William Keen Robertson

William K. Robertson has served as a director of our general partner since February 5, 2010. Mr. Robertson is Managing Member of Quintana Infrastructure and Development, LLC. Mr. Robertson served as a Managing Director for Quintana Capital Group GP, Ltd. from 2005 to 2010 and continues to serve as a director of its general partner and management company. Since October 31, 2007, Mr. Robertson has served as president of Quintana Minerals Corporation, a privately-held management company. Prior to joining Quintana, Mr. Robertson worked in private investments with The CapStreet Group, LLC, and, prior to that, in the energy and power investment banking department of Merrill Lynch, Pierce, Fenner & Smith Inc. Mr. Robertson is the brother of Corbin J. Robertson III.