Seeking information about mining leases in California

Hello, Does anyone know anything about mining leases in California? An ancestor of mine obtained land under the Homestead Act in Siskiyou County, CA. I recently read that chromite deposits had been found on his land (c. 1920) and that several men had obtained a lease for mining it. At this point, I'm just looking for an explanation of the process. How did people go about obtaining leases? Who was the responsible authority (county, state, federal)? What sort of paperwork was involved? Is any of it still extant? Is this worth pursuing? This isn't a topic that I know a lot about, so I'd appreciate a basic overview of the process for obtaining mineral leases. I'd be glad to provide more information if it would be helpful. Thanks!