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Yerington Mine

Past Producer in Lyon county in Nevada, United States with commodities Copper, Gold, Iron, Uranium, Silver, Molybdenum
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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. Mineral rights holdings
  18. Land status
  19. Ownership information
  20. Production statistics
  21. Reserves and resources
  22. Links to other databases
  23. Bibliographic references
  24. General comments
  25. Reporter information

Geologic information

Identification information

Deposit ID 10149678
MRDS ID M030104
MAS/MILS ID 0320190001
Record type Deposit
Current site name Yerington Mine
Alternate or previous names Yerington, Anaconda Copper, Empire Nevada, Yerington Mountain, Gallagher, Weed Heights
Included sites Macarthur

Comments on the site identification

  • All material from earlier MRDS records M035859 and MP90064 has been incorporated into the current record, as well as additional new information.

Geographic coordinates

Point of reference Pit
Geographic coordinates: -119.19408, 38.98351 (WGS84)
Elevation 1365
Location accuracy 10(meters)

Site location context

Political divisions (FIPS codes)

Lyon(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Yerington(quadrangle 1:24,000 scale)

Smith Valley(quadrangle 1:100,000 scale)

Walker Lake(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Walker(hydrologic unit)

Walker(hydrologic accounting unit)

Central Lahontan(hydrologic subregion)

Great Basin(hydrologic region)

Geographic areas

Country State County
United States Nevada Lyon

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 013 N 025 E 16 SWSESW Nevada

Comments on the location information

  • The Yerington Copper Mine is located in the flat area just west of the Walker River, east of the Singatse Range.

Commodities

Commodity Importance
Copper Primary
Gold Secondary
Iron Secondary
Uranium Tertiary
Silver Tertiary
Molybdenum Tertiary

Comments on the commodity information

  • Ore Materials: chalcopyrite, pyrite, bornite, covellite, chrysocolla, cuprite, tenorite, malachite, azurite, chalcocite (minor), native copper, melaconite, magnetite.
  • Gangue Materials: the ore body has low pyrite content, essentially no Au or Mo. Molybdenite has been seen in the mine only 12 to 15 times by Anaconda geologists. There is no Au, Ag, Mo trace element zoning. K-spar, biotite, quartz veining. Bornite is associated with high K-spar alteration. There is no trace of pyrrhotite, sphalerite, or galena in the ore body. In the root zone (present east end) albite flooding is recognized. The west end (top) was higher in pyrite, especially along certain structural zones. Along these zones a chalcocite enrichment blanket was formed. Bornite is present with chalcopyrite in the "middle" zone. The top (now west) is characterized by sericite, chalcopyrite, and pyrite.
  • 50 % Of The Ore Is Copper Oxide Minerals. Production Was About 25,000 - 30,000 Tpd Ore, And An Equal Amount Of Waste Was Mined. Sulfide Finely Disseminated And In Narrow Seams

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Bornite Ore
Covellite Ore
Chrysocolla Ore
Cuprite Ore
Tenorite Ore
Malachite Ore
Azurite Ore
Chalcocite Ore
Copper Ore
Melaconite Ore
Magnetite Ore
Feldspar Ore
Quartz Ore
Albite Ore
Sericite Ore
Biotite Gangue
Sphalerite Gangue

Alteration

  • (Local) ALBITIC AND POTASSIC ALTERATION WITH CHALCOPYRITE
  • (Local) PORPHYRY IS INTENSELY SILICIFIED IN HIGH GRADE ZONE

Analytical data

Result Overall Avg Cu content is less than 1%

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4
Model code 59
USGS model code 18b
Deposit model name Skarn Cu
Mark3 model number 8

