In New California Gold Rush, Old Mines Reopen

By JESSE McKINLEY
Published: February 10, 2011

SUTTER CREEK, Calif. — Standing in a cramped, slanted and slippery crevice some 500 feet below the earth’s surface, David Cochrane turned his eyes to a ribbon of marbled quartz — mainly gray, amber and white — and found the one hue he was actually looking for.

“Right there, see? It’s small but it’s very colorful,â€