The Spanish Mine is a gold mine located in Nevada county, California at an elevation of 3,051 feet.
About the MRDS Data:
All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.
Elevation: 3,051 Feet (930 Meters)
Primary Mineral: Gold
Lat, Long: 39.3818, -120.78610
Map: View on Google Maps
Spanish Mine MRDS details
Primary: Spanish Mine
District: Washington District
Land ownership: National Forest
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land or if it is in an area that is generally private property. It does not indicate a claim status and does not necessarily indicate an area is open to prospecting.
Administrative Organization: Tahoe National Forest (U.S. Forest Service)
Record Type: Site
Operation Category: Past Producer
Deposit Type: Hydrothermal vein
Operation Type: Surface-Underground
Discovery Year: 1883
Years of Production:
Mineral Deposit Model
Model Name: Low-sulfide Au-quartz vein
Form: Tabular, lens
Description: Melones Fault Zone
Description: Melones Fault Zone, Goodyears Creek Fault
Age Type: Host Rock
Age Young: Devonian
Age Old: Ordovician
Comment (Deposit): Unlike most of the gold-quartz veins in neighboring districts, the main quartz vein is generally barren with ore occurring only in a narrow zone in the soft hanging wall slate adjacent to the vein. The fracture zone and quartz veins are thought to be extensions of the fracture system and mesothermal quartz veins of the nearby Alleghany District. Recent exploration indicates the presence of a massive and disseminated sulfide gold-silver-copper-lead-zinc deposit at depth, which has not been exploited.
Comment (Geology): A smaller vein was encountered about 500 feet above the main workings. It consists of a 2-foot quartz vein with barite gangue, carrying sphalerite and bornite. As with the main zone, the pay was not in the quartz vein proper, but within 2 feet of the vein in the slate wall rock and gangue. One and one-half miles north and 1,500 feet shallower than the Spanish Mine vein workings, is a shallow high-grade barite deposit, which was mined independently of the Spanish Mine. In the 1900s, it became part of the Spanish Mine properties. Associated with the barite is a shallow oxidized orebody that averaged .26 oz gold and 3.5 oz silver. In 1919, average gold recovery from the mine ran from $0.50 to $1.25 per ton.
Comment (Commodity): Gangue Materials: Quartz, barite
Comment (Commodity): Ore Materials: Free-milling gold-bearing quartz stringers within wallrock adjacent to barren quartz vein Galena, sphalerite, bornite
Comment (Development): The Spanish Mine was discovered in 1883. By 1884, the mine was in operation, at first comprising 10 claims, each measuring 1,500 x 600 feet (207 acres). The mine was operated from1883-1898, 1903-1906, and then was idle until 1919 when the mine was briefly put back in operation. At that time, the mine consisted of nine patented claims named American, Spanish, Santa Anita, Santa Anita Extension, Pine Tree, Singleton, Grizzly, Savage, and Mexican, totaling 175 acres. The claims covered a two-mile stretch along the vein outcrop. It was equipped with 10 stamps and four Huntington Mills, operated by water under a 600-foot head. Mill capacity was about 4000 tons per month. Gold recovery ran $0.50 to $1.25 per ton. By 1931, a 50-ton selective flotation plant had be installed and processed ores ran as high as $3-$6 in gold, 2-3 ounces silver, 0.6% copper, 1.5% lead, and 2% zinc, producing 5 different concentrates: copper, lead, zinc, iron, and barite. In 1932, the upper tunnel was driven to 1,803 feet and the lower tunnel to 5,676 feet. In 1933, a 50-ton cyanide plant was installed to treat oxidized ore mined from the Barite Mine (barite deposit north of the Spanish Mine). In 1938, the mine produced 22,290 tons of ore, which yielded 4,542 ounces of gold, 45,164 ounces of silver, 234,440 pounds of lead, and 114,963 pounds of copper (by then the mine included ores from the assimilated Barite Mine to the north). The mine was shut down during World War II, and no activity occurred on the mine properties until the 1950s when National Lead leased the properties to produce from the near-surface barite deposit. The Ostler family purchased the property in the mid-1960s and mined approximately 100,000 tons of barite. Geo Drilling Fluids leased the property in the 1970s and produced another 100,00 tons of barite. In 1984, Homestake Mining acquired the property and undertook an exploration program focused on the gold ores. In 1987, Panorama Resources acquired the mineral rights and conducted their own exploration program involving geologic mapping, drilling, geochemical analyses, and geophysical surveying. This program demonstrated the presence of a significant massive- and disseminated-sulfide gold-silver-copper-lead-zinc deposit at depth. A permit to mine was obtained in 1990, but expired 5 years later with no mining activity accomplished.