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Rock type qualifier Yerington batholith (3 phases oldest to youngest: McLeod Hill quartz monzodiorite, Bear quartz monzonite, Luhr Hill Granite). 55-69 wt% SiO2, high-K, rocks sit at boundary between alkali-calcic and calc-alkaline
    Rock unit name Yerington Batholith
    Stratigraphic age (youngest) Middle Jurassic
    Chronological age 169.4
    Dating method U-Pb (zircon)
  • Host or associated Host
    Rock type Plutonic Rock > Porphyry
    Rock unit name Yerington Batholith
    Stratigraphic age (youngest) Middle Jurassic
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Stratigraphic age (youngest) Triassic
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier Flows
    Stratigraphic age (youngest) Triassic
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff
    Rock type qualifier Andesitic
    Stratigraphic age (youngest) Triassic
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock
    Stratigraphic age (youngest) Triassic
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier Breccia
    Stratigraphic age (youngest) Tertiary
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier Hornblende
    Stratigraphic age (youngest) Tertiary
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granodiorite
    Rock unit name Yerington Batholith
    Stratigraphic age (youngest) Middle Jurassic
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Hartford Hill Rhyolite
    Stratigraphic age (youngest) Tertiary
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Tonalite
    Rock type qualifier Dikes
    Stratigraphic age (youngest) Late Cretaceous
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Rock type qualifier Dikes
    Stratigraphic age (youngest) Late Cretaceous
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite
    Rock type qualifier Dikes
    Stratigraphic age (youngest) Late Cretaceous

Nearby scientific data

Pit (1) -119.19408, 38.98351
ListMap

Economic information

Geologic structures

Type of structure Local
Structure name THE ELONGATION OF THE ORE BODY IS PROBABLY RELATED TO A PRE-EXISTING STRUCT
Type of structure Local
Structure name FAULTS WHICH CUT THE ORE BODY ARE OF MINOR DISPLACEMENT.

Ore body information

  • Strike N60W
    Dip 05W
    Thickness 195M
    Length 1650M
    Width 490M
    Area 650HA
    Depth to top 60M
    Field Value
    Type of Orebody #1 DISSEMINATED
    Shape of Orebody #1 MASSIVE
    Type of Orebody #2 STOCKWORK
    Primary mode of Origin HYDROTHERMAL
    Primary Ore Control IGNEOUS
    Secondary Ore Control FRACTURING
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 SERICITIC
    Type of Wallrock Alter. #2 ADV ARGILLIC
    Type of Wallrock Alter. #3 SILICIFICATION
    Strike And Dip N60W:05W
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 15
    Min. Thick. Unconsol. Mat. 0
    Total Surface Area (HA) 650
    Date of Last Modification 830708
  • Name Elongate Distorted "V" Shape
    Strike N 63 W
    Dip 70 W
    Thickness 243.84M
    Length 1645.92M
    Width 487.68M

Controls for ore emplacement

  • THE PORPHYRY INTRUSIONS CARRY 80 - 90 % OF THE ORE

Comments on the geologic information

  • Silver Is Negligible: Gold And Silver Content Is Inconsequential
  • The Yerington Ore Body Is A Porphyry Copper Deposit. It Is Roughly Conformable To Its Host, A Quartz Monzonite Stock That Pitches About 5 Degrees Nw. Originally, In Mesozoic Time, The Cylindroid Shaped Stock Was Emplaced As A Steeply Pitching Body With Its Long Axis Dipping To The East. Since Miocene Time, The Body Has Been Rotated 60 Degrees To The West Resulting In Its Present, Gently Pitching Position. The Northern Edge Of The Ore Body Dips Steeply To The North, While The Southern Edge Dips North At A More Modderate Angle. A North-South Cross-Sectional View Varies From A Flat-Lying Lens On The East To A Distorted Inverted V Shape Toward The West. General Size Of Ore Body Is Large.
  • The "A" porphyry is altered quartz monzonite porphyry. The "B" porphyry is high in mafic minerals and plagioclase; it is pre-mineralization and accompanies the porphyritic quartz monzonite. Age dating (K-Ar) at Yerington indicates 150 Ma for all events related to intrusion and mineralization. -can't separate main intrusion from later mineralization age, etc. The host rock granodiorite and biotite and hornblende porphyries are indistinguishable by K-Ar age dating methods. The whole system evolved over 4-5 m.y. Copper is associated separately with each porphyry - that is, although the sulfides do not come in with the magma, they follow it very closely, and each porphyry has its own related copper mineralization. Contacts between different porphyry phases are knife-edge sharp, indicating multiple intrusion. Definite E -W-trending swarm of pre- and post-mineralization dikes. No deep rocks were brought to the surface by venting, etc....with the exception of the Yerington mine, essentially all of the districts production has been from rocks of Triassic age.

