OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 745 Explosion barriers

Subsection 745(1)

Employers must develop an explosion prevention plan for every coal mine. The plan must be certified by a professional engineer and be acceptable to the Director. An important means for combating coal dust explosions involves explosion barriers. These are typically passive in nature. The pressure wave of a coal dust explosion creates a cloud of stone dust or water droplets which suppresses the flame front following behind the pressure wave. Explosion barriers can also be of an active type whereby pressure sensors detect an oncoming pressure wave and trigger the barrier to suppress the explosion’s subsequent flame front.

Explosion barriers, if used, should be designed to stop explosions from travelling any further. Suitable explosion arresting materials and designs reduce the violent energy of explosions to almost zero as the explosion travels through the barrier. Barriers often use rock dust or water as the quenching material. The number of units comprising the barrier system and the speed at which they react to a passing shock wave are important variables to be considered in the design, as are the forces and energy associated with a potential explosion.

Any explosion barrier must be certified by a professional engineer. Explosion barriers are typically used at entrances to every production section, development district and ventilation split. Such locations are designed to confine explosions to the area in which they are most likely to occur, thus minimizing risk to other areas of the mine.

Subsection 745(2)

It is important in emergency response planning to know where explosion barriers are located. For this reason the location of all explosion barriers must be shown on the mine ventilation and emergency response plans.