Yuba Mine

Site Name

Primary: Yuba Mine
Secondary: Yuba Consolidated

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Commodity

Primary: Gold

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Location

State: California
County: Nevada
District: Washington District

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Land Status

Land ownership: Private
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 definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.
Administrative Organization: Nevada County Planning Department

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: Hydrothermal vein
Operation Type: Underground
Discovery Year: 1880
Years of Production:
Organization:
Significant: Y
Deposit Size: S

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Physiography

Not available

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Mineral Deposit Model

Model Name: Low-sulfide Au-quartz vein

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Orebody

Form: Tabular

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Structure

Type: R
Description: Melones Fault Zone

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Alterations

Alteration Type: L
Alteration Text: None reported

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Rocks

Name: Greenstone
Role: Host
Age Type: Host Rock
Age Young: Mesozoic
Age Old: Paleozoic

Name: Slate
Role: Host
Age Type: Host Rock
Age Young: Paleozoic

Name: Granodiorite
Role: Host
Age Type: Host Rock
Age Young: Paleozoic

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Pyrite
Ore: Galena
Ore: Pyrrhotite
Ore: Sphalerite
Gangue: Quartz

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Comments

Comment (Environment): This isolated deposit is situated on the south slope of the canyon of the South Fork Yuba River.

Comment (Deposit): The Yuba Mine deposit 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. The deposit consists of at least one main quartz vein emplaced in wallrock composed mostly of granodiorite; in places, the wallrock also contains slate, greenstone, and possibly limestone. It is not clear if the greenstone is part of the Shoo Fly Complex or is dike rock. The main 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 to the Graniteville Mining District. This vein is cut by a dike at one point. 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.

Comment (Development): 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.

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

Comment (Geology): Stratigraphy 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 and sedimentation that have been divided into four lithotectonic belts; the Western Belt, Central Belt, Feather River Peridotite Belt, and Eastern Belt (Day and others, 1988). The Western Belt is composed of the Smartville Complex, a late Jurassic volcanic arc complex (Beard and Day, 1987), consisting of basaltic to intermediate pillow flows overlain by pyroclastic and volcaniclastic rock units with diabase, metagabbro, and gabbro-diorite intrusives. The Cretaceous Great Valley sequence overlies the belt to the west, and 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 and its extension to the south along the west side of the Feather River Peridotite Belt. This belt is structurally and stratigraphically complex and consists of metasedimentary, metavolcanic, and plutonic rocks of Paleozoic to Mesozoic age, including a sliver of Calaveras Complex on its east side. The Feather River Peridotite Belt separates the Central Belt from the rocks of the Eastern Belt for almost 95 miles along the northern Sierra Nevada (Day and others, 1988). Its eastern margin coincides with the Melones Fault Zone of Clark (1960). Much of the ultramafic intrusives have been serpentinized. The Eastern Belt, or "Northern Sierra Terrane," is composed primarily of Devonian-to-Jurassic metavolcanic rocks, siliciclastic metasedimentary rocks of the Lower Paleozoic Shoo Fly Complex, and Mesozoic granitic rocks of the Sierra Nevada batholith. The Upper Devonian-Jurassic rocks unconformably overly the Shoo Fly Complex and are of island-arc origin (Brooks, 2000). They consist of the Devonian-Permian Taylorsville Sequence, Permian-Triassic Arlington, Goodhue, and Reeves Formations, and the Jurassic Sailor Canyon Formation. The Yuba Mine is situated within plutonic rock that is intruded into the Shoo Fly Complex. Regionally, the northern Sierra Nevada experienced a long period of Cretaceous to early Tertiary erosion, after which it underwent extensive Oligocene to Pliocene volcanism. The oldest Tertiary units are basal Eocene auriferous gravels, preserved in basement paleochannels, and associated bench gravels deposited by the predecessors of the modern Yuba and American Rivers. In contrast to the earlier volcanism, Tertiary volcanism was continental and deposited on top of the eroded metamorphic rocks, channel deposits, and Mesozoic intrusives. An important widespread unit of intercalated rhyolite tuffs and intervolcanic channel gravels is the Oligocene-Miocene Valley Springs Formation. The youngest volcanic unit, the Miocene-Pliocene Mehrten Formation, consists largely of andesitic flows and breccias overlying the Valley Springs Formation. Pliocene-Pleistocene westward uplift of the Sierra Nevada caused existing drainages to carve deep river gorges. During this process, the modern rivers became charged with placer gold deposits from both newly eroded basement rocks and from the reconcentration of the Eocene placers. The discovery of these modern Quaternary placers in the American River is what sparked the California Gold Rush.

