Browns Valley District

Site Name

Primary: Browns Valley District
Secondary: Bessie
Secondary: Chandler
Secondary: Danneborg (Donnebrouge)
Secondary: Fairview
Secondary: Hibbert and Burris
Secondary: Jefferson
Secondary: Last Chance
Secondary: Nineteen Hundred and One
Secondary: Northern Light
Secondary: Old Flag (Stag)
Secondary: Pennsylvania
Secondary: Rattlesnake
Secondary: Smithhurst
Secondary: Sweet Vengeance
Secondary: Too Handy

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Commodity

Primary: Gold
Secondary: Silver

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Location

State: California
County: Yuba
District: Browns Valley District

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Land Status

Land ownership: County
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: Yuba 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: District
Operation Category: Past Producer
Deposit Type: Hydrothermal vein
Operation Type: Underground
Discovery Year: 1850
Years of Production:
Organization:
Significant: Y

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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: L
Structure: Few reports of faults associated with quartz veins, relationships unclear.

Type: R
Structure: Swain Ravine-Spenceville Fault Zone

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Alterations

Alteration Type: R
Alteration: None reported in documents reviewed.

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Rocks

Name: Serpentinite
Role: Host
Age Type: Host Rock
Age Young: Mesozoic

Name: Gabbro
Role: Host
Age Type: Host Rock
Age Young: Jurassic

Name: Greenstone
Role: Host
Age Type: Host Rock
Age Young: Jurassic

Name: Diorite
Role: Host
Age Type: Host Rock
Age Young: Jurassic

Name: Diabase
Role: Host
Age Type: Host Rock
Age Young: Jurassic

Name: Granodiorite
Role: Associated
Age Type: Associated Rock
Age Young: Mesozoic

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Analytical Data

Not available

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Materials

Ore: Sphalerite
Ore: Galena
Ore: Chalcopyrite
Ore: Pyrite
Ore: Gold

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Comments

Comment (Location): Location selected for latitude and longitude is the Donnebrouge Mine shaft symbol on the USGS 7.5-minute Browns Valley quadrangle. This mine was one of the most important producers in the district.

Comment (Geology): The ore deposits of the Browns Valley District are situated at the far western edge of the Western Sierra Nevada Metamorphic Belt within metaigneous rocks of the Mesozoic Smartville Complex. The deposits appear to be distributed over an area of a few square miles. They comprise a set of north-south-striking and east-west-striking fissure-filling quartz veins that cut the complex. The veins contain native gold and very low percentages of sulfide minerals, which include pyrite, chalcopyrite, galena, and sphalerite. Vein thicknesses generally range from inches to 4 feet, but may be as much as 18 feet. Some veins exhibit ribbon structure.

Comment (Identification): This record summarizes, on the whole, the characteristics of many individual lode mines and prospects that comprise the Browns Valley District. There is no single mine that represents a dominant property of the district.

Comment (Location): The Browns Valley Mining District is situated in the lowest western foothills of the Sierra Nevada near the edge of the Central Valley. Most of the mines are concentrated at the east base of Browns Valley Ridge in a ravine that drains southward a little over a mile to intersect the Yuba River. Vegetation is mixed oak woodland and grass. There are scattered rural residences and ranches in the district.

Comment (Analytical Data): Gold was reportedly 0.763 fine at the Hibbert and Burris Mine. At the Donnebrouge Mine, about 80% of the ore values were as native gold. At least some of the concentrates were shipped to the smelter at Shelby near San Francisco.

Comment (Geology): REGIONAL GEOLOGY The Browns Valley District is situated in the northern portion of the Sierra Nevada Foothills Gold Belt. This belt averages 50 miles wide and extends for about 150 miles in a north-northwest orientation along the western slope of the Sierra Nevada Mountains. The Browns Valley District is almost 20 miles directly west of the Grass Valley District, home to California's two largest underground gold mines, the Empire and the Idaho-Maryland. Regionally, the Foothills Gold Belt approximately coincides with the Sierra Nevada Foothills Metamorphic Belt, which in this area can be subdivided into four major lithotectonic belts: Western Belt, Central Belt, Feather River Peridotite Belt, and Eastern Belt (Schweickert and others, 1999). The Western Belt in this area consists mainly of metamorphosed volcanic, sedimentary, and intrusive rocks of the Mesozoic Smartville Complex (Beard and Day, 1987). It is separated from the Central Belt by the Wolf Creek Fault Zone. The Central Belt consists of a complicated assemblage of Paleozoic-Mesozoic metasedimentary, metavolcanic, and metaplutonic rocks that have been intruded locally by Mesozoic plutonic rocks. The Central Belt is separated from the East Belt by the Feather River Peridotite Belt, which coincides in part with the Melones Fault Zone, a major structural boundary of the western Sierra Nevada. Rocks in this belt are largely peridotite and serpentinite, with lesser amounts of metasedimentary and metavolcanic rocks locally. The East Belt is dominantly metasedimentary and metavolcanic rocks of Paleozoic-Mesozoic age. Most of the metamorphic rocks in the belt in this area have been assigned to the Lower Paleozoic Shoo Fly Complex. The metamorphic complexes are intruded in places by Mesozoic plutonic rocks. On the west, near the Browns Valley District, the Sierra Nevada Foothills Metamorphic Belt is overlain by Cenozoic sedimentary deposits that cover the floor of the Central Valley. The Browns Valley District lies within the Western Belt, which in this area is composed of north-northwest-striking metaigneous rocks of the Smartville Complex. Most of the rocks are of mafic to intermediate volcanic or shallow intrusive origin. They are interpreted to be part of a rifted island arc. Part of the complex is intruded by an appendage of the Mesozoic Swedes Flat Pluton. The belt is also cut by several north-northwest-striking fault zones. Dips of foliation and bedding are generally vertical or nearly so, while strikes are dominantly NNW.

