Explosives Ravi Gadi

8/8/2019 Explosives Ravi Gadi

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EXPLOSIVESEXPLOSIVES


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What is an explosivesWhat is an explosives ::

AnAn explosiveexplosive cancan bebe solidsolid ,, liquidliquid oror aamixturemixture ofof substancessubstances.. WhenWhen aa suitablesuitablestimulus,stimulus, ((ee..gg electric,electric, flame,flame, spark,spark,

percussion) percussion) isis appliedapplied toto thethe explosiveexplosivesubstancesubstance itit isis capablecapable ofof developingdeveloping aasuddensudden highhigh pressure pressure by by thethe rapidrapidformationformation oror liberationliberation ofof stablestable gasesgases atathighhigh temperaturestemperatures..


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A short historyA short history ::

AnAn EnglishEnglish monkmonk andand scientist,scientist, RogerRogerBaconBacon discovereddiscovered thethe formulationformulation forforblack black powder, powder, aa secretsecret fromfrom ancientancient

ChinaChina forfor weaponsweapons andand becamebecame knownknown asasgunpowdergunpowder byby somesome usersusers.. BlackBlack powderpowderwaswas firstfirst usedused duringduring thethe 1313thth centurycentury..


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16001600 BlackBlack powderpowder waswas firstfirst usedused byby thethe GermanGerman andandHungarianHungarian minesmines byby placementplacement inin rockrock fissuresfissures andand jointsjoints..

16891689 BlackBlack powderpowder waswas introducedintroduced toto CornishCornish tintin minesmineswherewhere paperpaper cartridgescartridges werewere usedused toto packagepackage thethe blackblack

powderpowder..

18311831 WilliamWilliam BickfordBickford introducedintroduced minersminers safetysafetyfusefuse whichwhich mademade thethe useuse ofof blackblack powder powder explosiveexplosivechargescharges safersafer toto initiateinitiate..

18661866 AlfredAlfred NobelNobel introducedintroduced dynamite,dynamite, aa combinationcombinationofof nitroglycerinenitroglycerine andand KiselghurKiselghur.. (diatomaceous(diatomaceous earth)earth)WhichWhich absorbsabsorbs threethree-- fourfour timestimes itsits ownown weightweight ofofnitroglycerinenitroglycerine..

18851885 SmithSmith producedproduced delaydelay detonatorsdetonators.. 19501950ss AmmoniumAmmonium nitratenitrate waswas combinedcombined withwith variousvarious

combustiblecombustible andand began began toto replacereplace somesome quantitiesquantities ofofnitronitro--glyceringlycerin basedbased explosivesexplosives inin openopen casecase minesmines


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Family tree of Explosives:Family tree of Explosives:

Explosives

Mechanical Chemical

Industrial

Low High

Primary (Detonator) Secondary

Conventional Type(Has its ownsensitizer)

Blasting Agents

(ANFO, Slurry,Emulsion etc., which

require a primer)

Military

Nuclear


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Low Explosives:Low Explosives:

AA lowlow explosiveexplosive isis generallygenerally defineddefined asas oneone whichwhich doesdoesnotnot requirerequire aa detonatordetonator toto initiateinitiate itit.. ThisThis typetype ofofexplosiveexplosive isis normallynormally setset offoff byby aa flame,flame, heat,heat, oror aasparkspark whichwhich isis providedprovided byby thethe spitspit ofof aa safetysafety fuse,fuse, aawickwick oror anan electricelectric fusefuse headhead..

BlackBlack power power oror gungun powder powder isis classifiedclassified asas aa lowlowexplosiveexplosive andand itit isis aa mechanicalmechanical mixturemixture ofof ingredientsingredients(do(do notnot combinecombine chemicallychemically toto formform aa newnew compound)compound)wherewhere nonenone ofof thethe ingredientsingredients isis anan explosiveexplosive inin itselfitself..ItIt isis aa mixturemixture ofof charcoal,charcoal, sulphursulphur andand potassiumpotassiumnitratenitrate..


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Low Explosives:Low Explosives:

2KNO3 +S +3C K2S. + N2 + 3CO2PotassiumPotassium Sulfur Sulfur CharcoalCharcoal PotassiumPotassium nitrogennitrogen CarbonCarbon dioxidedioxide

nitratenitrate SulphideSulphide

BlackBlack powder powder doesdoes notnot produceproduce shockshock wavewave butbut burnburnrapidlyrapidly producing producing largelarge quantityquantity ofof gasgas.. AA simplifiedsimplifiedreactionreaction isis asas followsfollows..


