Underground off limits at Grosvenor as gas levels rise
RISING carbonmonoxide and other gas levels have forced the closure of Anglo American's Grosvenor underground mine.
The gas levels increased the risk of spontaneous combustion, forcing the company to enact a plan to restrict all access below ground.
An Anglo spokeswoman said longwall mining activity had ceased following the Grosvenor incident on May 6 to closely monitor "various gas levels".
She said the gas level increase this week was different to the May 6 event.
Due to the suspension of longwall mining, the risk of spontaneous combustion had been elevated because of coal oxidation in the longwall goaf environment.
The company said during normal longwall mining operations, this risk was very low.
"Over the past few days, we have seen levels of carbon monoxide and other gasses start to rise, such that we enacted our Trigger Action Response Plan for spontaneous combustion risk," the spokeswoman said in a statement released today.
"We made a precautionary decision to restrict people from entering the underground for safety reasons on Saturday (well before the removal would have been triggered).
"These crews were undertaking essential work to ensure the ongoing integrity and safety of the mine.
"All personnel onsite have been provided with updated information on the mine conditions and the response steps under way."
The mine is now undertaking a "range of measures" to address the risk of spontaneous combustion, including the addition of inert gases and changes to the ventilation network.
"We have established an exclusion zone around the entry of the mine," the spokeswoman said.
"No crews will return underground until the underground environment has been proven to be stable."
Anglo American's Metallurgical Coal business CEO Tyler Mitchelson said the company was still investigating the cause of the "methane ignition at Grosvenor Mine" on May 6.
"In the meantime, our team is monitoring elevated risks due to the cessation of the longwall for the past month," Mr Mitchelson said.
"Consistent with our risk management protocols, we made the early decision to fully restrict access to the mine when levels of certain gasses started to rise.
"Over the past couple of days, we commenced a range of measures to stabilise the area.
"Once gas levels are proven to be stable, work will continue to ensure the ongoing safety and integrity of the mine."
Four men from the May 6 explosion remain in hospital but are now stable. A fifth mine worker has been released from hospital.