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Olinghouse Mine

Producer in Washoe county in Nevada, United States with commodities Gold, Silver, Copper, Lead, Zinc, Arsenic, Antimony, Mercury
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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 10310550
Record type Site
Current site name Olinghouse Mine

Comments on the site identification

  • Alta Gold?s current Olinghouse Mine encompasses several historic Olinghouse district workings as well as previously unmined areas.

Geographic coordinates

Geographic coordinates: -119.427, 39.66585 (WGS84)
Elevation 1950
Relative position The Olinghouse gold mine is located in the Pah Rah Mountains, approximately thirty-five miles east of Reno, Nevada.

Site location context

Political divisions (FIPS codes)

Washoe(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Olinghouse(quadrangle 1:24,000 scale)

Reno(quadrangle 1:100,000 scale)

Reno(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Pyramid-Winnemucca Lakes(hydrologic unit)

Truckee(hydrologic accounting unit)

Central Lahontan(hydrologic subregion)

Great Basin(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management NV)

Bureau of Land Management NV 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 021N 023E 20,29 Nevada

Comments on the location information

  • The property consists of nine patented and 300 unpatented mining claims occupying an area of approximately 9 square miles. UTM is to near the center of the main pit.

Commodities

Commodity Importance
Gold Primary
Silver Primary
Copper Tertiary
Lead Tertiary
Zinc Critical Tertiary
Arsenic Critical Tertiary
Antimony Critical Tertiary
Mercury Tertiary

Comments on the commodity information

  • Commodity Info: Gold fineness is approximately 700.
  • Ore Materials: free gold, electrum
  • Gangue Materials: chalcopyrite, galena, pyrite, and sphalerite

Materials information

Materials Type of material
Gold Ore
Electrum Ore
Galena Ore
Pyrite Ore
Sphalerite Ore
Chalcopyrite Gangue

Alteration

  • (Local) With the exception of a broad zone of propylitic alteration, the alteration features at Olinghouse are unusually subtle. On the surface, the quartz veins are narrow and there is essentially no color anomaly. The replacement of plagioclase by K-feldspar surrounding the veins can be determined only in thin section, and the alteration halo is small.

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) > Mafic Volcanic Rock > Basalt
    Rock type qualifier vesicular
    Rock unit name Pyramid Sequence
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 12
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock unit name Pyramid Sequence
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 12
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Volcanic Breccia (Agglomerate)
    Rock type qualifier flow breccias
    Rock unit name Pyramid Sequence
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 12
  • Host or associated Host
    Rock type Sedimentary Rock > Mixed Clastic/Volcanic Rock
    Rock type qualifier lahars
    Rock unit name Pyramid Sequence
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 12
  • Host or associated Host
    Rock type Sedimentary Rock > Mixed Clastic/Volcanic Rock
    Rock type qualifier volcanic sediments
    Rock unit name Pyramid Sequence
    Stratigraphic age (youngest) Early Miocene
    Chronological age 16
    Stratigraphic age (youngest) Middle Miocene
    Chronological age 12

Nearby scientific data

(1) -119.427, 39.66585
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Ne-trending faults of the Olinghouse Fault Zone
Type of structure Regional
Structure description The NE-trending Olinghouse Fault runs through the property, a regional left-lateral strike-slip structure with dip-slip component, and recent movement (probably the site of a major earthquake in 1869). The north end of the Walker Lane fault zone passes just east of the Olinghouse district.

Ore body information

  • General form tabular

Controls for ore emplacement

  • Mineralization is both lithologically and structurally controlled, with mineralization hosted by the Pyramid sequence of andesitic to basaltic volcanic and volcaniclastic rocks, and controlled by NE-trending structures.

Comments on the geologic information

  • The Olinghouse deposit is underlain by a sequence of Oligocene to Miocene volcanic rocks, intrusions, and volcaniclastic sediments. Most units strike NNW and dip SW. The oldest rock units in the mine area are a sequence of Oligocene to Miocene ignimbrites composed of volcanic ash, ash flow tuff, rhyolite flows and lahars dated at 22.7 Ma. Although altered and mineralized, relatively minor production has come from these rocks. These tuffs are overlain by the Pyramid Sequence, the principal host rock for Olinghouse mineralization. The Pyramid Sequence consists of vesicular basalt, andesite, flow breccias, lahars, and volcanic sediments, all ranging in age from 12 Ma to 16 Ma. This sequence is unconformably overlain by the Kate Peak Formation, a thick sequence of post-mineral andesitic to rhyolitic flows, flow breccias and tuffs. The volcanic rocks are cut by a series of NE-trending structures, some of which show recent strike-slip movement. The structures are intruded by basaltic to dacitic dikes. Gold mineralization occurs in veins and vein swarms within and adjacent to the dikes following these structures. The principal productive structures are referred to as the Number 1, Number 2, Number 3, Blue Dike, Sunbeam, and Standard structures. The Number 1, 2 and 3 structures and the Blue Dike occur close together with moderate intervening waste, and comprise the open pit deposit. The veins occur within a broad, NE-trending, propylitic aureole occupying several square miles and roughly encircling the central Olinghouse district. The volcanic rocks exhibit nearly complete chloritization of the original mafic minerals and groundmass, and the plagioclase is altered to calcite, sericite, epidote, and albite. Epidote increases towards the central part of the district. As the veins are approached, the intensity of groundmass alteration increases and plagioclase feldspar is replaced by K-feldspar and sericite. Mafic phenocrysts are replaced by chlorite, epidote, K-feldspar, and goethite.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Discovery year 1994

Mining district

District name Olinghouse District

Land status

Ownership category Private
Area name Carson City BLM Administrative District
Ownership category BLM Administrative Area
Area name Carson City BLM Administrative District

Ownership information

  • Type Owner-Operator
    Owner Alta Gold Company

Comments on the workings information

  • The mine is operated by conventional open pit methods using 85-ton trucks and 992 loaders. Metallurgical studies conducted by McClelland Laboratories resulted in a processing method using initial gravity separation of the high grade ore (>0.09 oz/ton), pulp agglomeration of the gravity mill tails with the lower grade material, followed by conventional heap leaching.

