OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 672 Misfires

Subsection 672(1)

The handling of misfires is perhaps the most dangerous job in blasting and must be done under the direct supervision of an underground mine blaster.

Subsection 672(2)

These standard blasting practices have been legislated to stress their importance. The waiting period allows any defective detonator to detonate. It also provides time for the air to clear of fumes and smoke.

Disconnecting the blasting apparatus and short-circuiting the cable ends eliminates the possibility of an unintended detonation of the unblasted hole.

Once a parallel hole has been detonated, the blaster must search the broken rock pile for evidence that the misfire has detonated as well. If undetonated products are found, they must be carefully collected and then destroyed according to the manufacturer’s specifications.

Subsection 672(3)

Water reduces the sensitivity of the explosive, thereby reducing the potential for detonation and explosion.

Subsection 672(4)

Friction along the lead wires as they dislodge from the end of the detonator could initiate the detonator.