Production of metallurgical coal at Integra was 30,000t in the second quarter of 2011, compared to 245,000t for the same period last year, and thermal coal production was down to 25,000t from 65,000t.

The metallurgical coal output was negatively impacted by the start of a longwall move during the second quarter of 2011, while thermal coal production at Integra was hit by pre-stripping of overburden waste in preparation for developing a new mining pit, the company said.

Integra, which has seen a high turnover of key personnel, decided to temporarily cease operating on July 11 in consultation with the district mines inspector after ventilation problems led to a build up of methane to dangerous levels in the longwall tailgate.

The Department of Trade and Investment has launched investigations into the mine after it was "made aware of unsafe methane levels" and all of the company’s 280 employees told to evacuate the mine.

The mine is in the process of a longwall move, which is believed to have triggered the ventilation breakdown.

Resources Minister Chris Hartcher said the department was working with the operator, the union check inspector, the mine's occupational health and safety committee and a site check inspector to "investigate and resolve allegations of health and safety issues at the mine and restore the mine to full operations".

"I have been informed that whilst the mine is currently idle, certain essential employees have been permitted to enter the mine for inspections and pumping operations,” he said.

"I have requested a detailed report on this issue and will continue working with the department and mine operators to reach a satisfactory outcome."

Hartcher, who attended the New South Wales Minerals OHS conference in the Hunter Valley last week, told ILN safety was one of his key priorities in his portfolio and he was keen to maintain zero harm in the industry.

“My first ministerial statement was about the sad death of Peter Jones,” Hartcher told ILN, referring to the death of the worker at the Chain Valley mine in June.

“There is no point in having a mining industry unless it has a 100 per cent commitment to mining safety.”

According to Coal Services, Integra produced 1.4Mt of coal in the 12 months to June 2011.

Integra’s general manager of operations Andrew Betts said all personnel were withdrawn from the mine in a safe and efficient manner.

“The safety of our staff is – and always will be – our first and foremost priority,” he said.

“We’re not prepared to jeopardise the ongoing safety of our employees and we’re entirely committed to working with the District Coal Mines Inspector and our employees to ensure that normal operations are resumed in a controlled and safe manner.”

Betts said a comprehensive recovery plan including risk assessments and procedures had been prepared and the situation was being monitored closely.

“We have a number of people dedicated to resuming operations and while we work towards a solution we’ve been able to access underground areas to maintain essential maintenance and water pumping activities,” he said.

Production at Vale’s other major mine in Australia, Carborough Downs longwall mine in Queensland, was 368,000t versus 231,000t in the previous quarter, recovering from the geotechnical problems faced in the first quarter of 2011.