A “catastrophic” diesel engine failure at the Wongawilli underground coal mine created a “significant risk of igniting an explosion”, the Resources Regulator has said after an investigation.
Wollongong Coal has been told to make sure its engines have sufficient oil levels and maintenance, with the Regulator stating repeatedly that the incident could have caused methane in the mine to explode – with potentially tragic consequences.
“The catastrophic failure of a diesel engine system, where the products of internal combustion are potentially exposed to a methane-rich environment, presents a significant risk of initiating an explosion,” the Regulator said.
Luckily, no-one was hurt in the July 4 incident, where a diesel engine in a coal loader suffered a “catastrophic failure”, causing hot internal parts to be “ejected” through the engine block into the air.
A fitter was sent in to try and get the engine started again, and after noticing oil was low he poured 14 litres of oil into it before starting it up again. But it was “running rough” with a failed cylinder and was dragged up to the surface.
The Regulator named a lack of oil and/or poor oil condition as most likely causes of the excessive heat which caused the failure.
It found there was about seven months (about 700 operating hours) where oil changes could not be verified for the engines.
Engine oil analysis had not been conducted and daily inspection documents at Wongawilli “could not be located”.
“Incidents of this type and magnitude are rare, and the NSW Resources Regulator has not had any previous reports of similar incidents in recent years,” the investigation’s final report said.
“There is sufficient evidence to demonstrate this event would have ignited an explosive methane mixture had it been present in the mine atmosphere at the time that the incident occurred.”
The Regulator told Wollongong Coal and its contractors they needed to make sure machines were properly maintained, oil kept to an appropriate level, filters regularly changed, and engines used in accordance with the manufacturer’s instructions.
It was particularly strident in saying the attempt to get the engine started again after pouring in 14 litres of oil – after the catastrophic failure – should not have happened.
Wollongong Coal was contacted for comment.