Black Hills Corporation, through its subsidiaries, operates as a diversified energy company in the United States. The company’s Electric Utilities segment generates, transmits, and distributes electricity to approximately 205,400 electric customers in South Dakota, Wyoming, Colorado, and Montana; and distributes natural gas to approximately 36,000 gas utility customers in Cheyenne, Wyoming. This segment owns 841 megawatts of generation capacity and 8,660 miles of electric transmission and distribution lines. Its Gas Utilities segment distributes natural gas to approximately 543,200 natural gas utility customers in Colorado, Nebraska, Iowa, and Kansas. This segment owns 645 miles of intrastate gas transmission pipelines and 19,058 miles of gas distribution mains and service lines. The company’s Power Generation segment produces electric power and sells the electric capacity and energy primarily to its utilities under long-term contracts. Its Coal Mining segment produces coal at its coal mine located near Gillette, Wyoming and sells the coal to electric generation facilities. The company’s Oil and Gas segment explores, develops, and produces crude oil and natural gas primarily in the Rocky Mountain region. This segment’s principal assets include the operating interests in the properties in the San Juan basin, the Powder River basin, and the Piceance basin; and non-operated interests in wells located in the Williston, Wind River, Bear Paw Uplift, Arkoma, Anadarko, and Sacramento basins. As of December 31, 2014, it had total reserves of approximately 101 billion cubic feet equivalent of natural gas, crude oil, and natural gas liquids. Black Hills Corporation also provides appliance repair services to approximately 63,000 residential customers; and constructs gas infrastructure facilities and electrical systems for gas transportation and electric utilities customers. The company was founded in 1941 and is headquartered in Rapid City, South Dakota.