Explosion Prevention in Coal Mine TBM Drifts – An Operational Safety Knowledge Share

Nearly 300 years ago, since the first record of a colliery explosion in Belgium significant improvements have been achieved in the prevention of explosions in mines. However, based on the past surface TBM project safety statistics, gas explosion hazards are not unique to coal mines but also occur in TBM projects with 48 explosion fatalities recorded worldwide calling for continued diligence and improvements in explosion risk management. Success of TBM in civil engineering infrastructure in poor ground conditions resulted in consideration of its application to a coal mine in QLD. This paper provides a first time case study of TBM application in a coal mine drift development in identifying the explosion hazards and its management. The investigations were extensive with preliminary hazard identification from coal mining approach to application of various ventilation and explosion prevention controls. As in coal mine spontaneous combustion management, explosion hazard was managed by continuous nitrogen injection aimed at maintaining an explosive inert atmosphere in ahighly inaccessible TBM pressurized chamber area. The background to hazard identification and control solutions including continuous nitrogen inertisation provided herein would enhance explosion management in both civil and mining TBM applicationsworldwide.