CONTENT

• INTRODUCTION

• BLASTING ACCESSORIES

• PROPERTIES OF EXPLOSIVE

• INITIATING SYSTEM

• ELECTRIC DETONATORS

• NON ELECTRIC SYSTEM

• INITIATING BLASTING PATTERN

• REFERENCES

INTRODUCTION

THE PROCESS OF BREAKING ROCKS INTO SMALLER PIECES BY USE

OF EXPLOSIVES.

EXPLOSIVES IS A CHEMICAL COMPOUND OR MIXTURE, WHEN

EXPLODED BY ACTION OF HEAT, IMPACT, GIVES LARGE VOLUME OF

GASES IN A VERY SHORT TIME AT HIGH TEMPERATURE & PRESSURE.

• THE TYPES OF EXPLOSION ARE THE FOLLOWING:

MECHANICAL

ELECTRIC

NUCLEAR

CHEMICAL, FROM THE MINING POINT OF VIEW, ONLY THE

LAST ARE OF INTEREST

BLASTING ACCESSORIES

• VARIOUS IMPORTANT BLASTING ACCESSORIES ARE AS UNDER:

1. SAFETY FUSE

2. PLASTIC IGNITOR CORD.

3. DETONATORS.

4. CORD RELAY

5. DETONATING CORD

7. ANODET

8. OHM METER

9. EXPLODER

PROPERTIES OF EXPLOSIVE

• THE PROPERTIES OF EACH GROUP OF EXPLOSIVES GIVE PREDICTION OF THE

PROBABLE RESULTS OF FRAGMENTATION, DIS-PLACEMENT AND VIBRATIONS.

THE MOST IMPORTANT CHARACTERISTICS ARE:

• STRENGTH AND ENERGY DEVELOPED

• DETONATION VELOCITY

• DENSITY

• DETONATION PRESSURE

• WATER RESISTANCE

• SENSITIVITY

OTHER PROPERTIES WHICH AFFECT THEIR USE AND MUST BE TAKEN INTO

ACCOUNT ARE:

FUMES, RESISTANCE TO HIGH AND LOW TEMPERATURES, DE-SENSITIZATION BY

EXTERNAL CAUSES, ETC.

INITIATING SYSTEM

Electrical system

detonator of priming, only

electrical wires are attached.

Non-electric system

there is no electric wire

is required in the hole.

D-cord or detonating fuse

Instantaneous electric

detonatorsShort delay detonators

(millisecond delay)

Long delay detonators

(half second delay)

ELECTRIC DETONATORS

• ELECTRIC DETONATORS ARE USED TO INITIATE

OTHER EXPLOSIVE, DETONATING CORD AND SHOCK

TUBE

• IN ELECTRIC DETONATORS ELECTRIC ENERGY IS

SENT THROUGH COPPER LEG WIRE TO HEAT AN

INTERNAL CONNECTING BRIDGE WIRE.

• ELECTRONIC DETONATOR HAVE AN ELECTRONIC

COUNTER ON A MICROCHIP IN PLACE OF

PYROTECHNIC DELAY CHARGE.

ELECTRONIC DETONATORS

• ADVANTAGES:

HIGHER TIMING PRECISION (10 MICROSECOND

THAN 1-10 MS SCATTER)

INCREASE CONTROL TIME DELAY

GREATER SAFETY AGAINST ACCIDENTAL IGNITION

(CODED FIRING SIGNALS)

• DISADVANTAGES

HIGHER PRICE BECAUSE OF CHIP AND CAPACITOR

BACK TO ELECTRIC WIRING-RISK OF GROUND

FAULTS OR POOR CONTACTS

NON ELECTRIC SYSTEM

• NON-ELECTRIC INITIATION SYSTEMS INCLUDE A

CAP SIMILAR TO THAT OF AN ELECTRIC CAP, BUT

THEY ARE CONNECTED TO PLASTIC TUBING OR

A TRANSMISSION LINE THAT CARRIES AN

INITIATION (SHOCK AND HEAT) TO INITIATE THE

CAP.

• NOT USED IN UNDERGROUND COAL OR GASSY

MINES.

• PROVIDE NEARLY INFINITE NUMBERS OF

DELAYS IN BLASTING PATTERNS.

• DELAYS ARE AVAILABLE IN SHORT AND LONG

PERIODS AS WELL AS IN-HOLE AND SURFACE

DELAYS.

ADVANTAGES

ABILITY TO DESIGN BLASTS WITH A GREATER NUMBER OF HOLES THAN

TRADITIONAL ELECTRIC BLASTING.

DANGER OF STRAY CURRENTS ARE ELIMINATED WITH THE USE OF NON-

ELECTRIC SYSTEMS.

NON ELECTRIC SYSTEM

INITIATING BLASTING PATTERN

• ROW BY ROW PATTERN

• FIRING PATTERN

• V-FORMATION FIRING

PATTERN

• DIAMOND FIRING PATTERN

REFERENCES

• http://www.slideshare.net/yghule/drilling-and-blasting-powerpoint-2003?qid=1c433782-5895-4db0-

81a0-73674f50f9c4&v=qf1&b=&from_search=1

• http://www.slideshare.net/smhhs/explosives-andblasting?qid=1c433782-5895-4db0-81a0-

73674f50f9c4&v=qf1&b=&from_search=8

• http://en.wikipedia.org/wiki/Rock_blasting

THANK YOU