Summary: While drilling an underground exploration hole, a gas flame occurred, which was self-extinguished. The hole was placed onto gas diversion to make it safe. A gas detector located about half a metre above the drill hole did not detect any gas.
A second incident occurred that had to be extinguished by the operator.
There were no indications from the drilling return water or from gas meters that gas had been hit and the rig was operating as normal at the time. It is believed that the friction from the spinning rods against the jaws gave sufficient heat to initiate the gas fire.
Recommendations to industry: Mine operators should ensure appropriate controls are in place to:
- prevent an ignition source
- detect flammable gas
- sufficiently dilute flammable gas