It sent its former owners Gympie Gold broke after it was ravaged by fire in 2003.

The company yesterday confirmed that a team of Austar coal mine employees were working underground when a wall collapsed. Two employees - Phillip Grant, 35, and Jamie Mitchell, 49, from -- lost their lives.

District president of the Northern region of the Construction Forestry Mining and Energy Union Peter Jordan told ICN he was satisfied that the mine was being operated in a safe manner, although he conceded that Austar had always been a “difficult” mine.

The two deceased mine workers, who were part of a four-man crew operating a continuous miner in a cut-through when the incident occurred, were closest to the collapsed wall.

It is believed that two continuous operators further from the wall managed to leave the incident unscathed.

“It’s a tragic day for the family and the workforce,” he told ICN.

“It’s a difficult mine and it’s had issues over the years.

“We need an explanation for why such a large section of wall collapsed. It’s a big chunk of coal.”

Jordan said CFMEU check inspectors methodically reported on safety at the mine and that no unsafe work practices were reported.

Yancoal had introduced the Chinese-pioneered method of longwall top coal caving to Austar but there is no suggestion that this lead to the incident as it occurred in a cut-through.

“Mining activities were ceased and a recovery operation was initiated at the site. Local emergency services and the NSW Department of Trade and Investment, Regional Infrastructure and Services were immediately notified and attended the mine site,” Yancoal said in a statement.

Roof falls

Formerly known as Southland Colliery, Austar was one of the first coal mines bought by Chinese giant Yanzhou, who picked it up for $US23 million in 2004 after its former owners Gympie Gold went broke after a fire on Christmas Day 2003.

Industry expert Bob Gallagher analysed the problems encountered at Southland for ICN in 2004.

“There is a substantial history of development of heatings in the relatively high vitrinite content (higher oxidation susceptibility) Greta seam coals. Published data regarding R70 test results (Highton, 1995) indicate a value of 0.80, which falls into the medium risk category in regard to propensity to spontaneous combustion,” he wrote.

“Cross over test data from the same source indicate IRH values of 1.89 and 1.85 and TTR values of 6.05 and 4.93 for Pelton (Ellalong) and Abedare North samples from the Greta seam respectively. The risk index under this test method falls into the high risk propensity category.

“Development roadways at Southland are typically driven in the lower section of the seam at around 3.2 – 3.5 m height, with the longwall extracting a similar profile. The upper section of the seam contains high sulphur (pyritic) coal that is not extracted, and which caves into the void behind the longwall. The roof immediately above the seam is highly laminated.

“The SL2 longwall panel (extracted) prior to SL3 was mined by the advancing longwall retreat method (i.e. longwall extracting in the same direction as ongoing roadway development). To facilitate requirements of this method and allow driveage of the additional length of the SL2 maingate for use in SL3 tailgate, the majority of SL2 Maingate was driven with 3 headings.

“The mining of SL3 was delayed with a series of roof falls in the first third of the panel, followed by relatively trouble free mining for the remainder of the block. The mining horizon initially allowed for leaving a coal floor.

“After limited retreat (around 130m from the installation roadway), poor ground conditions were encountered and shortly after a series of face falls occurred, greatly slowing the rate of retreat over a period between August / September 2002 and February 2003.”

Safety

Yancoal said it would continue to work closely with emergency services and the regulator to find the bodies and establish the causes of the wall collapse.

NSW Minerals Council CEO Stephen Galilee said while the NSW mining industry is known for its strong safety record, the reality is that miners face dangers every day as they do their important work.

“This incident is a tragic reminder of why safety is the industry's number one priority,” he said.