Mass Fissure

Past Producer in Keweenaw county in Michigan, United States with commodity Copper
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. Production statistics
  18. Bibliographic references
  19. Reporter information

Geologic information

Identification information

Deposit ID 10082617
MRDS ID W060054
Record type Site
Current site name Mass Fissure

Comments on the site names

  • THE MASS FISSURE WAS EXPOSED IN THE AHMEEK MINE WHERE THE FISSURE CROSSED THE KEARSARGE AMYGDALOID.

Geographic coordinates

Geographic coordinates: -88.37644, 47.29306 (WGS84)

Site location context

Political divisions (FIPS codes)

Keweenaw(county)

Michigan(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ahmeek(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 057N 032W 33 SE OF NW Michigan

Commodities

Commodity Importance
Copper Primary

Materials information

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

Alteration

  • (Local) Chloritization

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

Nearby scientific data

(1) -88.37644, 47.29306

Economic information

Geologic structures

Type of structure Local
Structure description Mass fissure of the ahmeek mine was mined where it crossed the Kearsarge lo

Ore body information

  • General form FISSURE

Controls for ore emplacement

  • Fissure

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Year of first production 1909
Year of last production 1925
Production years STILL ACTIVE IN 1925

Mining district

District name Keweenaw Copper

Production statistics

  • Year 1925
    Period 1909-1925
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major recovered Cu Copper Copper 5246.7mt

Comments on the production information

  • MINING OF FISSURE WAS STILL ACTIVE IN 1925

Comments on development

  • THE MASS FISSURE WAS OPENED TO THE 26TH LEVEL OF THE AHMEEK MINE ON THE KEARSARGE LODE. ALONG STRIKE IT WAS DEVELOPED TO ABOUT 1,100 FT NW FROM THE KEARSARGE AND ABOUT 600 FT TO THE SW.

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

    WHITE, W.S., CORNWALL, H.R., AND SWANSON, R.W., 1953, BEDROCK GEOLOGY OF THE AHMEEK QUADRANGLE, MICHIGAN: USGS MAP GQ-27, SCALE 1:24000

  • Production

    BUTLER AND BURBANK, 1929

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUL-1995 Nicholson, Suzanne U.S. Geological Survey
Updater 01-MAR-1997 Sutphin, D.M. U.S. Geological Survey
Editor 01-MAY-1997 Mason Jr., G.T. U.S. Geological Survey

Beyond USGS

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