Comment (Economic Factors): No information is available regarding the total production (tonnages or dollars) from the Spanish Mine. It has been reported that during the early operations, the ore yielded $0.70 per ton. By the 1930s, ore was yielding $3-$6 per ton.
Comment (Identification): The Spanish Mine is located in the Washington Mining District in east-central Nevada County near the old mining town of Washington. Discovered in 1883, the mine produced continuously until 1898, and intermittently thereafter until 1939. The mine produced from thin gold-quartz stringers within the soft slate hanging wall of a thick, nearly barren quartz vein. Total production is unknown, but ores are reported to have yielded as much as $3.00 to $6.00 per ton.
Comment (Location): Location selected for latitude and longitude is the Spanish Mine symbol on the USGS 7-1/2-minute Alleghany quadrangle
Comment (Workings): Early mining methods were primitive. By 1888, the mine consisted of one tunnel 1,200 feet long with a vertical depth to surface of 350 feet. Ore was mined to the surface using the glory-hole method. One early account was given by Irelan (1888): "A Chinaman, armed with a churn drill is lowered (from the surface) to a sufficient distance by means of a rope. When the drill hole is deep enough, it is charged with about five pounds of powder and fired, causing a large quantity of the soft slate to slide to the bottom, whence it is taken out through the tunnel. Cars were drawn into the mine by mules, coming out by gravity". The ore averaged about $0.70 per ton. A description of the early crushing and processing operations is also given by Irelan (1888). By 1889, a 1,500-foot lower tunnel had been driven 300 feet below the upper tunnel, from which there were 7 upraises from the tunnel to the surface and 10 crosscuts in the vein. By the 1890s, all mining was being conducted through the lower tunnel. Raises were put up from the ends of the tunnel and the ore in the surface zones was worked by open cuts around the raises so that gravity was fully utilized. By the 1930s, the lower tunnel had been driven to 5,676 feet along the vein and the upper tunnel was extended to 1,803 feet.
Comment (Geology): REGIONAL GEOLOGY The northern Sierra Nevada basement complex has a history of both oceanic and continental margin tectonics recorded in sequences of oceanic, near continental, and continental volcanism. The complex has been divided into four lithotectonic belts: the Western Belt, Central Belt, Feather River Peridotite Belt, and Eastern Belt. The Western Belt is composed of the Smartville Complex, an Upper Jurassic volcanic-arc complex consisting of basaltic to intermediate pillow flows overlain by pyroclastic and volcanoclastic rocks with diabase, metagabbro, and gabbro-diorite intrusives. To the east it is bounded by the Big Bend-Wolf Creek Fault Zone. East of the Big Bend-Wolf Creek Fault Zone is the Central Belt, which is in turn bounded to the east by the Goodyears Creek Fault. This belt is structurally and stratigraphically complex and consists of Permian-Triassic argillite, slate, chert, ophiolite, and greenstone of marine origin. The Feather River Peridotite Belt is also fault-bounded, separating the Central Belt from the rocks of the Eastern Belt for almost 95 miles along the northern Sierra Nevada. It consists largely of Devonian-to-Triassic serpentinized peridotite. The Eastern Belt, or Northern Sierra Terrane, is separated from the Feather River Peridotite Belt by the Melones Fault Zone. The Northern Sierra Terrane is primarily composed of siliciclastic marine metasedimentary rocks of the Lower Paleozoic Shoo Fly Complex overlain by Devonian-to-Jurassic metavolcanic rocks. Farther east are Mesozoic granitic rocks of the Sierra Nevada Batholith. Most Upper Jurassic and older basement rocks of the northern Sierra Nevada were metamorphosed and deformed during the Jurassic-Cretaceous Nevadan Orogeny. Deformation