The Belle Ayr mine is a coal mine located 18 miles southeast of Gillette, Wyoming in the United States in the coal-rich Powder River Basin. The mine is an open pit, "truck and shovel", mine producing a low-sulfur, sub-bituminous coal from the Wyodak-Anderson seam that is used for domestic energy generation. Coal produced by the mine is shipped to its customers via railroad. The mine is currently owned and operated by Alpha Natural Resources after being acquired in a merger with Foundation Coal in 2009.
As of 2009, Belle Ayr had reserves of 406 mm tons of sub-bituminous coal and a maximum permitted production capacity of 45mm tons per year. Typical annual production has been in 26-28mm ton range for the last several years though. The average quality of the coal shipped from Belle Ayr is 8,550 BTU/lb, 0.33% Sulfur, 4.50% Ash, and 1.90% Sodium (of the ash). Train loading operations at the mine are done with a batch weigh bin system that is coupled to a "weigh-in-motion" track scale system. Silo capacity at the mine's rail loop, which can accommodate up to 5 unit trains, is 46,000 tons. In 2008, the mine produced just over 28.7 million short tons of coal, making it the 7th-most productive coal mine in the United States.
The Belle Ayr Mine began operations in 1972 and is the oldest, non-captive mine in the Powder River Basin. Since mining operations began, the mine has shipped over 574 million tons of coal to its customers. The Belle Ayr mine has changed hands many times through mergers and sales. Previous owners include AMAX, Cyprus AMAX, RAG, and Foundation Coal.