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. Its segments include the Powder River Basin (PRB) segment containing the Company's primary thermal operations in Wyoming; the Metallurgical (MET) segment containing the Company's metallurgical operations in West Virginia, Kentucky, and Virginia, and the Other Thermal segment containing the Company's supplementary thermal operations in Colorado, Illinois, and the Coal Mac thermal operation in West Virginia. The Company operates mining complexes in West Virginia, Kentucky, Virginia, Illinois, Wyoming and Colorado. It sells all of its coal to power plants, steel mills and industrial facilities. As of December 31, 2016, it operated 12 mines located in each of the coal-producing regions of the United States.