Herman Mine

Site Name

Primary: Herman Mine
Secondary: Osborne

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Commodity

Primary: Gold
Secondary: Lead

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Location

State: California
County: Placer
District: Westville 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: Placer 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: 1894
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: Sandstone
Role: Host
Description: Meta-
Age Type: Host Rock
Age Young: Devonian
Age Old: Ordovician

Name: Slate
Role: Host
Age Type: Host Rock
Age Young: Devonian
Age Old: Ordovician

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Analytical Data

Not available

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Materials

Ore: Gold
Ore: Silver
Ore: Pyrite
Ore: Galena
Gangue: Quartz

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Comments

Comment (Economic Factors): Information on production from this mine is sparse. Logan (1936) reported the mine yielded at least $200,000 (pre-1935 values).

Comment (Environment): This isolated deposit is on the southeast flank of Deadwood Ridge in a rugged canyon setting.

Comment (Workings): Workings in this mine consist of standard shafts, crosscuts, drifts, and winzes. Ore was mined by stoping methods. At least four levels and possibly six were developed as of the early 1900?s, with drifts running for several hundred feet on the upper three levels. In 1914, the 600-foot level reportedly had 1,500 feet of development.

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 Herman Mine vein was described as irregular and poorly defined (Crawford, 1896), with wallrock variously reported as ?slate?, ?quartzitic sandstone?, and ?sandy siliceous schist?. All of these lithologies are consistent with those generally recognized in the Shoo Fly Complex, within which the Herman Mine is situated. Also, Crawford (1896) reported the presence of a weathered or altered dike in the wallrock. Waring (1915) reported as many as three veins of ribbon quartz , which can be followed on the ground surface for 1,500 feet. The vein strikes slightly east of north and has reported dips ranging from 25-80SE. Widths range from 3 to 12 feet, with an average of 8 feet in the stoped areas. The deposit contains both native gold and silver as well as auriferous sulfides (pyrite and galena). Percentages of sulfides are not known, but Lindgren (1900) reported a ?large quantity? of sulfides in the quartz.

Comment (Identification): The Herman Mine may also include the feature known as the ?Osborne Tunnel,? which is about one-quarter mile northwest of the Herman Mine as shown on the USGS 7.5-minute Westville quadrangle. Some reporters equated the Herman Mine with the Osborne Mine. There is also some confusion in the literature related to another ?Herman Mine? in Placer County. The Herman Mine reported by Irelan (1888) is a placer mine near Iowa Hill and is not the same as the mine reported in this record.

Comment (Location): Location selected for latitude and longitude is the Herman Mine adit symbol on the USGS 7.5-minute Westville quadrangle. Access is off the unpaved Deadwood Road.

Comment (Development): The mine may have been discovered about 1894 (Lindgren, 1900). In the 1890?s, it operated with a 10-stamp mill and 32 employees (Crawford, 1896). In the early 1900?s, it expanded to 30 stamps with up to 45 employees. In 1916, ?good ore? was reported in the lower workings. According to Logan (1936), the Herman Mine was an annual producer from 1895 to 1902, and irregularly from 1903 to 1915. The mine was shut down in 1916, and may not have operated again until the 1930?s if at all. Logan (1936) reported little work at the mine in 1935. This deposit may have been worked through both the ?Herman Mine? and ?Osborne Tunnel? as shown on the USGS 7.5-minute Westville quadrangle. Amalgamation processes were used at this mine. Tailings were not impounded (discharged to a local canyon).

Comment (Commodity): Ore Materials: Native gold, native silver, and auriferous sulfides (pyrite, galena)

Comment (Commodity): Gangue Materials: Quartz

Comment (Deposit): The deposit at the Herman Mine is typical of sulfide-bearing gold-quartz veins found in the Sierra Nevada metamorphic belt. The wallrock is described as slate, sandstone, or schist. There are up to three veins of ribbon quartz , which can be followed on the ground surface for 1,500 feet. The vein complex strikes slightly east of north and has reported dips ranging from 25-80SE. Reported widths range from 3 to 12 feet, with an average of 8 feet in the stoped areas. A weathered or altered dike is present in the wallrock. Ore consists of native gold and silver, and auriferous sulfides. The percent composition of sulfides is not known.

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 Herman Mine is within 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): 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): 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. 130.

Reference (Deposit): Crawford, J.J., 1894, Gold - Placer County: Twelfth Annual Report of the State Mineralogist, California State Mining Bureau, p. 211.

Reference (Deposit): Logan, C.A., 1936, Gold mines of Placer County: 32nd Annual Report of the State Mineralogist, California Journal of Mines and Geology, p. 26-27.

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): 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): Waring, C.A., 1915, Placer County: 15th Annual Report of the State Mineralogist, California State Mining Bureau, p. 341-342.

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, Placer County: Eighth Annual Report of the State Mineralogist, California State Mining Bureau, p. 472.

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

Reference (Deposit): Crawford, J.J., 1896, Placer County: Thirteenth Annual Report of the State Mineralogist, California State Mining Bureau, p. 280.

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