Economic information about the deposit and operations

Operation type Surface
Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1865
Mining method Open Pit
Year of first production 1953
Plant type Beneficiation (Mill)
Plant subcategory Flotation
Milling method Flotation

Mining district

District name Mason
District name Yerington District

Mineral rights holdings

Type of mineral rights Patented

Land status

Ownership category Private
Area name Carson City BLM Administrative District

Ownership information

  • Type Owner
    Owner Don Tibbals
    ID 2600085
    Interest 100
    Home office Nevada
    Year 1985
  • Type Owner-Operator
    Owner Arimetco International, Inc.
    Interest 100
    Home office Arizona
    Year 1996
  • Type Owner-Operator
    Owner Quaterra Resources Inc
    Interest 100
    Home office Vancouver, Canada
    Year 2009
    First year 2005

Comments on the ownership information

  • In 1982 Don Tibbals Reached An Agreement To Purchase The Yerington Property From Anaconda Meinerals Co., Denver ,Co. At The Time Tibbals Planned To Convert Most Of The 8,143 Acres Into An Industrial Park Consisting Of About 50 Industrial Buildings, 170 Homes, 20 Apartments, Recreational Buildings, And Utilities Including A Sewage System.

Production statistics

  • Year 1953
    Description Oxide/ Copper In Precipitates 8394 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 8394mt
  • Year 1954
    Description Oxide/ Copper In Precipitates 24608 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 24608mt
  • Year 1955
    Description Oxide/ Copper In Precipitates 32045 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 32045mt
  • Year 1956
    Description Oxide/ Copper In Precipitates 29493 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 29493mt
  • Year 1957
    Description Oxide/ Copper In Precipitates 25547 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 25547mt
  • Year 1958
    Description Oxide/ Copper In Precipitates 24165 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 24165mt
  • Year 1959
    Description Oxide/ Copper In Precipitates 18347 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 18347mt
  • Year 1960
    Description Oxide/ Coppper In Precipitates 38733 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 38733mt
  • Year 1961
    Description Sulphide/ Copper In Concentrates 2275 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 2275mt
  • Year 1961
    Description Oxide/ Copper In Precipitates 26200 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 26200mt
  • Year 1962
    Description Oxide/ Copper In Precipitates 23919 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 23919mt
  • Year 1962
    Description Sulphide/ Copper In Concentrates 9635 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 9635mt
  • Year 1963
    Description Sulphide/ Copper In Concentrates 16885 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 16885mt
  • Year 1963
    Description Oxide/ Copper In Precipitates 22296 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 22296mt
  • Year 1964
    Description Sulphide/ Copper In Concentrates 15969 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 15969mt
  • Year 1964
    Description Oxide/ Copper In Precipitates 18448 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 18448mt
  • Year 1965
    Description Sulphide/ Copper In Concentrates 14322 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 14322mt
  • Year 1965
    Description Oxide/ Copper In Precipitates 20612 Mt Cu Produced
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 20612mt
  • Year 1966
    Description Sulphide/ Gross Cu Metal In Precipitat 13647 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 13647mt
  • Year 1966
    Description Oxide/ Gross Cu Metal In Precipitates 22154 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 22154mt
  • Year 1967
    Description Sulphide/ Coppper In Concentrates 8511 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 8511mt
  • Year 1967
    Description Oxide/ Gross Cu Metal In Precipitates 14051 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 14051mt
  • Year 1968
    Description Sulphide/ Gross Cu Metal In Concentrat 18952 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 18952mt
  • Year 1968
    Description Oxide/ Gross Cu Metal In Precipitates 17123 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 17123mt
  • Year 1969
    Description Sulphide/ Gross Cu Metal In Concentrat 9635 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 9635mt
  • Year 1969
    Description Oxide/ Gross Cu Metal In Precipitates 22719 Mt Cu Content
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 22719mt
  • Year 1970
    Description Sulphide/ 0.68% Cu (Mill Feed) 4216000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 1wt-pct
  • Year 1970
    Description Oxide/ 0.52% Cu (Mill Feed) 3885000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 1wt-pct
  • Year 1971
    Description Oxide Ore/ 0.51% Cu (Mill Feed) 4095000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4095000mt 1wt-pct
  • Year 1971
    Description Sulphide Ore/ 0.58% Cu (Mill Feed) 4298000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4298000mt 1wt-pct
  • Year 1972
    Description Sulphide Ore/ 0.53% Cu (Mill Feed 4334000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4334000mt 1wt-pct
  • Year 1972
    Description Oxide Ore/ 0/51% Cu (Mill Feed) 4153000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4153000mt 1wt-pct
  • Year 1973
    Description Sulphide Ore/ 0.53% Cu (Mill Feed) 4432000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4432000mt 1wt-pct
  • Year 1973
    Description Oxide Ore/ 0/36% Cu (Mill Feed) 5146000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 5146000mt 0wt-pct
  • Year 1974
    Description Sulphide Ore/ 0.53% Cu (Mill Feed) 4368000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4368000mt 1wt-pct
  • Year 1974
    Description Oxide Ore/ 0.38% Cu (Mill Feed) 5341000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 5341000mt 0wt-pct
  • Year 1975
    Description Sulphide Ore/ 0.51% Cu (Mill Feed) 4401000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 4401000mt 1wt-pct
  • Year 1975
    Description Oxide Ore/ 0.37% Cu (Mill Feed) 5263000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 5263000mt 0wt-pct
  • Year 1976
    Description Sulphide Ore 6 Mo End 6/30/76 Cu=0.49% 2146000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 2146000mt 0wt-pct
  • Year 1976
    Description Oxide Ore 6 Mo End 6/30/76 Cu = 0.49% 2038000 Mt Ore Processed
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 2038000mt 0wt-pct

