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Zeibright Mine

Past Producer in Nevada county in California, United States with commodities Gold, Copper
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10310718
Record type Site
Current site name Zeibright Mine

Comments on the site identification

  • There are two ?Zeibright? mines, one on the USGS 7.5-minute Blue Canyon quadrangle and the other on the Washington quadrangle. The deposit described here refers to that on the Blue Canyon quadrangle. This mine is considered the more significant of the two.

Geographic coordinates

Geographic coordinates: -120.75417, 39.33139 (WGS84)
Elevation 1300
Location accuracy 100(meters)
Relative position The Zeibright Mine is about 16 miles east-northeast of Nevada City.

Site location context

Political divisions (FIPS codes)

Nevada(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Washington(quadrangle 1:24,000 scale)

Truckee(quadrangle 1:100,000 scale)

Chico(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Yuba(hydrologic unit)

Lower Sacramento(hydrologic accounting unit)

Sacramento(hydrologic subregion)

California(hydrologic region)

Federal lands

Tahoe National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States California Nevada

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 017N 011E 34 California

Comments on the location information

  • Location selected for latitude and longitude is the Zeibright Mine adit symbol adjacent to the Bear River as shown on the USGS 7.5-minute Blue Canyon quadrangle.

Commodities

Commodity Importance
Gold Primary
Copper Secondary

Comments on the commodity information

  • Ore Materials: Native gold and auriferous sulfides (pyrite, chalcopyrite, and pyrrhotite)

  • Gangue Materials: Quartz, dike rock

Materials information

Materials Type of material
Gold Ore
Pyrite Ore
Chalcopyrite Ore
Pyrrhotite Ore
Quartz Gangue

Alteration

  • (Local) None specifically reported, although there is a vague reference by MacBoyle (1919) to the slate wallrock being ?slightly changed at contact with the ledge.?

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate
    Rock unit name Shoo Fly Complex
    Stratigraphic age (youngest) Devonian
    Stratigraphic age (oldest) Ordovician
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic)
    Rock type qualifier dike
    Stratigraphic age (youngest) Mesozoic

Nearby scientific data

(1) -120.75417, 39.33139
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Melones Fault Zone

Ore body information

  • General form Tabular

Controls for ore emplacement

  • Ore shoots in quartz veins formed along fractures in the metamorphic country rock. The genetic relationship of the mineralization to the dike is not certain.

Comments on the geologic information

  • 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.


  • 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 Zeibright 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.
  • 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 Zeibright Mine is situated within the metasedimentary terrane of the Lower Paleozoic Shoo Fly Complex. The ore deposit consists of a quartz vein-dike complex that is emplaced in slate wallrock. The vein complex reportedly is nearly perpendicular in orientation and averages about 20 feet in width. On his economic geology map of the Colfax folio, Lindgren (1900) showed two north-trending quartz veins very near the deposit at the Zeibright Mine. The vein complex at the Zeibright Mine may be of similar strike. It appears to be part of a regional group of northerly trending veins that extends from Blue Canyon northward through the Washington and Graniteville mining districts.

    According to Logan (1941), the ore is present in an ?impregnated dike? that carries bands of quartz on both walls; there was no ore outside the dike. Besides native gold, the ore deposit contains auriferous pyrite, chalcopyrite, and pyrrhotite. Concentrations of the sulfides are not known, but are assumed to be low. MacBoyle (1919) reported an ore shoot that extended at least 400 feet down-dip and had a length on the vein of about 160 feet.

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Discovery year 1890

Mining district

District name Emigrant Gap District

Land status

Ownership category Private
Area name Nevada County Planning Department
Ownership category National Forest
Area name USFS Tahoe National Forest

Ownership information

  • Type Owner
    Owner Donner Mine Camp, Incorporated
    Year 2007

Comments on the workings information

  • According to Logan (1941), the vein was initially developed by adits, one of which was 990 feet long. Subsequent mining was accomplished through a vertical shaft that reached 1,750 feet in 1940 (the current depth may be about 1,900 feet). Stoping at that time reached a depth of 800 feet.

Comments on other economic factors

  • Clark (1970) estimated production at the Zeibright Mine to be in excess of $1 million. There was significant production during the 1930?s.

Comments on development

  • The mine is known to have been in operation in 1902 based on a report in the Mining and Scientific Press (1902). The name was derived from the first mine owners, F. Zeitler and W.F. Englebright. From 1918 to 1934, the Zeibright Mine was operated by the Bear Valley Mining Company. According to records filed in the Online Archive of California (http://oac.cdlib.org/), the mine was subsequently owned and operated by the Empire Star Mines Company and Newmont from 1934 to the 1950?s. It was worked extensively during the 1930?s when large tonnages of low-grade ore were mined. These tonnages included 10,285 in 1934, 129,866 in 1936, and 260,479 in 1939. There were approximately 200 employees in 1939. In 1940, a tailings dam failed (this facility was possibly at the Omega Diggings, about three miles northwest of the mine), which caused suspension of mining and milling, although development of ore bodies continued.

    For many years, the mine property has been operated as a camp for youth groups. A clean-up operation at the property was ordered by the U.S. EPA in 2006 to remove lead and arsenic contamination at the site?s former assay building. (http://www.epa.gov/compliance/resources/newsletters/cleanup/cleanup29.pdf)

    Amalgamation, flotation, and cyanidation processes were used at this mine.

Comments on the environmental information

  • The Zeibright Mine is situated in a forested area on the north slope of the canyon of the Bear River.

Reference information

Bibliographic references

  • 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.

  • 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.

  • Deposit

    Clark, L. D., 1960, Foothills fault system, western Sierra Nevada, California: Geological Society of America Bulletin, v. 71, p. 483-496.

  • Deposit

    Clark, W.B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 45-46.

  • 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.

  • 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.

  • Deposit

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

  • Deposit

    Logan, C.A., 1941, Nevada County: 37th Annual Report of the State Mineralogist, California Journal of Mines and Geology, p. 431.

  • Deposit

    MacBoyle, E., 1919, Nevada County: 16th Annual Report of the State Mineralogist, California State Mining Bureau, p. 260-261.

  • Deposit

    Mining and Scientific Press, 1902, Placer County: Mining and Scientific Press, v. 85, no. 10, p. 135.

  • 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.

  • 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.

General comments

Subject category Comment text
Deposit The Zeibright Mine is situated within the metasedimentary terrane of the Lower Paleozoic Shoo Fly Complex. The ore deposit consists of a quartz vein-dike complex that is emplaced in slate wallrock. The vein complex reportedly is nearly perpendicular in orientation and averages about 20 feet in width. It is assumed to have a northerly strike, similar to a regional group of veins that extends from Blue Canyon northward through the Washington and Graniteville mining districts.

The ore is reportedly present in an ?impregnated dike? that carries bands of quartz on both walls; there appears to be no ore outside the dike. Besides native gold, the ore deposit contains auriferous pyrite, chalcopyrite, and pyrrhotite. Concentrations of the sulfides are not known, but are assumed to be low. MacBoyle (1919) reported an ore shoot that extended at least 400 feet down-dip and had a length on the vein of about 160 feet.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-2007 Higgins, Chris T. California Geological Survey CGS (Formerly CDMG)
Editor 20-FEB-2008 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

External references

Maps centered on this site

Authoritative California resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.