The Black Hills of South Dakota experienced a gold rush around 1876 after an expedition led by General George Custer discovered gold there. One particular little valley (or "gulch", as they're called in mining areas) was once (twice, actually) a booming little town known as Galena. The last of the mines here, which mostly produced silver, had closed by the end of the depression with the exception of The Double Rainbow, which was reopened by The Homestake Mining Company when the Hunt brothers ran silver up to $50/oz.