General Mining Law

The u.s. general mining law of 1872 was created to encourage mineral exploration and development on federal lands in the western United States, offer an opportunity to acquire clear titles to mines already being worked, and to help settle the American West. The law permitted free access to individuals and/or corporations to prospect for rocks, ores, and minerals on public lands and allowed them, after making a discovery, to stake a claim on the deposit sanctioning the development of ores and minerals from that site (originally applying to all minerals except coal).

Federal lands acquired by treaty, cession, or purchase as part of the general territory of the United States, including lands that passed out of but reverted back to federal ownership, were specifically included in the mining law administration. However, those lands acquired from a state or a private owner through gift, purchase, or condemnation are not covered by the law. Under complicated circumstances, public lands may be closed to prospecting and mineral exploration.

The General Mining Law of 1872 was the principal motivation behind the sudden growth of mineral resources in the 19th-century American West as well the associated services and industries involved in mineral production. Hard-rock minerals development included gold, silver, copper, lead, molybdenum, and uranium, with major gold and silver mining districts built under the Mining Law [Page 737]in California, Colorado, and Nevada. In Arizona and Colorado during the early part of the 20th century, major discoveries of porphyry copper, molybdenum, and tungsten led to extensive development and industrial growth. The law continues to support much of the West's widespread mineral development on public domain lands and although it is not as wide-ranging, it represents a major revenue generator for the United States because most hardrock mining occurs on federal lands.