OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 664 Underground mine blaster

Subsection 664(1)

The underground mine blaster is responsible for overall blast safety. Several safety precautions are listed and the blaster must ensure they are followed. If flammable gases or coal dust are present in higher concentrations than expected, a blast may trigger an explosion of the surrounding atmosphere which could travel through the entire mine.

Use of the correct explosive charge ensures the proper blasting of materials to be mined and minimizes damage to surrounding rock.

The defined precautions must also be taken to avoid premature initiation of charged holes.

Subsection 664(2)

If explosive gases are present, the blaster is responsible for ensuring that additional safety measures are taken. A blaster must not load or fire explosives if more than 1 percent of methane (or 20 percent of the lower explosive limit of a flammable gas) is present. Here the concern is that the blast might release additional quantities of methane that could accumulate to an explosive level during the blast itself.

Similar limitations are placed on the blaster to ensure that any coal dust is treated with non-combustible dust, or has been thoroughly wetted down to minimize the potential for a major gas or coal dust explosion.

Subsection 664(3)

If the atmosphere within 25 metres of a hole contains more than 1 percent of methane (or 20 percent of the lower explosive limit of a flammable gas), the blaster must ensure that loading or blasting is not performed. Any drilled hole must not be loaded and must be filled with stemming material.

Subsection 664(4)

This subsection is intended to protect workers from the effects of a blast. Blast guards are required to warn approaching workers. Blast guards must be stationed at a minimum distance of 75 metres from the blast area. The blaster is required to take refuge in a safe place before initiating the blast.

Subsection 664(5)

Although at least 10 minutes waiting time is mandatory, the underground blaster must ensure that this minimum requirement is consistent with the explosive manufacturer’s specifications. If necessary, a longer period can be defined in the mine operating procedure.