43 C.F.R. § 3811.1
Vacant public surveyed or unsurveyed lands are open to prospecting, and upon discovery of mineral, to location and purchase. The Act of June 4, 1897 (30 Stat. 36), provides that "any mineral lands in any forest reservation which have been or which may be shown to be such, and subject to entry under the existing mining laws of the United States and the rules and regulations applying thereto, shall continue to be subject to such location and entry," notwithstanding the reservation. This makes mineral lands in the forest reserves in the public land states, subject to location and entry under the general mining laws in the usual manner. Lands entered or patented under the stockraising homestead law (title to minerals and the use of the surface necessary for mining purposes can be acquired), lands entered under other agricultural laws but not perfected, where prospecting can be done peaceably are open to location.
43 C.F.R. § 3811.1