The largest coal mines in the United States are located within the prolific Powder River Basin of northeastern Wyoming. Massive surface extraction sites such as the Black Thunder Mine and the North Antelope Rochelle Mine represent the largest coal-producing operations in North America, consistently accounting for a massive percentage of total domestic coal output. These mega-mines utilize efficient surface-mining techniques to extract thick, low-sulfur sub-bituminous coal seams, supplying electric power plants across the country.