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Hog Ranch Mine

Producer in Washoe county in Nevada, United States with commodities Gold, Silver, Mercury, Uranium
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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 10310380
MRDS ID M232557
Record type Site
Current site name Hog Ranch Mine
Alternate or previous names Western Hog Ranch Mine, Krista Pit, East Deposit, West Deposit, Geib Pit, Bell Spring Deposit, Airport orebody, 139 orebody, White Mountain orebody, NBMG Sample Site 2410
Related records 10047581

Comments on the site identification

  • This record is an updated version including duplicate information from M232557, W700443, and W700584, which have been deleted. This record incorporates all information in earlier MRDS record M242957 for the Hog Ranch Mine plus additional updated material.

Geographic coordinates

Geographic coordinates: -119.4513, 41.15793 (WGS84)
Elevation 1910
Relative position The mine is located at the north end of the Granite Range about 230 km north of Reno and 35 miles north of the town of Gerlach.

Site location context

Political divisions (FIPS codes)

Washoe(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Butte Spring(quadrangle 1:24,000 scale)

High Rock Canyon(quadrangle 1:100,000 scale)

Vya(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Smoke Creek Desert(hydrologic unit)

Black Rock Desert(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management CA)

Bureau of Land Management CA BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States Nevada Washoe

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo T037N 022E 02,03,07,06,11,19,24,25,26 Nevada
Mount Diablo T038N 023E Nevada

Comments on the location information

  • UTM is to central portion of the Krista pit, one of several pits at Hog Ranch.

Commodities

Commodity Importance
Gold Primary
Silver Primary
Mercury Tertiary
Uranium Tertiary

Comments on the commodity information

  • Ore Materials: free gold, minor auriferous pyrite
  • Gangue Materials: pyrite, stibnite, realgar, stibnite, cinnabar, native sulfur, alunite, chalcedony, iron oxides, quartz, clay

Materials information

Materials Type of material
Gold Ore
Pyrite Gangue
Stibnite Gangue
Realgar Gangue
Stibnite Gangue
Cinnabar Gangue
Sulfur Gangue
Alunite Gangue
Chalcedony Gangue
Quartz Gangue
Clay Gangue

Alteration

  • (Local) There are two disticnct alteration systems present: a large one associated with the north Hog ranch deposits and a smaller one around the Bell Springs deposit to the south. The northern system is dominated by clay mineralization zoning from near-surface kaolinite to illite at depth.
    Host rocks are affected by pervasive hydrothermal silicification, opalization, and kaolinization.

Mineral occurrence model information

Model code 104
USGS model code 25a
Deposit model name Hot-spring Au-Ag
Mark3 model number 45

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff
    Rock type qualifier rhyolitic lapilli
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 15.1
    Dating method K-Ar
    Type of media whole rock on non-hydrated peralkaline r
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 15.1
    Dating method K-Ar
    Type of media whole rock on non-hydrated peralkaline r
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock
    Rock type qualifier explosion breccia
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 15.1
    Dating method K-Ar
    Type of media whole rock on non-hydrated peralkaline r
  • Host or associated Host
    Rock type Sedimentary Rock > Mixed Clastic/Volcanic Rock
    Rock type qualifier sinter
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 15.1
    Dating method K-Ar
    Type of media whole rock on non-hydrated peralkaline r
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock type qualifier flows, domes, pyroclasitcs, and extrusives (peralkaline)
    Rock unit name Canyon Rhyolite
    Stratigraphic age (youngest) Miocene

Nearby scientific data

(1) -119.4513, 41.15793
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description The mineralization is possibly localized along a major ring-fracture system associated with the Cottonwood Creek Volcanic Center.
Type of structure Regional
Structure description The Hog Ranch property is located in the transitional zone between the Columbia Plateau physiographic province to the north, and the Basin and Range province to the south with a collapsed caldera or failed caldera system possibly present.

Ore body information

  • General form disseminated

Controls for ore emplacement

  • Mineralization is strongly fracture controlled.

