Discovery

Discovery is the finding of a valuable mineral deposit within the boundaries of a mining claim. BLM's regulations define it in one line: "Discovery means that a mining claimant has found a valuable mineral deposit" (43 CFR 3830.5).

What the law requires

The Mining Law says "no location of a mining claim shall be made until the discovery of the vein or lode within the limits of the claim located" (30 U.S.C. 23). BLM's regulations state that a lode or placer claim "is not valid until you make a discovery within the boundaries of the claim" (43 CFR 3832.11(b)). BLM's brochure "Mining Claims and Sites on Federal Lands" explains that the rights of a mining claim "protect against a challenge by the United States and other claimants only after the discovery of a valuable mineral deposit."

The prudent man rule

The statute does not define a valuable mineral deposit. The BLM brochure explains that the government adopted the "prudent man rule," first stated by the Department of the Interior in Castle v. Womble (1894):

"...where minerals have been found and the evidence is of such a character that a person of ordinary prudence would be justified in the further expenditure of his labor and means, with a reasonable prospect of success, in developing a valuable mine, the requirements of the statute have been met."

The brochure notes that the U.S. Supreme Court approved this definition in Chrisman v. Miller (1905).

The marketability test

According to the brochure, a 1962 Solicitor's opinion (M-36642) called for "a distinct showing that the mineral could be mined, removed, and marketed at a profit," and the Supreme Court approved it in U.S. v. Coleman (1968). The marketability test "is supplemental to the prudent man rule," and the claimant must show "a reasonable prospect of making a profit from the sale of minerals from a claim or a group of contiguous claims."

Physical exposure and mineral character

• Interior decisions require a discovery on each mining claim "based on an actual physical exposure of the mineral deposit within the claim boundaries" (BLM brochure).
• For placer claims, each 10-acre aliquot part must also be mineral-in-character (43 CFR 3832.21(b)(2)).

How discovery is tested

Mining claims found by BLM or federal courts to lack a discovery "are generally declared to be null and void," and BLM may review a mining claim through a validity determination or a mineral contest (CRS Report R48166, 2024).

Why it matters in mining claim research

Recording and paying fees do not make a mining claim valid. BLM's regulations say recording "does not make a claim or site valid if it not otherwise valid under applicable law" (43 CFR 3833.1(b)). Mining claim records show that a mining claim was located and maintained, not that a discovery exists. The difference matters most on withdrawn land, where rights depend on a discovery made before the withdrawal date.