At 9.05 pm on 15 April 2014, James Mitchell (49) and Phillip Grant (35) died when a major rib/sidewall pressure burst occurred in a longwall development roadway (known as a gate road) during mining operations at the Austar Coal Mine, near Cessnock in the NSW Coalfields. At the time of the incident, seven workers were operating a bolter miner and shuttle car to develop a gate road for a future longwall panel. The bolter miner had bolting rigs attached to
each side for installing bolts in the roof and ribs to support the strata.
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. 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.
Co-workers attempted to rescue the men but the area was deemed unstable. The mine’s emergency procedures were initiated. Their bodies were recovered during the following days. The incident occurred in a development panel known as Maingate A9 longwall development roadway, B Heading, about 25 metres inbye from the second cut-through. The incident site was approximately 10 kilometres in from the mine’s entrance and 555 metres vertically below the surface. At this depth, the sidewall (rib) and roof strata of the coal seam was subject to significant stress.1
Maingate A9 was in a geologically disturbed area near an upthrow fault and shear zone. The workers were mining toward the upthrow fault when the incident happened.
The roof and ribs at the incident site were supported by steel mesh and bolts. The roof was supported by a combination of steel mesh and chemically anchored roof bolts and cable bolts. The rib was supported by a combination of steel mesh and chemically and mechanically anchored bolting systems.