Comment (Identification): This district comprises many small lode-gold mines at or within two miles of the settlement of Browns Valley. Known individual mines and prospects are listed above under "Other Names." the more notable producers were the Hibbert and Burris, Donnebrouge, Pennsylvania, and Jefferson. A few placer mines are also present (Cleveland, Lone Jack ). Useful references on mines in this district include Waring (1919) and O?Brien (1952). Available information on mines in this district is somewhat sparse.

Comment (Development): This district was discovered during the Gold Rush when miners exploited placer deposits. In 1850, one miner reportedly recovered several thousand dollars from a quartz vein. Lode mining was prevalent through the 1860's and 1870's, and was then intermittent through World War I. The Donnebrouge Mine reopened in the 1940's and was intermittently active until at least 1970. History of the district subsequent to 1970 is uncertain. A ?Brown?s Valley Mine? was operated in the 1930?s by the Empire Star Mines Company (http://content-backend-a.cdlib.org/view?docId=kt3v19n6jq&chunk.id=c01-1.7.8.4) Amalgamation processes were used at some of the mines.

Comment (Geology): LOCAL GEOLOGY The Browns Valley District is situated in the westernmost part of the Smartville Complex, which consists here mainly of metamorphosed mafic and intermediate marine volcanic rocks and shallow intrusive rocks. Metamorphosed felsic volcanic rock, serpentinite, and granodiorite were reported to be intersected in a few of the mines, although it is not clear if the granodiorite is part of the metamorphic complex or is a much younger body intrusive into it. A few NW-trending fault zones are shown to pass through the district, and there are reports of faults in some of the mines. Individual ore deposits in the district typically consist of quartz veins, some of which exhibit ribbon structure. The most common wallrock observed is diabase and diorite, with fewer reports of greenstone, gabbro, serpentinite, and ?porphyry.? the wallrock is reportedly very hard in some of the mines, with gouge in places; there is no mention in the documents reviewed of any alteration, however. Ore shoots typically had lengths of a few hundred feet maximum. Quartz veins in the mines of the district are reported in published literature to strike north-south with moderate (35-50 degrees) dips to the east or west; a few veins strike NNW. There are a few reports of east-west strikes also. Lindgren (1895), however, shows dominantly east-west strikes of quartz veins in the district. At one of the most productive mines in the district, the Donnebrouge, a strike of N35W and dip of N25E was reported (O?Brien, 1952). Thicknesses of veins range from inches to 18 feet, although most are less than 4 feet. Ore in the mines of the district was composed mostly of native gold and minor amounts of auriferous sulfides (pyrite, chalcopyrite, galena, and some sphalerite). Ore mined during the 1950?s at the Donnebrouge Mine reportedly graded from $10 to $60 per ton in parts of the workings. Overall, ore in the district probably averaged about 1-3% sulfides, although there was a report of 12% at one mine.

Comment (Workings): Mines and prospects in this district were developed through standard underground methods that included shafts, winzes, raises, and drifting. Ore and waste were removed by conventional stoping; in some operations, waste and mill tailings were used as backfill in the underground workings. Waring (1919) provides the most detail overall for mines in the district. The deepest workings are probably at the Pennsylvania Mine, which reportedly reached an inclined depth of at least 1,600 feet. The nearby Donnebrouge Mine was worked to at least 1,500 feet deep on the incline. Otherwise, mines appear to have been less than 1,000 feet deep. Drifts turned from the shafts were typically hundreds of feet in length although a few were possibly as much as a few thousand feet in length.

Comment (Production): Total production from lode mines in the Browns Valley District was estimated by Clark (1970) to be about $3 million to $5 million. (at $35/troy oz = 2.7 to 4.5 tonnes Au (PS))

Comment (Reference): Additional information on the Donnebrouge Mine and the Hibbert and Burris Mine is contained in File Nos. 322-5725 and 329-8368 respectively (CGS Mineral Resources Files, Sacramento).

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References

Reference (Deposit): Waring, C.A., 1919, Yuba County: Fifteenth Annual Report of the State Mineralogist, California State Mining Bureau, p. 419-459.

Reference (Deposit): Crawford, J.J., 1894, Yuba County: Twelfth Annual Report of the State Mineralogist, California State Mining Bureau, p. 318-322.

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, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 31.

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.

Reference (Deposit): Preston, E.B., 1890, Yuba County: Tenth Annual Report of the State Mineralogist, California State Mining Bureau, p. 798-799.

Reference (Deposit): O?Brien, J.C., 1952, Mines and mineral resources of Yuba County: California Journal of Mines and Geology, v. 48, no. 2, p. 143-179.

Reference (Deposit): Logan, C.A., 1935, Review of gold mining in east-central California: California Journal of Mines and Geology, v. 31, p. 8-9.

Reference (Deposit): Logan, C.A., 1931, Yuba County: Twenty-seventh Annual Report of the State Mineralogist, California Division of Mines, p. 252.

Reference (Deposit): Logan, C.A., 1930, Yuba County: Twenty-sixth Annual Report of the State Mineralogist, California Division of Mines, p. 191-192.

Reference (Deposit): Lindgren, W., 1895, Smartsville folio, California: U.S. Geological Survey Atlas of the U.S., Folio 18, 6 p.

Reference (Deposit): Crawford, J.J., 1896, Yuba County: Thirteenth Annual Report of the State Mineralogist, California State Mining Bureau, p. 499-502.

Reference (Deposit): Koschmann, A.H., and Bergendahl, M.H., 1968, Principal gold-producing districts of the United States: U.S. Geological Survey Professional Paper 610, 283 p.

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.

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California Gold

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