Comments on the production information

  • June 30, 1978, Is The Date Proposed By Anaconda For Permanent Termination Of Work At The Yerington Mine And Mill Site Early Production - Although Copper Was Discovered In The Yerington District In 1865, There Was Little Production Untill 1912 When A Smelter And Connecting Railroad Were Built. By 1930, When Mining Virtually Ceased, Over 52,600 Tonnes Of Copper Had Been Produced From Ore Averaging 2% Cu.

Reserves and resources

  • Type In-situ
    Estimate year 1975
    Indicated 24500000mt ore
    Demonstrated 24500000mt ore
    Total resources 54000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.33 wt-pct Copper Major 1975
  • Type In-situ
    Estimate year 1975
    Total resources 24500000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.33 wt-pct Copper Major 1975
  • Type In-situ
    Estimate year 1975
    Total resources 27800000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.48 wt-pct Copper Major 1975
  • Type In-situ
    Estimate year 1976
    Indicated 20300000mt ore
    Demonstrated 20300000mt ore
    Total resources 20300000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.32 wt-pct Copper Major 1976
  • Type In-situ
    Estimate year 1976
    Indicated 25200000mt ore
    Demonstrated 25200000mt ore
    Total resources 25200000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.47 wt-pct Copper Major 1976
  • Type In-situ
    Estimate year 1982
    Total resources 114999999mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.343 wt-pct Copper Major 1982
  • Type In-situ
    Estimate year 1991
    Demonstrated 68940000mt ore
    Total resources 68940000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.621 wt-pct Copper Major 1991
  • Type In-situ
    Estimate year 1993
    Demonstrated 88000000mt ore
    Total resources 88000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.21 wt-pct Copper Major 1993
  • Type In-situ
    Estimate year 1996
    Demonstrated 45000000mt ore
    Total resources 45000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.23 wt-pct Copper Major 1996

