Duane C. Radtke, 73, joined the board of directors in August 2010 and served as chairman from June 2019 until January 2021. Since 2008, Radtke has served as president and CEO of Valiant Exploration LLC, a privately-held, family-owned investment company. Previously, he served as president and CEO of Dominion Exploration and Production, a subsidiary of Dominion Resources Inc. Prior to working at Dominion, Radtke was a senior executive with Santa Fe Snyder. Radtke earned a bachelor's degree in mining engineering from the University of Wisconsin.