Comments on other economic factors

  • Past production between 1898 and 1957 from district mines now included in Alta?s land position totaled 42,705 ounces of gold, 29155 ounces of silver, 3,987 pounds of copper, and 1,200 pounds of lead from more than 25,258 short tons of ore. In 1996, the total resource at Olinghouse was estimated to be 22,751,000 short tons of ore grading 0.03 ounces of gold per ton. The mine began production in September, 1998 and is scheduled to produce 100,000 ounces/year beginning in 1999. Alta reports current (1998) reserves, calculated at $300/oz Au, at 12,257,000 short tons grading 0.042 oz/ton (512,800 ounces) at a stripping ratio of 4.5:1. The reserve occurs within a mineral deposit containing a resource of slightly over one million ounces at an uncut grade of 0.042 oz/ton Au.

Comments on development

  • Prospecting began in the Olinghouse area in 1860, with district production peaking from 1901-1903, and minor production continuing intermittently through recent years. Modern exploration began in 1986 when Western Goldfields secured a small land position in the eastern part of the district and drilled 21 holes. Although gold mineralization was encountered in most of these holes, their land position did not allow testing the heart of the district, and the property was dropped. Phelps Dodge secured a land position in the central part of the district in 1991 and by 1993 had drilled 37 reverse circulation drill holes and 7 core holes. In 1993 Phelps Dodge elected to sell their interest in the property, whereupon Alta Gold purchased the property in 1994. By the end of 1994, Alta had submitted a plan for exploration to the BLM calling for drilling of 550 holes, trenching, and bulk sampling of adits, to begin in 1995. The 1995 drilling program confirmed earlier ore estimates and increased reserves. In early 1996, Alta Gold began its third phase of drilling on the Olinghouse gold project, where preliminary results had confirmed the presence of high-grade mineralization. The program, consisting of 42,000 ft. of core and reverse-circulation drilling, began with the twinning of a previous hole to verify assay values. This first core hole cut two different ore zones and contained significant visible gold. At a 330-ft depth, the hole cut 64 ft grading 1.97 oz Au/ton, including a 31.5 ft interval at 3.9 oz Au/ton. The same hole cut 61 ft grading 0.049 oz Au/ton. The second core hole 400 ft west also contained visible gold. Following 1996 drilling results, Alta began the permitting process to mine the deposit and submitted a draft EIS for the Olinghouse Mine Project to the BLM in 1997. The final EIS was issued in February 1998, and the mine began production in September 1998. The mine is scheduled to produce 100,000 ounces/year over its projected 6-year mine life, beginning in 1999. The mine is operated by conventional open pit methods, with the Green Hill pit the first to produce ore, to be followed by the Payback pit with possible later mining of the Keystone and Sunbeam pits. The best exploration indicators for the Olinghouse deposits have been abundant gold veins and old mine workings, the abundance of placer gold, the volume of rock affected by alteration, and the concentration of epidote in the center of the district. Soil sampling has also been effective at locating new deposits.

Reference information

Bibliographic references

  • Deposit

    Pay Dirt, 5/1/96

  • Deposit

    Pay Dirt, 11/1/96

  • Deposit

    Denver Mining Record, 8/2/95

  • Deposit

    Denver Mining Record, 6/5/96

  • Deposit

    Denver Mining Record, 9/4/96

  • Deposit

    Northern Miner, 8/28/95

  • Deposit

    Northern Miner, 9/11/95

  • Deposit

    Northern Miner, 1/22/96

  • Deposit

    Skillings Mining Review, 1/20/96

  • Deposit

    Skillings Mining Review, 10/26/96

  • Deposit

    Draft Environmental Impact Statement, Olinghouse Mine Project, Sept. 1997

  • Deposit

    Final Environmental Impact Statement, Olinghouse Mine Project, Feb.1998

  • Deposit

    Alta Gold Co, 1997 Annual Report

  • Deposit

    Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.

General comments

Subject category Comment text
Deposit Gold occurs as small wires and free grains in generally open veins, along with quartz, calcite, goethite, epidote, stilbite, heulandite, hydrothermal K-feldspar, and sparse adularia. The adularia has been dated at 10.46 Ma (Larry Garside, personal communication). The pyrite content is less than 2% and is generally oxidized. Open space structures are common. Traces of chalcopyrite, galena, and sphalerite are associated with the ore, with higher base-metal concentrations within the high-grade ore shoots. Ore grade mineralization is most closely associated with K-feldspar, chlorite, and the zeolite minerals stilbite and heulandite. Orebodies occur in a series of closely spaced, NE-trending, near-parallel structures with mineralization occurring along faults, in shear zones and adjacent to dikes. The silver content of the ore seldom exceeds 0.1 oz/ton, with most silver occurring in electrum.Geochemical values of arsenic, antimony and mercury in the ore are generally low.

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.