Comments on the reserve resource information

  • Matrix 1 Is Tonnage And Grade Of Pit Sulphide Ore. Matrix 2 Is Tonage And Grade Of Acid Soluble (Oxide) Ore. Reflects Production For 1977 And 1978 Matrix 3 Is Tonnage And Grade Est. Of Flotation Tailing In Percent Total Cu From Sulfide Mill. Matrix 4 Is Tonnage And Grade Est. Of Leach Tailings In Percent Total Cu From Leach Vat. Reflects Production For 1977 And 1978. Dump Leaching--No Tonnages Available. Column 4 Reflects Production For 1977 And 1978.
  • Oxide Resource Est 15.6 Million Mt @ 0.32 % Cu. Former Owner Was Anaconda Co. 1991 Mas Reserves, Cu:(Randol 1993/94) Oxide: 0.22 Wt-Pct - 81,850,000 Mt Ore Sulfide: 0.36 Wt-Pct - 68,940,000 Mt Ore

Comments on the workings information

  • Large open pit more than a mile long and a half mile wide, elongate WNW-ESE

Comments on other economic factors

  • According To The 1995 Annual Report The Yerington Pit Is Currently Flooded.
  • Yerington is considered by the USGS to be one of the ?Giant Porphyry-Related Metal Camps of the World.?
    From 1953 through 1996, the Yerington Copper open pit mine produced 1.75 billion pounds of copper metal from 162 million tons of ore with average grade of 0.54% Cu. The mine also produced more than 11,450 kilograms of gold and 164,720 kilograms of silver.

Comments on development

  • Copper mineralization was discovered in the Singatse Range west of Yerington in 1865 resulting in the development of many small hand-dug mines. In 1941, International Smelting and Refining Company, a subsidiary of Anaconda Copper Company, acquired the property. During the ensuing four years, exploration confirmed the presence of approximately 60,000,000 tons of ore with copper content ranging from 0.9% to 0.95%. In 1951, Anaconda took direct control of the Yerington site and began construction and installation of equipment for mining operations. Anaconda actively mined the site from 1953 into 1978. In 1977, the Atlantic Richfield Company (ARCo) purchased a number of holdings from Anaconda, including the Yerington site, just as it was planning to close down. ARCo closed the site on June 30, 1978.
    In 1978, ARCo sold all of its holdings at the site, including the townsite of Weed Heights, to Don W. Tibbals. Tibbals subsequently leased portions of the property site to other companies who conducted various mining and copper processing activities.
    From 1978 through the present, the U.S. Bureau of Land Management ( BLM), the U.S. Geological Survey and the Nevada Division of Environmental Protection (NDEP) and the U.S. Environmental Protection Agency (EPA) have identified a variety of environmental concerns at the Yerington mine site including contamination of groundwater with heavy metals and, some cases, radionuclides (uranium and thorium). Approximately half of the land at the Yerington mine site was and is currently managed by the BLM.
    In 1988, Tibbals sold a large portion of his land and unpatented mining claims to the Arizona Metals Company (dba Arimetco) who operated the site from 1989 to 1996, producing copper from a solvent extraction electrowinning (SX-EW) process.
    In January 2000, faced with government enforcement actions, fines, falling copper prices, and other financial problems, Arimetco abandoned the Yerington operations and declared bankruptcy.
    In March 2002, NDEP, BLM and EPA signed a Memorandum of Understanding (MOU) headed by NDEP but also defining how the agencies would work together in the oversight of the old mine site.
    In January 2005, the EPA agreed to become the regulatory lead agency for investigation and cleanup at the Yerington Mine site. EPA will continue to coordinate with NDEP and BLM as it proceeds forward ensuring the cleanup progresses.
    Primarily as a result of Arimetco's failure at Yerington, substantially stronger requirements for corporate guarantees as an acceptable instrument for financial assurance were adopted in 2001. Annual reviews of corporate guarantees were required by regulation in 2002. ?The BLM regulations governing mining were first adopted in 1981 and amended in 1998 and 2000. Among other things, these require quarterly inspections of mines on public lands to ensure compliance with all permit conditions. ?Every mining operation on public land is now subject to the National Environmental Policy Act, which provides opportunity for public comment during the planning process for a mine.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit General Location Is About 53 Km SE Of Carson. Mining Method Is Open Pit. Mill Is Dismantled. Past Prod. 177,000 Mt Cu From 144 Million Mt Ore (179). Pit Extends Omtp M/2 Sec. 21 And The Se/4 Sec. 17.
Deposit The Yerington ore body has been tilted on its side, until the original top of the body is now at the west end. The tilting dips west 70 degrees, as measured by the Tertiary-pre-Tertiary contact which lies at this angle to the west of the mine. 6,000 to 7,000 feet of vertical section of the deposit is exposed because of this tilting.
MacArthur forms part of the famous Yerington porphyry copper district which includes three deposits with historical resources totaling approximately 1.2 billion tons of ore averaging approximately 0.45% Cu.

