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Mena Mine

Past Producer in Jefferson county in Colorado, United States with commodities Uranium, Copper, Nickel, Lead, Bismuth, Zinc, Silver, Molybdenum, Iron
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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. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Ownership information
  17. Production statistics
  18. Links to other databases
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10013716
MRDS ID D010159
MAS/MILS ID 0080590016
Record type Site
Current site name Mena Mine
Alternate or previous names Hoffmeister Homestead Prospect, Black Judge Shaft, Nigger Shaft

Geographic coordinates

Point of reference Main Entrance
Geographic coordinates: -105.30208, 39.85374 (WGS84)
Elevation 2088
Location accuracy 50(meters)
Relative position 7.6 MILES N 31 DEG W FROM GOLDEN. Used map fig. 27, p. 88 of PP-520 and GoogleEarth images to locate a point near the middle of the mine workings. There should be additional points for Black Judge Shaft, Hoffmeister Adit, North Adit, South Adit.\n, 100 ft.

Site location context

Political divisions (FIPS codes)

Jefferson(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ralston Buttes(quadrangle 1:24,000 scale)

Denver West(quadrangle 1:100,000 scale)

Denver(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Clear(hydrologic unit)

South Platte(hydrologic accounting unit)

South Platte(hydrologic subregion)

Missouri(hydrologic region)

Federal lands

LG(Federal land areas administered by LG)

Geographic areas

Country State County
United States Colorado Jefferson

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 002S 071W 26 NW OF NW OF OF NE Colorado

Comments on the location information

  • ALONG RALSTON CREEK ; INFO FROM LAND.ST :(1975)

Commodities

Commodity Importance
Uranium Primary
Copper Tertiary
Nickel Critical Tertiary
Lead Tertiary
Bismuth Critical Tertiary
Zinc Critical Tertiary
Silver Tertiary
Molybdenum Tertiary
Iron Tertiary

Materials information

Materials Type of material
Bornite Ore
Chalcocite Ore
Covellite Ore
Molybdenite Ore
Niccolite Ore
Pyrite Ore
Silver Ore
Sphalerite Ore
Uraninite Ore
Pitchblende Ore
Ankerite Gangue
Calcite Gangue
Chlorite Gangue
Quartz Gangue

Alteration

  • (Local) Breccia Fragments Are Highly Altered With Potassium Alteration Being Prominent

Analytical data

Result ADAMS AND OTHERS' (1953) ANALYSIS OF SAMPLE FROM UNDERGROUND WORKINGS CONTAINED 0.31% U, 0.29% CU, 0.015% PB, 0.06% ZN. SHERIDAN AND OTHERS' (1967) PARTIAL ANALYSIS OF PITCHBLENDE ORE SAMPLE CONTAINED 0.28% EQUIV. U, 0.24% U, 10.82% CU, 0.12% PB, 0.17% ZN, 0.10% MO, 5.8% BI, 43.6 OZ/TON AG, 0.008% NI, 0.004% CO. ORE GRADES FROM 1956-60 RAN 0.16 TO 0.32% U3O8.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Pegmatite
    Rock unit name Granitic Pegmatite
    Rock description Granitic Pegmatite
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Metamorphic Rock > Gneiss
    Rock unit name Idaho Springs Formation-Hornblende Gneiss Unit
    Rock description Idaho Springs Formation-Hornblende Gneiss Unit
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Metamorphic Rock > Amphibolite
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite

Nearby scientific data

Main Entrance (1) -105.30208, 39.85374
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Front Range Uplift, Denver Basin
Type of structure Local
Structure description Rogers Fault Zone

Ore body information

  • Strike N20W
    Thickness 0.7M
    Length 25M
    Depth to top 0M

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1949
Discoverer Fred Schwartzwalder
Year of first production 1956
Year of last production 1962

Mining district

District name Ralston Buttes District
District name Front Range

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Ken Nickerson
    Home office Denver, Co.
    First year 1968
  • Type Owner
    Owner Madelene Walch
    Home office Denver, Co.
    First year 1968
  • Type Unknown
    Owner Oscar Dahlberg
    Interest 100
    Home office Colorado
    Year 1975

Production statistics

  • Year 1956
    Accuracy Accurate
    Description Ap_Grade: ^0.32% U3o8
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Ore Uranium Uranium 0wt-pct
  • Year 1959
    Accuracy Accurate
    Description Ap_Grade: ^0.23% U3o8
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Ore Uranium Uranium 0wt-pct

Comments on the production information

  • 1962 FIGURES ARE FROM CDM, WHICH REPORTED CONSIDERABLY HIGHER TONNAGES FROM 1956-60 THAN SHERIDAN AND OTHERS' CITED ABOVE.
  • PRODUCED ABOUT 1,000 TONS U ORE. [copied from deleted record 10107838 = D002863].

Comments on the workings information

  • NORTH SIDE OF RALSTON CREEK: BLACK JUDGE IS 22-FT-DEEP INCLINED SHAFT WITH 13 FT OF DRIFT AND STOPES FROM BOTTOM; HOFFMEISTER IS APPROX 50-FT ABANDONED ADIT DRIVEN NW; NEW (NORTH) ADIT DRIVEN NNW APPROX 95 FT; NEW 90-FT SHAFT. SOUTH SIDE OF RALSTON CREEK: NEW (SOUTH) ADIT DRIVEN SE APPROX 250 FT WITH 20-FT WINZE SUNK NEAR PORTAL.

Comments on development

  • ORIGINALLY WORKED BY HOFFMEISTER IN 1912-14 AS CU PROSPECT. PITCHBLENDE DISCOVERED IN 1949

Reference information

General comments

Subject category Comment text
Deposit INTERLAYERED HORNBLENDE GNEISS, AMPHIBOLITE, BIOTITE GNEISS, AND CALC-SILICATE GNEISS HAVE FOLIATION TRENDING N 60 TO 90 W, DIPPING SW. PITCHBLENDE OCCURS AS COLLOFORM COATINGS ON ROCK FRAGMENTS AND FRACTURE SURFACES AND AS STRINGERS AND VEINLETS WITH SULFIDES AND METALS IN ANKERITE-CEMENTED BRECCIA IN MAJOR BRANCH OF ROGERS FAULT SYSTEM. GENERAL PPARAGENESIS: 1) FAULTING, BRECCIATION, WALLROCK ALTERATION; 2) K-FELDSPAR DEPOSITION; 3) DEPOSITION OF COARSE- AND FINE-GRAINED ANKERITE; 4) DEPOSITION OF PITCHBLENDE, THEN MINOR QUARTZ; 5) MINOR FRACTURING; 6) DEPOSITION OF LATE ANKERITE, CALCITE, BASE-METAL SULFIDES AND ASSOCIATED METALS.
General Doug Causey - Combined data from DEP_ID 10142723 and deleted that record.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-AUG-77 Hassler, J. William U.S. Geological Survey
Reporter 01-JAN-83 Banke, Carl M. (Hasler, J. William) Colorado Geological Survey
Reporter 27-FEB-84 Minecom U.S. Bureau of Mines
Updater 01-MAY-93 Spanski, Gregory T. U.S. Geological Survey
Editor 03-AUG-09 Wilson, Anna B. U.S. Geological Survey

Beyond USGS

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

External references

Maps centered on this site

Authoritative Colorado resources

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