Comments on the geologic information

  • The Hog Ranch property is located in the transitional zone between the Columbia Plateau physiographic province to the north, and the Basin and Range province to the south. The region exhibits characteristics of both provinces. The Krista pit exhibits features common to a typical disseminated hot-spring Au-Ag deposit which has strong structural control. Gold values are largely found in, and are highest in the more intensely silicified (chalcedonized) rocks. Probable near surface mineralization. Slightly anomalous radioactivity has been reported from petrified wood in late Miocene sedimentary rocks. Uranium occurrences are found along Hog Ranch Creek for several miles.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Year of first production 1986
Year of last production 1995
Production years 1986-1995

Mining district

District name Leadville District (closest)

Land status

Ownership category BLM Administrative Area
Area name Susanville BLM District

Ownership information

  • Type Owner-Operator
    Owner Romarco Minerals Inc.
    Year 2004

Comments on the workings information

  • The mine was developed by at least 4 open pits: Krista, East, Geib, and Bell Springs, as well as a crushing and heap leach facility and a gold recovery plant.

Comments on other economic factors

  • From 1985 to 1992, the mine produced 8.5 million short tons of ore with an average grade of 0.036 ounces per ton.
    Total production from Hog Ranch from 1986?87 was 80,000 ounces of gold and from 1988?95, 118,045 ounces of gold and 25,400 ounces of silver.

    In1984 reserves were reported at 2.5 million tons of ore grading 0.085 opt gold. In 1988, Proven and probable reserves were 5.5 million tons of ore grading 0.064 opt Au. with a geologic resource of 20.1 million tons of ore grading 0.029 opt Au.

    In 1996 Western Mining reported a remaining measured and indicated resource of 1.45 million tonnes at an average grade of 1.13 grams of gold per tonne, plus an additional inferred resource of 0.4 million tonnes at a grade of 1.85 grams of gold per tonne

Comments on development

  • The area underwent exploration for uranium in the 1970s prior to the gold discovery. The Hog Ranch area was staked about 1980, optioned by Noranda about 1984, who, with Ferret Exploration did extensive drilling and exploration on it. In Aug. 1984, Geomex owned a 63% working interest in Hog Ranch and was doing more drilling and metallurgical testing on it. Imperial Metals had acquired an interest in Hog Ranch by Feb, 1986. Western Goldfields and Ferret Exploration acquired the property and were seeking operation permits in March 1986 which were granted, and operations commenced in April, 1986. In August 1986, Orofino Resources acquired a 10% interest in it with other partners Western Goldfields, 50% ; Geomex Minerals, 30%; and Montagu Mining Investments, 10%. Leach pads were being filled in Sept, 1986. In April 1987, Royal Resources Corp bought up all Montagu's stock including its 10% Hog Ranch interest. First pour was in late 1986 with expected production of 50,000 oz Au/year. Western Goldfields increased its interest to 65%. Initial mining was mostly at the Krista pit with continued work to develop ore south of Krista. Feasibility study for the Bell Spring deposit 4 miles SW of the Krista pit was underway with plans to start development on it in 1988. Active mining occurred until 1992 after which gold recovery continued during closure and reclamation until 1996.
    With higher gold prices in the 2000s, there was renewed exploration interest in the Hog Ranch area, and in 2004-Romarco Minerals Inc. announced that it had begun a Phase II drilling program at the Hog Ranch Project as follow up to its Phase I program, which discovered both high grade gold mineralization that may support underground mining, and a broad zone of significant grade mineralization that is well within open pit mining depths. The best intercepts from Phase 1 were penetrated in drill hole HR-04-3, and consisted of 70 feet (21.3 m) interval averaging 0.152 oz/ton gold (5.23 g/t) that begins approximately 225 feet (69 m) below the surface. Within this 70 foot interval were two 5 foot (1.5m) high grade intervals assaying 0.837 oz/ton gold (28.7 g/t) and 0.502 oz/ton gold (17.2 g/t), respectively. The Phase II program includes drill holes that are designed to extend the mineralization penetrated in HR-04-3, and also holes that will begin testing other high priority targets on the property.
    The planned drilling program will consist of approximately 4500 feet (1372m) of diamond core drilling in six holes.Of the six planned drill holes, three are to be drilled about midway between the previously-mined Geib and Krista Pits. Two of the holes will attempt to extend the mineralization found in HR-04-3 along strike, and one hole will test for an extension of the mineralization down dip. One of Romarco's primary target areas has always been the Krista Pit, which was the largest deposit mined by Western Hog Ranch Company. Two holes will be drilled under the north and south ends, respectively, of the Krista Pit to test for feeder structures in those areas. In the Geib pit area, one hole will be drilled to test a target below and adjacent to the pit at an interpreted structural intersection.
    In 2000, Seabridge Gold leased the Hog Ranch property from Platoro and in 2006 was drilling to test deeper parts of the Hog Ranch gold system with the possibility of developing an underground mine on the property.

