It can be stored on the ground for long periods of time without creating environmental problems. Anthracite is mined in only a few areas, mostly in the eastern Pennsylvania region. It is used extensively in municipal water purification and treatment plants and for home heating. Coal Production in the United States Coal is mined in 32 states. Lignite coal is produced primarily in western North Dakota and in eastern Montana.
Appalachian mines produce primarily bituminous coal from both surface and underground mines .
Appalachian coal tends to be high in energy content and low in sulphur . Illinois Basin mines also produce primarily bituminous coal but are generally underground operations, yielding coal that is high in energy content but also high in sulfur . Powder River Basin coal is of the sub-bituminous type and generally mined from the surface. Basin coal, while often lower in energy content , is known for its particularly low sulfur content . The way the layers or seams of coal occur and the has much to do with how it is mined and its ultimate cost to consumers.