIDK.

being carried on, or in which any persons are employed, or in place opening into, from, or out of such mine, quarry, any therewith. tunnel, or underground place,or in communication 4. The

store

may

failure to

The ranges

The

latter

with

comply

if at keepingexplosives which

any

it is licensed

certain

regulationsas

are

divided

into four

classes,and

accordingto class,between quantityof explosivethat

exceed

If two

to

distance

the

distance

or

substance

25 may

yds. and be

2 miles.

kept in

the store

shall

: "

more

separatedfrom or

for

protectedworks.

from

not

be used

for the division under it is disqualified

time

by

not

and

fire in the

one

kept in the store, they

are explosives

each

other

character

by as

an

will

communicating

be

must

of such interveningpartition effectually prevent explosion with

the other.

This rule

is,

: however, subjectto the followingqualifications "

1.

Explosives of

mixture),Class

III.

Class

I.

(gunpowder), Class

Class (nitro-compound),

II.

(nitrate

IV. chlorate

mix-

STORAGE

AND

ture, safety fuse and second

a

be

be allowed.

that

of the

165

EXPLOSIVES.

various

explosivesof

(ammunition) class

opened unless the inner door Detonators

part of the allowed "

OF

as

do not

the tain con-

exposed iron or steel,may be kept with each other nators partition.(For a few hundred detoany intervening cupboard in the porch of the store, so arranged that it

without

may

such

division of the sixth

any

cannot

USE

is, No.

are

quantity of size copper

6

weighed with explosive. No.

shells with

Ib. per 1,000.

approximately5

is closed,

of the store

their

6 detonators

fulminate

No. 8 detonators

as

cases

"

weigh Ib.

weigh 8-66

1,000.)

per

Explosivesof the first division of the sixth (ammunition) class may be kept with each other without intervening any partition. 3. Explosivesof the second division of the sixth (ammunition) class which contain any exposed iron or steel may be kept with each other without any intervening partition. 4. Explosivesof the third division of the sixth (ammunition) class may be kept with each other without intervening any 2.

partition. Electric fuses may The or

be

store must

concrete,

liable to

or

kept with detonators. well and substantially built in solid rock, earth

excavated

and so made ignition, having access persons

danger from

of other

closed

thereto, and

detailed

official

Capt. Thomson's What

and

of brick,stone

or

mine

as

to to

prevent

secure

,

refuse not authorised un-

it from

without.

Particulars

123."

be

is the The

"

Guide

in be found regulationsmay to the ExplosivesAct, 1875."

Quarries

Act?

Quarries Act (1894,57 "

58

Viet.,Chap.

Quarries 42) appliescertain provisionsof the Metalliand ferous Mines 1875, to all Acts, 1872 Act, 1894.

The

quarriesmore 124."

What

is

a

than

"Quarry"

20 ft.

deep.

under

the

Quarries

Act?

"quarry" under the Quarries Act, 1894, is any place(not being a mine) in which persons work gettingminerals, any A

part of which

is

more

than

20 ft. deep.

166

THE

125."

Give

SHOT

the

Act

-FIBER'S

GUIDE.

Special Rules

under

relating

Following are

to

the

the

Quarries

Blasting. the

Special rules under

Quarries

Act

relatingto blasting: "

1. All

explosivesshall be conveyed from the magazine to and closed as kept till used in secure packages so made of the from and explosives danger escape sparks. any

and any

workman

Every

when

them,

that purpose free from

by iron

any

locked

own

interior of the box

provided for kept clean and

box

shall be

boxes. kept in separate and secure carrying,handling or using explosives,or

provided by the

be thawed No

or

No

shall be

to be thawed,

explosives require

shall be

2.

use,

possessing explosives shall keep their

shall

person

when

near

any

doing.

so

When

with

in his

quarry,

prevent

to

grit.

while

person

of workmen

gang

exclusively.The

Detonators smoke

or

in actual

not

the

steel

or

owner

other

any

for that

means

tool shall be used

explosive. Wooden

than

for

warming

pans.

stemming

or

used

shall be

pans

explosivesshall

no

in such

charging

only

rammers

warming

proper

and

purpose,

otherwise

or

and

safe

for

hole

a

pushing

in

explosives. No no

made

shall

fuses

straw

further

be

shall

charge

ussd.

until after the lapse of 30

3. Due

warning shall be

blastingmay

be

nor

rent

far

as

system of signals before

efficient

an

In

it is finished.

when

and

shall

dailyit

blasting occurs

into any

mm.

given by

commenced,

hole

the

into

explosive

of any

firing a charge

After

introduced

be

take

possible

as

quarries where

place only

at

fixed

stated intervals. Where

danger

shall be taken 4. A

blasting may

give

them

to

sufficient

be used

must

from

by

due

number

of

arise

the

to

means

warning1. shall

shelters

proper

employed) except

the persons

public, efficient

be

where

provided (which

all leave the quarry

,

daring blasting. 5. If a shot

it until

near

go

been

has

has

The

apparently missed

after the

lapse of

half

whose

shot

or

person

be

near

unrammed,

persons

a

6. for

bored,

charge which

a

such

shall

person

be

allowed

hour, except wh"re

an

to

electricity

used.

of the

immediately give warning not

fire,no

manner

The

as

quarry

not owner

blasting,copies

and office,

in

a

or

has

missed

to affect

or

out.

fire shall

missed

fire shall

that

shall

be

a

hole

to bore

it in

to bore

taken

unexploded charge.

regulations as of

has

If it is necessary

ignite the

shall be

sufficient number

apparently missed shot

fire, care

shall frame

of which

A

same.

picked

has

to intervals

kept constantly

placesin and

and

affixed in the

adjacent to the

signals quarry

quarry.

168

chests

Explosives

y.

shall be kept

apart be

liable

dillerent

to

in

substantial

a

struck

by

containing detonators

shall

not

not

are

parties

or

of workmen

gangs

possible.

as

kept

CfUIDF.

to be

they

boxes

far

as

FIXER'S

belonging

shall

Detonators

10. where or

SHOT-

THE

blows

locked of

box kind.

any

placed inside

be

and

placed

Detonators

the

explosives

or

receptacle

chests. 11.

No

unauthorised

shall have

person

chest

to any

access

containing explosives. 12.

No

person

13.

No

tool

for

charging only shall be No

shall

used

be rammed

15.

a

shot

the

hole

If

other

protect

and

way

used

rammers

explosives nitre-glycerine

due

the

of

but

fails

warning

be

must

firing the

persons

danger, and

do

to

put powder into

or

Wooden

so

hole,

given

shots

to

shall

to effectively

most

as

a

persons.

off

goes

steel s^aall be

or

violence, or forcibly pressed into

under-ground

of the

out

using explosives.

or

explosive.

any

stemming

or

with

neighbourhood,

the

themselves and

warn

charging

iron

partlyof

or

hole with

a

firing shots

in

station

for

carrying,handling

steel

or

stemming

or

Before

persons

of iron

made

explosive shall 14.

white

smoke

its work,

any

a

shall not

person until

made,

crack

after

the

charge re-

lapse

of 30 minutes. 16. be

If a hole

put

up

17. No

explosive

far

of be

the

removing be

not the

on

left

missed

a

invariablybe exploded by it is not

19. When

shall be taken

care

succession,

so

as

to

a

to

the

of

shall

of

any

the

hole

taken

where

cases

charge

a

be

charged

once

of

it is

to

bore

holes

new

fuses

prevent the chance

shall

a

be fired

simultaneously,

the

shots

may

mistake

about

the number

that

so

of

a*

explosive.

should

shots

has

exploded by firinga

exploded by a detonator sufficient strength.

of

with

that

to be

detonator that

except

In

out.

shall

be

of any

require

arrange

near,

tamping,

the hole, but Care

necessary

go

at

in case

minutes.

stemming bortd, or picked

charge

High explosives which

to

or

in

signal shall

fire,a danger

allowed

any

of it.

top

possible from

18.

be

tamping

unrammed,

without

charge

as

shall

after the lapse of 30

part

fire shall

missed

apparently person

shall

practicable fresh

no

until

emergency,

missed

has

and

off

go

in cf

reports. 20.

All

remnants

be

examined

holes

shall

of the

explosives have

after

been

blasting

left behind

dynamite, blasting gelatine,gelignite,tonite, or nitro-glycerine

upon 21. or

No

socket

gun-cotton shall be

or

;

any

to

any

whether

see

such

other

any

remnants

of

taining explosive con-

exploded by firinga

tor detona-

them.

boring shall of

a

hole which

tonite,or gelignite,

any

be

done has

in

been

or

metal

blasted

tool introduced with

into

the bottom

dynamite, blastinggelatine,

or gun-cotton. explosive containingnitro-glycerine

'STOP

127."

AGE

Give

AND

under Requirements relating to Shot-firing.

12

The

Coal

Mines

Coal Mines

end

an

to

General

to 1896.

