Guadalupe Mine, New Almaden, New Almaden Mining District, Santa Clara County, California, USAi

Regional Level Types
Guadalupe Mine	Mine
New Almaden	- not defined -
New Almaden Mining District	Mining District
Santa Clara County	County
California	State
USA	Country

A former Hg occurrence/mine located about 7.4 km WNW of New Almaden and about 7 miles SW of San Jose, along the E side of Guadalupe Creek, on private land (fee ownership). Discovered in 1846 by Josiah Belden. Owned by James Rolfe, III (1957). Owned by the Guadalupe Rubbish Disposal Inc. (95%), California (1982) and by Rancho de Guadalupe Inc. (5%), California (1982). Owned by the Laco Mining Co. Produced during the periods 1854 to 1886, 1901 to 1906, 1908 to 1918, 1935 to 1937, and 1943 to 1947. MRDS database stated accuracy for this location is 10 meters.

Mineralization is hosted in Late Cretaceous serpentinite. The ore body is irregular, strikes N55W and dips 35SW at a thickness of 12.19 meters, a depth-to-top of 100 meters, a depth-to-bottom of 304.8 meters a width of 107 meters and a length of 45.72 & 137 meters. Ore body No. 1 is an irregular replacement body . Ore body No. 2 is tabular in a fissure vein . The primary mode of origin was hydrothermal activity. Primary ore control was lithology and the secondary control was fracturing. Local alteration includes silica carbonate alteration of serpentine. Local rocks include rocks of the Franciscan Complex, unit 1 (Coast Ranges).

Local geologic structures include a serpentine-sediment contact, shearing and folding.

Workings include surface and underground openings with a length of 8,046.5 meters. Underground workings at a length of 9,144.01 meters . 5 main shafts, more than a dozen stopes, several thousand square feet of open pits in a little more than a quarter of a square mile. The mine is divided into 2 parts, an older group of underground workings south of Guadalupe Creek known as the Old Mine, and the newer more scattered workings underlying Los Capitancillos Ridge N of the creek. The underground openings are inaccessible. Named workings include the Good Friday shaft, McGurk tunnel, Old Hill mine pits, Canyon tunnels, Caplan tunnel, Moreno tunnel, Upper and Lower water tunnels, Hicks tunnel, New Guadalupe inclined shaft, Office Mine pit, Old inclined shaft, Engine shaft, Virginia shaft, Maryland #1 shaft, Maryland No. 2 shaft, and an air shaft on the S side of the hilltop. North of the hill are the Kelly cuts, Upper Kelley workings, and New Prospect tunnels. At the east end of the hilltop, but still west of Senator Mine, are the East Hilltop workings.

Production data are found in: U.S. Bureau of Mines file data; Bailey & Everhart; and Holmes.

Production statistics: Year: 1874 (period = 1846-1874): 20,000 flasks Hg (estimate). Year: 1947 (period = to 1947): Hg (estimate) ^2 to 5% Hg (1,581 grams/metric ton. Year: 1947 (period = 1875-1947): 92,623 flasks Hg produced. Defense Minerals Exploration Administration (DMEA) report indicates about 115,000 flasks produced.

Reserves data: Estimated reserves of 2,000 tons of 5% ore. 1942 direct exploration with help of the U.S. Bureau of Mines, found moderate tonnage of low-grade ore; 1957 Direct exploration by the DMEA, found some ore.

Other Databases

Link to USGS MRDS:	10040741

Other Regions, Features and Areas containing this locality

References