Arch shed light on the events of Monday, January 13, in a Form 8-K disclosure announcement on Friday.
The coal company said it received an imminent danger order at the Leer mine for “excessive measurable limits of methane air mixture”.
“Employees were immediately withdrawn from the area and the problem was corrected,” Arch said.
The longwall at the mine started producing coal last month with a ramp-up of production scheduled for this quarter.
The mine is targeting more than 3 million short tons per annum of metallurgical coal for domestic and export markets.