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High Explosives:High Explosives:

HighHigh explosivesexplosives detonatedetonate atat velocitiesvelocities whichwhich varyvary betweenbetween40004000 andand 75007500 m/sm/s dependingdepending onon theirtheir composition,composition,densities,densities, degreedegree ofof confinement,confinement, diameterdiameter etcetc.. TheyThey

produce produce largelarge volumevolume ofof gasgas withwith thethe reactionreaction beingbeingexothermicexothermic andand consequentlyconsequently thethe temperaturestemperatures ofofdetonationdetonation areare extremelyextremely highhigh..

TheseThese explosivesexplosives requirerequire aa shockshock wavewave toto intimateintimate themthemandand thisthis isis providedprovided byby aa detonatordetonator.. WhenWhen confinedconfined inin aadrilldrill hole,hole, thethe explosiveexplosive onon detonationdetonation producesproduces extremlyextremlyhighhigh pressurepressure gasesgases whichwhich impactimpact energyenergy inin thethe formform ofofshockshock andand heaveheave intointo thethe surroundingsurrounding rockrock..

TheThe performance performance ofof aa highhigh explosiveexplosive dependsdepends uponupon thethevolumevolume andand temperaturetemperature ofof thethe gasesgases producedproduced andand onon thethevelocityvelocity ofof detonationdetonation (VOD)(VOD)


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High Explosives:

High Explosives:

ManyMany ofof thethe highhigh explosivesexplosives developeddeveloped inin thethe 1919thth CenturyCenturycontainedcontained nitroglycerine,nitroglycerine, nitrocellulosenitrocellulose andand laterlatertrinitrotoluenetrinitrotoluene (TNT)(TNT)..

TheThe developmentdevelopment ofof blastingblasting agentsagents inin thethe 19501950ss hashas ledled totoaa bigbig reductionreduction ofof thethe useuse nitroglycerinenitroglycerine asas aa componentcomponent ininhighhigh explosivesexplosives.. TheThe mainmain constituentconstituent ofof blastingblasting agentsagents isisammoniumammonium nitratenitrate whichwhich isis notnot anan explosiveexplosive inin itselfitself..


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Types of Explosives:Types of Explosives:

a)a) GelignitesGelignites

b)b) Ammonium nitrateAmmonium nitrate Fuel Oil (ANFO)Fuel Oil (ANFO)

c)c) WatergelsWatergelsd)d) EmulsionsEmulsions

e)e) Veolocities of Detonation (VOD)Veolocities of Detonation (VOD)


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Characteristics of Explosives:Characteristics of Explosives:

a)a) Chemical stability or Shelf lifeChemical stability or Shelf life

b)b) DensityDensity

c)c) Velocity of detonation (VOD)Velocity of detonation (VOD)d)d) StrengthStrength

e)e) SensitivitySensitivity

f)f) Fume characteristicsFume characteristicsg)g) Water ResistanceWater Resistance


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Initiation Systems:Initiation Systems:

ExplosivesExplosives willwill detonatedetonate whenwhen subjectsubject toto::oo ShockShock

oo FrictionFriction

oo ImpactImpact

oo HeatHeat

InIn anan efforteffort toto makemake explosivesexplosives reasonablyreasonably safesafe totostore,store, transporttransport andand useuse theirtheir sensitivitysensitivity toto shock,shock,

friction,friction, impactimpact andand heatheat hashas beenbeen reduced,reduced, soso thatthatonlyonly anan initiatorinitiator cancan detonatedetonate anan explosiveexplosive


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Initiation Systems:Initiation Systems:

SomeSome formform ofof initiationinitiation systemssystems areare neededneeded..TheseThese areare::

oo SafetySafety fusefuse andand plainplain detonatorsdetonators..

oo DetonatingDetonating cordcord..

oo

ElectricElectric andand ElectronicElectronic detonatorsdetonators..oo NonelNonel oror shockshock tubetube detonatorsdetonators..


