Sorry, no jurisdiction in the world can you legally commercially mine gold without paying a royalty and taxes to the government. I'm not talking about an NSR to a property vendor.
"In California, the royalty rate on gold mining is typically a percentage of the gross production value, ranging from 12.5% to 25%. The rates vary based on negotiations and market conditions"
The corporate income tax rate in California is 8.84%. The federal corporate income tax rate is a flat 21%.