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Buckhorn Mine

Producer in Eureka county in Nevada, United States with commodities Gold, Silver, Copper, Zinc, Arsenic, Mercury, Tungsten, Thallium, Antimony
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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 10310544
MRDS ID W016362
Record type Site
Current site name Buckhorn Mine
Alternate or previous names North Buckhorn pit, Junkyard pit, South Buckhorn workings, Ghost Zone, Glory Hole, NBMG sample locations 1512-1516, 1551-1554, 1557, 1558
Related records 10107309, 10271092

Comments on the site identification

  • This record incorporates contains all information in earlier MRDS record W016362 for the historic Buckhorn Mine plus additional updateds material.

Geographic coordinates

Geographic coordinates: -116.48981, 40.18852 (WGS84)
Elevation 2050
Relative position The Buckhorn Mine is located approximately 6 miles northeast of Cortez.

Site location context

Political divisions (FIPS codes)

Eureka(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Buckhorn Mine(quadrangle 1:24,000 scale)

Crescent Valley(quadrangle 1:100,000 scale)

Winnemucca(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Pine(hydrologic unit)

Humboldt(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Geographic areas

Country State County
United States Nevada Eureka

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 027N 049E 31 Nevada

Comments on the location information

  • The Buckhorn Mine is located approximately 110 km south of Carlin, 95 km NW of Eureka.

Commodities

Commodity Importance
Gold Primary
Silver Primary
Copper Secondary
Zinc Critical Secondary
Arsenic Critical Tertiary
Mercury Tertiary
Tungsten Critical Tertiary
Thallium Tertiary
Antimony Critical Tertiary

Comments on the commodity information

  • Commodity Info: AG:AU ratio is 15:1. gold recovery is 67%.
  • Ore Materials: gold
  • Gangue Materials: quartz, kaolinite, montmorillonite, adularia, jarosite, goethite, pyrite, sericite, calcite, gypsum, plagioclase. native gold within skeletal limonite after pyrite and marcasite

Materials information

Materials Type of material
Gold Ore
Kaolinite Ore
Montmorillonite Ore
Adularia Ore
Jarosite Ore
Goethite Ore
Pyrite Ore
Sericite Ore
Calcite Ore
Gypsum Ore
Plagioclase Ore
Limonite Ore
Marcasite Ore
Quartz Gangue

Alteration

  • (Local) Argillization of basaltic andesite host rock is the main alteration. Underlying and overlying sediments are silicified. The upper two-thirds (100 ft.) of the mineralized zone is oxidized, the lower third is pyritic. The oxidation of the upper portion is believed to be hypogene, not supergene. In the oxide zone, white kaolinite-rich rocks are found at the center surrounded by purple montmorillonite-rich rocks in peripheral locations. The change in color typically marks the edge of the possible ore zone. Major elements introduced during alteration include Si, Al, K, and Ti. Major elements depleted in altered rocks are Mg, Ca, Na, Mn.

Mineral occurrence model information

Model code 150
USGS model code 25c
Deposit model name Epithermal vein, Comstock
Mark3 model number 16

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier basaltic flows
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16.3
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock type qualifier plugs and flows
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 15.3

Nearby scientific data

(1) Andesite and basalt flows
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description A system of parallel normal faults strikes N10W and controls mineralization. Displacements are less than a few hundred feet.
Type of structure Regional
Structure description Roberts Mountains Thrust

Ore body information

  • General form tabular

Controls for ore emplacement

  • High angle normal faults acted as conduits for hypogene hydrothermal fluids while subsidiary fracture systems increased permeability in the basalts allowing the development of stockwork mineralization. Overlying graben fill sediments may have locally acted as an impermeable cap rock.

Comments on the geologic information

  • See Wells and Elliot (1969) USGS open-file report for geochemical and geologic maps of the mine area. Basaltic andesite flows are about 400 ft. thick as determined from resistivity measurements. Beneath the Tertiary rocks are either the cherty Fourmile Canyon Formation, or carbonates of the lower plate assemblage. Extensions of the Jurassic Mill Canyon stock may be present at depth. Rhyolite plugs and flows (15.3, 0.4 ma) exposed four miles southwest of the mine area may be related to hydrothermal system responsible for Au mineralization at Buckhorn.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Metallic
Deposit size Small
Significant Yes
Discovery year 1908
Discoverer Joe Lynn, W. S. McRea, William Ebbert, John Swan
Year of first production 1910
Production years 1910; 1914-1916; 1931-1932; 1936; 1984-1991

Mining district

District name Buckhorn District

Land status

Ownership category Private

Ownership information

  • Type Owner
    Owner Cominco American, Inc.
  • Type Owner
    Owner Equinox Resources Ltd. Joint Venture
  • Type Operator
    Owner Cominco American, Inc

Comments on the workings information

  • Prior to 1985, mine workings consisted of two glory holes and a 1,750 ft. haulage road, along with extensive subsidiary workings. In 1985, ore was being mined by open pit at a rate of 750,000 tons per year with an average stripping ratio of 1.38:1.

Comments on other economic factors

  • In 1993: geologic reserves were reported to be . 1.1 million tons of ore grading 0.11 opt Au. In 1997, Buckhorn and Buckhorn South (Zeke) geologic reserves were reported to be 24 million tons of ore grading 0.046 opt Au.

Comments on development

  • The first claims were staked in 1908. In 1910, Buckhorn Mines Co. was organized and a mill was constructed in 1913. This cyanide plant operated 1914-1916, processing oxidized ore mined by glory hole method. Pardners Mines Corp. reopened the mine and operated a flotation mill 1935-1937 to treat sulfide ore. From 1938 to 1978 production was limited to working of the dumps. In 1978, Bar Resources Ltd.aAttempted to process oxide ore from an open pit, but failed due to mining and treatment problems caused by high clay content of the ore. Bethlehem Copper Corp.acquired an interest in the property in 1979. Cominco American's involvement began in 1980 with the purchase of Bethlehem copper. During 1980, Bethlehem blocked out a potentially bulk-mineable orebody in the area of the 1978 Bar Resources pit. A feasibility study was initiated in March 1983. Construction began in September and gold was poured in June 1984. Total capital costs for Cominco American mine development were $12 million. Production costs were $200/oz gold.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit Ore occurs as three lenses (North Buckhorn, Junkyard, Glory Hole) along a zone 3000 feet long and 100-1000 feet wide. Barren areas between ore lenses typically contain less than 50 ppb gold.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAY-2003 LaPointe, D.D. Nevada Bureau of Mines and Geology
Editor 01-SEP-2007 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 Nevada resources

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