Spontaneous combustion risk flagged at mine before blast
An independent mining consultant flagged the risk of spontaneous combustion as a result of applying an external heat source at Grosvenor mine in 2014 and 2019.
The Queensland Coal Mining Board of Inquiry has entered its fourth week of hearings and will explore issues around Grosvenor mine, including the blast on May 6 2020 and the 27 methane exceedances that occurred between July 1 2019 and May 5 2020.
On Friday, the inquiry heard from B3 Mining Services managing director Basil Beamish who was tasked with assessing the behaviour of the Goonyella middle seam with respect to spontaneous combustion at the request of Resources Safety and Health Queensland.
Dr Beamish was asked to explore the potential for spontaneous combustion in the Goonyella middle seam coal under normal mining conditions.
He was also to assess whether there was any increased potential of induced coal spontaneous combustion because of external heat sources, the impact of increased virgin rock temperatures as workings become progressively deeper and increased potential for coal spontaneous combustion because of induced heat from the use of polyurethane resin injection.
The inquiry heard Dr Beamish had previously undertaken a spontaneous combustion assessment on coal taken from Grosvenor mine in 2014 and 2019.
On both occasions he said a report had highlighted that if the coal were to be artificially raised to a higher elevated temperature than the mine ambient, then the risk of the spontaneous combustion would be increased.
"In 2019, that particular comment became more than just a paragraph; it actually became a separate chapter or separate section of the report in its own right," Dr Beamish said.
"Primarily because we did do some additional testing that we had refined in that five-year period from when the original report in 2014 was done that enabled us to establish the sort of temperature that the coal would need to be heated to create a spontaneous combustion event."
Because of the COVID-19 lockdown for Greater Brisbane announced on March 29, the public hearings for the board of inquiry have been adjourned until Tuesday, April 6.