Hallador Energy Company, through its subsidiaries, engages in the production of steam coal in the Illinois basin for the electric power generation industry. The company owns the Oaktown 1 and Oaktown 2 underground mines in Oaktown, Indiana; and Ace in the Hole mine located near Clay City, Indiana. It is also involved in gas exploration activities in Indiana. The company was founded in 1949 and is headquartered in Terre Haute, Indiana.