features in the lithotectonic blocks of northern Sierra Nevada are best developed in the Eastern, Central, and Feather River Peridotite Belts, where they have been collectively described as the "Foothills Fault System" (Clark, 1960). Compressive deformation produced northwesterly trending faults, folds, and regional greenschist facies metamorphism (Harwood, 1988). Many of the intrusive granitic plutons of the Sierra Nevada were also part of this compressive episode. Most of the dominant faults dip steeply east and display reverse displacement. LOCAL GEOLOGY The Washington District is located on the western edge of the Northern Sierra Nevada Eastern Belt (Northern Sierra Terrane) lithotectonic unit. The Spanish Mine is less than 1 mile east of the Melones Fault Zone, which bounds the Feather River Peridotite Belt. Locally, the district is underlain by slate, schist, and quartzite of the Paleozoic Shoo Fly Complex. A few serpentinite bodies intrude the bedrock. The Bowman Lake Batholith lies to the east. The quartz veins in the Spanish Mine are thought to be the southeastern extension of the Jurassic-Cretaceous mesothermal fracture-filling quartz veins, which produce from the famous pocket gold mines in the Alleghany Mining District to the north. The Alleghany fracture system is thought to be both the result of regional compression as well as more local compression associated with the many nearby intrusive rocks. Unlike the Alleghany District quartz veins where the gold is dispersed in pockets throughout the vein itself, most of the gold in the Spanish Mine occurs in thin free-milling quartz veinlets in the soft slate of the hanging wall of a quartz vein system. The foot wall is hard slate. While the entire vein system is up to 90 feet thick, the main vein, which is on the footwall, is only four feet wide. It consists of solid quartz with little to no gold, and was often left in place during mining. It strikes N 14? W and dips 80? west.
Reference (Deposit): Irelan, W., Jr., 1888, Nevada County, Washington mining district: California State Mining Bureau Report 8, p. 442-443.
Reference (Deposit): Lindgren, W., 1900, Colfax folio, California: U.S. Geological Survey Atlas of the U.S., Folio 66, 10 p.
Reference (Deposit): Lindgren, W., 1911, Tertiary gravels of the Sierra Nevada: U.S. Geological Survey Professional Paper 73, p. 139-141.
Reference (Deposit): Clark, L. D., 1960, Foothills fault system, western Sierra Nevada, California: Geological Society of America Bulletin, v. 71, p. 483-496.
Reference (Deposit): Clark, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 128.
Reference (Deposit): Crawford, J.J., 1896, Nevada County, Spanish Mine: California State Mining Bureau Report 13, p. 264.
Reference (Deposit): Harwood, D.S., 1988, Tectonism and metamorphism in the northern Sierra terrane, northern California, in Ernst, W. G., editor, Metamorphism and crustal evolution of the western United States (Rubey Volume VII): Prentice-Hall, Englewood Cliffs, New Jersey, p. 764-788.
Reference (Deposit): Logan, C.A., 1930, Nevada County, Spanish Mine: California State Mining Bureau Report 26, p. 128-129.
Reference (Deposit): Logan, C.A., 1941, Nevada County, Spanish Mine: California State Mining Bureau Report 37, p. 428.
Reference (Deposit): Loyd, R.C. and Clinkenbeard, J, 1990, Mineral land classification of Nevada County, Califonia: California Dept. of Conservation, Division of Mines and Geology, Special Report 164.
Reference (Deposit): Additional information on the Spanish Mine is contained in File No. 331-9114 (CGS Mineral Resources Files, Sacramento) and in Mine File No. 91-29-0003 (California Department of Conservation, Office of Mine Reclamation)
Reference (Deposit): MacBoyle, E., 1919, Nevada County, Spanish Mine: California State Mining Bureau Report 16, p. 249.
Reference (Deposit): Hobson, J.B. and Wiltsee, E.A., 1893, Nevada County, Spanish Mine: California State Mining Bureau Report 11, p. 292-293.