Solid Energy has temporarily suspended mining at Huntly East Mine after inspectors found an accumulation of methane in a recently-mined area of the underground mine.
The decision was made last night following a Prohibition Notice issued by the Department of Labour's (DoL) High Hazards Unit.
Solid Energy chief operating officer Barry Bragg said the company remains confident that its mines are operating safely.
He said the inspectors have asked for more information about the accumulation of methane and how the company are managing that methane.
Although coal extraction and development had been suspended, mine personnel are permitted to carry out maintenance and other work underground.
"We will provide the required information to the Department today and we will meet the inspectors again tomorrow," Mr Bragg said. "We are aware of no reason why the prohibition notice should not be lifted as soon as we have provided the information the Department is seeking and expect to resume full mining activities shortly afterwards."
Last year a worker at Huntly East Mine described the mine as a "time bomb", when explosive levels of methane were detected in November.
At the time Mr Bragg said there had been higher than usual methane levels detected after miners struck a geological fault, but standard procedures were implemented.
This involved removing the workers from the mine and using an auxiliary fan to ventilate the mine.