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SAFETY DURING BLASTING OPERATION

GUIDELINES FOR BLASTING AND SAFE USE OF EXPLOSIVES

Among all of the professions on earth, there is none that demands a stricter commitment to safety, proper training, product education, and respect for the rights of others than that of the Blasting Engineer and Explosive engineer.

THE GUIDE LINES MAY DIVIDE INTO FOUR GROUPS: - BEFORE DRILLING - DURING DRILLING AND CHARGING - DURING BLASTING - AFTER BLASTING

THE DRILLING AND BLASTING WORK PROCESS

 THE FRONT ROW CHARGE SHOULD BE ADEQUATELY DESIGNED TO MOVE THE FRONT ROW BURDEN.  BACK ROW HOLES SHOULD BE DRILLED AT AN OPTIMUM DISTANCE FROM THE FINAL DIGLINE TO PERMIT FREE DIGGING AND YET MINIMISE DAMAGE TO THE WALL.  THE MAIN CHARGE AND BLAST HOLE PATTERNS SHOULD BE OPTIMIZED TO GIVE THE BEST- POSSIBLE FRAGMENTATION AND DIGGING CONDITIONS FOR MINIMIM ‘PF’.  MINIMUM TWO FREE FACES SHOLD BE AVAILABLE FOR BLASTING. BASIC DESIGN PRINCIPLES  ADEQUATE DELAY SHOULD BE USED TO ENSURE GOOD MOVEMENT TOWARDS FREE FACES AND CREATION OF NEW FREE FACES FOR FOLLOWING ROWS.

DURING DESIGN THE FOLLOWING POINTS SHOULD KEEP IN MIND:  IS IT A CONTROLLED BLASTING  ARE THERE ANY CRITICAL STRUCTURES TO TAKE CARE  ARE THERE ANY HISTORICAL STRUCTURES  PERMISSIBLE LIMITS FOR THOSE CRITICAL STRUCTURES  THE MAXIMUM CHARGE MAY EXPLODE TO RESTRICT THE DAMAGE TO STRUCTURES AND ADJACENT ROCK MASS.  THE MAXIMUM SIZE OF FRAGMENTATION.

CONTROLLED BLASTING TECHNIQUE Used to reduce overbreak and minimise the fracturing of the rock of the boundary of an excavation Used to reduce overbreak and minimise the fracturing of the rock of the boundary of an excavation Basic controlled blasting techniques are Basic controlled blasting techniques are 1) Line Drilling Dia of hole - 50 to 75mm Dia of hole - 50 to 75mm Spacing – 2 to 4 dia Spacing – 2 to 4 dia No explosives No explosives Depth upto 9.0m Depth upto 9.0m

2)Presplitting Dia of hole - 50 to 100mm Dia of hole - 50 to 100mm Spacing – 6 to 12 dia Spacing – 6 to 12 dia Explosives- spring loaded on detonating chord Explosives- spring loaded on detonating chord Depth upto 15.0m Depth upto 15.0m 3)Cushion blast Dia of hole - 50 to 150mm Dia of hole - 50 to 150mm Depth upto 30.0m Depth upto 30.0m 4)Smooth blast CONTROLLED BLASTING TECHNIQUE

DRILLING -THE DESIGN SHOULD BE EXPALINED CLEARLY TO DRILLING TEAM. - THE DESIGN SHOULD BE MARKED BEFORE DRILLING STARTS. NO OF HOLES AND DIRECTION OF HOLES IN EACH ROUND. - PROPER CARE SHOULD BE TAKEN TO MAINTAIN THE DRILL HOLE ANGLE. - THE DEPTH OF EACH HOLE SHOULD MAINTAIN AS PER DESIGN. - THE NO OF HOLES SHOULD BE CHECKED AFTER DRILLING.

