Information somewhere in BLM website
"Location and Validity of mining claims in California"
May have to order a hard copy
Learning how claims lay on the lat and lon of BLM maps
without this basic info your not going anywhere
Land Matters, LR2000, maybe even look at PLP if they are still around, these are good research sites to start, county is law .
Most are concerned with BLM, everything mineral claim related "MUST" have the counties blessing in California.
Go to county to find active, up to date on the spot information, claim owners, acres, fee's paid, everything legit
Then go talk to BLM, but you still have to know location on a map