DJR Energy Team

David Lehman

President & CEO

David H. (Dave) Lehman is a petroleum geologist, executive and businessman with extensive experience in all aspects of the upstream oil and gas business. Dave began his industry career at Exxon, where he held many positions of significant responsibility as an executive. These included Manager of worldwide new business opportunities for Exxon Exploration Company; and Advisor for Global Exploration to Exxon’s Upstream Director. After 27 years at Exxon, he became an entrepreneur and successfully built, and profitably sold, two oil and gas companies; making outsized returns for his investors. DJR Energy is his third venture. He holds degrees in Geosciences from Franklin and Marshall College, and The University of Texas at Austin.

Jeff King

Chief Financial Officer

Mr. King has significant experience in oil & gas investment banking, equity research, and commodities transactions. Prior to joining DJR Energy, he was a managing director in Scotiabank’s energy commodities group based in Toronto. Prior to Scotiabank, Mr. King worked at Credit Suisse as an investment banker in New York where he executed numerous oil & gas M&A and financing transactions. Prior to this, he worked as an equity research analyst at Investec Securities in London, covering the UK E&P sector. He received his BS in economics and minor in geology from the University of Colorado.

Jerry Austin

Vice President Production Operations

Jerry Austin has substantial Oil and Gas operations experience working in the upstream and mid-stream energy sectors. Prior to joining DJR Energy, he consistently delivered superior business and operational results as a Senior Site Operations Manager with Amoco Production Co. and Crescendo Resources in the Anadarko Basin and with BP America Production Company in Wyoming’s Greater Green River Basin. After a proven track record, as a site manager, Jerry was assigned to the role of Area Operations Manager for BP’s Rockies Region and later as the San Juan Basin Manager in Colorado and New Mexico. Jerry graduated with a Bachelor of Science degree in Business from East Central University and completed BP’s Operations Academy at Massachusetts Institute of Technology (MIT). He has also served on the board of directors for Petroleum Association of Wyoming and Colorado Oil & Gas Association.

Jack Rosenthal

Vice President Geoscience

Mr. Rosenthal has more than 10 years of experience in upstream oil and gas operations. He successfully developed the geological foundation for major acquisitions in the Denver-Julesburg basin as a leading member of the DJ Resources team. Mr. Rosenthal now serves as Geoscience Supervisor directing and participating in acquisition programs throughout the Rockies and mid-continent. These in depth evaluation projects have both delineated numerous development targets and driven recent acquisitions in the San Juan Basin. Jack received a BA in geology from Franklin and Marshall College.

Chuck Mallary

Vice President Drilling & Completions

Chuck has over 30 years of experience in wellbore construction. After earning a Bachelor of Science degree in Petroleum Engineering from the Colorado School of Mines, he worked in Alaska, California, Indonesia and Australia for ARCO, BP and Conoco Phillips before returning to Denver. In the Rockies he has worked for EOG Resources, Noble Energy and Laramie Energy. In 1995 he drilled his first horizontal well in Indonesia’s Java Sea, and since then has drilled and completed numerous horizontal wells on the North Slope of Alaska, the Green River Basin of Wyoming, the Williston Basin of North Dakota, and the DJ Basin of Colorado. Chuck has authored four SPE papers related to the development and adoption of new technology in the field of wellbore construction.

Kurt Froistad

Land Manager

Kurt has over 38 years of experience as a Professional Landman. During that time, he has been engaged in all facets of oil and gas land work in multiple basins throughout the US, with a focus on the Mid-continent, Rockies and Texas. Kurt began his career with Anadarko Production Company. He has since worked with several other successful companies, including Meridian Oil, Burlington Resources, ConocoPhillips, and Encana, holding positions from staff Landman to Vice President of Land. He received his BS in Business-Mineral Land Management from the University of Colorado.

Sharon Crumb

Senior Landman

Ms. Crumb has worked in the oil and gas industry for thirty-seven years. Prior to her three years with DJR, she worked at Bill Barrett Corporation for ten years and prior to that Independent Petroleum and Patina Oil & Gas Corp. She was influential in DJR’s asset divesture to BCEI in July 2014. Ms. Crumb has extensive knowledge in curative, due diligence, lease and title matters. She has set up and maintained numerous lease records systems and obligations. She has also frequently handled substantial contracts including Purchase and Sale Agreements, Assignments, Communitization Agreements, Exploration Agreements and Farmouts, and Joint Operating Agreements.

Ningning Li

Completions Manager

Ningning has 13 years of diversified operations, engineering and management experience in oilfield completions. After graduating from University of California-Irvine, Ningning joined Schlumberger as a Field Engineer in Bakersfield, California. She progressed to a Sales Engineer position located in Denver. Ningning was recruited by Zeox Corporation as a Technical Sales Manager followed by Regional Sales Manager at Superior Well Services and Western Region Manager at GoFrac. Each of these roles focused on providing technical support and training to clients regarding drilling and completions activities. In 2013 she joined Emerald Oil as a Senior Operations Engineer before joining Black Hills Exploration and Production in 2014 as a Senior Petroleum Engineer. She has also authored several SPE papers on optimizing multi-stage horizontal fracs in resource plays.

Tim Baumgart

Vice President Midstream & Marketing

Tim has substantial Oil and Gas experience in the Upstream, Midstream, and Marketing sectors successfully growing and developing business value across the major domestic basins. This includes 18 years of work experience and leadership at Amoco Production Company, 12 years as Midstream Manager for BP America Production Company, and 8 years at Noble Energy as Vice President of Marketing. He received his BS in Business Management from the University of South Dakota.

Matt Gibson


Matt has over 15 years oil and gas industry experience. Prior to joining DJR, he served as the E&P Controller of Antero Resources Corporation from 2014-2019. From 2003 to 2014, Matt held audit positions of increasing responsibility at Ernst & Young both in the Oklahoma City and Denver offices serving a variety of industries with a focus on upstream oil and gas clients. Matt is a Certified Public Accountant and holds a Bachelor of Accountancy degree from the University of Oklahoma.

Don Koenig

Director of Reservoir Engineering

Don has more than 22 years of experience working all facets of Reservoir Engineering including field development, business development, EOR and SEC Reserve Reporting. He held technical and management positions for Marathon Oil Company, EOG Resources and Whiting Petroleum Corp since graduating from Montana Tech in 1997 with a B.S. in Petroleum Engineering. The last 13 years of his career have focused on finding and developing horizontal, unconventional fields in the Rockies.