May 5, 2026 - Core Natural Resources, Inc. reported a mine safety event involving its subsidiary Mingo Logan Coal LLC at the Mountaineer II mine in Logan County, West Virginia. On April 29, 2026, the mine received an imminent danger order under section 107(a) of the Federal Mine Safety and Health Act of 1977.

The order followed an inspector’s finding of elevated methane levels at an air intake entry while equipment was energized. Methane between the intake entry and the stopping line at certain crosscuts exceeded 5.0%, and levels in the center of the intake entry ranged from 1.0% to 2.2%. Mine personnel promptly acted to reduce methane and restore acceptable levels.

The Mine Safety and Health Administration terminated the 107(a) order the same day, and no injuries or illnesses resulted from this temporary condition.