These Kule

rules

follows

ground as

(a) It

shall not be stored

(") It

shall not canister

or

case

Provided

into

(c)A

only

used

plosive ex-

in the

"

the

in

mine, except than

more

cartridgesin

secure

a

on

5 Ib. "

of application

the

owner,

the

workman

shall not have

of such

one

(d) In

the

shall not

cases

use

substances

of

have

or

stemmer, and

or

shall be

time

at one

in any

for

charging or stemming his possessionany iron

in

rod

in use

placemore

one

canisters.

or

process

charger,tamping

used

for

other non-inflammable

onlyclayor

stemming,

and

blasting,a person pricker,scraper,

steel

or

shall

be

provided by the

of the mine.

owner

(e) No

explosiveshall

and, when

hole

a

rammecl, and than

hole

no

6 in. from

shall

charged, bored

be

which

the

person

shall

the

locked

a

both

agent shot

mine, at either

last before to be

shot shall not 1. Unless the

place where

that such such

a

gas

is

is for the time

gas

dusty competent

shot

is to be

within

four

a

and

a

fired,and

radius

of 20

inspectionsunder gas has

all

has tiguous con-

yds.,and

Rule

4

corded re-

been

reported be fired,the

"

competent has

and

dry

ventilatingdistrictin which the shot is to

be fired

of less

of the mine, manager it to be fired until he

shot is to be fired,inflammable

a

the

presentin

of the

or

allow

or

the

in any

which

un-

f

or

accessible

(g) If

safetylamp or

be

fire.

the direction of

under

place itself where the seam placesof the same safe for such found place firing:.

examined

a

hole of insufficient size,

a

explosive shall not charge at a distance

of this Act,

owner,

fire the

not

of

use

in pursuance

appointed by

person

for

the

the charge has missed

where

shall be fired except by

shot

such

been

hole

any

pressed into forcibly

be

has

(f) In anyplace in being requiredby or

has

be

agent or manager Secretary of State may by order exempt such mine mine, much of this rule as forbids taking an explosivesubstance so the mine, except in cartridges.

from

no

that any

enacts

shall

under

:

into the

containing not

of any

than

collected

are

of

causes

in the mine.

be taken

that

common

12, which

substance below

of

number

a

accident.

Acts

mine

General

EegulationActs providea comprehensive set of rules designedto put

Regulation

1887

169

EXPLOSIVES.

OF

the

Rule

The

USE

has

person, been

so

been cleared

place sufficient gas fire the shot ; or

appointedae aforesaid,has repoited to away,

and

be

that

issuingor accumulated

examined

present,and has found there is not at to render

or

near

it unsafe

to

170 2. Unless water

If the

(h) shot

place where

shall not

that is to say

be fired unless

the

place

a

in all

2. In the

of the

dry and dusty,then

the

following conditions is observed,

of

and firing,

all

bi

of places in which

case

it from

prevent

inflame

cannot

is to be fired is

one

floor,unless the explosive is to

gas :

contiguous accessible places at the time of firingin a wet are 20yds. therefrom ing, thorough watering or other treatment equivalent to waterdust whether where is lodged, roof,floor,or sides ; or parts

radius

state from

in

"

1. Unless

within

inflame

shot

a

firingthe shot is so used with prevent it from inflaming gas, or is of

to

as

that it cannot

nature

a

explosiveemployed

other contrivance

or

such

the

GUIDE.

SHOT-FIREKS

THE

inflaminggas or

gas

dust

watering would

used

so

with

water

dust,

or

injure the

other

or

is of such

or

roof

contrivance a

or as

that

nature

it

:

(i) If such dry and dusty place is part of a main haulage road, or is a place contiguousthereto,and showing dust adhering to the roof and sides, shot shall be fired there unless

no

observed;

such

fired,and

level

same

of the

one

all workmen is to be

not

persons,

conditions

have

been

from

all

except the men exceeding 10,

removed

from

as

In this act

are

or

main

airway terminating

is,in

haulage road for moving use

(I)Where the

read

a

a

word

the

road

a

by

trams of

seam

means

provisionsin

though

as

"

mine

is not

shot the

on

a

at

main a

other

or

intake

main

has

part of

or

seam

air

and

course

being

power.

divided into separate

were

an

; and

for the time

mechanical

has

as

air course,

return

been,

a

tricts, disventilating

relatingto ventilatingdistricts shall "

seam

over more-

the

with the shaft

such

means

which

steam

this act "

in which

seam

in

"

"

independentreturn

the

(h) as

observed,and

firingthe shot, and such other necessarilyemployed in attending to boilers,engines, machinery, winding in inspectingthe mine.

engaged

ventilatingdistrict independentintake commencing from

an

been

in sub-head

been

communicating

seams

horses, or apparatus, signals,

(k)

(h)(1)(2) have

mentioned

particularplace has

the ventilatingfurnaces, steam

"

in sub-head

mentioned

to the applicable

be

"

or

2. Unless may

conditions

the

1. Both

substituted for the words

be

lating venti-

"

district."

(m) the

(/)

as

(k),and are

much

of this rule

requiresthe explosivesubstance taken into of the provisionsof sub-head much so relates to a dry and dusty place,and the provisions(g\ (h),(i), which shall of clay or stratified ironstone not to seaois apply (1)

So

mine

to be in

not worked

as

cartridges,and

with

in connection

any

and

coal seam,

which

contain

no

coal in the working.

128."

What under

The

is the

the Coal

object Mines

objectof SpecialRules

those contained

in the

Special

Regulation

is to

general

of

Rules,

Act

?

provideregulations beyond

rules "for

the

conduct

and

AND

STORAGE

guidance of the employed in or

of a mine or persons actingin the management state and about a mine as, under the particular

of such

circumstances

mine,

and

calculated

best

appear

may

to

provide for the safety, of those employed in or discipline and

prevent dangerous accidents convenience

171

EXPLOSIVES.

OF

USE

proper

to

the mine."'*

about

the Coal

under

mine

129."

Give

not

compulsory in

every

in mines under

so

the

Act.

Special

of

set

a

Act, but

Mines

Mines

Metalliferous

is

specialrules

of

establishment

The

Shot-firing

for

Rules

in Mines.

Special Rules vary in different mining districts but generallyinclude the following : provisions

Special Rules,

"

The Act

Under-

Manager and Deputies shall enforce the provisionsof the SpecialBulea relatingto the use of gunpowder or other explosive

and

substances

in the mine.

No person

shall, without

have authority,

in his possession

in the

mine

shall break any explosive. No person any cartridgein the mine. Explosives shall be kept in a box or case, which shall be securely shall have access to the same. locked,and no unauthorised person

No

person

shall fire shots without

authorityfrom

the manager

under

or

manager.

No person

shall have

charger,tamping tamping. Every person are

persons

rod

in his

about

shall take

the

placeuntil

to fire

of reach

out

and

such

of

to

means

possession any

stemmer,

or

a

iron

shall he

nor

or

steel

use

coal

pricker,scraper,

shot shall,before firing, see

danger from

prevent

any

shot has gone,

and

dust for

coal

or

that all other

the probable effects of such

shot; inadvertentlyapproaching person immediately before firingshout

"Fire."

Each

deputy having charge

of

his

shall, before

a

district in which

shift,read

commencing of the ventilatingdistrict inspections if any

note

inflammable

gas

has

the

in which

been

shots

reports

of

are

the

to be fired

last four

his district is situated,and

reported;

and

if inflammable

gas

he reported to be present in any part of the ventilating district, Bule 12. observe the requirements of General must the person After a sbot has been fired, who has fired the shot, or some

has been

other competent person, as shall,as soon practicable examine take steps for its security. and, if necessary,

Every ger

or

a

case

of

a

shot missing fire shall be

deputy,by

the person

in

reported to

charge of the shot

miss-fire. *

Sec. 51, C.M.B.

Act, 1887.

the place,

the under-mana-

at the time

of the

172

THE

130."

State

the in

SHOT-

GUIDE.

Shot-firing Mines

firing from Stone

FIBER'S

clauses

Rules

Power

Cables

in the

tricity Elec-

relating to Shotin Sinkings and

Drifts. The

SpecialRules for the Installation ana ^se "fElwtridty"l Mines only contain three clauses relatingto shot firing. They are as

Special Rules for the Installation

and

Use

of follows

Electricityin

placed

lightingor

cables

power

be use(j for firingshots, except in stone

switch

or

"

from Electricity

Mines.

button

:

is

drifts,and

then

provided, which

in a fixed locked

box, and

only when

a

ping, button,

shall

shall not

sinking shafts

on

specialfiringplug, or

switch

be

shall

only be accessible to the authorised

shot firer. The

firingcables before

wires shall not

or

it is

for

required

be connected

the

immediately after the shots are cables wires or are shot-firing

When

to this box

firingof shots, and

mediately until im-

shall be disconnected

fired. used

in the

vicinityof

or

power

lightingcables,sufficient precautions shall be taken to prevent the shotfiringcables or wires from coming in contact with the lightingor power cables.

131."

State Coal

the Mines

Provisions Order

of the

now

Explosives

in force

in

(September,

1908). EXPLOSIVES

IN

COAL

MINES

ORDERS.

Explosivesin Coal Mines Orders are issued under Sec. 6 of the Coal Mines RegulationAct, 1896, which enacts that a Secretary of State,on being satisfied that any explosiveis,or is likely to become, dangerous,may by Order prohibitthe use thereof in any mine or in any class of mines either absolutely or subject to conditions.

new

conferred by the above Section,a of the power December This Order, issued on 17, 1906.

In pursuance Order was

which force

revokes on

and

March

consolidates

Absolute hibition Of

ecr-

tain Explosives iu Unsafe

Mines-

into

1,1907, and contains the following provisions: 1.

Pro-

all previous Orders,came

has such

(a) In been

all coal mines

found

quantity as

sive, other

than

within to be a

in which

inflammable

gas

the

in previous three months indicative of danger, no explo-

permitted explosiveas

defined, shall be used

"

in

or

taken

for the

hereinafter purpose

of

STORAGE

into the

use

ehaft

seam

drift

or

(6) In

dry

in

and

as

which

case

for

the

of the

mine,

is in process

of

or

may

said, the

Prohibition

Mines. the

and a

any

or

communicating,

sunk

or

road

any

drift

or

being deepened

being driven

or

parts thereof as aforepermitted explosives is prohibited

coal mines

of

use

to be

of mineral

amount

of the

(") Every charge shot hole

into

use

or

the following conditions are observed :" charge shall be fired by a competent Every (") (hereinaftercalled the shot firer)appointedin person agent or manager writing for this duty by the owner, whose of the mine, and not being a person wages

Explo-

consist of

plosive, throughout, no exshall defined,

unless

of

sives in Unsafe

on

any

of being

process

be.