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Safety fuse & Plain DetonatorsSafety fuse & Plain Detonators(Capped Fuse):(Capped Fuse):

AA plainplain detonatordetonator consistsconsists ofof anan aluminiumaluminium tubetube 4242 mmmmalongalong andand 66..44 mmmm inin diameterdiameter whichwhich containscontains anan explosiveexplosive

chargecharge pressedpressed inin thethe bottombottom ofof thethe tubetube.. SafetySafety fusefuse consistsconsists ofof aa centrecentre cottoncotton surrondedsurronded byby aa traintrain

ofof speciallyspecially preparedprepared gungun powderpowder enclosedenclosed inin layerslayers ofof jutejuteyarnyarn andand waterproofingwaterproofing materialsmaterials.. OneOne endend ofof thethe safetysafetyfusefuse isis fittedfitted toto thethe detonatordetonator andand crimpedcrimped withwith aa crimpercrimper

(made(made ofof nonnon--ferrousferrous material)material).. SafetySafety FuseFuse burnsburns atat aa raterate ofof 120120 SecondsSeconds perper metremetre..


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Detonating Cord:Detonating Cord:

AA detonatingdetonating cordcord isis carriercarrier ofof detonatingdetonating wavewave whichwhich isisusedused toto detonatedetonate thethe primerprimer..

TheThe corecore loadingloading isis mademade ofofPETNPETN andand rangerange fromfrom 55 toto

1010f/mf/m lengthlength ofof cordcord.. Generally,Generally, thethe typetype availableavailable inin thethemarketmarket areare thethe 1010g/m,g/m, 2020g/m,g/m, 3030g/mg/m andand 4040g/mg/m ofofPETNPETN..

TheThe detonatingdetonating cordcord cancan bebe intimatedintimated byby aa detonatordetonator.. ThereThereareare manymany usesuses ofof detonatingdetonating cordcord includingincluding productionproduction

blastingblasting toto firefire mainmain shots,shots, presplittingpresplitting,, smoothsmooth blasting,blasting,seismicseismic exploration,exploration, cuttingcutting treetree limbslimbs andand oldold pierpier pilespiles..


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Electric Detonators:Electric Detonators:

ItIt lookslooks thethe samesame asas thethe plain plain detonatorsdetonators but but thethe onlyonlydifferencedifference isis thethe twotwo legleg wireswires attachedattached toto thethe detonatorsdetonators..MostMost ofof thethe detonatorsdetonators hashas thethe resistanceresistance ofof 11 toto 22 ohmsohms andandthethe currentcurrent neededneeded toto detonatedetonate thethe detonatorsdetonators isis 11..55amperesamperes..

ThereThere areare twotwo typestypes ofof electricelectric detonatorsdetonators whichwhich areare thetheinstantaneousinstantaneous typetype andand thethe delaydelay typetype..

TheThe instantaneousinstantaneous willwill detonatedetonate atat zerozero secondsecond uponuponinitiationinitiation.. TheThe delaydelay detonatorsdetonators areare manufacturedmanufactured inin thethesamesame wayway asas thethe instantaneousinstantaneous butbut thethe onlyonly differencedifference isis thethe

presencepresence ofof aa delaydelay elementselements.. ElectricElectric delaydelay detonatorsdetonators seriesseries areare::

11.. HalfHalf secondsecond seriesseries::

22.. CopperCopper shortshort delaydelay seriesseries::


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NonelNonel System or Shock tube System:System or Shock tube System:

TheThe inventioninvention ofof aa shockshock tubetube oror signalsignal tubetube isis basicallybasically aamodernmodern versionversion ofof safetysafety fuse,fuse, wherewhere aa flameflame cancan traveltravelthoughthough thethe centrecentre ofof thethe tubetube

TheThe tubetube isis mademade ofof plasticplastic withwith 33mmmm ODOD andand 22mmmm IDID.. AnAnexplosiveexplosive powderpowder calledcalled HMXHMX coveredcovered thethe insideinside surfacesurface ofofthethe tubetube.. TheThe powderpowder detonatesdetonates atat aa velocityvelocity ofof aboutabout 20002000m/sm/s

andand thisthis sendssends aa detonatingdetonating wavewave toto thethe detonatordetonator.. TheThe plasticplastictubetube isis notnot destroyeddestroyed afterafter detonationdetonation ofof thethe explosiveexplosivepowderpowder..

TheThe tubetube cancan onlyonly bebe initiatedinitiated byby aa detonatordetonator oror byby aa nonelnonelexploderexploder..