DURING CHARGING TRANSPORT OF EXPLOSIVES:  TRANSPORT OF EXPLOSIVES FROM THE MAGAZINE TO TEMPORARY STORAGE SHALL BE DONE IN DAYLIGHT.  THE MECHANICAL VEHICLE USED FOR TRANSPORT SHOULD BE APPROVED MY ‘DGMS’.  EVERY VEHICLE USED FOR EXPLOSIVE SHALL BE MARKED WITH WORDS ‘ EXPLOSIVE’ IN RED LETTERS ATLEAST 15 cm HIGH ON WHITE BACKGROUND.  EXPLOSIVES AND DETONATORS SHALL BE TRANSPORTED IN SEPARATE VEHICLES / TRIPS

VAN CONSTRUCTION DIESEL

MAIN MAGAZINE

 ATLEAST TWO FIREEXTINGUISHERS SHALL BE THERE IN VEHICLE USED FOR TRANSPORT OF EXPLOSIVE.  IN SHAFTS, EXPLOSIVES SHALL NOT BE CONVEYED DURING THE MAN WINDING HOURS, AND NOT MORE THAN MAN WINDING SPEEDS.  THE WINDING ENGINE DRIVER, BANKSMAN SHALL BE INFORMED BEFOREHAND.  THE QUANTITY OF EXLPOSIVE AND NO OF DETONATORS SHOULD BE CHECKED BEFORE CARRYING TO UNDER GROUND/ SHAFT

 THE CHARGE AND THE DETONATOR NUMBER TO PUT INTO EACH HOLE SHOULD BE CHECKED.  THE DETONATOR SHOULD BE CHECKED FOR BREAKAGE OF LEADS AND ANY DEFECT.  IN EACH HOLE STEMMING SHOULD BE DONE AS PER DESIGN AND THE MATERIAL SHOULD BE PRESCRIBED ONLY.  AFTER CHARGING IN ALL THE HOLES, THE CONNCTIONS SHOULD BE MADE BY SHOT FIRER WITH HELP OF BLASTING INCHARGE.  ALL THE CONNECTIONS SHOULG BE CHECKED ONCE AGAIN BY SHOTFIRER AND BLASTING INCHARGE BEFRE CONNECTING TO MAIN CABLE.

Loading Explosives: No operating equipment within 50 feet of loaded holes No operating equipment within 50 feet of loaded holes Load only those holes intended to be fired in the next round Load only those holes intended to be fired in the next round Warning signs posted Warning signs posted Check all holes for Check all holes for depth prior to loading depth prior to loading

APPARATUS ALL THE BLASTING APPARATUS AND THE APPARATUS USE NEAR BY SHOULD BE EITHER INTRINSICALLY SAFE OR FLAMEPROOF AND APPROVED BY DGMS INTRINSICALY SAFE OPERATUS ARE LOW POWER EQUIPMENTS LIKE -BELLS -RELAYS -TELEPHONES -SIGNALLING -REMOTE CONTROL -EXPLODERS.

AFTER BLASTING  THERE IS CHANCE OF ‘MISFIRES’ AND ‘BLOWN OUTSHOTS’. SO, MEN SHOULD NOT BE ALLOWED TO RETURN TO THE PLACE UNLESS THERE IS CLEARENCE SIGNAL FROM THE SHOTFIRER OR BLASTING INCHARGE.  MINIMUM TIME GAP OF 5 min FOR ELECTRIC BLASTING AND 30 min FOR NON-ELECTRIC BLASTING SHOULD BE GIVEN BEFORE ENTERING THE BLASTING ZONE.  EXPLOSIVES THEORETICALLY CONTAIN SUFFICIENT OXYGEN TO COMPLETE COMBUSTION, BUT COMBUSTION IS SELDOM PERFECT AND ‘CO’ IS LIABLE TO PRESENT IN THE BLASTING FUMES.

IN ADDITION POST DETONATION FUMES CONTAIN NITOROUS FUMES. SO, MEN SHOULD NOT BE ALLOWED TO RETURN TO THE PLACE UNTIL THE FUMES HAVE BEEN CLEARED BY THE VENTILATION. AFTER THE STIPULATED TIME GAP THE SHOT FIRER/BLASTING INCHARGE SHOULD CHECK FOR ANY MISFIRES OR BLOWN OUT SHOTS. IF BLAST IS ALL RIGHT THE FINAL SIREN MAY GIVEN FOR CLEARANCE.

