“The introduction of the inert nitrogen throughout the weekend has enabled us to starve the affected area of oxygen and extinguish the flames,” An Xstrata spokesman told ILN.

“Our intent is to maintain the environment and introduce coolants into the affected area by the end of the week.

“This is a positive step forward for the management of the fire and we will continue to be guided by the real time gas monitoring data as to when we may be able to re-enter the underground to assess the damage.”

The fire caused an emergency evacuation of around 50 miners on Wednesday night.

There is around-the-clock real time gas monitoring throughout the new longwall operation and the cause of the fire remains unclear.

Few details have emerged, but ILN understands that men at the face first heard a bang and then saw an orange glow in the goaf behind them which was the fire.

While it is not possible to determine how long the mine might remain closed, some of the workforce could help out other Xstrata longwall mines in the state.

“All employees are currently being paid and, if necessary, we will consider redeploying our people to other Xstrata coal operations until such time as the mine is reactivated,” the spokesman said last week.

Blakefield South, designed to replace the nearby Beltana mine in the Upper Hunter Valley, is the company’s newest Australian coal mine and commissioned its new longwall equipment in June.

Ramp-up activities have been underway for several months.