In the first nine months of 2015, Wyodak added $9 million to Black Hills’ coffers, up from $7 million a year earlier.

Wyodak turned in a glowing quarterly performance despite the fact sales were down slightly — from 1,082,000 tons in the third quarter of 2014 to 1,041,000 tons in the latest quarter, according to Rich Kinzley, the company’s chief financial officer.

Kinsley told analysts during a November conference call to discuss quarterly earnings that Wyodak’s realized prices were 13% higher during the July-September period — $16.30/ton — than the comparable period of 2014.

Part of the reason for the price increase was a contract reopener last year with PacifiCorp, an Oregon-based utility that operates a mine-mouth power plant served by Wyodak.

Wyodak produced and sold about 3.1 million tons of coal in the first nine months of 2015, leaving the mine on track to approach last year’s output of about 4.3 million tons.Wyodak is Black Hills’ only coal mine.