Collection consists of 45 scrapbooks compiled by the United States Bureau of Mines concerning mines and mining operations in Colorado. Clippings in the scrapbooks are arranged by county and mining activity. The Colorado counties principally treated in this collection are: Chaffee, Clear Creek, Custer, Dolores, Fremont, Hinsdale, La Plata, Routt, Saguache, San Miguel, and Summit. Although primarily composed of clippings, the collection also contains reports, brochures, pamphlets, plats, photographs, and other material. An index to the collection exists and is a compilation of the tables of contents compiled at the front of each volume. The index was updated in 1997 using placenames, mining companies, and subjects found on reference cards held in the Stephen H. Hart Library's CWA reference file. This updating enhanced the older index by the addition of previously unlisted entries as well as the addition of additional county and date information whenever it was recorded. As this new information is now included in this more comprehensive index, the reference cards have been removed from the CWA file.