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Commonwealth Mine

Past Producer in Cochise county in Arizona, United States with commodities Silver, Gold, Silica, Molybdenum, Copper, Lead, Vanadium
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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. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Ore body information
  13. Controls for ore emplacement
  14. Economic information about the deposit and operations
  15. Mining district
  16. Land status
  17. Ownership information
  18. Reserves and resources
  19. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10103554
MRDS ID M030569
Record type Site
Current site name Commonwealth Mine
Alternate or previous names Pearce Mine, Includes Eisenhart Vein, North, Rinaud, Smith, Footwa Ll, Main, Extension, Ritter, Brockman, Hartery Veins, Discovery Stope
Related records 10232286

Geographic coordinates

Geographic coordinates: -109.81509, 31.90069 (WGS84)
Elevation 1396
Relative position 1/2 MI E OF PEARCE.

Site location context

Political divisions (FIPS codes)

Cochise(county)

Arizona(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Pearce(quadrangle 1:24,000 scale)

Chiricahua Peak(quadrangle 1:100,000 scale)

Douglas(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Willcox Playa(hydrologic unit)

San Pedro-Willcox(hydrologic accounting unit)

Middle Gila(hydrologic subregion)

Lower Colorado(hydrologic region)

Geographic areas

Country State County
United States Arizona Cochise

Public Land Survey System information

Meridian Township Range Section Fraction State
Gila and Salt River 018S 025E 05 NE4 Arizona

Comments on the location information

  • INFO FROM LAND.ST :(1992)

Commodities

Commodity Importance
Silver Primary
Gold Primary
Silica Primary
Molybdenum Tertiary
Copper Tertiary
Lead Tertiary
Vanadium Critical Tertiary

Materials information

Materials Type of material
Argentite Ore
Cerargyrite Ore
Chalcocite Ore
Chalcopyrite Ore
Chrysocolla Ore
Embolite Ore
Galena Ore
Gold Ore
Iodyrite Ore
Molybdenite Ore
Proustite Ore
Pyrite Ore
Silver Ore
Tetrahedrite Ore
Wulfenite Ore
Alunite Gangue
Calcite Gangue
Fluorite Gangue
Gypsum Gangue
Hematite Gangue
Jarosite Gangue
Kaolin Gangue
Limonite Gangue
Rhodochrosite Gangue
Sericite Gangue
Siderite Gangue
Quartz Unknown

Alteration

  • (Local) Propylitic, Silicification, Oxidation; Alteration More Intense In And Near Vein Fractures. Sericitic And K-Spar Alteration Closest To The Veins, With Extensive Argillic And Propylitic Alteration Away From The Veins.

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Pearce Volcanics;Brockman Andesite
    Rock description Pearce Volcanics;Brockman Andesite
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Nearby scientific data

(1) -109.81509, 31.90069
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Flows Dip 35-40e
Type of structure Local
Structure description Fissure Veins And Fault Breccia Zones; N-S Faults Are Premineraliz Ation, Others Are Postmineralization

Ore body information

  • General form TABULAR, STRINGERS, MASSIVE
    Strike MAIN VEIN N-S
    Dip 60 E
    Thickness 18.29M
    Length 1219.2M
    Width 106.68M
    Depth to bottom 152.4M

Controls for ore emplacement

  • Fracture Zones Where Oxidized; Ore Also Deposited In Fault Breccia On Hanging Wall

Comments on the geologic information

  • ONE OF ARIZONA'S MAJOR SILVER PRODUCERS.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant Yes
Discovery year 1895
Discoverer John Pearce
Year of first production 1895
Year of last production 1979
Production years 1895-1942, OTHER

Mining district

District name Pearce District

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Phelps Dodge Corp.
    First year 1987
  • Type Owner
    Owner C. O. R. Ford Corp.
    Home office Dallas, Tx.
    First year 1979

Comments on the production information

  • IN RECENT YEARS THERE HAVE BEEN SPORADIC SHIPMENTS OF TAILINGS TO THE HIDALGO SMELTER AT PLAYAS, NEW MEXICO. SO FAR, ABOUT 100,000 TONS OF TAILINGS HAVE BEEN SOLD FOR USE AS HIGH-SILICA SMELTER FLUX. IT IS ESTIMATED THAT UP TO A MILLION TONS OF TAILINGS REMAIN. IN ADDITION THERE ARE APPROXIMATELY 150,000 TONS OF MINE DUMP MATERIAL IN THE AREA THAT AVERAGE 2.5 OZ OF AG/T.