Conditional

depend

or

hereinafter

shaft

any

found,

be.

may

of

purpose

2. In all such

Other

case

been

is in

naturallywet

not

are

has

gas

which

permitted explosive as

taken

or

the

the

a3

173

EXPLOSIVES.

therewith

which

a

dusty part

therewith the

mines

than

OF

in which

seams

being driven,

or

afl.coal

used

USE

communicating

other be

or

sunk

deepened or

AND

shall have

cartridge

or

gotten.

explosiveshall be

placed in

stemming,

sufficient

cartridgesof not

each

and

than

more

properlydrilled

a

such one

charge shall descriptionof

explosive. cartridge shall

(c) No forth

in

required by (d) No

the

of inflammable

the

use

cable

a

shall himself

the

cable

persons he fire,

cable

marking

any

hereto. of

means

efficient electrical

an

a

is fired

up

by

electrical

an

purpose

which

the cable

to the

apparatus

is less than

charge

the

shot-firer

20yds. in length.

and

shall

do

so

before

to the

electrical

handle

positionor

released

or

safetyplug

or

shot-firer whilst

prescribedin (7t)Where are

as

soon

shall on

explosiveshall be used

(g) Each

two

or

not fired

for gas

be

provided with

safetyplug or push button, which operated until the shot is required to

handle

custody of the

firing apparatus shall

shall not

or

shall be removed

the

set

manner

to the

(/) Every

shots

to

securityagainst the ignition permittedigniterfuse, as hereinafter defined.

for the

couple

addition

couple firingapparatus. He shall also himself he shall all Before that see doing so, firingapparatus. in the vicinity have taken proper shelter. Should the charge miss the firingapparatus. shall immediately disconnect the cable from

coupling the

in

charge

hereto,

in

to afford reasonable

by

or

gas,

(e) Where He

as

in the

it is marked

fired except by

shall be

enclosed

apparatus so

shall not

Schedule

First

charge

unless

used

be

Schedule

Third

the

the Schedules more

shots

are

as

a

has

shot

at all times

been

fired

and

fired. in the

remain

a

movable re-

placed which The

movable re-

personal

duty. in the

and

manner

the

subjectto

ditions con-

hereto.

being

the simultaneously,

fired in the same

shot-firer shall make

immediately before the firingof each finds the placewhere the shot

shot unless he

contiguous accessible places within

be

be

20

yds. free

from

shot and

place and such an

tion examina-

shall

gas and safe

not

firo

an^.all for firing

is to ba fired

174

SHOT-FINER'S

-THE

Provided iu

fuse the

that

in

three

previous

inflammable

which

In

3.

Prohibition

intakes

of

the

all Explosives in Main

every iu

prohibited

Roads,

in

the

main

haulage

in which

the

such

other

with

in

exceeding

not

persons

shaft

the

the

in

removed

been

engaged

men

in

and

roads

have

danger.

explosive is

of any

use

within

of

shot is to be fired,and

the

communicating

seams

addition

the

safety

a

found

indicative

mine

all workmen

level, except and

as

of

use

been

not

to be

coal

unless

seam

has

gas

quantity

in such

months

Conditional

shall prohibit the

in this order

nothing

mine

any

GUIDE.

on

firing

all

from the

same

the

shot,

number

in

10

from

as

are attending to ventilatingfurnaces, steam employed necessarily boilers,engines, machinery, winding apparatus, signals, or horses, or in

mine

inspecting the conditions

sides

20 yds. from

wet, either This and

as

the

shall

the

application of

100

yds. of

the

authorise

of

purpose

Prohibition

conditions

of

Detonators.

into

use are

Detonators

(a)

and

purpose,

shall

speciallyauthorised issued

separate the

In

deemed

from

of

are

by

before

use

bag

other

or

so

the

being

be

surface

of the

the

for the

following

a

control

mine,

or

the

person

or

manager

other

or

in

of

some

agent,

owner,

manager

persons

writing.

shaU

keep all detonators securelylocked case or box,

mines shall

of

surface,it shall not be primers for charges are fitted

being

taken

into the

established

taken

into

authorised

to

or

they apply

to

the

from

3 of this Order

stratified shafts in

or

Sec. 47

shaft and

of the

immediately in

thick

a

felt

shock. shall not

nodular

course

shaft,provided

under

person

protect them

1, 2 and

clay

the

if the

only other

or

5. Sees.

Order.

or

from

workshop

are

receptaclesufficient

Application

the

to shot-firers

in

sunk

before

a

and

shot-firer

of

Order.

taken

or

unless

under

the

persons

used

of this section

fitted in

primers Explosives Act, 1875, the

be

to

shaft

the

on

only agent

owner,

in

case

any

2 of this

or

explosive.

contravention

detonators

with

a

issued

1

in

:"

shall

authorised

about

other

any

case a

other

until

to them

the

by

and

(b) Shot-firers

be

haulage roads

explosive

mine

any

agent or manager speciallyappointed in writing by

persons

for the

of

firing,thoroughly

main

be used

owner,

or

roof,

distance

a

thereto.

the

any

not

observed

the

under of the

face.

of

use

shall

4. Detonators

Conditional

coal

of

water

portions of the

part

every

intake, within

or

explosive is prohibited by Sees.

of such

use

and

it is used, is,at the time

to such

not

Order,

road

apply

within

are

this

haulage

where

shall not

section

where

main

place naturally or from

intakes

This

of the

the

section

permitted explosive is used

a

in Sec. 2 of

prescribed

floor, and

unlesi

or

;

the

of

apply to

ironstone, nor being

sunk

from

the surface,or

being

Where

each

from

driven

seam

a

mine as

the

deepened, or to drifts and other outlets surface,except as provided by Sec. 1 of the Order.

contains

if it were

several a

separate

separate mine.

seams

this Order

shall

apply to

176

The

2. much

shot-tiring

longer and

danger) The

3. that

it be

time

of

fresh

a

the

shall

be

than

12

bored

the

previous

shot

firer

shall,

The wires

also

missed

fire

exploded

by

otherwise

the

If

and

as

of

of

with

charge.

a

interfered

the

with,

minutes

five

nor

from

the

wedged

be

cannot

charge

parallel

himself

assure

firing

expiration

missed-fire

holes, before

shots shall

and

firing

cable

by

until

missed-fire

shot,

shall

be

fired

by

down

charge

of

wire

finds

shall

it,

he

at

the

firer.

missedin

aid

to

search

that

it has

to

person

no

same

shall

is satisfied

or

allow

same

cord,

or

the shot

attach

firing

after

by

in

put the

charge,

means

he

he

be

new

a

Immediately

second

refuge

before

or

the

drilled

and

charge,

the

(or reach

in.

shot.

missed

drawn

after

firing

the

to

be

down

blowing

length

beyond

operator

of

danger

exploder.

less

for

the the

until

in

yds.

30

the

place

from

not

than

place

his

protected shall

less

insulated.

examine

hole

not

who

shot

shall

be to

effectively

shot

Holes

6.

be

GUIDE.

not

necessary

approached

distance

men

shall

disconnecting

safely,

5.

cable

adequately

missed

shall

a

may

shall

is

A

SHOT-FIRERS

be

shot-firer

he

4.

as

THE

covering re-

for been

interfere

with

material.

the

When

7.

great

care

other

tools. Shot

8.

be

firers

shall

of

and

the

that

that

see

packed

the

in

explosives

detonator

struck

explosive

is

possible and

down,

with

supposed

or

Whenever

recovered

blown

material not

if the

shall,

goaf. be

be

containing

charge

shall

in

charge

mineral

unexploded

an

securely

be

unexploded

an

taken

shall

portion

any

for

searching

pick

contain

to not

able, recover-

nators deto-

miss-fire

returned

to

or

the

under-

manager.

in

face

holes

and

use,

the

they

air

Detonators

12.

Shot

every

shall

shall

be be

of

just sufficient

drilled

without

firers and

case

special permission,

be

used

for

ing: break-

at

such

diameter

to

that

angle

an

the

pass

do

they

cartridges not

directly

current.

11.

purpose,

without

not,

ends.

fast

Shot

10. in

shall

Explosives

9.

of

shall

shall

also

missed-fire

a

make

charge

be

not in

daily report

a

specially shot

shall

or

report other

in

fired the

writing

unusual

in

book to

occurrence.

the

mine.

provided the

for

Under-Manager

that

APPENDICES.

NOTE

Second

The

APPENDICES

of the

Report

published during

been

abstract

an

TO

has

been

the

I. AND

Commission

Royal

printing of

made

from

the

Summary

relatingto Shot-firingin Appendix of

"

the

"

Garforth

in

detector

gas

having

therein

Main

of

I., and

clusions Con-

description

a

referred

Guide,"

is reproduced

to

II.

Appendix

APPENDIX

SUMMARY

Mines

on

Shot-Firer's

The

"

II.

OF

I.

CONCLUSIONS

MAIN

RELATING

TO

SHOT-FIRING. the Second

(From

regulations in

various

The

1.

and

complicated

very

all the

code, and

one

2.

Main

which

haulage

roads,

within

on

3.

the

shots

should

mine,

and,

be

supplied to Intakes. caused

been

firing of

be if

at

or

fired

when

as

far

4,820,

the

the

Face as

be

of

main

confined to

the

tions recommenda-

"" -

possible

shifts.

as

serious

subjected

and

number

men

ticable, prac-

issued

(Page 113.)

to

should

Working few

be

as

shot-firing on

shots

a

practicable, between Cd.

So

Owing

by

such

the

near

shot-firingare

to

shot-firers. "

possible,

as

*

S.F.G.

as

Mines.*)

on

shot-firing should

make precautions. We this point. (Page 116.)

Shot-firing

regard

consolidation.

and

limits

in

to

Roads

have

narrow

as

strictest

regulations

Haulage

force

require

copies should

accidents

Royal Commission

of the

Report

Ripping are

"

in the

(Page 119.)