ItsIts usageusage isis moremore appropriateappropriate inin areasareas wherewhere electricelectricdetonatorsdetonators areare notnot advisableadvisable toto bebe usedused.. BesidesBesides thethe initiatinginitiatingsystem,system, otherother accessoriesaccessories areare neededneeded toto makemake aa blastingblasting roundroundtoto workwork properlyproperly andand safelysafely..


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Relay Connectors:Relay Connectors:

RelayRelay connectorsconnectors areare blastingblasting delaydelay elementselements primarilyprimarily forforuseuse inin surfacesurface miningmining andand quarryingquarrying operationsoperations.. ThereThere areare 22mainmain typestypes:: detonatingdetonating relayrelay connectorsconnectors (DRC)(DRC) andand NonelNoneltrunktrunk lineline delaysdelays (TLD)(TLD)..

AA DRCDRC consistsconsists ofof22 delaydelay detonators,detonators, ofof fromfrom 55 millisecondmillisecond

(ms)(ms) toto 6060 msms durationduration.. TheThe completecomplete unitunit isis inin thethe shapeshape ofof aasealedsealed plastic plastic dogdog bonebone.. TheThe DRCDRC isis insertedinserted atat ananappropriateappropriate positionposition inin thethe detonatingdetonating cordcord lineline..

AA TLDTLD unitunit consistsconsists ofof aa plastic plastic bunchbunch block block connectorconnectorwhichwhich houseshouses aa novelnovel delaydelay detonatordetonator attachedattached toto aa lengthlength ofof

signalsignal tubetube.. TheThe delaydelay periods periods vary,vary, dependingdepending onon thetheparticular particular manufacturersmanufacturers productproduct.. TheThe relayrelay typetype ofof eacheachTLD,TLD, whichwhich functionsfunctions unidirectionallyunidirectionally,, ensuresensures truetrue holehole--byby--holehole initiationinitiation withwith correctcorrect sequencingsequencing..


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Circuit Testers:Circuit Testers:

WhenWhen usingusing electricalelectrical initiatinginitiating systemsystem itit isis necessarynecessary toto testtestthethe continuitycontinuity ofof eacheach detonator,detonator, thethe shortshort firingfiring cable,cable, andandthethe resistanceresistance ofof thethe entireentire blastingblasting circuitcircuit..

ThisThis isis donedone withwith anan approvedapproved circuitcircuit testertester oror aa blastingblastinggalvanometer,galvanometer, anan instrumentinstrument thatthat appliesapplies aa veryvery lowlow andand safesafeelectricelectric currentcurrent..

ForFor exampleexample oneone suchsuch circuitcircuit testertester cancan deliverdeliver aa maximummaximumcurrentcurrent ofof 5050 mAmA fromfrom thethe battery battery assemblyassembly whenwhen shortshort

circuitedcircuited..

ThisThis amountamount ofof currentcurrent isis farfar belowbelow thatthat requiredrequired toto firefire oneonedetonatordetonator.. SuchSuch testingtesting isis alwaysalways carriedcarried outout fromfrom aa placeplace ofofsafetysafety..


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Exploders:Exploders:

ExplodersExploders oror blastingblasting machinesmachines areare usedused inin thethe electricalelectricalinitiationinitiation system,system, thesethese areare availableavailable dependingdepending onon thethenumbernumber ofof electricelectric detonatorsdetonators inin thethe circuitcircuit.. TheThe commoncommonrangerange isis forfor 11,,1212,,2525,,3030 andand 100100 detonatorsdetonators..

SomeSome explodersexploders areare compoundcompound-- woundwound generatorgenerator types,types,whereaswhereas otherother areare battery battery operatedoperated capacitorcapacitor dischargedischargetypestypes..

AA typetype ofof dynamodynamo--condensercondenser exploderexploder cancan firefire 100100detonatorsdetonators inin seriesseries.. ThisThis isis aa handhand--drivendriven generatorgeneratortogethertogether withwith aa condensercondenser isis incorporatedincorporated inin thisthis exploderexploder..AA neonneon lampslamps indicatesindicates whenwhen thethe condensercondenser isis chargedcharged withwithaa leastleast 12001200 voltsvolts AC,AC, andand aa buttonbutton switchswitch appliesapplies thethevoltagevoltage fromfrom thethe condensercondenser toto thethe outputoutput terminalsterminals..


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Explosives Ravi Gadi