Scott Sommerdorf | The Salt Lake Tribune In this 2013 photo, Enefit mining engineer Ben France gestures towards the darker, "mahogany zone" of the oil shale deposit revealed in a "box cut" on the company's private holdings in eastern Uinta County. Enefit recently relinquished its federal oil shale leases in the region, although it continues to own private land and state leases with shale deposits.