4. Explosives for the Mining Industry Flashcards
What are the three kinds of explosions?
- Mechanical
- Chemical
- Nuclear
Explosive
a substance which when properly initiated is rapidly converted into gases at high temperatures and pressures
Low Explosives
Initiated by flame (black powder)
High Explosives
Cannot be initiated by flame under normal circumstances and requires shock or impact for detonation
Blasting Agents
chemical mixtures containing no ingredient that is itself an explosive and requires a primer
What are the 3 major suppliers of blasting agents?
- Austin Powder
- Dyno Nobel
- Orica
What 3 things are explosives made up of?
Fuels (chemical) + Oxidizers (oxygen source) + sensitizers (drives the reaction)
What are 6 ideal characteristics of explosives?
- Low cost
- High energy yield per unit weight
- Easy to handle
- Unlimited resistance to water and low temperatures
- Reliable initiation by detonators/primers
- Unlimited shelf life
- Does not create a poisonous gas
What are 2 advantages of dynamite?
- shoots under unfavourable conditions
- very good initiation
- excellent for urban control blasting
What are 2 disadvantages of dynamite?
- mechanical sensitivity
- headaches
- expensive
What are 2 advantages of ANFO?
- easy to load
- easy and safe to manufacture
- mechanical insensitivity
- inexpensive
What are 2 disadvantages of ANFO?
- must be initiated with a primer
2. dissolves in water
What are 2 advantages of slurries/watergels?
- good water resistance
2. good for reliable detonation in small diameter blast holes
What are 2 disadvantages of slurries/watergels?
- may deteriorate in storage due to gel breakdown
2. becomes hard at low temperatures
What are 2 advantages of emulsions?
- very water resistant
2. very high VOD
What are 2 disadvantages of emulsions?
- expensive
2. sensitivity decreases with shelf life
Safety Fuse
long thin cord of black powder wrapped in textile and covered waterproof coatings; used to set off plain detonators
Detonators/Blasting Caps
most common initiation device activated by heat, shock or electric spark
What are the 3 types of detonators?
- Plain
- Electric detonators
- Electric delay detonators
When do you use plain detonators?
when electric initiation is prohibited due to extraneous electricity
Detonating Cord
connects blast hole charges so they can detonate at the same time; eliminates the need for multiple detonators
Primer
cap-sensitive explosive used to initiate other explosives or blasting agents containing a detonator
Booster
cap-sensitive explosive used to initiate other explosives or blasting agents not containing a detonator
