Coyote was expected to be back in 100% operation by early fall. Now, however, the tentative return date has been pushed back to late November, according to Cris Oehler, spokeswoman for the Fergus Falls, Minnesota-based company.

Oehler said repairs still are being made to equipment damaged in the December 4, 2014, incident. A serious mechanical failure in one of the plant’s turbine-driven feed pumps tripped Coyote offline and some boiler tubes ruptured, causing a fire. The entire plant was idled for a couple of weeks before it resumed partial operation in late December 2014. No official damage estimates have been publicly disclosed.

Coyote burns about 2.5 million tons of lignite coal annually from Dakota Westmoreland Co.’s mine-mouth Beulah surface mine. Dakota Westmoreland is a subsidiary of Westmoreland Coal Corp. of Denver, Colorado.

Coyote’s partial idling has had some impact on the mine’s production. Beulah produced 1 million tons in the first half of 2015, with output falling almost 70,000 tons in the second quarter, according to the federal Mine Safety and Health Administration (MSHA).

However, MSHA figures show the mine’s output rebounded by about 77,000 tons to 581,604 tons in the July-September period, for a total of 1.65 million tons so far this year. Company officials were not available for comment on the reason for the Q3 increase.

The mine, which has about 120 employees, produced almost 2.8 million tons in 2014.

Otter Tail co-owns Coyote with Northern Municipal Power Agency, Montana Dakota Utilities and NorthWestern Energy.

Otter Tail also owns and operates the 475-megawatt Big Stone coal plant near Milbank, South Dakota, and the 138-megawatt Hoot Lake coal plant near Fergus Falls. A $384 million project to install a dry scrubber and rebuild a baghouse at Big Stone recently was completed.

Big Stone and Hoot Lake both burn low-sulfur Powder River Basin coal.