Mena Mine

The Mena Mine is a uranium mine located in Jefferson county, Colorado at an elevation of 6,850 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Satelite View

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Site Name

Primary: Mena Mine
Secondary: Hoffmeister Homestead Prospect
Secondary: Black Judge Shaft
Secondary: Nigger Shaft

Commodity

Primary: Uranium
Tertiary: Molybdenum
Tertiary: Silver
Tertiary: Zinc
Tertiary: Bismuth
Tertiary: Nickel
Tertiary: Copper
Tertiary: Iron
Tertiary: Lead

Location

State: Colorado
County: Jefferson
District: Front Range

Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

Holdings

Not available

Workings

Not available

Ownership

Owner Name: Oscar Dahlberg
Percent: 100.0
Home Office: Colorado
Info Year: 1975

Owner Name: Madelene Walch
Home Office: Denver, Co.
Years: 1968 -

Owner Name: Ken Nickerson
Home Office: Denver, Co.
Years: 1968 -

Production

Year: 1959
Description: Ap_Grade: ^0.23% U3o8
Year: 1956
Description: Ap_Grade: ^0.32% U3o8

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Underground
Year First Production: 1956
Year Last Production: 1962
Discovery Year: 1949
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Type: R
Description: Front Range Uplift, Denver Basin

Type: L
Description: Rogers Fault Zone

Alterations

Alteration Type: L
Alteration Text: Breccia Fragments Are Highly Altered With Potassium Alteration Being Prominent

Rocks

Name: Gneiss
Role: Host
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Pegmatite
Role: Associated
Age Type: Host Rock Unit
Age Young: Neoproterozoic

Name: Pegmatite
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Pegmatite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Neoproterozoic

Name: Pegmatite
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic

Analytical Data

Analytical Data: 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.

Materials

Ore: Pitchblende
Ore: Bornite
Ore: Molybdenite
Ore: Pyrite
Ore: Chalcocite
Ore: Silver
Ore: Sphalerite
Ore: Covellite
Ore: Niccolite
Ore: Uraninite
Gangue: Chlorite
Gangue: Quartz
Gangue: Ankerite
Gangue: Calcite

Comments

Comment (Workings): 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.

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

Comment (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.

Comment (Production): 1962 FIGURES ARE FROM CDM, WHICH REPORTED CONSIDERABLY HIGHER TONNAGES FROM 1956-60 THAN SHERIDAN AND OTHERS' CITED ABOVE.

Comment (Development): ORIGINALLY WORKED BY HOFFMEISTER IN 1912-14 AS CU PROSPECT. PITCHBLENDE DISCOVERED IN 1949

Comment (Production): PRODUCED ABOUT 1,000 TONS U ORE. [copied from deleted record 10107838 = D002863].

Comment (General): Doug Causey - Combined data from DEP_ID 10142723 and deleted that record.

References

Reference (Production): SHERIDAN AND OTHERS, 1967, P. 75; COLORADO DIV. MINES ANN. OPERATORS REPTS.

Reference (Deposit): NELSON-MOORE, J.L., COLLINS, D.B., AND HORNBAKER, A.L., 1978, RADIOACTIVE MINERAL OCCURRENCES OF COLORADO AND BIBLIOGRAPHY: COLORADO GEOLOGICAL SURVEY BULL. 40, P. 193

Reference (Deposit): SIMS, P.K., AND SHERIDAN, D.M., 1964, GEOLOGY OF URANIUM DEPOSITS IN THE FRONT RANGE, COLORADO: USGS BULL. 1159, P. 93-94

Reference (Deposit): ADAMS, J.W., AND OTHERS, 1953, URANIUM OCCURRENCES IN THE GOLDEN GATE CANYON AND RALSTON CREEK AREAS, JEFFERSON COUNTY, COLORADO: USGS CIRC. 320, P. 13, 15-16.

Reference (Deposit): SHERIDAN, DOUGLAS M. AND OTHERS, 1967, GEOLOGY AND URANIUM DEPOSITS OF THE RALSTON BUTTES DISTRICT, JEFFERSON COUNTY, COLORADO: USGS PROF. PAPER 520, p. 87-91.

Colorado Mining Photos

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