U.S. Silica Holdings, Inc. (NYSE:SLCA) said today that in view of the unusual market activity in the Company’s stock, the Exchange has contacted the Company in accordance with its usual practice. The Company stated that its policy is not to comment on unusual market activity. 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 250 products to customers across these end markets. U.S. Silica Holdings, Inc. is headquartered in Frederick, MD.