Mineral Policy Center Position Statement
Within the 1872 Mining Law, there is a single provision that effectively protects the public interest. Known as the “millsite” provision, it limits the amount of public land available for mining companies to use for dumping waste, processing ore with toxic chemicals, or doing any other activity that is “ancillary” to mining.
The language specifically says that, for every one 20-acre “mining claim” – where minerals area actually taken from the ground, a company is allowed one five-acre “millsite claim,” which can be used to dump waste and process ore.
Modern mines, which extract precious metals from immense quantities of ore and wasterock, routinely use much more public land than that for the dumping of their waste and other such activities and for years had been getting away with violating the millsite limitation.
That's why, in 1997, the former Interior Solicitor John Leshy issued a legal opinion stating that the Interior Department had to enforce the “millsite” limitation in order to comply with the plain language of the law. Solicitor Leshy also noted that, if the limits on public land did not leave enough land for the huge mines to conduct their activities, there are at least two legal avenues available. First, a mining company may undertake a land exchange with the federal government. Second, the mine could apply for a special use permit to allow them to use excess millsite land under certain conditions.