OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 721 Surface fans

Subsection 721(1)

The main ventilation fan must be located to ensure used contaminated air is not recirculated back into the mine through an adjacent mine portal. The fan must also be protected from explosions and other air blasts. If a fan is damaged by an explosion, the entire ventilation system might fail, leaving trapped workers exposed to contaminated air. Placing the fan at least five metres away from the nearest side of the mine opening ensures the fan is protected. The requirement for non-combustible air ducts increases the likelihood that they will survive a fire or explosion.

Subsection 721(2)

Explosion doors and or weak walls are required to provide protection for the main surface ventilating fans against air blast. The lives of mine workers could be at risk if the ventilation system failed. Air blasts can be generated by explosions or by a sudden unexpected large scale cave-in of roof rock in a mining section or sudden collapse of mine pillars. Some air blast protection is offered by the “off-set” requirement of subsection (1). Further protection must also be provided by using either explosion doors and/or weak walls located in direct line with possible explosive forces. Any such forces would thus preferentially open the explosion doors or destroy the weak wall and not pass through the main fan(s).

Subsection 721(3)

Despite the requirement of subsection (1), this subsection does allow the main ventilation fan to be located directly in front of or over a mine opening if certain criteria are met. The specified criteria limit the potential for damage of the main ventilation fan(s) in the event of an explosion or other air blast.