U.S. Silica Holdings, Inc. (NYSE: SLCA) today announced that Don D. Weinheimer was appointed Vice President and General Manager of Oil and Gas effective July 30, 2012. In announcing the appointment, Bryan Shinn, President and Chief Executive Officer, commented, “Don is a terrific addition to our executive management team. He is an accomplished leader with a history of successfully growing revenue and earnings across a variety of businesses in the oilfield service sector. He brings a deep Oil and Gas industry background, extensive marketing capabilities and practical technical expertise to our company. We expect that Don and his team will continue to accelerate our growth trajectory in the energy sector.” Mr. Weinheimer has worked in the Oil and Gas Industry for over 30 years, including a long career with Halliburton Energy Services, where he held roles of increasing responsibility in Business Development, Production Enhancement and Strategy. Most recently, he was the Senior Vice President of Strategy, Marketplace Development and Technology for Key Energy Services in Houston, Texas, with primary responsibility for growing Key’s services in the U.S. marketplace. Mr. Weinheimer has a Bachelor of Science in Agricultural Engineering from Texas A&M University. About U.S. Silica U.S. Silica Holdings, Inc., a Delaware corporation, is the second largest domestic producer of commercial silica, a specialized mineral that is a critical input into the oil and gas proppants end market. The company also processes ground and unground silica sand for a variety of industrial and specialty products end markets such as glass, fiberglass, foundry molds, municipal filtration and recreational uses. During its 100-plus year history, U.S. Silica Holdings, Inc. has developed core competencies in mining, processing, logistics and materials science that enable it to produce and cost-effectively deliver over 200 products to customers across these end markets. U.S. Silica Holdings, Inc. is headquartered in Frederick, Maryland.