“For two bits I’d shove out of here. If we can get jus’ a few dollars in the poke we’ll shove off and go up the American River and pan gold. We can make maybe a couple of dollars a day there, and we might hit a pocket.”
Lennie leaned eagerly toward him. “Le’s go, George. Le’s get outta here. It’s mean here.”
“We gotta stay,” George said shortly. “Shut up now. The guys’ll be comin’ in.”

– John Steinbeck

Of Mice and Men, Chapter 2. George to Lennie. During this time in America people were panning gold, and doing anything for just a little bit of cash.