Yuba Mine (Yuba Consolidated; Yuba Quartz Mine; Yuba Qtz; Yuba claim; Yuba River), Omega, Washington Mining District (Omega Mining District), Nevada County, California, USAi

Regional Level Types
Yuba Mine (Yuba Consolidated; Yuba Quartz Mine; Yuba Qtz; Yuba claim; Yuba River)	Mine
Omega	- not defined -
Washington Mining District (Omega Mining District)	Mining District
Nevada County	County
California	State
USA	Country

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A former lode Au occurrence/mine located in the center of sec. 11, T17N, R11E, MDM, about 3.8 km (2.5 miles) ENE of Omega and about 5 miles ESE of Washington, spanning the South Yuba River, on National Forest land. Discovered in 1880. MRDS database stated accuracy for this location is 100 meters. Location selected for latitude and longitude by the USGS is an abandoned-building symbol (probably mine related) at the site of the Yuba Mine as shown on the USGS 7.5-minute Blue Canyon quadrangle. This is apparently the same mine as that listed as the "Yuba River" by Clark (1970a).

The Yuba Mine is known to have been in operation at least as early as 1888, with a 15-stamp mill on site (Irelan, 1888). In 1919, there was a 20-stamp mill in operation. By this time, there were at least 16 claims under Yuba Consolidated Gold Mining Company (MacBoyle, 1919). The main development during this period was in the original Yuba, Mayflower, Grey Eagle, Central, and Blue Jay claims. Amalgamation processes were used at this mine. Consumption of mercury in the 1880?s was 0.177 ounces per ton of ore.

Mineralization is a Mesozoic deposit (Mineral occurrence model information: Model code: 273; USGS model code: 36a; Deposit model name:
Low-sulfide Au-quartz vein; Mark3 model number: 27), hosted in Paleozoic granodiorite of the Bowman Lake Batholith, Paleozoic slate and Mesozoic-Paleozoic greenstone. The ore body is tabular. Controls for ore emplacement involved ore shoots in quartz veins formed along fractures in the plutonic-metamorphic country rock. Local rocks include Mesozoic granitic rocks, unit 4 (Klamath Mountains and Northern Sierra Nevada).

The Yuba Mine is situated within granodiorite of the Paleozoic Bowman Lake Batholith. This plutonic complex is intruded into the metasedimentary terrane of the Lower Paleozoic Shoo Fly Complex. Irelan (1888) reported the ore deposit at the original Yuba Mine to consist of a quartz vein emplaced in wallrock composed mainly of granodiorite. In places, the wallrock also contained slate and greenstone; Lindgren (1900) also reported the presence of limestone. It is not clear if the greenstone is part of the Shoo Fly Complex or is dike rock. This vein strikes north-northeasterly, dips about 50-70SE, and ranges from 2 to 16 feet in width; the average width is 6 feet. It appears to be part of a regional group of northerly trending veins that extends from the South Fork Yuba River northward to the Graniteville Mining District. According to Irelan (1888), the vein could be traced to the northwest for about four miles from a point across the Yuba River from the mine. MacBoyle (1919) stated there are three veins at the Yuba claim: the Main, West, and East, with nearly all work done on the Main Vein. This vein may be the one referenced by Irelan (1888). The Main Vein is cut by a dike at one point. According to Irelan (1888), the ore is present in quartz that has a ?fragile? character and can be easily broken. Besides native gold, the ore deposit contains auriferous pyrite, pyrrhotite, galena, and possibly sphalerite. Concentrations of the sulfides are not known, but are assumed to be low. This interpretation is based on a statement in Irelan (1888) that sulfides were ?not in sufficient quantity to be worked on the spot.? MacBoyle (1919) reported an ore shoot that extended at least 800 feet down-dip and had a length on the vein of about 800 feet.

Regional geologic structures include the Melones Fault Zone.

Initial development of the mine was through an adit that was at least 1,100 feet long. From this adit an inclined winze was sunk at least 600 feet. Additional workings in the 1880's amounted to 3,000 feet of levels. Later, the adit was extended to 1,600 feet and the winze to 960 feet (MacBoyle, 1919). Little timbering was required in this mine. There are numerous workings including shafts, drifts, adits, crosscuts on many levels, open cuts and diamond drillings. Also there were numerous ore treatment rooms and several millsites with a powerplant.

commodity information: Lindgren (1900) described the gold as coarse.
Ore materials: native gold and auriferous sulfides (pyrite, galena, pyrrhotite). Irelan (1888) interpreted some previously reported galena to be sphalerite. Gangue materials includes quartz.

Clark (1970) estimated production at the Yuba Mine to be in excess of $2 million (period values). MacBoyle reported that about $2 million (period values) in gold was produced from the Yuba claim alone.

Production records were issued by the Mono Mining Co. Nevada.

Mineral List

6 valid minerals.