003 Rock Blasting

8/13/2019 003 Rock Blasting

1/15

Rock Blasting

1.0 OBJECTIVE

This method statement outlines proper method of rock blasting.

2.0 SCOPE

The scope of this method statement covers building and civil engineeringworks.

3.0 REFERENCES

Approved Blast Design

4.0 DEFINITION

Nil

.0 RESPONSIBI!ITIES

Project Managerite !ngineerite upervisor

".0 #$ND!IN% $ND STOR$%E OF &$TERI$!

ee Attachments A and B for details

'.0 P!$NT( &$C#INER) $ND E*+IP&ENT

Drilling machines" vibrometer seismograph

,.0 PREP$R$TOR) -ORS

#.$ %!N!&A' ( M!T)*D +!D

Method that are best used to do blasting works in this area is b,-controlled blasting with -powder factor of not more than /.0/kg1m0using AN2*" earth tremor is limited to not more than PP3 $/mm1s and -Airblast of not more than $45dB'" which is usuall, an accepted level in-controlled blasting works done in a communit, area measured from thenearest building.

#.4 B'AT PATT!&N


2/15

Rock Blasting

The blast pattern that is going to be used is -staggered pattern with a 6/o

vertical hole and a 3 cut from the center.

#.0 B'AT !7+!N8!

hock tube detonator 9N*N!': is used as an initiation s,stem to thee;plosive charge to act as a dela,er from one to another not more than#ms to reduce -air blast and earth tremor as well as to reduce the riskcaused b, lightning and electrical power.

#.< A=& B'AT

Air blast is the effect of tremor in the air which can affect the environmentif not controlled below the accepted level. The formula below is used topredict air blast.

Air blast > A(c log $/ ? D 1 9@:/.000 dB'

A 9constant: > $ 4 Distance from the e;plosion hole

@ > @eight of e;plosive

#.5 2'C &*8

#.5.$ 2l, &ock !ffect

!ffect from -fl, rock is the most dangerous to humans" communit,will be more sensitive if there is signs that there is fl,ing rockaround the blasting area. )owever" the blasting surface shall alwa,sbe projected to the direction awa, from the public areas.

tone movement to the front depends on the specific charge.&esearch taken b, the wedish Detonic &esearch 2oundation showsspecific charge /.4kg m0 will not cause front stone movement" it willhowever" onl, cause the stones to crack.

#.5.4 2l, &ocks Projection

&esearch done b, the wedish Detonic &esearch 2oundation alsofound that the projection is influenced b, the function of the

e;plosion hole ' > 4/d

410

with certain specific charge. =t is foundout that the distance of projection from certain specific charge ate;plosion hole from $ to < inches.


3/15

Rock Blasting

#. A2!TC 1 !8+&=TC

#..$ All safet, rules at work area must be obe,ed b, all workers who areinvolved with blasting.

#..4 afet, of workers and public asset must be given serious attention.tandard safet, procedure must be obe,ed full,.

#..0 afet, in the handling of e;plosive should be followed and given seriousattention. !ver,one must full, adhere to all general safet, codes providedb, the e;plosives manufacturer.

#..< !;plosives that are carried must be guarded b, a certified licensedcompan, as reEuired b, the authorit,.

#..5 afet, briefings must include all those involved" workers and guardsbefore blasting is done.

/.0 -OR &ET#ODO!O%)

6.$ Blasting holes must be dug according to the specification stated. )ollowholes will be marked and told to the shotfirer. )owever" if this cannot bedone" then the, are to be left alone to avoid over charge. The holes must

be checked and water must be scoop out and measured the depth of theholes.

6.4 @hen e;plosive is brought to the blast site" no one is allowed to be in thedistance of 0/m e;cept limited numbers of blast workers. All radios"mobile phones" smoking eEuipment is not allowed to be an,where within0/m from the blasting area.