Comment (Geology): Structure 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 the 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. Regionally, the metamorphic rocks display northerly trending and steeply dipping foliation, bedding, and contacts. LOCAL GEOLOGY 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.

Comment (Identification): Originally worked under the Yuba Claim, the mining operation was later expanded to include many other adjacent claims along the Yuba River in this area.

Comment (Location): Location selected for latitude and longitude 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.

Comment (Commodity): Commodity Info: Lindgren (1900) described the gold as coarse.

Comment (Commodity): Ore Materials: Native gold and auriferous sulfides (pyrite, galena, pyrrhotite). Irelan (1888) interpreted some previously reported galena to be sphalerite.

Comment (Commodity): Gangue Materials: Quartz

Comment (Workings): 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.

Comment (Geology): REGIONAL GEOLOGY The northern Sierra Nevada is home to numerous lode and placer gold deposits. It includes the famous lode districts of Alleghany, Johnsville, Sierra City, Grass Valley, and Nevada City and the famous placer districts of La Porte, North Columbia, Cherokee, Michigan Bluff, Forest Hill, and Dutch Flat. The geological and historical diversity of most of these deposits and specific mine operations are covered in numerous publications produced over the years by the U.S. Bureau of Mines, U.S. Geological Survey, California Division of Mines and Geology (now California Geological Survey), and others. A regional geologic map covering the area is the 1:250,000-scale Chico Quadrangle compiled by Saucedo and Wagner (1992). Schweickert and others (1999) provided a more recent overview of the region.

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References

Reference (Deposit): Beard, J. S. and Day, H. W., 1987, The Smartville intrusive complex, Sierra Nevada, California: The core of a rifted volcanic arc: Geological Society of America Bulletin, v. 99, no. 6, p. 779-791.

Reference (Deposit): Brooks, E. R., 2000, Geology of a late Paleozoic island arc in the Northern Sierra terrane, in Brooks, E. R. and Dida, L.T., editors, Field guide to the geology and tectonics of the northern Sierra Nevada: California Division of Mines and Geology Special Publication 122, p. 53-110.

Reference (Deposit): Schweickert, R.A., Hanson, R.E., and Girty, G.H., 1999, Accretionary tectonics of the Western Sierra Nevada Metamorphic Belt, in Wagner, D.L. and Graham, S.A., editors, Geologic field trips in northern California: California Division of Mines and Geology Special Publication 119, p. 33-79.

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. 53.

Reference (Deposit): Day, H. W. and others, 1988, Metamorphism and tectonics of the northern Sierra Nevada, in Ernst, W. G., editor, Metamorphism and crustal evolution of the western United States (Rubey Volume VII): Prentice-Hall, Englewood Cliffs, New Jersey, p. 738-759.

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): Irelan, W., Jr., 1888, Nevada County: Eighth Annual Report of the State Mineralogist, California State Mining Bureau, p. 435-436.

Reference (Deposit): Lindgren, W., 1900, Colfax folio, California: U.S. Geological Survey Atlas of the U.S., Folio 66, 10 p.

Reference (Deposit): Logan, C.A., 1941, Nevada County: 37th Annual Report of the State Mineralogist, California Journal of Mines and Geology, p. 374-468.

Reference (Deposit): MacBoyle, E.M., 1919, Mines and mineral resources of Nevada County: Sixteenth Annual Report of the State Mineralogist, California State Mining Bureau, p. 62-63, 259-260.

Reference (Deposit): Saucedo, G.J. and Wagner, D.L., 1992, Geologic map of the Chico Quadrangle, California: California Department of Conservation, Division of Mines and Geology Regional Geologic Map Series, Map No. 7A, scale 1:250,000.

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California Gold

"Where to Find Gold in California" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in California. Read more: Where to Find Gold in California.