One of the highest quality deposits of silica sand in the United States is in Morgan County, giving rise to a sand-mining industry. Local mining started after the Civil War along the Oriskany sands formation, which runs from New York to southern Virginia. At first, men used sledge hammers and wedges to break large rocks into smaller ones, which were transported by mule-drawn carts to steam-powered crushers and mills. The stone was reduced to sand, then carried by rail to glass manufacturers. In 1893, Henry Harrison Hunter of Berkeley Springs won a blue ribbon at the World's Columbian Exposition in Chicago for the quality of sand that he had mined and processed.

By the early 1900s, many small companies had begun rudimentary mining operations along Warm Springs Ridge, just north of Berkeley Springs. One of these eventually developed into Berkeley Glass Sand Company, incorporated in 1911.

Meanwhile, Pennsylvania Glass Sand Company had, since 1894, been mining Oriskany sand in the same geological formation in Pennsylvania about 80 miles north of Morgan County. The growing business soon acquired the Hancock Works, which had been started by Noah Speer in 1872 along the Potomac River north of Berkeley Springs in West Virginia. The Pennsylvania investors opened a second plant on the east side of Warm Springs Ridge in 1904. In July 1927, the company was incorporated as Pennsylvania Glass Sand Corporation. Looking for larger silica reserves to support its investment in larger processing facilities, the company absorbed Berkeley Glass Sand and other companies, including the Hazel-Atlas Glass Sand Company near Great Cacapon.

The darkest day in Morgan County sand-mining history came June 7, 1926, before the companies were consolidated. As a Berkeley Glass Sand crew prepared an explosion, a spark prematurely set off what the company maintained was dynamite but others claimed was dangerous black powder. Six men were killed. Their deaths inspired John Unger, a local blind singer, to compose "The Miner's Doom," a ballad that was recorded in 1927 by early country music star Vernon Dalhart.

The modern era began in 1929 when Earle T. Andrews, a young engineer, was assigned by Pennsylvania Glass Sand Corporation to design and construct a new Berkeley Plant, the largest and most advanced silica facility of its time. The Berkeley Plant was still the core of the Morgan County sand-mining industry more than 70 years later. Andrews went on to become general manager of operations in 1941 and was president from 1963 to 1968, when the company was acquired by ITT. His son, Hale E. Andrews, then took over until his retirement in 1985. During these decades, a number of expansions and modernizations were made to supply markets in the glass, fiberglass, plastics, metallurgical, and chemical industries.

In 1985, U.S. Borax & Chemical Company, a subsidiary of the British RTZ Corporation, acquired Pennsylvania Glass Sand and the rest of ITT's sand-mining business. In February 1996, the company—now known as U.S. Silica—became affiliated with D. George Harris & Associates. As the 21st century began, the Berkeley Springs operation was part of a corporation with $250 million annual sales and facilities at 21 locations. About 200 people were employed at the mine, processing plant, laboratory, and corporate headquarters in Berkeley Springs.