6.0 Before filling the e;plosive works is done" all eEuipments and machinesused must be taken out and parked at least 5/m awa, from the blastingarea.

6.< 8onnection works on the initiation s,stem must be done b, a shotfirerwho is competent and earlier identified.

6.5 irens will be turned on according to the method that has been decidedbefore in the circular. !ver,one must be awa, from the dangerous areaFroads coming in shall be closed. @hen the situation is safe" siren will thenbe stopped.

6. 3ibrometer seismograph must be installed in a place that has been earlier

identified prior to the blasting.

6.G hotfirer can start the blasting when the siren is stopped and there is asafe sign.


4/15

Rock Blasting

6.#. After blasting is done" wait for about $5 minutes before commencing to an

inspection" as to let the dusts and gasses subside. *nl, those which aregiven authorities shall commence inspection and decide whether it is safeor otherwise.

6.6 @hen ever,thing is considered safe a signal will be given" roads coming inwill be reopened after blasting is done.

6.$/ =f a misfire happens procedure must be followed" as shown in AttachmentA.

6.$$ &ecords of vibrometer seismograph must be taken and collected forconsultant inspection and certified.

6.$4 'eftover e;plosives must be destro,ed at site on the same da, b, theshotfirer himself and witnessed b, consultant.

6.$0 =f a misfire happens when during the wait" wait at least $5 minutes beforeclosing in to do inspection on reasons misfire happens. The shotfirer isresponsible to take the necessar, steps to correct the situation and followthe rules.

6.$< Procedure used to handle misfire is shown in Attachment A must be

followed as a guide.

$ttacnt $&ISFIRE

TCP! *2 M=2=&! H

$. !Euipment or material failure


5/15

Rock Blasting

$.$ =nitiation s,stem

$.$.$ Detonator failure1fault,- 8heck shock tube" if there is still intact fi; new detonator and

shoot$.$.4 !;ploder failure1fault,

- 8hange to new e;ploder$.$.0 2iring cable fault,

- &e(connect the wire or change to new cable$.4 !;plosive failure1fault,

$.4.$ =nsensitive e;plosives such as e;pired e;plosives$.4.4 DesensitiIed e;plosive

$.4.4.$ @ater ingress into AN2*$.4.4.4 Transient pressure AN2* or bulk e;plosive$.4.4.0 Decoupled e;plosive ieJ break in the e;plosive column

=f misfire cause b, e;plosive failure" follow the treatment of misfireprocedure.

$.0 TechniEue failure$.0.$ @rong choice of primer

- Make sure using cap sensitive e;plosive$.0.4 Poor primer assembl,

- Placed the detonator inside the primer properl,

$.0.0 Attachment of detonator1 to cord or tubing- The electrical connections or the tubing are wrongl, connected"

check connections and re(shoot$.0.< Disconnected charge

- +sing bagged AN2* in wet causing it to float" make sure all waterhas been blown out from the hole before charging

$.0.5 +nsuitable e;plosive( Never use AN2*

$.0. Damage wires cord or tubing- Damage tubing can stop e;plosion propagation re connect new

tube

$.0.G =nsufficient capacit, of e;ploder- 8heck capacitive charge or replace new batter, or use another

e;ploder

4. 2ailure due to site conditions4.$ %round condition

- 2racture Iones or bedding planes ma, lead to ground movement

during blasting which can cause cut(offs in the e;plosive column. =fthis happened follow the treatment of misfire.

4.4 Dela, patterns


6/15

Rock Blasting

( 'ong dela, times can cause ground movement which lead to cut(offthe tubing. 2i; new N*N!' and shoot.

RECO%NITION OF &ISFIRE

$. !;istence of undisturbed ground or lacks of fracturing or a few of the blastholes are still intact.

4. Presence of undetonated e;plosives in the rock pile.

0. Poor fragmentation be,ond the normal practice.


7/15

Rock Blasting

or air. Metal pipe" even if tipped with rubber or plastic" should not be used forthis purpose. Neither is it safe to use metal tool" spoon or augers for digging out

the stemming.