1909. N

178

SHOT-FIRER'S

THE

As

4.

substitute

a

watering before firinga shot, it is further to the as experiments should be made soda and wood pulp tamping. (Page 120.)

that

suggested

of

effectiveness

GUIDE.

for

should be testingfor gas before shot-firing Garappliance similar to the stringent, and some rules

The

5.

to

as

"

more "

forth

should

detector

gas

be

into

brought

general

use.

(Page 120.) 6.

Precautions

General

in the

gas

same

explosivesshould

Other

safety fuse, and

the

"

of

for

deputies. (Page 121.) be

fired

be fired either

use

appointed

their abilities to test

to

and

explosives should

Persons

firing.

as

firemen

as

way

Permitted

7.

Shot-

be examined

should

shot-firers

as

to

as

straws

or

only by electricity. or by electricity proper squibs should be prohibited.

(Page 122.)

permitted explosivesare required to be used, be shot hole should charged and stemmed by or under personal supervisionof the shot-firer. (Page 124.) 8.

Where

9.

Firing

well

of

the

should

Order

Explosives as

in the

shots

fast

"

should

requirethe

drilled.

properly

as

"

The

be

hole

prohibited. be

to

be

a

the

The

properly placed

standardisation

cartridge of explosives would

the

of the

size

great advantage.

(Pages 124, 125.)

question

of

defining more clearly the amount stemming required and of fixingsome proportion between of the explosiveand the length of stemming should amount The

10.

shots

There

should

which

should

approach of

proper

such

test

on

should

shot

"warming should

12.

the be

(Pages 125, 126.)

considered. 11.

of

be

be

a

uniform

provide,

made

The

lines recommended in hand.

one

sufficient interval.

should The

use

glycerine explosivescontaining nitrocompulsory. (Pages 126, 127.) "

be taken

no

miss-fired

for

Testing of Explosives. the

a

dealing with

alia, that

inter

except after

pans"

rule

revision

by the

of the

Bobbinite

Government Committee

(Page 128.)

Storage of Explosives. Explosives should be provided and stored at the colliery. (Pages 128, 129.) by the owners 13.

"

APPENDIX

(c) TESTING

lies in the

of possibility clear in the

made

circumstances

before

the

shot

lurk

with

appliance W.

similar

the

of

should

a

safety lamp,

brought

of managers "

that radius the

to

fact that

it is think

we

place of of 20 yds.

the

that

some

into who

are we

gas

impossible

designed by generaluse.

detector,"

gas

cap

a

it should

"

detector

gas

be

"

"

of

face

fired in any be seen can

be

must

sides which

or

"

the

to

of this

use

roof

think

We

safety lamp, and

a

form

the information

For

shot

no

working

the

near

carefullytested within is fired. Having regard

any

E. Garforth

with

of

in fissures in the

detect

to

be

or

indication

any

flame

firingshould may

GAS.*

being present.

gas

rules that

where

reduced

the

on

FOE

at greatest risk in shot-firing

The

be

II,

not

Mr.

already familiar

are

able

pp.

181-2),with which

to

reproduce

the attached

illustrations

Mr. Garforth

tector," kindly furnished us, not only of the gas dealso of a safetylamp specially designedby him for describes of detecting firedamp. Mr. Garforth

"

has

but the

purpose

the arrangement "

The

follows

as

detachable

of the hand,

pressure

becomes

filled with

contents

of the ball

lamp through

a

: "

indiarubber

in the roof and, after the

by

(Figs.74, 75, 76,

a

air contained it is allowed

sample are

then

into

ball is inserted

of the

in it has to

been

break

a

expelled

expand, whereupon

The

suspected atmosphere.

introduced

on

to

of the

the flame

safety gauze-protected pipe, which

it

brass

the

exactly fits. If firedamp be present it is shown by an elongationof the lamp flame, and by a blue cap burning at the top of the gauze pipe,which latter is fitted with small spring valve raised when desired by the serrated brass a nozzle

nozzle "

the

of the

of the ball.

To

indicate

main

to surround

Cd.

From

a

low

percentage of firedamp when

found

in

airways, working places or other parts of a lamp is fitted with an extinguisherwhich is made the wick tube, consequently,when the extinguisher

return

mine, the

*

ball

the

Second

Report

of the

Royal

Commission

on

Mines,

p. 121-

4.820, 1009. N2

180

SHO

THE

is raised

lowered

or

officialfrom

by

the bottom

be altered from

method, and

T- FIR

a

of the

the addition

of

G UIDE.

lamp, the

small

a

*S

actuated

screw

largeto

a

Eli

a

or

by the hand flame

of the

non-luminous

nut, regulating

one. a

more

of the

lamp By

can

this

delicate

flame is obtained with less adjustment of a non-luminous the light, and much to extinguish liability quickerthan by the ordinary pricker arrangement. Attached to the extinguisher with it is a white enamelled and movod graduated standard which is placed immediately behind the flame, whereby the heightof the cap or halo of a non-luminous firedampflame may be measured. The lamp is also fitted with a magnifyingglass, be used or not as desired without so arranged that it can obstructingthe lightof the lamp. It also enables a nonluminous flame to be more easilyseen, and, when required, throws a brighter lighton the roof or obscure places. The improvements herein described do not interfere with 20 years'experiencehas the tin shield of the lamp, which an proved to be the safest arrangement in resisting explosive current at a travelling high velocity. of detectingfiredamp by means As the method of the indiarubber ball has been in dailyuse for the past 24 years, it is interesting that the opinionof more liery to know than 100 col'

'

"

"

officialsis "

:

"

(a) That the ball enables

firedamp which cannot lamp, which for reasons Davy.' gas as the

be

to discover deputy,or fire-trier, found by the ordinary tin shield a

well known

is not

as

sensitive to detect

'

"

(6) That

it is safer to

bring a suspected atmosphere to the of the ball than to introduce a lamp into gas. lamp by means discovered be safelyand can (c) That firedamp when promptly dealt with by fixingthe necessary sheets to render it harmless, which precautions the tin shield not taken when are lamp has failed to indicate gas. risk of the lamp being extinguished (d) That there is not the same when usingthe ball as when testingin the ordinary which is important,especially if the officialis 1J miles way, from the shaft where workmen tions be awaitinghis instrucmay before they can proceedto work. (e) More tests can be made in a given time with the ball, consequentlyan officialis assisted in his work by knowing the preciseconditions of the coal face,return airways,"c." "

"

"

181

FIG. 74." INSERTING ROOF

FIG. 75.

TO

"

COLLECT

FORCING THE

FLAME

THE

A

THE

INDIARUBBER

SAMPLE

OF

COLLECTED OF

THE

THE

BAG

ATMOSPHERE LAMP

LEVEL

INTO

A

SUSPECTED

FIREDAMP

OR WITH

BREAK

IN

THE

ATMOSPHERE.

THE

EYE.

ON

TO

182

HALF

THROUGH

SECTION

FIG.

SECTIONAL

ELEVATION

THROUGH

A

76."

B

C.D

THE

HALF

GAKFORTH

DETECTOR With

detachable

tinguisher luminous

glass.

screw

FIREDAMP

LAMP.

iudiarubber

adjustment standard flame, graduated witli

ELEVATION

OUTSIDE

movable

bag, to

produce and

a

:

magnif;

184

SHOT-FIRER'S

THE

vided

safetyvalves explosion. with

In

relieve the pressure

the conditions

order to render

in each

to

experiment,the

GUIDE.

as

set

nearly alike

as

is

of dust

requisiteamount

by

up

the

possible ground

explosion. The size of the is based upon samples taken from the highestparts of particles After being ground it is spread on roadways in the mine. tion shelves running on both sides of the galleryin imitanarrow of the ledgesand crevices presentedby the packs. "c., of an underground roadway (seeview of interior). from

nut

coal

FK;.

The

amount

each

previous to

77.

"

VIEW

OF

of coal dust

INTERIOR

OF

GALLERY.

having

agreed upon

it is raised in suspensionin the air-current of

a

small

air-current,and from and

a

or

cannon,

either

by the merely mechanical

been

by

spread,

the

action

firing of the

suspensionit is ignitedby the flame which is charged with blastingpowder,

whilst in

large cannon

represents in its effect

a

blown-out

shot, such

as

was

the

majority of the. great collierydisasters,including the explosionat the Altofts Collieries in 1886. of remedial measures The experimentsinvolvingthe use are The explosionof the coal dust is obtained similar in nature.

cause

of the

185

APPENDICES.

in

the same precisely strewn by coal dust

but

way,

is

arranged that

so

in its passage dust, or lengthsof

encounters

carbonate less

of disposition

the

dust,

watering,stone

galleryclear

of dust, called dust-

zones.

The

effects of such

reducing the by

of the

pressure

of which

instruments, many

of

means

checking the velocityand tically explosionare recorded automain

measures

specially designedfor the purpose. The Altofts galleryis on a natural scale and both in sectional area and in length,that has either in this country or abroad The experimentscarried out have

been

undertaken the

lengths the explosion

of

the flame

of

zones

the

of

with

reinforce

to

largest, used

been

ever

during the present form

(1909)

year

part of

series

a

of the whole nature investigating experiencegained during this periodhas

the idea of

explosions. The

served

is the

work.

for such

scientific character, and

a

been

have

the

hope that in

stone

dust

an

effective

remedy has been secured.

followingexperiments indicate clearlythe effect of exploding coal dust (1) alone, (2) adjoininga dustless zone, and (3)adjoininga stone dust zone. In the first (experimentNo. 61, July 17th, 1909), a length of 367 ft. of the main intake was spread with coal dust, 1 Ib. or being used per running foot of the gallery, per 41 cubic ft. of gallery space. On explodingthe coal dust a flame about 1 70 ft. long shot manifest signs of the open end of the tube, and there were out of the setting up of great internal pressure. In the second (experimentNo. 55, July 2, 1909), a similar weight of coal dust was exploded,but this time the explosive 150 ft. in force was caused to pass through a dustless zone which are of recording instruments, length. By means attached it was to the gallery, found that the pressure rapidly attained a maximum of 1131b. per square inch, greater by The

over

68 Ib. than

dust

zone.

that

This

is

obtained

which

explainedby

at

Turning which

a

now

stone

so

to

dust

that the

"

dustless

experiment area

takes

of the

coal

in front "

zone

of the

is in

actual

existent. realitynon-

(July 8th, 1909), in place of that which in the

No.

the

end

the fact that, in the initial

stage of the explosion,dust is driven

explosionwave,

the

57

186

THE

EtiS

SHOT-FIR

described previously

GUIDE.

