Safety & Planning
Safety & Planning
Safety is paramount and all workers are trained in Health and Safety regulations and procedures.
An accident involving explosives can kill or cause serious injury.
Careful planning and numerous design considerations for each specific site are done before deciding on the method best suited for a site.
Surveys
Pre and post-blast surveys are important to document the condition of the structures, windows, and foundations.
Considerations
On a site where ground vibration, fly rock, and air blast are a concern, certain factors must be considered:
- Rock type and geology of the rock
- Hole diameter
- Burden and spacing of holes
- Type of explosive
- Column charges and explosive factors
- Number of holes & charge mass per delay
- Ground & surface water
- Machines available to excavate blast
Monitoring
Ground vibration monitoring is mandatory for all blasting in built-up and developed areas.
A Seismograph measures and records the ground and air vibrations from a blast.
A maximum allowable charge mass per delay is set to stick within the recommended Peak Particle Velocity (PPV) limits.
PPV is the maximum speed that a particle of soil or rock moves in each of three mutually perpendicular directions that are vertical, transverse, and Longitudinal. This is measured in millimeters per second.