Arch Coal, Inc. is a coal producer. The Company is engaged in the production of thermal and metallurgical coal from surface and underground mines located throughout the United States, for sale to utility, industrial and steel producers both in the United States and around the world. The Company operates mining complexes in West Virginia, Kentucky, Maryland, Virginia, Illinois, Wyoming and Colorado. The Company's segments include the Powder River Basin and Appalachia. The Powder River Basin segment includes operations in Wyoming. The Appalachia segment includes operations in West Virginia, Kentucky, Maryland and Virginia. The Company also sells coal from operations in Colorado and Illinois. Powder River Basin consists of Black Thunder and Coal Creek mines. The Company's mines in Appalachia include Coal-Mac, Lone Mountain, Mountain Laurel, Beckley, Vindex, Sentinel and Leer. The Company operates, or contracts out the operation of approximately 10 active mines in the United States.