U.S. Silica Holdings, Inc. is a performance materials company. The Company is engaged in the production of commercial silica, which uses in the oil and gas industry and in a range of industrial applications. The Company, through its subsidiary EP Minerals, LLC, is engaged in the production of industrial minerals, including diatomaceous earth, clay and perlite. It operates through two segments. In the Oil & Gas Proppants segment, it serves the oil and gas recovery market primarily by providing and delivering fracturing sand, or frac sand, which is pumped down oil and natural gas wells to prop open rock fissures and increase the flow rate of oil and natural gas from the wells. The Industrial & Specialty Products segment consists of approximately 600 product types and materials used in a range of industries, including container glass, fiberglass, specialty glass, flat glass, building products, fillers and extenders, foundry products, chemicals, recreation products and filtration products.