Fire has historically being the biggest single cause of underground hardrock mining disasters and traditional primary ventilation systems and practices were developed, over a long time and after many such disasters and subsequent inquiries, to provide the safest practicable conditions for miners in the event of a major fire. The reduction in the use of timber underground and the introduction of sophisticated fire mitigation systems in modern diesel vehicles has resulted in a significant reduction in major fires. However, major fires still occur and most risk assessments still identify a major fire as a very serious threat. This paper discusses some recent trends towards intrinsically risky mine ventilation design practices especially the use of the second means of egress as part of the exhaust circuit, and the use of the truck haulage ramps as the primary intake. It identifies the factors that have led to these changes and offers some alternative designs. It proposes a classification system and hierarchy or ranking of primary ventilation methods and a set of progressive criteria that should be applied to all ventilation designs to determine their fitness for purpose.
Author: D.J. Brake
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