1. Explosives

2. What is an explosive?
Explosive is a solid or liquid substance or a mixture of substances which on application of suitable stimulus is converted in a very short time interval into other more stable substances, largely or entirely gaseous with the development of heat and high pressure

3. Classification of Explosives
LOW EXPLOSIVES
Deflagrate rather than detonate, Low reaction velocity, no water resistance, highly flammable, very sensitive, 2,000-5,000 FPS EG, black powder
BLASTING AGENTS
Combination of oxidizer and fuel, cannot be detonated by just
blasting cap.
HIGH EXPLOSIVES
Can be detonated by
blasting cap
DYNAMITES
Composed of nitro glycerin & filler material
WATER GELS, SURRIES & EMULSIONS
Can be classed as high explosives or blasting agent, depending on its cap sensitivity & chemical composition mixture of oxidizers, fuels and sensitizers which contain 5-40% water. Available in a wide range of densities, commonly packed in polyethylene tubing excellent water resistance.
STRAIGHT DYNAMITES
weight strength is equivalent % of nitro glycerin.
AMONIA DYNAMITES
Ammonia nitrate substituted
BULK MIXED COMPOUNDS
Ammonium Nitrate and fuel oil mixed on the job by the consumer; very economical, good fumes if mixed properly; no water resistance.
GELATIN DYNAMITES
Combination of nitroglycerine & nitrocellulose.
PRE-MIXED NCN
Nitocarbonitrate mixtures prepared by manufacturer, light density, no water resistance.
STRAIGHT GELATIN
SPECIAL GELATIN
TWO COMPONENT
Each individual component is non explosive can be shipped by any means.
SEMI GELATIN

4. Velocity of Detonation 2000 to 7000 m/s
Pressure
>1800 GPa
Temperature
3000o K to 4000o K

5. Pressure in a blast hole can exceed 10 GPa (100,000 atm) sufficient to shatter the rock near the hole, and also generate a stress wave that travels outward at a velocity of 3000 to 7000m/sec.

6. Explosive Classification
Initiation Explosives
Low Explosives.
High Explosives.
Blasting Agents

7. Initiating Explosives
Initiating explosives are used in small quantities to initiate detonation in larger and less sensitive high explosives. They are supplied in copper or aluminum tubes to form detonators, or are used in detonating cord.

8. Low Explosives
Blasting or black powder. Used for dimension stone work, will heave the stone rather than fracture it.
Splitting products. Usually are of plastic construction and have blasting powder in them. May be fired by a fuse head inserted like a primer in a rifle cartridge.

9. High Explosives NG-EXPLOSIVES SOME SLURRY SOME EMULSIONS
SPECIAL PRODUCTS

10. Blasting Agents
ANFO
SOME SLURRY
SPECIAL PRODUCTS

11. Significant Developments In Commercial Explosives
YEAR
DEVELOPMENT
13th Century
Mention of saltpeter and other blasting powders in Arabian and Chinese writings
1242
Black powder formula by Bacon
1846
Sobrero discovered nitroglycerine
1861
Alfred Nobel sets up nitroglycerine plant
Dynamite and Blasting gelatine commercially manufactured
1880's
Permissible Dynamites investigated
1950's
Ammonium Nitrate and combustibles as dry powders (ANFO)
1957
Watergel (Ammonium Nitrate, TNT and Aluminum powder)
1964
Emulsions (Emulsified Ammonium Nitrate and Nitric Acid)
Watergel (Mono Methyl amine Nitrate, or Hexamine Nitrate or Aluminum powder)
Heavy ANFO (Up to 50% Emulsion and ANFO)

12. Nitroglycerine Explosives
Nitroglycerine (NG), a major component of The dynamites, when in pure form, is relatively unsafe and sensitive to impact. Straight dynamites contain % nitroglycerine. They have poor fume characteristics. Ammonia dynamites have largely replaced straight dynamites.
Gelatines contain liquid nitroglycerine with nitrocellulose supplied as cartridges or "sticks".
Nitroglycerine C3 H5 (ONO2) 3
NOW DISCONTIUED IN USAGE

14. AMMONIUM NITRATE FUELOIL (ANFO) and Other Blasting Agents
Ammonium nitrate (AN), mixed with fuel oil (FO) in the ratio of 94.5:5.5 by weight.
NH4N03+CH2→3N2+7H20+C kcal/kg
ANFO is the least expensive explosive available. When correctly used, ANFO performs as well as dynamites and is much safer. However, it absorbs water hence, it cannot be employed in wet conditions. Density is low.