"

found dustless,"it was experiment was instead of rising, that the pressure, decreased, and died away it could be released at the mouth of the soon as as wholly gallery. The plans given in Fig. 78 illustrate diagrammaticaily the results of this set of experiments.

Mouth

JVe

of Mouth Downcast

of

Downcast

of 95

evidence flame feet

for

Flame ffS ffcf in Stone Oust Zone

Point

Point

Paint

EXPERIMENT

No.

EXPERIMENT

61.

(JULY 17, 1909). Length

of main

intake,

600

ft. ; sectional Numbers

a

experiments have certain

the flame

of

an

No.

55.

EXPERIMENT

it appears class of stone

explosion.

at

ignition

No.

57.

(JULY 8, 1909;.

Length of return, 295 area, 41 sq. ft. indicate position of safety valves.

made, and that

ignition

(JULY 2, 1909).

FIG.

Later

of

ft. ; sectional

area,

28 sq. ft.

78.

tended

to

dust

confirm

the

tests

viously pre-

satisfactorily proved suitablyapplieddoes arrest

to have

been

APPENDIX

EXAMINATION

IV.

TO

RELATING

QUESTIONS SHOT-FIRING.

(i.)Describe

blasting gelatine, and

is

(ii.)What

it is used.

how

state

construction

the

(iii.) Explain their

and

employed

safety-fuse commonly

the

of

advantages

is it fired

how

electric

some

and

fuses

ordinary

with

compared

as

?

safety fuse.

(iv.) Give

rules

some "

ensuring safety

for

far

shot-firing,"as

(v.) Draw

and

blasting the

drills

(vi.) Describe

hand

of

set

a

the

List."

sharpened.

are

and

nature

is

What

passed

how

Explain

them.

charging

for

holes

boring

for

before

the

upon

the

is

of

some

Permitted

"

which

test

explosive

an

of

composition

explosives placed

the

or

possible.

as

tools

for

blasting

in

has

placed

be

to

this

upon

list?

(Board

(vii.) A

which

tunnel, for

the

and

the the

words

would

shot

fired

be

rules

applying use,

you

must

in

a

chemical

(c) Black-damp

Give

?

here.

and

why

be

taken

and

Ireland

?

1901.) also

and

road which

is

dry

When

in your

own

sive explo-

What

?

before

and

?

District, 1902.)

composition

;

Mining,

enlarged.

sinking pit

(a) Air; (b) Fire-damp

and

be

to

shots

(Manchester is the

haulage

a

airway,

return

precautions firinga

(ix.) What

as

dusty, requires

should

(viii.)What

is used

main

of

Principles

of Education,

of

after

188

SHOT-FIRER'S

THE

is the

{x.) What

explosivemixture

most

air ?

and

GUIDE.

Show

what

gases

of

would

fire-damp be formed

explosionof such a mixture, givingthe relative proportionsof the resultant gases. take to (xi.)What precautions would prevent you explosionsof coal dust in a mine ? State the most (xii.) important requirementsof the Coal in a Mines Regulation Act as to shot-firing What the requirementsas to are fierymine. What detonators ? other precautionswould enforce ? understand What do you by you permittedexplosives ? by

an

"

"

(Liverpooland When (xiii.)

North

shot misses fire,what

a

taken and

District,1902.)

Wales

to be

precautionsare

in your own words the General SpecialRules applying thereto. Give

?

(Manchester and

Ireland District,1903.)

(xiv.)State shortlythe requirementsof the Coal Mines Regulation Acts as to explosivesin reference to

(a) Quantity to be taken at a time (6) Stemming and blasting; (c) Missed

shots; locked

(d) When

safetylamps is dry and dusty ;

the mine

inflammable

(e) When

used

are

gas has been

or

reported

be present.

to

(xv.) Why

;

is coal dust

a

part of the mine find it ?

What

of

source

would

danger ?

you

be most

arrangement should

In

what

likelyto you adopt

keeping down dust ? the requirementsof the Coal Mines Acts are ? where coal dust is existing is the danger arising from a blown-out shot, for

(xvi.)What What (xvii.)

and When (xviii.) (xix.)Name

how

are a

?

only to be used ? permittedexplosives and few of these permitted explosives, their constituents,

name

(xx.) What

is it caused

are

the

requirements of

RegulationActs

as

to

the

? blasting

Coal

Mines

189

APPENDICES.

(xxi.)Name

as

as

many

mining, and state they are composed.

which

the circumstances

Name (xxii.)

under

explosives ingiedientsof

the

which

consider

you

high explosivepreferableto ordinary gunpowder.

a

acquaintedwith the last ExplosivesOrder ? If so, state shortlywhat it is. precautionswould you adopt for the safety

Are (xxiii.)

you

(xxiv.)What

of the

where

men

How

shots

ously fired simultane-

are

electric deal with you cables when shot-firing shot-firing

?

light and at a depth surface ?

(xxvi.)In

of the various

can

in

used

(xxv.) What

you

would

of

more

than

600

yards

the

from

(StaffordDIstrict,1904.)

important requirementsof the Coal Mines Regulation Act as to shot-firing in a fierymine ? And what are the specialrules What other ? (1902) that apply to shot-firing precautionswould you adopt ? shots and coal shots, firing roofing down instruct your what precautions would you the most

are

"

"

shot-firer to take

in respect to the use cable, and also as to his

battery and when

position

? firing

(Liverpooland North In (xxvii.)

of the

Wales

District,1904.)

proportionsare mixtures and pure air explosive ;

what

the presence

has

of coal dust

of

and

damp fire-

pure

what

upon

effect

such

tures mix-

?

(Newcastle District, 1904.) State (xxviii.)

requirementof the Acts and SpecialRules main haulage roads on regard to shot-firing

the in

and

(xxix.)What

main

returns.

percentage of fire-dampwhen is necessary

mixed

with air-

"

(a) To show a faint cap ; (6) To readilyexplode; (c) To be at the most explosivepoint? (Manchesterand

Ireland District,1904.).

190

SHO

TUE

(xxx.) Give

the

*S

T-F1RER

G VIDE.

permitted explosiveswith which are practically acquainted. State you which you preferfor use in coal and hard rock and why. What class of explorespectively, sives of the

names

liable to

are

should

(xxxi.)Under a

circumstances

how

?

does

coal dust

become

danger in mines ? Where do you mainly ; and what precautionswould of

source

find it

in

take

you

be dealt with

they

what

in winter, and

freeze

fiery mine

a

minimise

to

the

danger ? (Manchester and Ireland District,1905.) What (xxxii.)

do shots mine

What (xxxiii.)

first,in

:

the

best

method

fiery mine

a

there is

where

no

;

provisionsof the Act of explosiveson use

the

roads

of

firing

second, in

a

?

gas

the

are

to

consider

you

with

reference

main

haulage

?

(Newcastle District,No. 3, 1905.)

(xxxiv.)Why

is coal dust is worked

circumstances

(xxxv.) In what

explosiveson underground ? would

take

which

is it necessary that Permitted List be

the

Mention

before

the

using

only used

precautionsyou in

them

order

to

safety.

ensure

(xxxvi.)What

mine

dangerous in a dry with safety lamps ?

special precautionshave to be taken in mines worked by safetylamps when usingelectricity Give reasons for firing shots ? for the need of these precautions. (East Scotland District,1906.)

Describe (xxxvii.) Give

the

various

gases

their chemical

found

in coal

compositionand

the

mines. means

Describe the part detectingtheir presence. played by coal dust in an explosion. of

What

are

and

the various what

presence

means

harmless

sources

would

from you

which

take

it is got, to render its

?

(West Scotland

District,No. 2, 1906.)

192

SHOT-FIRER'S

THE

(xlvi.)What

GUIDE.

the

Eules provisionsin the Electricity from a power electric regulatingshot-firing or lightcircuit ? are

Four (xlvii.)

shots What

in are

a

sinkingpit

ready for firing. them objectionsto firing

the

(a) By tape fuse

are

;

? (b) By electricity

How What (xlviii.)

are

can

these

the

provisionsof the Coal Mines

Acts

objectionsbe

?

overcome

tion Regula-

Explosives in Coal Mines of explosives Order, 1899, respectingthe care underground ; the charging and stemming of and

the

shots ; and the detonators above Describe (xlix.)

storage, custody and below

and

in detail the

ground

of

use

?

ming operationof charging,stem-

and

firinga shot where there is no dust, showing how you would deal with a fire and givingthe precautions you would throughout.

coal misstake

(Manchester and Ireland District,1906.)

(1.)Where

accumulations

Describe so

What (li.)

i

of coal dust

likely in collieries underground, and to ,be found the dangers arising therefrom ? what are are

how

deal with

the chief differences between

are

coal dust

the risk of accidents.

to reduce

as

would

you

most

the nitrate

classes nitro-glycerine Give examples of two of each of explosives ? scribe dewith their respectivecompositions,and the specialprecautionswhich must be

of ammonium

taken

with

and

each

the

class.

(Liverpool and North

(Hi.)What

are

the rules

in coal mines ,

Wales

regulatingthe ?