*nce the stemming is removed a new primer ma, be inserted in the borehole incontact with e;plosive column and an attempt to fire the hole made. 8are mustbe taken even after this attempt is tried. There have been cases where thesecond primer did not initiate the entire powder column but generated enoughheat to cause the original misfired charges to start burning. This will result indangerous Khang fireL which ma, detonate several minutes later. The sound ofre(primed charge is not certain indication that the original misfire hascompletel, detonated.

=n the event that the misfire cannot be re(fired" the least dangerous method isto remove e;plosives with a water1air jet" in manner described above forremoving stemming. =f the e;plosives column is AN2* or other bulk e;plosive"this method will normall, work well.

*ccasionall," a primer will detonate but not initiate a portion of powder column.These misfire are often due to ground movement cutoffs" inadeEuate priming"deteriorated e;plosive" or bridge charges in the borehole. @hen these partialmisfire occur" it ma, be ver, difficult to detect une;ploded charges in muck pile"or in a remaining bootleg of shot" no one should ever drill into bore hole or the

remnant of a borehole that previousl, contain e;plosive. Man, accident havealso occurred when drilling was done too close to a misfired charge. uch amisfire can be detonated if the drill steel wanders and strike the charge. =t isalso possible that merel, drilling in close pro;imit, to a misfire can cause it towarn the operator to shovels" backhoes" or front(end loaders to be on the alertfor the e;plosive while digging.

HH Blasters )andbook $Gth!ditionH hotfirers course note

Attachment BGENERAL SAFETY PRACTICE CODE

=N A88*&DAN8! T*

MAN+2A8T+&!& TANDA&D

1. TR$NSPORTIN% EP!OSIVE &$TERI$!S


8/15

Rock Blasting

A'@AC J keep matches" lighters" open flame and other sources ofignition at least 5/ feet awa, from parked vehicles carr,ing

e;plosive materials.

A'@AC J follow 2ederal" tate" and local laws and regulationsconcerning transportation.

A'@AC J load and unload e;plosive materials carefull,.

N!3!& J park vehicle containing e;plosive materials close to people orcongested areas.

N!3!& J leave a vehicle containing e;plosive material unattended.

2. #$ND!IN% EP!OSIVE &$TERI$!S

4.$ %eneral

A'@AC J use permissible e;plosive materials in flammable" gass," ordust, atmosphere when reEuired b, applicable 2ederal" tate and locallaws and regulation.

A'@AC J keep e;plosives materials awa, from children and

unauthoriIed person" and livestock.

N!3!& J use e;plosive materials unless completel, familiar with safeprocedures or under the direction of a Eualified supervisor.

N!3!& J handle e;plosive materials during the approach of anelectrical storm. 2ind a safe location awa, from the e;plosivematerials. @hen a storm is approaching" consult ,oursupervisor. This applies to both surface and undergroundoperations.

N!3!& J fight fires involving e;plosive materials. &emove ,ourselfand all other persons to a safe location and guard the area.

N!3!& J put e;plosive materials in pockets of ,our clothing.

3. PROTECTIN% EP!OSIVE &$TERI$!S

A'@AC J ensure that there are no foreign objects" loose powder ormoisture in a fuse detonator before inserting the safet, fuse.

A'@AC J avoid the use of Kshot breaksL to prevent prematureinitiation or damage of the initiation s,stem. =f Kshort breaksL must beused all loaded holes should be considered the determining the siIe of theblast area.


9/15

Rock Blasting

N!3!& J insert an,thing into a fuse detonator e;cept safet, fuse.

N!3!& J use e;plosive materials that have been water soaked" even ifthe, now appear to be dried out.

N!3!& J investigate the contents of a detonator.

N!3!& J pull wires" safet, fuse" shock tube" plastic tubing" ordetonating cord out of an, detonator or dela, device.