Reserves and resources

  • Type In-situ
    Estimate year 1986
    Total resources 2267000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 84.706 g/mt Silver Major 1986
    Gold Au 5.647 g/mt Gold Major 1986

Comments on the reserve resource information

  • KEITH REPORTED THAT UP TO A MILLION TONS OF TAILINGS REMAIN AND THAT IN ADDITION APPROXIMATELY 150,000 TONS OF MINE DUMP MATERIAL IN THE AREA THAT AVERAGES 2.5 OZ OF AG/T. NIEMUTH (1987) REPORTS THAT THE OPENP PIT RESERVES ARE ONLY PARTIALLY DRILLED. THE UNDERGROUND FIGURE IS FOR DRILLED RESERVES.

Workings at the site

  • Type of workings Underground
    Length 9144M
    Overall depth 152.4M

Comments on the workings information

  • LENGTH OF WORKINGS ESTIMATED FROM MINE MAPS; TWO INCLINED SHAFTS, 62 DEG, WITH EXTENSIVE WORKINGS ON 8 LEVELS. THE WATER LEVEL WAS AT 700 FT, AND A MAJORITY OF MINING WAS DONE ABOVE THE WATER-TABLE, ALTHOUGH SHAFT "C" WAS EVENTUALLY SUNK TO 1,000 FT. THERE ARE ABOUT 20 MILES OF UNDERGROUND WORKINGS.

Comments on development

  • OPERATORS HAVE INCLUDED COMMONWEALTH MINING AND MILLING CO, MONTANA TO NOPAH MINING & MILLING CO, COMMONWEALTH DEVELOPMENT CO, GOURMET CHIEF INC. (1975). TAILINGS BEING REWORKED, 1976-79, FLOTATION METHODS. IN MID-1980'S MADE INTERMITTENT SHIPPINGS OF TAILINGS.

Reference information

Bibliographic references

  • Deposit

    SMITH, 1927, MS THESIS, UNIVERSITY OF ARIZONA.

  • Deposit

    KEITH, 1973, ABM BULL 187.

  • Deposit

    ABM FILE DATA.

  • Deposit

    SCOTT, 1916, MINING AND ENGINEERING WORLD, V. 45, P. 187-188.

  • Deposit

    HOWELL, 1977, MS. THESIS, UNIVERSITY OF ARIZONA.

  • Deposit

    ADMR FILE DATA

  • Deposit

    HEYLMUN, E.B., 1988, COMMONWEALTH SILVER-GOLD MINE, ARIZONA: CALIFORNIA MINING JOURNAL, V. 57, NO. 5, P. 14-16.

  • Deposit

    NIEMUTH, N.J., 1987, ARIZONA MINERAL DEVELOPMENT 1984-1986: ARIZONA DEPARTMENT OF MINES AND MINERAL RESOURCES DIRECTORY 29, 46 P.

  • Deposit

    SAWYER, M.B., GURMENDI, A.C., DALEY, M.R., AND HOWELL, S.B., 1992, PRINCIPAL DEPOSITS OF STRATEGIC AND CRITICAL MINERALS IN ARIZONA: UNITED STATS BUREAU OF MINES SPECIAL PUBLICATION, 334 P.

  • Other Database

    CIMRI

  • Production

    KEITH, 1973, P. 69; HEYLMUN, 1988, P. 16; SAWYER AND OTHERS, 1992.

  • Reserve-Resource

    NIEMUTH, 1987.

General comments

Subject category Comment text
Deposit IRREGULAR AG-AU HALIDES AND MNOR SULFO-SALTS WITH SOME MANGANESE IN QUARTZ-CALCITE FISSURE VEINS AND IN FAULT BRECCIA ZONES IN SILICIFIED TERTIARY RHYOLITE AND ANDESITE.
Deposit THIS REPORT WAS MODIFIED FROM RECORD M030569 OF JAN WILT IN MOLYBDENUM FILE, CONTACT PERSON T.G. THEODORE, USGS. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAY-1983 Peterson, Jocelyn A. U.S. Geological Survey
Updater 01-MAY-1990 Bolm, Karen S. U.S. Geological Survey
Updater 01-NOV-1993 Orris, Greta J. U.S. Geological Survey

Beyond USGS

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

Operator history (post-MRDS)

MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:

  • Phelps Dodge Corp. — acquired by Subsidiary of Freeport-McMoRan (2007)
    Acquired by Freeport-McMoRan Copper & Gold in 2007 in what was then the largest mining-industry deal ever (~US$26 B).

Curated by qvyshift.com from publicly-reported M&A activity (SEC filings, press releases, USGS Mineral Yearbooks). Not authoritative — verify against primary sources before relying on it. The MSHA panel above is the current authoritative source for actively-permitted mines.

External references

Maps centered on this site

Authoritative Arizona resources

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