Give

a

District,1906.) use

of

explosives

list of the authorised

explosivesand any details with which with the be acquainted connected may in

use

of any

one

of them.

(StaffordshireDistrict, 1906.)

you

ciency effi-

193

APPENDICES.

is it

(liii.) Why

dangerouspracticeto by holding the wires of a safetylamp ?

test

a

cable cover

shot-firing

a

metallic

the

to

(Newcastle District,1907.) Describe (liv.)

(lv.)Why

that may blastingin mines.

be

means

any

should

place be

a

visited

adopted to after

soon

sede super-

firinga

shot ?

(Southern District,1907.) What (Ivi.)

must

do before

you

shot has missed

a

(a) Where

(b)Where Do (Ivii.)

consider

you

a placewhen re-entering

fire

fuse is used ; and is used ? electricity

that the rule for miss-shots

is the firing medium electricity

if so, in what way ? of air and fire-dampat the highestexplosive

A mixture (Iviii.)

pointis passingalong an 4 ft. 6 in. at

airway 5

ft. 8 in.

veloc ty of 460 ft.per minute. quantityof fresh air must be added so

What that of

tion requiresaltera-

And

?

by

where

cannot

you

a

detect the gas

ordinarysafetylamp

an

the

on

flame

?

(Manchester and Ireland District,1907.)

(lix.)Wliat

is

and what fire-damp, testingfor it to ascertain

have

means

you

of

its percentage in the

air?

(Ix.)How

the

can

detector ? this What (Ixi.)

safetylamp Describe

be used

fire-damp lamps arranged for

some

as

a

use.

precautionsare required by law to be taken in the firingof shots by electricity ground underit is ? Say in what circumstances permissibleto use ordinary powder, and whether sive you preferit to any permittedexployou

know

of in the

case

of

(a)Coal getting; (b)Rock heading. Give (Ixii.)

some a

S.F.G.

very

definition of coal dusts

dangerous and

a

as

between,

safe form.

To

say,

what 0

104

SHOT-FIRER'S

THE

GUIDE.

extent, if any,

do you consider precautionsare beyond those alreadyenforced by

necessary law? What

precautions are main

roads.

necessary in should such

Why

firingshots in operationbe

dangerous ? Do (Ixiii.)

consider

you

all collieries liable to

explosions? exempt What (Ixiv.)

(Ixv.)Name

If not, the

name

;

point out rules which

coal dust

are why some regulatethe

of shots in dry and dusty mines. firing explosiveshave you had experienceof, and what are the regulations in force at any colliery with which you are acquaintedin addition to those enforced by law ? of the most two important rules relatingto shots. firing

(StaffordDistrict, 1907.) Describe (Ixvi.)

in

detail

the

arrangements

in firingshots by electricity with safetylamps.

make

for

worked

would

you

mine

a

Describe would make for the arrangements (Ixvii.) you and what storingand distributing explosives, would make for the safe keepregulations ing you in men's of unused explosives the sion possesafter their day's work was done.

(West Scotland Describe (Ixviii.)

the

round and

of say

take

as

"

District,1908.)

operation of charging and firinga of a sinkingshaft, shots at the bottom what specialprecautionsyou would "c. signalling,

to

have

Where

the

"

primers for sinkingshots to be prepared? Previous to firing a shot, what precautionswould (Ixix.) shot ? you take to prevent having a blown-out in the specialrules to be observed What are the

case

"

of

a

missed

(Liverpooland

North

of the more (Ixx.)Mention some explosives contained "

of

December,

17

shot

"

Wales

?

District,1908.)

important in the

1906.

"

permitted

Coal Mines

What

are

the

Order rules

relative to detonators contained in that Order ?

195

APPENDICES.

do

How (Ixxi.)

explosives vary

as

regards

(a) Temperature of ignition; flame temperature? (6) Maximum methods

what

and

latter

the

reduce

have

been

temperature

employed to in artificially

? safety explosives

of the Detail carefully the provisions (Ixxii.) "_

Give (Ixxiii.)

Metalliferous

RegulationsActs as to explosivesand blasting. of the more roughly the compositionof some important explosivesused in mining.

Mines

(Assistant Inspectorshipof

Mines

Examination,

February, 1908.)

QUESTIONS

PRACTICE

ON MINES

COAL 1. Name

the

exceptionsto

2. What

are

the rules

IN

ORDER. of the Order. application in cartthe use of explosives ridges

the

to

as

EXPLOSIVES

THE

? 3. Give

and relatingto charging,drilling

the clause

"

"

permitted explosives," permitted igniter main haulage road." and fuse," road State the conditions regulating the use of detonators. Give the rules regulatingthe use of electrical firing

4. Define

"

"

5. 6.

apparatus 7. What

8. How

"

.

shots

more

is the

use

are

the

9. What

Under

what

fired in the

are

of fuse rules

appointment of

11. How

requiredto

precautionsare or

10.

ming. stem-

be

taken

when

two

place?

same

? regulated

and regulatingthe qualifications shot-firers ?

circumstances

are

certain

absolutely prohibited, and prohibited? detonators are permitted to

explosives(a) (6) conditionally '

used

be

in

sinking

shafts ? 12. State

the rule a

13. State

as

to

watering in

the

neighbourhood of

shot. the rule

in firing

as

main

to withdrawal

roads haulage,

of and

men

during

intakes

shot-

INDEX.

Chapter

shown

Headings

thus

EXPLOSIVES,

Sectional

New

Quoted

Permitted

,,

Firing, 119 Firing or attempting

through boring into ploded Charges, 117 with Electric Through contact

Fire,

to

]23

Wires,

Arising

of

out

Through Through Through

Ignition,

premature

116 At

a

At

a

At

a

At

a

At

a

At

a

At

a

At

a

Colliery in Kinross, 117 115 Colliery in Lanarkshire, Collieryin Northumberland, Durham Quarry, 117 Fife Quarry, 117 Quarry in Derbyshire, 115 Quarry in Gloucestershire,

At

a

Staffordshire

At

a

Sunderland

At

a

Warwickshire

Pit

Clay

At

Easter

At

Glasgow,

AtHett,

in

Jaw

Flint,

115

Mine,

With

Range

another

Level,

CsrtainExplosives

[127

of

of

Explosion of, of using, 127

Danger

Explosibility of, 128 Nitro-glycerineExplosives,

6

Disadvantages Firing, 100

And

away

of

Series

and

Parallel

123

Defective

using

Cables,

117

Of

testing Fuses, Ratio

Afterflame

Classified, 110

Albion

In

a

In

a

In

Durham

In

handling Explosives,

In

Lancashire

Derbyshire Mine, 119 Midland Colliery,121,

Altofts

110

FROM

THE

INFLAMMABLE 125-157

Ammonal

AT-

Ammonite,

9

8, 10 9

8, 9 7

Cartridges, 83 Experiments with, 98

Ammonite

133

134

Dust Experiments, CollieryExplosion, 184

Ammonal,

TION IGNI-

71

Explosives,

Coal

Amasite,

Collieries, 117, 118 frequent in Winter, 112

of

Colliery Disaster,

Albionite, Altofts

123

Collieries', 1 20

MOSPHERES,

119

172

Lamps, of

Advantages

123

by sending Explosives

OF

of

Mines,

Acetylene, Temperature Miners'

RESULTING

123

of, 56

Care

Collieries,93

Worsley Mesnes Colliery,121 by bunching Cartridges, 117 Caused by Charge blowing through

More

taking Proper Cover, 119 of Defectively Insulated

Exploders, 53-57 Apparatus for charging, 57

Caused

by

use

Prohibition

Absolute

At

Caused

tion, Cau-

Accumulator

St. Etienne

Coal,

of

113-115 Detonators, Ripping Shots, 118

With

115

At

in

not

Cable,

in Unsafe

At

Caused

want

Through using Short Cable, While testing Cable, 121

115

115

and

120

Colliery,91 Colliery, 115 Colliery,

122

neglect

Through Through

115

Signal

Delayed Ignition, 123 ignitingExplosive.?,113, 110 between misunderstanding

Workmen, 120

Unex-

121

Through

121

Linlithgow, 115 Linnyshaw Colliery,118

to

133

9

Accidents when

After

At

of Testing Explosives,

,,

10

Accidents

Metlwds

,

Albionite,

Explosives

Abbcite,

EXPLODERS,

,,

,,

Authors

1"31 34"59

138, 183

198

INDEX.

BLASTING

Nitrate

Group, 7 glycerineGroup, 8 Legal Definition of, 163

Ammonium

Nitro-

And

Ammunition, Amvis, 9, 117 Anthracite, Occlusion Aphosite, 10

Blasting

Oxygen by, 129

Apparatus for charging Accumulators, 57 sions Appendix I., Summary of Main Concluthe on Shot-firing from Second of the ComReport Royal mision

Mines, 177

on

II., Comments from

Garforth

Second

the

Report

Commission

Royal

III.,British

Coal

Testing

Gas

on

description of

British Coal Address

,

187 Shot-firing, Application of Explosives in

to, 151

Bunching

Cambrite, Mines

Coal

"

84, Cartridges,

117

9

Camerton

Explosion,150 Rugeley Collieries, Shot-

Cannock

174

Different

of

Resistances

Substances,

Experiments, 138, 183 Association, Dr. SnelVs

Questions Relating

to

Approximate

Dust

Medical

Britonite, 9 "

Examination

Order,

plosion Ex-

Committee, Experiments of, quoted, 97 Bobbinite, Experiments with, 98 Evidence Minutes of Committee, quoted. 155

British

Experiments,

of

Bobbinite

of

the

containing Nitrates,

of, 94

of, 129 Bobbinite, 8, 10, 12

Lamp,

183

IV.

