Summary: A hire drill rig had completed drilling a hole as part of a shot pattern and was in the process of removing the steels from the hole and racking them in the carousel. The operator lifted the lead steel to the top of the mast and the steel disconnected at the saver sub causing the steel to fall about 2 metres, penetrating the drill deck adjacent to the operator’s cab. The operator was not injured and reported the incident.
Recommendations to industry: Mine operators should maintain and adjust alignment of drill heads and carousels for return of drill pipe to minimise the risk of decoupling when unsecured. Inspections of mobile plant should be plant model specific and include alignment and wear in drill masts and guides where applicable.