N!3!& J take part or alter the contents of an, e;plosives materials.

N!3!& J e;pose e;plosive materials to sources of heat e;ceeding$5/o2 or to open flame" unless such materials or procedures for their use"have been recommended for such e;posure b, the manufacturer.

N!3!& J strike e;plosive materials" with or allow them to be hit b,objects other than those reEuired in loading.

N!3!& J subject e;plosive materials to e;cessive impact or friction.

N!3!& J allow loaded firearms in the vicinit, of" nor shoot near

e;plosive materials" magaIines or vehicles loaded with e;plosivematerials.

4. +SIN% EP!OSIVE &$TERI$!S 5 DRI!!IN%( !O$DIN% $ND T$&PIN%


10/15

Rock Blasting

A'@AC J take precautions during pneumatic loading to prevent theaccumulation of static electric charges.

N!3!& J place an, parts of the bod, in front of the borehole e;ceptthose reEuired for the loading" tamping or stemming operations.

N!3!& J force e;plosive materials into a borehole.

N!3!& J load a borehole containing hot or burning material.Temperature above $5/o2 could be dangerous.

N!3!& J spring a borehole near other holes loaded with e;plosivematerials.

N!3!& J stack more e;plosive materials than needed near workingareas during loading.

N!3!& J drop large diameter" rigid cartridges 9$


11/15

Rock Blasting

A'@AC J insert the detonator completel, into a hole in the e;plosivematerials made with a non(sparkling punch designed for the

purpose" or in the cap well of a manufactured booster.

A'@AC J secure the detonator within the primer.

A'@AC J point the detonator in the direction of the main e;plosivecharge.

A'@AC J secure the detonator to a primer cartridge so that no tensionis placed on the leg wires" safet, fuse" shock tube" plastic tubing" ordetonating cord at the point of entr, into the detonator.

A'@AC J be certain the detonator is full, inserted in the primercartridge or booster and does not protrude from it.

N!3!& J use cast primer or booster if the hole for the detonator is toosmall.

N!3!& J enlarge a hole in a cast primer or booster to accept adetonator.

N!3!& J punch e;plosive material that is ver, hard or froIen.

N!3!& J force or attempt to force a detonator into e;plosive material.

5.0 'oading the Borehole

A'@AC J use the first cartridge in the borehole as the primer cartridgewhen two inch diameter or smaller cartridges are used.

N!3!& J drop large diameter" rigid cartridge 9


12/15

Rock Blasting

N!3!& J pull the wires too tightl,. This ma, break them or damagethe insulation.

.4 'arge Diameter 8artridges

tep $ J Punch a hole straight into one end of the cartridge.tep 4 J =nsert the detonator into the hole.

tep 0 J Tie leg wire around the cartridge twice using a half(hitch.92or better protection" one can use tape to fasten the wire:

'. &$IN% PRI&ER -IT# F+SE OR NON6E!ECTRIC DETON$TORS

tep $ J Punch a hole straight into a cartridge right to thecenter part.

tep 4 J =nsert the fuse or non(electric detonator into the hole.

tep 0 J &un the fuse or detonator along the cartridge and fasten itwith tape securel,.

,. +SIN% EP!OSIVE &$TERI$!S 5 %ENER$! PREC$+TIONS

#.$ Protecting Courself

A'@AC J keep e;plosive materials awa, from food" e,es" or skin. 2lushareas of contact with large Euantities of water.

A'@AC J avoid e;posure to e;cessive noise from blasting. 8ompl,with 2ederal" tate and local laws and regulation.

A'@AC J fire the shot from a position outside the blast area 9awa,from where fl, rock might occur:" or if necessar, to be in theblast area" from an adeEuate blast shelter that providesprotection from fl,ing materials.

A'@AC J remain in a position awa, from the blast are until post(blastfumes" dusts" or mists have subsided.

