Depending on use of VALIDITY it can be real different;
Validly filed claim: A claim which has been located and filed properly both locally and with BLM
Valid claim: Claim which is accepted as what a prudent man would continue to use and is commercially marketable for profit.
Making a claim valid through a validity test is what is being referred to. This entails a legal process with persons licensed specifically for this. They need to test for results through samples that have to maintain a chain of custody to determine the following:
Prudent man test (rule): "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… Castle v. Womble, 19 L.D. 455, 457 (1894)
Marketability test (rule): Addition to the “Prudent Man Test” originally for the common varieties of minerals is at times used in locatable minerals. Purpose is for evidence that a mineral deposit is not of economic value and cannot in all likelihood be operated at a profit may well suggest that a claimant seeks the land for other purposes. United States v. Coleman 390 U. S. 599 (1968) & Foster v. Seaton, 106 U.S.App. D.C. 253 was explained as “such a `mineral locator or applicant, to justify his possession, must show that by reason of accessibility, bona fides in development, proximity to market, existence of present demand, and other factors, the deposit is of such value that it can be mined, removed and disposed of at a profit.'”
In some cases usually with non-precious locatable minerals the following standard could be added:
Excess Reserve or Too Much Test: A little know test that could be used for non-precious locatable minerals but more often for mineral leases; this is where the amount held under claim is more than what would be profitable to market. Clear Gravel Enterprises v. Keil, 505 F.2d 180 (9th Cir. 1974), cert.
The area of problems that can cause this to be invalidated would be if at any time the chain of custody of mineral samples is broken or if the testing authorities are found not to be licensed properly for the agency and test being done. Testing us usually done on every 10 acres with exceptions allowed in some instances.