Location
This extensive placer-mining district is in eastern Placer County in the vicinity of the old mining camp of Last Chance, 10 miles northeast of Michigan Bluff and 15 miles northeast of Forest Hill. It includes the "diggings" here and at Star Town, Deadwood, and American Hill. Last Chance got its name when a starving miner used his last bullet to kill a deer. The mines in the district were operated almost steadily from the early 1850s until about 1920. There was some activity again in the 1930s, and the El Dorado and Last Chance mines have been intermittently worked in recent years.
Geology
Most of the gold has come from three southwest-trending Tertiary channels. The lowest but youngest is the El Dorado channel, which is steep, only about 100 feet wide, and contains coarse gold. The next youngest is the Sharp Stick channel, which contains clay and coarse boulders. The oldest is the Big Channel which is quartzitic, well-cemented, and up to 800 feet wide. The gravels are capped by andesite. Bedrock is slate and schist of the Blue Canyon Formation (Carboniferous), which encloses some narrow north-striking gold-quartz veins.
Mines
Beaman Ledge, Bear Wallow, Central, Darling, Deep Canyon, Double O, El Dorado, Elkhorn, Golden Riffle, Grizzly, Harkness, Home Ticket $200,000+, Hornby, Last Chance, Little Hope, Missouri Flat, New Caledonia, Pacific, Pacific Slab, Peters, Rattlesnake, Rublin, Sharp Stick, Star Town.
Bibliography
Lindgren, Waldemar, 1900, Colfax folio: U.S. Geol. Survey Geol. Atlas of the U.S., folio 66, 10 pp.
Lindgren, Waldemar, 1911 Tertiary grovels of the Sierra Nevada: U.S. Geol. Survey Prof. Paper 73, p. 158.
Logan, C.A., 1936, Gold mines of Placer County, placer mines: California Div. Mines Rept. 32, pp. 49-96.
Waring, C. A., 1919, Pla,cer County, drift and hydraulic mines: California Min. Bur. Rept. 15, pp. 352-379.