Materials

Blasting Materials, Temperature

Mines, 179

on

Dust

and

STONE

AND

99

Peculiarities of

SHAFTS

PIT

IN

HEADINGS,

and

firers' Qualifications at, 154 Chase Shot-firingRule

Cannock

61

referred

to, 92

Arkite, 6

AscertainingPolarityof Mains, 56 James, quoted, 142 J. B., quoted, 145

Ashworth, Mr. Atkinson, Mr. Atkinson, Mr.

Attaching

W.

H.,

reference

Detonators

to

Capt. Desborough (see Desborough) Carbonite, 9

Carbonite, Experiments with, Carbonite

to, 138

Cartridges,

80-82

Average Percentage

of

Miss-fire

Shots,

89

Group,

98

4

Care

of Accumulator Exploders,56 Cartridges,Standardizing size of, 178 Causes of Failure 88-91 in Shot-firing,

Celtite, 9

Austrian

for

Test

Cell

Explosives,69

Tester, 76, 77

Characteristics Ballistic Tests Barometric

Of

Explosives,85

of

Pressure

in

Relation

to

plosions,Charge Ex-

137

Bedson, Dr. Phillips, quoted, 131 Bedson, Experiments of Prof.,cited,140, for

Explosives,71

1, 9 No. 3, 9

Bellite,No.

IgniterFuse,

133

and

Quarries, 10

Chlorate

Mixture, Legal Definition

Chlorine

Peroxide, 17

of,162

CUfflte/9 Clydach Vale Explosion,134 Clydite, 9 Coal

16

Nippers, 18 Bigg-Withers, Mr., Time Fuse, 28 BLASTING ACCIDENTS, Chapter IV. (seeAccidents), 109-157 BlastingGelatine, 6, 10 Coal

with, 115

Consumption

of hi British Mines

10

Cutters

in

Relation

Risks, 137 Coal Mines Commission,

Patent

Quarries,

Limite, 5,

Cilfynnydd Explosion,135

Bichel,M., quoted, 133 Bickford,Mr. Wm., referred to, 12 Bickford's Safety Fuses, Table of, 12 Electric Fuse, 23 Gutta-percha Fuse, 28

Accidents

Nitrates, 7

Ammonium

Meaning of, 133 Charging and Stemming, 79, 80-86, 178 Cheddite, Consumption of, in British Mines

150

BelgianTest

of

Nitro-glycerine Explosives,4

and

to

Explosion

111

Gas, Temperature of Explosionof, 127 of, 128 Gas, Range of Explosibility Dust (seeDviSt) tion Regulation Act, General Interpretaof, 145 ferred reMining Institute of America to, 130, 143

Line, Coilinga Shot-firing

65

200

INDEX.

Electric Fuse, 19

Low-tension,

20

A

Co.'s, 25

Tirmann,

23

Forgie,Mr. successful

Shot-

Elementary Primary Cell,47 Ensuring Complete Detonation, 81 Ethane, Temperature of Explosion of, 127 Everett, Edgcumbe's Charging Set, 57 Questions,

DepolarisingMixtures,

EXPLODERS,

Induction, 34 Dimensions of Dry Cell,54

Local,

in relation

Pressure

to, 137

Explosives,145

for

of, caused

Detonator, 21

High-tension,20, 23, 25, Low-tension, 20-24, Selection of, 26 Venus, 28

Galvanometer

20

26

Galloway,Prof.,quoted, 131,

142

for

Testing, 77 Garforth Gas Detector, 179 Gar forth,Mr. W. G., referred to, 138, Hall

Garswood

136

Number

Mixture

Ignition,15

Electric

Magneto, With Safety Firing Attachment, 47, Wood's Dry Battery,51 Explosion at Courrieres, 7, 142 At Wingate Grange Colliery, 131 How produced, 1 Explosions,Annual Loss of Life by, 134 Permitted

Explosives,70

Head, 19 Wires, 25

[51, 52

34-36

to

for

Fuses, Delayed Action, 27 Electric,20

Current

Due

Test

Detonators)

49

33-59

Barometric

151

Mercuric, 13 (secStandard

9

Exciting and

quoted,

Fryar, Mr. J. W., quoted, 101 Fulminates, 13 Legal Definition of, 162

Fuse

187

J. T.,

Fracturite..9 French

95 firing,

Electronite, 9

Examination

of, 133

Areas, 136

Principlesof

Excellite.

70

Gas,

Charge, 88 of Explosives,Duration

Flame

Roburite

Electrical

in Coal

Firing Explosives

High-tensionand How ignited,20

142

Colliery, Experiments

at,

1 by Shot-firing, Periods of Immunity from, 134 Primary and Secondary, 135

Testing for Gas, 179 [147 Gases and Vapours, 125 [127 Explosion of, 126 than by Flame, Ignition of, otherwise Range of Inflammabilityof, 128 Gelatine of, in Glycerine Dynamite, Consumption British Mines and Quarries, 10

1"31

EXPLOSIVES,

Act, 1875, 160 Chief

of

Characteristics

Group,

Nitro-

4

Classification of, 3 133 Comparative Safeties of Different, of

Consumption

British

in

Mines

and

favourable Density most 87 Ignition, Coal

to

Order, General

Mines

plete Com-

pretation Inter-

of, 145 In

Coal

Order,

Mines

17, 37, 53, 119.

172, 195 3

for,69-71

Tests

in

Geloxite, Explosion caused General

Rule

12 referred

German

Test

for

by, 145

to, 146 .

119

Explosion,134

Gunpowder,

9

Mines

9

Luck,

Gowerton

British

Explosives,71

Gerrard, Mr., quoted, Good Conductors, 61 Good

Nitro-GlycerineGroup, Extra-Carbonite,

of, Quarries, 10

Consumption

Quarries, 10

and

In

Gelatines, 6 Gelignite, 6

9, 80, 87

Consumption of,in

British

Mines

Quarries, 10 Failure to Fire Shots, Causes "Fast"

Shots,

Faversham ';

Favier

Prohibition 9

Powder,

Poudre,"

of,87-91 of, 178

7

Great

Legal Definition of, 161 Western CollieryExplosion,134

Grisounite

Couche,

Grisoutine

II., 5

93

Fayol,Prof. Henri, quoted, 131 Fire

Damp, Detection

129

also Methane) (see.

of, 151

Firing(see Shot-firing)

Hall, Mr. Henry, cited, 133, 140, Hang- Fire Shots, 91-95, 123 Haylite No. 1, 9

146

and

201

INDEX.

Heating

Effect

Compression Waves

due, to

Medium

5 per cent. Nitro-glycerines, perature Tem(see also Fire Damp),

Methane

141

Hedley, Mr. A. M., quoted, 148 Helsby Magneto Exploder, 35 6 High per cent. Nitro-glycerines, Holden Firing Apparatus, 90 Driving Houghton Colliery,Cross Measure at, 103 and

Association

Mining

Britain

Great

of

to, 139, 183 Fires, 88, 178

Quantity

Explosion of,

127

of

Stemming,

of

a

tigations Inves-

to, 85

as

Minite, 9

HygrometricalObservations

Wingate

at

142

Grange,

of Occurrence

Mode

Monobel

of

Illustrations

Explosives,10

Shot-tiringCables,

64

Explosions,Periods Immunity Drill, 105 Ingersoll-Sergeant

Review

Trades

Kolax,

Methods

New

quoted, 139,

87

Nisbet, Mr. Norman, quoted, 103 Nitrate Mixture, Legal Definition of, 161 Nitro-compound, Legal Definition of, 161

Explosives,3 Nitro-glycerine in handling,111 Accidents Advantages of, 6 Characteristics of, 4 Disadvantages of, 7 High per cent, sub-group, Chief

Kynite, 9 Kynite, Condensed,

9

Low

ExplosivesCo.'s Fuse. 22 Explosives Co.'s System of Packing

Lancashire

Reference

to, 119

TING RELA-

REGULATIONS

AND TO

THE

STORAGE

EXPLOSIVES, Wire Leakage between OF

AND

USE

Earth,

ing Test-

159-176 and

134 Lithanode

Oxygen by,

129

Cells,57

Magneto Exploders,34-37 in production Main Factors

Caroonite,

Exploders,37-41, 53 Book of High Explosivesquoted,

Nobel's

Non-Detonants Non-

as

Detonating

Staffordshire

North

quoted,

Dust

of Shots

-

firing Rule by

Shot-

fired per Annum, 140 with Shot-firing in connection

No. No.

1, 9 2, 9

Obach

Cell, 49 Occlusion, 129, 137

Gas

Shot

Explosions caused

of

Oaklite plosions, Ex-

140, 141 a

Mixtures, 8

92

Risks, 151

of

Coal Getters, 97

Mechanical

5, 9

Normanite,

Number

Exploder,90 in which Explosion of 126

9

Nobel

Nystagmus

Fuses, 47

Low-tension

sub-group,5 Congealation,111

firing,1

Explosion,134

Llanerch

of

Nobel

Number of

cent,

per

Temperature Thawing, 111

110

for, 78 Between Wires, Testingfor,77 for ExplosivesStores, 164 Licences Loss of, by ExploLife, Average Annual sions,

Lignite,Occlusion

per

6

sub-group,4

cent,

Medium

Fuses, 28

Special Rules,

S.F.G

Explosives

Testing

of

quoted, 133

9

LAWS

103

9

Negro Powder,

Mine, Experiments at, 94

Karwin

of CollieryManagers,

Association

Proceedingsof, quoted,

141

Jointing Shot-firingLines, 67,

Green

National

to

Coal

9

Powder,

Experiments at, 98 Colliery, Explosion,134

Moor Morfa

Shot-tirers,175 of Firing Line, 96 Insulation Insulators, 61 Introduction, 1 and

Explosion,

of,134

from

Instructions

Dust

129

Identification of Permitted

Manner

ridges, Cart-

to

80-82

Minimum of

Hydrogen, Temperature

Manet

Fuses, 28-31

Detonators

attaching

Of

plosive, Miss Ex-

become

Vapours

125

Iron

carryingE.D.

referred

Gases

How

Explosion of, 127

of of

Methods

ceeds, pro-

Odite, 9 Ohm's

Law, 61, 95

202

INDEX.

