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Gratiot Copper Mine

Past Producer in Keweenaw county in Michigan, United States with commodities Copper, Silver
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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. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Ownership information
  16. Production statistics
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10082844
MRDS ID W062202
Record type Site
Current site name Gratiot Copper Mine

Geographic coordinates

Geographic coordinates: -88.34504, 47.31472 (WGS84)
Elevation 338
Location accuracy 100(meters)
Relative position ABOUT 1 MI NE OF THE CENTER OF MOHAWK, MICHIGAN

Site location context

Political divisions (FIPS codes)

Keweenaw(county)

Michigan(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mohawk(quadrangle 1:24,000 scale)

Hancock(quadrangle 1:100,000 scale)

Hancock C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Keweenaw Peninsula(hydrologic unit)

Southcentral Lake Superior(hydrologic accounting unit)

Southern Lake Superior(hydrologic subregion)

Great Lakes(hydrologic region)

Geographic areas

Country State County
United States Michigan Keweenaw

Public Land Survey System information

Meridian Township Range Section Fraction State
Michigan T57N R32W 22 SE OF SE Michigan
T57N R32W 27 Michigan

Comments on the location information

  • LAT/LON IS IS FOR THE MAIN ENTRANCE

Commodities

Commodity Importance
Copper Primary
Silver Primary

Materials information

Materials Type of material
Copper Ore
Calcite Gangue
Quartz Gangue
Prehnite Gangue
Epidote Gangue

Mineral occurrence model information

Model code 96
USGS model code Unassigned
Deposit model name Native Cu
Mark3 model number 99

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt
    Rock unit name Portage Lake Volcanics
    Rock description Portage Lake Volcanics
    Stratigraphic age (youngest) Stenian
    Chronological age 1095
  • Host or associated Host
    Rock type
    Rock unit name Kearsarge Amygdaloid
    Rock description Kearsarge Amygdaloid
    Stratigraphic age (youngest) Stenian
    Chronological age 1095

Nearby scientific data

(1) -88.34504, 47.31472
ListMap

Economic information

Ore body information

  • General form FISSURE

Controls for ore emplacement

  • Lode

Comments on the geologic information

  • COPPER FILLS VESICLES, FRACTURES, AND INTERSTICES BETWEEN FRAGMENTS AND REPLACES ROCK IN THE VICINITY OF OPENINGS. COPPER OCCURS AS DISSEMINATED GRAINS ASSOCIATED WITH OTHER POST MAGMATIC MINERALS AND AS SMALL MASSES.

Economic information about the deposit and operations

Development status Past Producer
Deposit size Small
Significant No

Mining district

District name Keweenaw Copper

Ownership information

  • Type Operator
    Owner Seneca

Production statistics

  • Year 1910
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major recovered Cu Copper Copper 121mt
  • Year 1911
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major recovered Cu Copper Copper 20000mt
  • Year 1920
    Period 1910-1920
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major recovered Cu Copper Copper 142.4mt
  • Year 1920
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major recovered Cu Copper Copper 15.3mt
  • Year 1923
    Material ore Cu
    Ore mined 10mt
    Accuracy Accurate

Comments on the production information

  • IN 1920, 13,158 TONS OF ORE WERE HOISTED OF WHICH 35 PERCENT WERE STOCKPILED.

Comments on the workings information

  • THE MINE IS LOCATED AT THE TOP OF THE KEARSARGE AMYGDALOID IN THE PORTAGE LAKE LAVA SERIES. THE AMYGDALOID TOP OF THE KEARSARGE FLOW HAS BEEN MINED TO VERTICAL DEPTHS OF 3,000 TO 4,000 FEET FOR 2 MILES ALONG STRIKE IN THE MOHAWK QUADRANGLE.

Comments on development

  • ECON.COM: ORGANIZED IN FEB 1906.

Reference information

Bibliographic references

  • Deposit

    BUTLER, B.S., AND BURBANK, W.S., 1929, THE COPPER DEPOSITS OF MICHIGAN: USGS PROF PAPER NO. 144, 238 PP.

  • Deposit

    DAVIDSON, E.S., ESPENSHADE, G.H., WHITE, W.S., AND WRIGHT, J.C., 1954, BEDROCK GEOLOGY OF THE MOHAWK QUADRANGLE, MICHIGAN: U.S. GEOLOGICAL SURVEY, GEOLOGIC QUADRANGLE MAPS OF THE UNITED STATES, GQ 54, 1:24,000.

  • Production

    BUTLER AND BURBANK, 1929, P. 86.

General comments

Subject category Comment text
Deposit THE FLOW TOP OF THE KEARSARGE FLOW HAS BEEN THE MOST PRODUCTIVE AMYGDALOID IN THE MICHIGAN COPPER DISTRICT.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JAN-96 Sutphin, D.M. (Cannon, W.F.) U.S. Geological Survey
Updater 01-MAR-97 Sutphin, D.M. U.S. Geological Survey
Editor 01-MAY-97 Mason Jr., G.T. U.S. Geological Survey

Beyond USGS

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

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