Black Hills Corp. (NYSE: BKH) today announced that its oil and gas subsidiary, Black Hills Exploration & Production, Inc., signed a definitive agreement to sell approximately 85 percent of its Bakken and Three Forks shale assets in the Williston Basin for approximately $243 million, subject to customary pre-closing and post-closing adjustments. The sale has an effective date of July 1, 2012, with an estimated closing date on or before Sept. 30, 2012. The sale includes all of Black Hills’ interests in the Williston Basin assets owned jointly with Helis Oil & Gas and others, including approximately 73 gross wells and 28,000 net lease acres. As of the end of the second quarter, net year-to-date production from these properties totaled approximately 149 thousand barrels of oil and 171 thousand Mcf of natural gas. Total proved reserves for these properties, as of Dec. 31, 2011, were 2.2 million barrels of oil and 3.4 BCF of natural gas. The properties represent approximately 15 percent of Black Hills’ oil and gas production for the first six months of 2012 and 13 percent of year-end 2011 proved reserves. “Upon the conclusion of our oil and gas strategic review in late 2011, we announced our intent to optimize the substantial upside value of our existing oil and gas properties, primarily by proving up the probable and possible reserve potential,” said David R. Emery, chairman, president and chief executive officer of Black Hills. “The divestiture of these assets has effectively and immediately captured the future potential value that we projected for this portion of our oil and gas portfolio.” Helis, as operator of the properties, engaged Tudor, Pickering, Holt & Co. to market its interests in the properties. It offered the non-operated working interest owners in those properties the opportunity to market their interests in conjunction with Helis. Helis, and its working interest co-owners, including Black Hills, accepted the offer of QEP Resources, Inc.’s wholly-owned subsidiary, QEP Energy Company.