The alpha and omega of Alpha Natural Resources is coal mining. One of the top coal producers in the US, the company produces steam and metallurgical coal at 60 active mines and 22 coal preparation plants, primarily in central and northern Appalachia and the Powder River Basin in Wyoming. Alpha's sales are split between low-sulfur steam coal, used mainly for electricity generation, and metallurgical coal, used primarily for steelmaking. The company produces about 84 million tons of coal per year. Alpha controls about 4 billion tons of proved and probable coal reserves. Faced with increasing debt and tightening federal regulations, the company entered into Chapter 11 bankruptcy protection in August 2015.