Comments on the environmental information

  • Magmatism associated with continental extension under reducing conditions

Reference information

Bibliographic references

  • Deposit

    Harvey, D.S., Noble, D.C., McKee, E.H., 1986, Hog Ranch Property: in Isochron West, No 47.

  • Deposit

    Drossulis, Kim, 1988, Geology of the Hog Ranch Mine, Washoe Co., NV: in GSN 1988 Spring Field Trip Guidebook.

  • Deposit

    NBMG Mining District File 314: Numerous Press Clippings

  • Deposit

    NBMG Spec. Pub MI-1987-1995

  • Deposit

    Bonham, H.F., 1986, NBMG Map 91

  • Deposit

    Jones, R.B., 1984, NBMG Field Examination

  • Deposit

    Garside, L.J., 1973, Radioactive Mineral Occurrences in Nevada: NBMG Bull 81.

  • Deposit

    Staff, 1988, Directory of Nevada Mine Operations Active During Calendar Year 1987: Nevada Division of Mine Inspection, 84p.

  • Deposit

    Western Mining Corp, 1990, Annual Report for Fiscal Year 1989-1990.

  • Deposit

    Wwestern Mining Corp, 1991, Annual Report For Fiscal Year 1990-1991.

  • Deposit

    Nevada Division of Minerals, 1994

  • Deposit

    Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.

  • Deposit

    Bussey, Steven D. , 1995, Gold mineralization and associated rhyolitic volcanism at the Hog Ranch Mine, Northwest Nevada:GSN symposium proceedings, Geology and ore deposits of the American Cordillera

  • Deposit

    Drossulis, Kim, 1988, Geology of the Hog Ranch Mine, Washoe County, Nevada; Geological Society of Nevada, Special Publication - vol.7, pp.67-77.

  • Deposit

    Romarco Minerals press release, May 2004.

General comments

Subject category Comment text
Deposit The mineralization is contained in six orebodies. Ore zones consist of low-grade gold disseminated in flat-lying tabular bodies, with higher grade pods in areas of quartz+ adularia veining. Alteration at the Bell Springs deposit is predominantly silicification of tuffs that contain abundant fine-grained adularia and pyrite. Gold mineralization is related both spatially and temporally to peralkaline silicic volcanism and with a probable ring-fracture system. Opalitic veining occurs. Gold occurs as finely disseminated flecks, and in some places, is associated with pyrite.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-AUG-1988 Paidakovich, Matthew E. U.S. Geological Survey
Updater 01-DEC-1988 LaPointe, D. D. (Tingley, J.V.) Nevada Bureau of Mines and Geology
Updater 01-SEP-1991 Moyer Lorre A. (Marcus, S.) U.S. Geological Survey
Updater 01-NOV-1992 Phinisey, J. D. (Marcus, S.) U.S. Geological Survey
Updater 01-SEP-1994 Li, Zhiping ( Moyer, L.) U.S. Geological Survey
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.

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