In 2007, the region produced 436 million short tons (396 million tonnes) of coal, more than twice the production of second-place West Virginia, and more than the entire Appalachian region. The Powder River Basin is the largest coal-producing region in the United States. The region includes the Black Thunder Coal Mine, the most productive in the United States, and North Anteleope Rochelle Mine, the second most productive. In recent years, the region has become a major producer of natural gas, both conventional natural gas and coal-bed methane.