Idledale District

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

Geologic information

Identification information

Deposit ID 10013504
MRDS ID D009847
Record type District
Current site name Idledale District

Geographic coordinates

Geographic coordinates: -105.24836, 39.66527 (WGS84)
Elevation 2048
Relative position MILES N W FROM MORRISON

Site location context

Political divisions (FIPS codes)

Jefferson(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Morrison(quadrangle 1:24,000 scale)

Denver West(quadrangle 1:100,000 scale)

Denver(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper South Platte(hydrologic unit)

South Platte(hydrologic accounting unit)

South Platte(hydrologic subregion)

Missouri(hydrologic region)

Geographic areas

Country State County
United States Colorado Jefferson

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 004S 070W 29,32 Colorado

Comments on the location information

  • ALONG BEAR CREEK AND SAWMILL GULCH AT IDLEDALE, LAT-LONG GIVEN IS FOR WRIGHT LEASE (FOOTHILLS MINE), DISTRICT'S LARGEST MINE ; INFO FROM LAND.ST :(1976)

Commodities

Commodity Importance
Uranium Primary
Copper Tertiary
Lead Tertiary
Zinc Critical Tertiary

Materials information

Materials Type of material
Chalcopyrite Ore
Coffinite Ore
Galena Ore
Pitchblende Ore
Pyrite Ore
Sphalerite Ore
Ankerite Gangue
Calcite Gangue
Chlorite Gangue
Fluorite Gangue
Quartz Gangue

Alteration

  • (Local) Fe Oxidation

Analytical data

Result WEIGHTED AVERAGE ORE GRADES RANGED FROM 0.22 TO 0.44% U308, WITH OVERALL AVERAGE 0.25 TO 0.28% U308

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Gneiss
    Rock unit name Idaho Springs Formation
    Rock description Idaho Springs Formation
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic

Nearby scientific data

(1) -105.24836, 39.66527

Economic information

Geologic structures

Type of structure Regional
Structure description Front Range Uplift, Denver Basin
Type of structure Local
Structure description Bear Creek Shear Zone, Junction Ranch Fault, Cherry Gulch Fault

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1955
Year of first production 1955
Year of last production 1968

Mining district

District name Idledale District

Land status

Ownership category Private

Production statistics

  • Year 1955
    Accuracy Accurate
    Description Ap_Grade: ^0.30% U308
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Ore Uranium Uranium 0wt-pct
  • Year 1956
    Accuracy Accurate
    Description Ap_Grade: ^0.30% U308
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Uranium Uranium 0wt-pct
  • Year 1958
    Accuracy Accurate
    Description Ap_Grade: ^0.22% U308
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Ore Uranium Uranium 0wt-pct
  • Year 1960
    Period 1955-1960
    Accuracy Accurate
    Description Cp_Grade: ^0.28% U308
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major U3O8 Ore Uranium Uranium 0wt-pct

Comments on the production information

  • PARTIAL PRODUCTION RECORD. ANNUAL FIGURES FOR 1961-68 NOT AVAILABLE. CUMULATIVES FOR 1955-68 FROM NELSON-MOORE AND OTHERS (1978). ORE GRADES ARE WEIGHTED AVERAGES OF OREGRADES FOR GRAPEVINE MINE AND WRIGHT LEASE.S

Workings at the site

  • Type of workings Unknown
    Length 709.57M
    Overall depth 117.65M

Comments on the workings information

  • ONE INCLINED SHAFT (55-FT), TWO VERTICAL SHAFTS (92-FT AND 186-FT), 1275 FT OF DRIFTS, 720 FT OF CROSSCUTS, SURFACE PROSPECT PITS

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit COUNTRY ROCK CONSISTS OF VARIOUS GNEISSES, MIGMATITES, AND LENSES OF AMPHIBOLITE AND OTHER ROCKS, WITH FOLIATION TRENDING NW, DIPPING STEEPLY SW. NNW-TRENDING JUNCTION RANCH FAULT INTERSECTS WNW-TRENDING BEAR CREEK SHEAR ZONE AT IDLEDALE. MINERALIZED VEINS IN EACH MAJOR STRUCTURE ARE COMPOUND, BRANCHING, OR ANASTAMOSING FRACTURES SUBPARALLEL TO TREND OF HOST STRUCTURE. SHARPLY DEFINED FISSURE WALLS ENCLOSE QUARTZ-CEMENTED BRECCIA IN CARBONATE MATRIX. PITCHBLENDE COATS FRACTURES, PYRITE GF AMPHIBOLITE AND OTHER ROCKS, WITH FOLIATION TRENDING NW, DIPPING STEEPLY SW, NEW-TRENDING JUNCTION RANCH FAULT INTERSECTS WNW-TRENDING BEAR CREEK SHEAR ZONE AT IDLEDALE, MINERALIZED VEINS IN EACH MAJOR STRUCTURE ARE COMPOUND, BRANCHING, OR ANASTAMOSING FRACTURES SUBPARALLEL TO TREND OF HOST STRUCTURE. SHARPLY DEFINED FISSURE WALLS ENCLOSE QUARTZ-CEMENTED BRECCIA IN CARBONATE MATRIX. PITCHBLENDE COATS FRACTURES, PYRITE GRAINS, AND ALTERED BRECCIA FRAGMENTS. EARLY PERIOD OF BRECCIATION CONSISTS OF
Deposit VARIOUSLY SIZED ANGULAR FRAGMENTS OF COUNTRY ROCK IN VUGGY, FINE-GRAINED QUARTZ MATRIX. SECOND BRECCIATION PRODUCED SMALL FRAGMENTS OF RELATIVELY UNIFORM SIZE. TWO-STAGE MINERALIZATION DETERMINED AT WRI
Deposit INDIVIDUAL RECORDS PREPARED FOR FOLLOWING MINES AND PROPERTIES: GRAPEVINE MINE, QUATMAN LEASE, WRIGHT LEASE (FOOTHILLS MINE). ; INFO.SRC : 1 PUB LIT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JAN-83 Schwochow, Stephen D. Colorado Geological Survey
Editor 16-NOV-11 Wilson, Anna B U.S. Geological Survey Changed record type from site to district.

Beyond USGS

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

Authoritative Colorado resources

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