Investigation report into double fatality at Austar coal mine released
An investigation report into the deaths of two men at Austar Coal Mine in 2014 has been released by the NSW Government.
The men, James Mitchell, 49, and Phillip Grant, 35, died on April 15, 2014, when a major rib/sidewall pressure burst occurred in a longwall development roadway at the mine, located near Cessnock in the NSW Coalfields.
At the time of the incident, seven workers were operating a bolter miner, with bolting rigs attached to each side, and shuttle car to develop a gate road for a future longwall panel.
Mr Mitchell and Mr Grant were on the left side of the bolter miner when a major pressure burst of coal from the rib occurred, which saw a large section of the left rib, which was supported with steel bolts and mesh, moved sideways into the roadway where the two men were working. Both men were engulfed by the rib material and died at the scene.
The report said coworkers attempted to rescue the men but the area was deemed unstable.
Their bodies were recovered during the following days.
The report recommended that mine operators should conduct research when developing strata control plans.
“A previous major incident of rib failure occurred in July 2011, which was investigated by the mine. From this investigation, the mine operator formed the view that the pressure bumps indicated that the strata had settled and that these bumps did not represent a risk to people at the mine,” the report stated.
“The methodology for ranking risk was confined only to considering occurrences in Australia. However, the geological conditions at Austar may not have been encountered previously in Australia and overseas lessons were not taken into account. Therefore, pressure bursts were not identified as a risk.
“International research reveals that pressure bursts in coal mines generally occur at depths of more than 300m, with the majority of burst occurring at depths of more than 400metres. That research also shows that the risk of a pressure burst is increased in areas of significant geological disturbance and the presence of massive strata in close proximity to the seam.
“The incident occurred at a depth of 555m in an area of the mine subject to disturbed structural geology and variable thickness massive sandstone units in the near roof overburden. A significant pressure bump had occurred on the afternoon shift 24 hours before the incident in B Heading of MG9 in close proximity to the incident scene.”
The report outlined several other recommendations, including taking consideration of the history of the seam, changes in geological conditions, and the hierarchy of controls for managing risk.
To read the full report, including recommendations, click here.