N!3!& J handle an, e;plosive materials or position ,ourself near an,e;plosive materials when initiating a blast.

N!3!& J fire the shot from in front of the blast.

N!3!& J breathe the dust or vapors from e;plosive materials.

#.4 Protecting *thers

A'@AC J clear the immediate areas of persons.

A'@AC J not clear


13/15

Rock Blasting

A'@AC J sound adeEuate warning prior to the blast.

A'@AC J use a blasting mat or other protective means when blastingclose to residences or other occupied buildings or other location whereinjur, to persons or damage to propert, could occur as a result of fl,rock.

N!3!& J fire a blast without a positive signal from the person incharge.

N!3!& J permit an,one to handle e;plosive materials or positionthemselves near e;plosive materials when a blast is to beinitiated.

#.0 Protecting The Blast Area

A'@AC J clear the immediate area of vehicles" eEuipment" and e;trae;plosive materials.

A'@AC J design a blast to avoid e;cessive air blast" ground vibration"and fl,rock. 8ompl, with 2ederal" tate and local lawsregulation.

N!3!& J allow an, source of ignition within 5/ feet of a blast sitee;cept approval safet, fuel lighter.

/. +SIN% EP!OSIVE &$TERI$!S 5 NON6E!ECTRIC$! INITI$TION

6.$ %eneral

A'@AC J follow manufacturers warning and instruction especiall,hook up procedures and safet, precautions.

A'@AC J discontinue operations during the approach and progress of

electrical storm.

N!3!& J hold non(electric leads during firing. This ma, cause injur, ordeath.

N!3!& J use tubing or detonating cord leads for an, purpose otherthan that specified b, manufacturing.

6.4 MiniaturiIed Detonating 8ord ,stem

A'@AC J use e;plosives that are insensitive to initiation b, theminiaturiIed detonating cord.


14/15

Rock Blasting

N!3!& J join two sections of miniaturiIed detonating cord. Adetonation will not pass through such connection.

6.0 hock Tube ,stem

A'@AC J ensure that shock tubing connections to detonating cord areat right angles to prevent angle cut(offs.

A'@AC J avoid situation where initiation s,stem components canbecome entangled in machine" eEuipment" vehicles or movingparts there of.

N!3!& J drive an, vehicle over shock tube.

N!3!& J pull stretch kink or put tension on a shock tube such that thetube could be caused to break or otherwise malfunction.

10. +SIN% EP!OSIVE &$TERI$!S 5 $FTER6B!$ST PROCED+RES

$/.$ Disposal of !;plosives Materials

A'@AC J treat deteriorated or damaged e;plosive materials withspecial care. The, ma, be more haIardous than e;plosivematerials in good condition.

A'@AC J dispose of e;plosive materials using proper methods. 8heckwith ,our supervisor or the manufacturer.

N!3!& J rouse an, e;plosive material packaging.

N!3!& J burn e;plosive materials packaging in a confined space.

$/.4 Misfires

A'@AC J wait at least 0/ minutes with fuse detonator misfires and atleast $5 minutes with electric and other non(electric detonator misfires"unless the manufacturer recommends otherwise" before returning to ablast area. 8ompl, with 2ederal" tate" and local laws and regulation.

A'@AC J shunt the bare wires of a misfired electric detonator b,twisting them together and taping them to the metal shell toprotect against e;traneous sources of electrical energ,.

N!3!& J drill" bore" or pick out an, e;plosive materials that have beenmisfired. Misfires should *N'C be handled b, a competent


15/15

Rock Blasting

e;perience person knowledgeable of the blast design"including the location and t,pe of all e;plosive materials.

$/.0 Blast(%enerated 2umes

A'@AC J assume to;ic fumes are present from all blasts or burninge;plosive materials and sta, awa, until the, have dissipated.

A'@AC J compl, with applicable 2ederal" tate" and local lawsregulation for sale fume levels before returning to blast area.

Documents

003 Rock Blasting