The root zone and core of the deposit produced oxide minerals high in copper-silicates with the silica derived from the decomposition of plagioclase. No chalcocite blanket developed because of low original pyrite content of the deposit. Chrysocolla is the dominant oxide mineral here.
About half of the ore is copper oxide minerals. Production was about 25,000 - 30,000 tpd ore, with an equal amount of waste mined. Sulfide minerals are finely disseminated and in narrow seams.
Deposit Major Alteration Types: Pre-main stage endoskarn (garnet, albite ? clinopyroxene); main stage potassic (biotite ? K-feldspar), sodic-calcic (actinolite, sodic plagioclase), propylitic (actinolite, chlorite); late stage sericitic, sodic, chloritic.
Alteration Zoning: Likely contemporaneous central potassic with deeper and lateral sodic-calcic with peripheral propylitic; albitic (albite-chlorite) and sericitic alteration overprint the earlier alteration with sericitic alteration increasing at shallower levels.
Major Vein types and Relative Ages: Common veins oldest to youngest in ore zone: quartz?K-feldspar; chalcopyrite ? pyrite or bornite ?quartz ? chlorite; epitdote ? quartz ? chlorite + chalcopyrite ? pyrite or bornite; epidote + quartz ? chlorite + chalcopyrite ? pyrite or bornite; pyrite ? quartz ? chalcopyrite ? tourmaline.
Metal Zoning: central magnetite-bornite ?chalcopyrite, or ?chalcocite/digenite. Outer chalcopyrite- ?magnetite ?pyrite and outermost pyrite.
Deposit Associated Deposits: Casting Copper (skarn), Douglas Hill (skarn), Bluestone (skarn), Mason Valley (skarn), McConnel Mine (skarn), MacArthur (porphyry), Bear-Lagomarsino (porphyry), Buckskin Mine (Au-Cu veins), Ludwig Mine (carbonate replacement/skarn)

Reporter information

Type Date Name Affiliation Comment
Reporter 09-JUL-97 Buckingham, David A. U.S. Bureau of Mines
Updater 31-DEC-09 Anderson, Claire U.S. Geological Survey
Reporter 01-NOV-06 LaPointe, D.D. Nevada Bureau of Mines and Geology
Editor 01-SEP-07 Schruben, Paul G. U.S. Geological Survey

Beyond USGS

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

Current status (per MSHA)

StatusAbandoned since 06/22/1978
MSHA mine ID2600085
Mine name (MSHA)Yerington Mine
Current operatorAnaconda Minerals Company
Current controller (parent)Atlantic Richfield Company
Mine typeSurface (Metal / non-metal)

MSHA cross-reference per the original MRDS record. Mine status and operator reflect MSHA's last published Mines export (February 2025); MSHA's public bulk feed has been unavailable since, so this may be out of date. See the Mine Data Retrieval System for current status.

Open MSHA's Mine Data Retrieval System for inspections, accidents, and violations for this mine.

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.