NEW!!! California, Permitted, Production Ready, Gold Mine for Sale. The Discovery Day Gold Property is one of only a few permitted, production ready properties with its own on-site mill available in California, consisting of 48 unpatented BLM mining covering over 950 acres of land and encompassing the entire prolific Knownothing mining district. The claim block contains 5 historical producing mines, the Discovery Day, Gilta, Hansen, Knownothing and Jeannette. As a group this collection of mines produced over 60,000 ounces of gold, and were considered some of the most valuable in the state.