Wyodak Resources Development Corp., a subsidiary of Black Hills Corp. (NYSE: BKH), is a surface coal mine near Gillette, Wyo., and is the oldest operating surface coal mine in the United States. Wyodak has reserves of 213 million tons — a 40-year supply at expected production levels — in the Powder River Basin. Black Hills Corp. is a growth-oriented, vertically-integrated energy company with a tradition of exemplary service and a vision to be the energy partner of choice. Black Hills Corp. is based in Rapid City, S.D., and serves 777,000 natural gas and electric utility customers in Colorado, Iowa, Kansas, Montana, Nebraska, South Dakota and Wyoming. Black Hills Corp. generates wholesale electricity and produces natural gas, oil and coal. Black Hills Corp.’s 1,948 employees partner to produce results that are improving life with energy. More information is available at www.blackhillscorp.com.