Summary: During the process of trimming and supporting after a shot, the roof came in releasing gas. Workers smelled carbon dioxide (CO2) and the gas monitor on the miner alarmed (1.25% methane). This tripped the miner off. All personnel were in the safe zone at the time. As per the site trigger action response plan the crew was immediately withdrawn.
Recommendations to industry: Mine operators should review how the potential hazards associated with shotfiring as a means of remote mining are assessed and controlled. This should include the potential disturbance of additional ground / strata and the effectiveness of removing in situ gas.