From the site: "Commodities covered by the Minerals Information Team (MIT) of the U.S. Geological Survey. Included are crushed stone operations considered active in 1998 with production greater than 30,000 tons, ferrous metal processing plants considered active in 1997, miscellaneous industrial minerals plants and/or mines considered active in 1997, or in 2001 for fullers earth and kaolin (This file is an update of the 1998 data set.), nonferrous metal processing plants considered active in 1997, refractory, abrasive, and other industrial minerals plants and/or mines considered active in 1997, or in 2001 bentonite and fire clay, and sand and gravel operations considered active in 1998 with production greater than 30,000 tons. Companies represented were surveyed byt the MIT.

Shapefiles representing six mineral operations nation wide were downloaded from the National Atlas of the United States website, clipped individually to a 1:24,000 WV boundary then merged into a single shapefile. Published April 2002."