Location and History
This district is in the Sierra Nevada west gold belt in western El Dorado County. A belt of lode-gold mines extends from the Pyramid mine south through Shingle Springs to the vicinity of Brandon Corner, a distance of 10 miles. The district was first worked during the gold rush. The town was settled in 1850; the name derived from "a shingle machine used at a cluster of springs". There was extensive mining acrivity here during the 1930s.
Geology and Ore Deposits
A north-trending belt of greenstone, green schist, and slate four to six miles wide, which has been intruded by numerous serpentine bodies, both large and small, extends through the central part of the district. A granodiorite-gabbro intrusion lies to the west. The ore deposits consist chiefly of large but low-grade bodies of mineralized talcose, amphibolite-chlorite schist or greenstone with numerous quartz vein lets and stringers. The values occur in disseminated auriferous pyrite found in both the wall rock and the quartz veins and stringers. The ore bodies commonly are found in both the wall rock and the quartz. Some quartz veins with high-grade pockets and abundant sulfides exist. Some of the deposits were mined by open-pit methods.
Big Canyon $3 million+, Brandon, Bugtown, Crystal $ 100,000+, French Creek, Greenstone, Marcelias, Pyramid $1 million, Sugar Loaf, Vandalia $100,000+
Clark, W.B., and Carlson, D.W., 1956, El Dorado County, lode-gold deposits: California Jour. Mines and Geol.. vol. 52, pp. 401-429.
Irelan, William, Jr., 1888, Vandalia and Big Canyon mines: California Min. Bur. Rept. 8, pp. 172-175.
Lindgren, Waldemar, and Turner, H. W., 1894, Placerville folio: U.S. Geol. Survey Geol. Atlos of the U. S., folio 3, 3 pp.
Logan, C.A., 1938, El Dorado County, Big Canyon, Pyramid, and Vandalia mines: California Div. Mines Rept. 34, pp. 219-223, 244-246, and 254.