MISFIRES MISFIRE- IS ONE WHICH THE DETONATOR FAILS TO EXPLODE OR HAVING EXPLODED, FAILS TO IGNITE THE CHARGE. REASONS-  DEFECTIVE SHOTFIRING EXPLODER BY WHICH REQUIRED VOLTAGE IS NOT GENERATED.  BAD CONNECTION BETWEEN EXPLODER AND SHOTFIRING CABLE, BETWEEN CABLES AND DETONATOR LEADS.  DEFECTIVE SHOT FIRING CABLE, BROKEN WIRES INTERRUPTING THE CIRCUIT OR DAMAGED INSULATION CAUSING A SHOT CIRCUIT.  BROKEN DETONATOR LEADS  BAD EXPLOSIVE (EITHER DUE TO BAD MANUFACTURE OR DUE TO DETERIORATION DURING STORAGE).

DEALING WITH MIS-FIRES DISCONNECT THE CABLE AND WAIT FOR PRESCRIBED PERIOD.  CHECK MAIN CABLE AND DETONATOR IF ALL THE SHOTS ARE FAILED  CHECK SUB CONNECTIONS, AND PARTICULAR DETONATOR LEADS, IF SOME HOLES ARE FIALED.  RECONNECT,IF ANY DEFECT CONNECTIONS FOUND AND CONNECT THE CABLE AND FIRE ONCE AGAIN.  IF AGAIN FIALED, FENCE THE ENTRANCES TO THE PLACE.  DRILL A FRESH HOLE ATLEAST 30 cm AWAY FROM THE MISFIRED HOLE AND AS FAR AS POSSIBLE PARALLEL TO MISFIRED HOLE.  CHARGE THE NEW HOLE WITH PROPER STEMMING IN THE USUAL MANNER.  FIRE THE NEW HOLE IN THE USUAL MANNER.  SEARCH FOR THE UNFIRED DETONATOR AND CHARGE. IF THEY ARE NOT FOUND LAOD THE MATERIAL BY MANUAL IN A SEPARATE BUCKET DISTINCTLY MARKED AND SEND IT TO THE SURFEACE FOR FURTHER SEARCH.

DESTROY THE MISFIRED EXPLOSIVE (CHARGE) AND DETONATOR ON THE SURFACE, IF TRACED OUT. IF NOT FOUND, REPORT THE CIRCUMSTANCES FULLY TO THE SHOT FIRER OF THE NEXT SHIFT.

ENVIRONMENT The detonation of three different ammonium nitrate- fuel oil (ANFO) mixture illustrates the principle of oxygen balance. The detonation of three different ammonium nitrate- fuel oil (ANFO) mixture illustrates the principle of oxygen balance. 1) 94.5% AN-5.5% FO( Oxygen balanced) 1) 94.5% AN-5.5% FO( Oxygen balanced) 3NH 4 NO 3 + CH 2 = 7H 2 O+CO 2 +3N Kcal/Kg 3NH 4 NO 3 + CH 2 = 7H 2 O+CO 2 +3N Kcal/Kg 2) 92% AN-8.0% FO( Fuel excess) 2) 92% AN-8.0% FO( Fuel excess) 2NH 4 NO 3 + CH 2 = 5H 2 O+CO+2N Kcal/Kg 2NH 4 NO 3 + CH 2 = 5H 2 O+CO+2N Kcal/Kg 3) 96.6% AN-3.4% FO( Fuel shortage) 3) 96.6% AN-3.4% FO( Fuel shortage) 5NH 4 NO 3 + CH 2 = 11H 2 O+CO 2 +4N 2 +2NO+ 600Kcal/Kg 5NH 4 NO 3 + CH 2 = 11H 2 O+CO 2 +4N 2 +2NO+ 600Kcal/Kg

FIRST AID HIT INJURY BY PROJECTILES HIT INJURY BY PROJECTILES INHALATION OF EXPLOSIVES INHALATION OF EXPLOSIVES INHALATION OF BLASTING FUMES INHALATION OF BLASTING FUMES

WARNING NOT TO USE MOBILE / CELL PHONE MOBILE / CELL PHONE HAND SETS & HAND SETS & WELDING WELDING

Emergency Response Fire Thunder storm Explosive van accident Any un-attended explosive materials

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