The Montana Department of Environmental Quality (DEQ) has partially approved the proposed expansion of the Rosebud mine, while also partially disapproving acreage where mining could potentially damage groundwater. The mine, located in the northern Power River Basin and 12 miles west of Colstrip, is owned by Western Energy Co., a subsidiary of Westmoreland Coal Co.

DEQ formally issued a surface mining permit for the expansion, which would add 6,746 permitted acres to the existing coal mine. Known as Area F, the expansion would yield approximately 70.8 million tons of recoverable coal and extend the operational life of the mine by about eight years. This means the mine could operate until 2038.

Westmoreland Coal, which emerged from bankruptcy in mid-March, posted a reclamation bond of $13.75 million, which covers the first five years of mine development.

The area of disturbance would be approximately 4,260 acres, of which 2,159 acres would be mined. The remainder would be disturbed by highwall reduction, soil storage, scoria pits, haul road construction and other mine-related activities.

In addition, DEQ conducted a Cumulative Hydrologic Impact Assessment, which identified the possibility that mining near the northwestern border of the project could impact groundwater outside the proposed permit boundary. Because of the potential risk to groundwater, DEQ partially disapproved permitting of 74 acres (2.2 million tons of coal reserves) of the proposed expansion.

The DEQ said if the mine operator demonstrates, through additional studies, that mining could be accomplished without damaging the groundwater, it could potentially permit future coal mining in the area.

Almost of all Rosebud’s current production goes to the Colstrip Power Station. It is currently under two long-term contracts with the plant.