Park

Resistance

SlipExplosion,134

Partial Detonation,

Conductors,

Paying

out

Payne,

Dr.

Peculiarities

Shot-

Peg

Holes

Boring Percussive Theory,

Ripping Ammonal, Rippite, 9 RISKS

Nitrates, 94 for

in 137

Explosive

69

Identification

of, 10 Legal Definition of, 175

PRACTICAL

of 1894 cited, 140 quoted, 151, 177-182 Recovery of Miss-fire Charges,175 Prevention of Blown-out Shots,

175

Russbach

Pot

Russelite.

79-107

when

For

Sarrau's

ACT, THE,

160, 165

Rack-bar Rate Reason

of

165 ,

Blasting,107

Exploder, 37 depositionof Coal Dust, for Dust

becoming

146

Inflammable,

131

Regulations as to Storage of Gunpowder and Mixed Explosives,164 Report of Commission appointedby Societe de r Industrie Minerale quoted, 130, 132, 143 H.M.

Inspectors of Explosives quoted, 85, 93, 113 Inspector of Mines for Liverpool District quoted, 123 Mines. Second, on Royal Commission quoted, 177 Resistance, Electrical,19 Of Electric Fuses, 97

in

use

Quarries

Blasting,166

112

Fiery Mines,

16

Legal Definition of, 163 Method of using,13 Rate of burning of, 13 Etienne dents Collieries,Shot-firingAcci-

St. Helen's

relatingto

thawing Dynamite,

SafeguardsagainstExplosions from Shot154 firing, Safe Rule to follow in Stemming, Only, 86 Safety Fuse, 12

St.

Act, Special Rules

for

9

Qualificationfor Position of Shot-firer, 11 Quarries Act Rule quoted, 91

Quarry, Legal Definition of Quarrying by Simultaneous

sphere, Atmo-

Mines

For

Stemming, 86 Premature Ignition,116 PreventingSpread of an Explosion,142 Primary Object of Altofts Tests, 141 Primer Manner of preparing,15 Cartridge,

.QUARRIES

Inflammable

an

No. 3, 9 Commission

Rules for

APPLICATIONS,

Precautions

of

Road," Legal Definition of, 175 Main, Legal Definition of, 175 Roburite Co.'s Exploder Tester, 75 Electric Fuses, 25

On

refer led to, 138

Co. Colliery

EX-

THE

Roburite

Pole-finding Papers, 58 Pearson's

BY

109, 125

Royal

List, 5, 9, 80 Tests for, 69-71 Permitted IgniterFuse, 17 Legal Definition of, 175 Permonite, 9 Permonite II.,9 Phoenix Powder, 9 Pitite, 9 "

CAUSED

"

and

Pope

9

IMMEDIATELY

Explosives,Consumption of, 10

Watering, 145 Compared with Gunpowder, 97 H.M. Inspectorsof Explosiveson,

61

PLOSIVE, Chapter IV., Part I., 109-124 Risks resultingfrom the Ignitionby the

81 Cartridges,

Permitite, 10 Permitted

95

of

10

Rex.te,

taining con-

Firing Line, 47,

Table

Approximate, Ignition(see.Hang Fire)

Retarded

61

firingLine, 65 Henry, quoted, 130, 143 of Blasting Materials a

of

Resistances,

16

at, 93

Powder,

9

Theory, 91 Saxonite, Explosion caused by, 145 Experiments with, 98 American, The, quoted, 58 Scientific Senghenydd Explosion. 134 Separation of Coal from Shale Dust Blast, 151

by [107

Series

and

Shaft

Sinking,Methods

Parallel

Methods

of

of

Firing,100,

Shot

-firingin,

CollierySinking,100

[178

100-103

Sherwood

Shot-firer, Qualifications of, 11, 110. 154, Causes of Failure in, 87-91 Shot-firing, From Power Cables, 172 In

Frozen

In

Headings,

In

Pit

Ground,

101

99

Shafts, 99, 100, 102

Number

of Explosions caused by, 1 Sinking, Regulationsat Dawdon Colliery 101

Regulations,General. Series

and

Parallel

175,

Methods

177, 178 of, 100

20-*/

INDEX.

Shropshire Shot -firingRule

referred

to,

Testing Exploders, 74, 75 for Earth," 78 Risks and Precautions, "

92

Snell, Dr.

151

Simeon, quoted,

SofteningNitro-glycerine Explosives,86 SolderingJoints in Wires, 67 SpecialRules for Mines, 166 SpecialRules for Quarries, 166 SpecialRules for the Installation and Use in Mines of Electricity quoted, 172 fot Shot-firing Wires, 62, 63 Specifications Standard

for

Mixture

Stokes, Mr. Stone

A.

Storage

of

Rack-

Dust

a

Explosion, 141

Electric

Fuse, 23 Fuse, 27

Titanite, 9

36

Tdnite

Cartridges,82

Transactions

of

Institution

the

of Mining

Engineers quoted, 93, 142, 143, Trauzl

plosives, Tutol, Ex-

Mixed

and

Gunpowder

Exploder, 41

Fuses, 27

Time

Altofts, 186

at

in

Factor

Time

30, 31

Case,

bar

9

Thunderite,

Percentage of, 142

with,

Experiments

Detonator

Three-post

Tirmann

H., quoted, 144

Effective

Dust,

Theedam's

Timsbury Explosion, 150

14

Detonators,

Stemming, 80-86, 17 "* Only Safe Rule to follow, 86 SterlingMagneto Exploders, 35, Dynamo Exploders, 37-47

73

Tetryl Detonators, 14 Thawing Explosives,112

Block

Lead

149

Test, 70

9

164, 178 Stores

for

Urpeth CollieryExplosion, 145

164 Explosives",

6, 9

Stowite.

Stuart, Mr.

D.M.D.,

quoted,

Suggested Remedies Danger,

for

Dust

I..

Consumption Mines

and

Shot-Firing

on

Mines, 177

on

of

Explosives

in

Quarries for the

Safety Fuse,

III., Standard

Mixture

for

Colliery, Experiments

at, 98

V., Conductors

and

Approximate

"c., of

Colliery Explosion,

Insulators, 61 Resistances.

61

Wires, 63 Shot-firing parative Experiments as to the ComMerits of Explosives,98 in Midland IX., Explosion Fatalities 144 District, Inspection Tamping (see Stemming) Temperatures at whichBlasting Materials Explode, 127 At which Gases be Ignited,127 may Of Ignitionof Coal Dust, 131 Test Gauge for Drill Bits, 80 69, 78 for

use

in

Dusty Mines, 69-71,

178

Fiery

Strength of Detonators,

141.

Coal

142, 143, 145

Mines

Inspection

and

required to start Watery Vapour, Amount an Explosion, 142 Watteyne,M. Victor, quoted, 134 Wattstown Explosion,134 Westphalite,Explosion caused bv, 145 Westphalite Whitehaven

No.

1, 9

No.

2, 9

CollieryExplosion, 145

Williamson,

Mr.

R.

8., quoted, 155

Wingate Grange Explosion, 131, 142, 149 for use in Headings, 106 63 Shot-firing, Wood, Mr. E. Seymour, quoted, 102 Wood's Dry Battery Exploder, 51

Wires

Woolwich

Test, 5, 6, 69

71 XL

Fuses, 71, 72

Testing, Cables,

Midland

District, 143

VIII..

Testing Explosives

In

Cell

Dry

VII.,

Effective

Glebe

145

tors, Detona-

Watering Dust, 138,

Dimensions, Exploders, 54

Electric

Explosion

Victorite, 9 Virite, 8, 10 Volf, Mr. L., quoted, 93 Voltmeter for Testing Circuits, 76

Washington

12

14

IV.,

TESTING,

to

149

10

II.. Bickford's

VI.,

Victoria

Relation

in

Risks, 137,

British

Year,

produced by Explosion, 127

Ventilation

141

of Conclusions Summary by the Royal Commission Table

Vacuum

149

allayingthe

Detonator

Case, 30, 31

77

Complete Circuits, 76,

77

Ystradgynlais,Experiments at, 98

145,

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Electro-technical time snld. From

has

Classes

a

SUBJECT.

No.

of Dynamo Determination Routin's Method.

41.

Efficiency by

in Continuous-Current Losses Dynamo Armatures. Efficiency Test of Two Equal Transformers by the Differential (Sumpner's) rent

43.

No. 45.

j t

T-, "6' "e

j

47.

,

of

or

Dynamo

A, , Absolute

The

the Characteristic Machines. v"t"r*

AT Measurement

Measurement

of

Capa-

of Inductances.

48. The Test of a Rotary Converter.

Method. of the Measurement Efficiencyand Factor of a Polyphase InduePower tion Motor Method. by the Wattmeter

44.

SUBJECT. Determination Curves

Separation ot Hysteresisand Eddy Cur-

42.

i

j

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Chapter I." Remarks II.

Measurements and

"

,,

Chapter VII.

Testing Apparatus,

on

"

tial, Current,Potentance. Battery Resis-

VIII.

,,

IX.

"

"

,,

III." Natural and IV. Measurement

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Fault

sistance. Re-

X XI.

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V.

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of Inductive

city. Capa-

Measurement

Localisation ot Disconnections. Localisation of Earth and Contacts.

Current.

of Conductor

"

"

Measurement

of

of Insulation

"

"

sistance. Re-

Corrections of Localisation Tests. Submarine Cable Testing durin inng and Manufacture. Laying

Working. VI.

,,

In the

"

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Appendices numerous

THE

tables and

INTERNATIONAL

XII."

and

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Cable

Testing during

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curves

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are

given.

AND

CONVENTION

TELEGRAPH

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78