15. Mixing ANFO When mixing ANFO the following sign must be displayed:
DANGER EXPLOSIVES
NO SMOKING OR FLAME
No source of flame or spark must be brought within 10 metres of the operation.
If any ANFO is left over, then it must be stored in a Licensed Magazine.
It be placed in a sealed, leak proof, non metallic container.
This container be labelled, “EXPLOSIVES MIXTURE”.
This ANFO will be used as soon as practicable.

16. Cartridge Explosives
NG EXPLOSIVES ?
SLURRY ?
ANFO ?

17. Slurries
Ammonium Nitrate (AN) slurries and emulsions have been developed for blasting in watery conditions. AN with sensitiser, combustible material and thickener + 20% Water produced as slurries, gels and emulsions.
Much higher pressure
Waterproof
Higher VOD
Denser
Can be pumped.
Costs are higher than ANFO

18. Slurries Composition OXIDISERS FUELS SENSITIZERS
Such as AN, SN or CN
FUELS
OIL
SENSITIZERS
Chemical - Organic Amines, Perchlorate Salts, Small Particles of AL
Physical - Entrapped Air Bubbles

19. BULK MIX TRUCKS OR ANFO TRUCKS Mix and deliver AN/FO/AI Powder
Bulk Loading System For Explosives
ADVANTAGES
Packaging Cost Saved
Loading rates much faster
Better Coupling
Rigid quality specifications variable
SUITABILITY
Normally suited for large operations.
Shared services for smaller operations.
Schedule to be arranged and also size of shot to be tailored to suit capacity of trucks.
Increased coupling allows larger charge per hole but may cause vibrations at times.
BULK MIX TRUCKS OR ANFO TRUCKS
Mix and deliver AN/FO/AI Powder

20. Bulk Trucks
Bulk Trucks (Site Mix Trucks) Raw materials for making explosives like AN, SN solutions from support plant, are carried in trucks and explosive mixed at site. Pump Trucks for delivery of plant-mixed slurry or emulsion.

21. Bulk Explosives
ANFO in dry hole application, low cost and easy mixing but has low density and unsuitable in wet holes

22. Special Application Explosives
Special explosives are needed for controlled blasting, underwater blasting, and blasting of high temperature rock.
PIPE CHARGES
LOW ENERGY
EXPLOSIVES
PRODUCT WITH
VARIABLE ENERGY

23. Cast Primers These are made from a mixture of PETN and TNT.
Are used to initiate bulk explosives.
Have a very high VOD.
They have a high density of 1.5 and readily sink in water.

24. INITATED BY SHOCK TUBE AND DETONATOR, DETONATING CORD
CAST BOOSTERS
PRIMERS
MIXTURES OF PETN AND TNT,
HIGH DENSITY 1.6 g/cc TO 1.7 g/cc
Detonation velocity 7000m/s
INITATED BY SHOCK TUBE AND DETONATOR, DETONATING CORD
RELIABLY INITIATE BULK
Their high strength, high density and very high velocity of detonation (7000 m / s) make them suitable for priming ANFO mixtures and slurries.
An additional advantage is their lower sensitivity to shock, friction and impact. explosives.

25. Medical Aspects Now a days more consideration given to medical aspects
Less toxic gases
Non-headache producing explosives
For opencast workings not much problem
For underground workings carbon monoxide, oxides of nitrogen and fumes are kept within acceptable limits
Some explosives cause skin irritation and eczema