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Rock Blasting (Rock excavation method), Conducting survey on local…
Rock Blasting (Rock excavation method)
Definition
Using explosive materials to break & fracture rocks into fragments in a controlled manner
Drilling multiple holes and inserted with explosives before being detonated
Produce uniform - sized fractured rocks
Key elements and procedures
(Step 1) Pre-explosion planning & surveys
Purpose
Using dangerous materials, especially in urban areas is more complex
Explosion can create vibration & irritate local residents
Explosion can cause damages to the surrounding buildings
Requirement
Record keeping
Seismic reading
Public relations
(Step 3) Loading the holes
Materials
Step 1 : Inserting Primer
Step 3 : Inserting Bulk blasting agent
Slurry or mixture intended for explosion, but not considered explosives
Cheapest slurry : Ammonium Nitrate Fuel-Oil (Common fertilizers with diesel fuel
Will not explode if the hole is wet
Step 2 : Connecting Detonator to Primer
Blasting cap & wires from each hole are connected to blasting machine
Detonator initiate the blast
Step 4: Inserting Stemming
Rock chips from hole drilling
To make sure the blast energy is forced outwards not upwards
(Step 2) Drilling the holes
Pattern
Pre-determined pattern before drilling
Uniform pattern create uniform rocks fragments after explosion
Diameter & amount
Larger holes with larger explosives create larger vibrations & damage
Suitable pattern is the holes are close together and the diameter is small
Equipment
Blast Holes Driller
(Step 4) Blasting [explosion]
Before explosion, the area is cleared out from people and equipment
Siren warning and 'fire in the hole' is shouted before explosion
There are delays of each hole exploding
Consideration factors
Fly rocks / airborne rocks
Laws and Regulations
Causes vibrations
Conducting survey on local residents about the explosion
A independent, third party consultant is required to prevent falsification and speculation of seismic reading
Explosives such as dynamite, etc.
Because there must be movement for good rock breakage
Dynamite stick
Blasting cap & wire
Example of Bulk Blasting Agent
Rock Stemming to cover the blast holes
Worker inserting blasting cap into dynamite
Need careful management & studies to prevent damages on surrounding buildings
Blasting is not always allowed by local authorities
Can cause damages and injuries
