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Crooks Gap - Green Mountain Uranium District

Past Producer in Fremont county in Wyoming, United States with commodity Uranium
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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. Geologic structures
  12. Economic information about the deposit and operations
  13. Mining district
  14. Ownership information
  15. Production statistics
  16. Bibliographic references
  17. General comments
  18. Reporter information

Geologic information

Identification information

Deposit ID 10400480
Record type District
Current site name Crooks Gap - Green Mountain Uranium District
Alternate or previous names Crooks Gap - Green Mountain uranium area

Geographic coordinates

Point of reference Approximate
Geographic coordinates: -107.8292, 42.39 (WGS84)
Location accuracy 10000(meters)
Relative position District should be depicted as a polygon, not a point. These coordinates are near the western edge of the approx. 160 sq. mi. "district", at the major mines near Crooks Gap.

Site location context

Political divisions (FIPS codes)

Fremont(county)

Wyoming(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Jeffrey City(quadrangle 1:24,000 scale)

Bairoil(quadrangle 1:100,000 scale)

Casper(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Sweetwater(hydrologic unit)

North Platte(hydrologic accounting unit)

North Platte(hydrologic subregion)

Missouri(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management WY)

Bureau of Land Management WY BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States Wyoming Fremont

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 028N 092W 16, 20, 21, 22, 28, 29, 32 Wyoming

Comments on the location information

  • Fred's Folly Claim is shown on p. 67 of 115, DMEA-3462 in extreme NE4 of Sec. 21. This would be where the Reserve Mine is.

Commodities

Commodity Importance
Uranium Primary

Materials information

Materials Type of material
Uraninite Ore
Coffinite Ore
Uranophane Ore
Autunite Ore
Pyrite Gangue
Calcite Gangue
Selenium Gangue

Analytical data

Result Grade of ore mined is reported to be in the range: 0.18 to 0.23% U3O8.

Mineral occurrence model information

Model code 204
USGS model code 30c
Deposit model name Sandstone U

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
    Rock type qualifier coarse-grained friable arkose sandstoens, conglomeratic sandstones, and interbedded layers of carbonaceous sandstones.
    Rock unit name Battle Springs Formation
    Stratigraphic age (youngest) Eocene
    Stratigraphic age (oldest) Eocene

Nearby scientific data

Approximate (1) -107.8292, 42.39
ListMap

Economic information

Geologic structures

Type of structure Local
Structure name synclinal troughs

Economic information about the deposit and operations

Operation type Surface-Underground
Development status Past Producer
Commodity type E
Significant Yes

Mining district

District name Crooks Gap - Green Mountain uranium area

Ownership information

  • Type Unknown
    Owner Gaddis Mining Co.
    Year 1955

Comments on the ownership information

  • Trey and Cindy claims were held by Mile High Minerals, Denver, CO, as of 1956. See DMEA Docket No. 3992. Last few pages of Docket contains useful and accurate location maps, especially relative to the Sun, Sundog, and Snowball Claims.

Production statistics

  • Year 2010
    Material 4,838,938 short tons ore from 7 mines.
    Ore mined 4389811mt

Comments on the production information

  • According to the values reported on MS-94 (Gregory and others, 2010), the 7 productive mines in the district produced a total of 4,838,438 short tons of ore (not uranium). There is no mention of the ore grade, therefore total contained uranium can not be estimated. The productive mines are Hazel and Beatrice (23 tons), Crooks Gap Mines (3,300,000 tons), Green Mountain (523,438 tons), Sundog (139 tons), Snowball and Pay Dirt (267,446 tons), Heald (6,641 tons), and Big Eagle (741,251 tons).
  • Production includes 3,300,000 short tons (2,993,100 tonnes) from the "Crooks Gap Mine" (Gregory and others, 2010). Uncertain what the "Crooks Gap Mine" corresponds to.
  • Production includes 523,438 short tons (474,758 tonnes) from "Green Mountain" (Gregory and others, 2010). Uncertain what "Green Mountain" corresponds to.

Reference information

Bibliographic references

  • Deposit

    MINOBRAS, 1976, Uranium Guidebook for Wyoming, 63 p. and appendix.

  • Location

    Geological Survey of Wyoming, 1970, Mines and Minerals Map of Wyoming: Geological Survey of Wyoming, scale 1:500,000.

  • Deposit

    Stephens, J.G., 1964, Geology and uranium depoists at Crooks Gap, Fremont County, Wyoming: U.S. Geological Survey Bulletin 1147-F, 82 p, plate 1, scale 1:48,000.

  • Deposit

    Love, J.D., 1954, Wyoming, in Geological investigations of radioactive deposits, semiannual progress report, December 1, 1953 to may 31, 1954: U.S. Atomic Energy Commission TEI-440, 245 p.

  • Production

    MINING MAGAZINE, 1989, p. 45.

  • Deposit

    DMEA Docket No. 3462, 115 p., http://minerals.usgs.gov/dockets/scans/wy/dmea/3462_DMEA.pdf

  • Deposit

    Gregory, R.W., Jones, R.W., and Cottingham, K.D., 2010, Uranium Map of Wyoming: Wyoming State Geological Survey Map Series 94, scale 1:500,000.

  • Deposit

    Dahlkamp, F.J., Uranium deposits of the world—USA and Latin America, Wyoming Basins: SpringerLink, p. 149-207, available for download at http://www.springerlink.com/content/x74946/?MUD=MP. [Note that the bibliography, p. 381-414 is not available online, and since this is an online only publication, it is therefore not available at all].

  • Deposit

    DMEA Docket No. 3688, http://minerals.usgs.gov/dockets/scans/wy/dmea/3688_DMEA.pdf

General comments

Subject category Comment text
General From TEI-440, p. 180: " Yellow uranium minerals occur in sec. 32, T28N, R92W, in arkosic conglomeratic sandstone in the lower Eocene rocks on the east side of Crooks Gap. The locality has been examined by geologists of the AEC. Minerals were observed in places thorugh a section of about 75 feet of rocks, but are concentrated adjacent to carbonaceous shale partings, carbonized wood fragments, and in highly ferruginous zones. The mineral was indentified as phosphuranylite [formula omitted here], and a selected sample contains 0.17 dU. The uranium-bearing zone is about 200 feet above the base of a sequence of brown and gray coarse clastic rocks, chiefly arkosic sandstones containing lenses of giant granite boulders, variegated claystones, and carbonacous shale, the total thickness of which is more than 1,000 feet. A sample of water from a spring, likewise in sec. 32, T25N, R92W, contained 250 ppb of U. The uranium appears to have been deposited in many places where there are concentrations of carbonized wood fragments, carbonaceous shale partings, or very ferruginous sandstones."
General Mill or processing facility is north of Jeffrey City.

Reporter information

Type Date Name Affiliation Comment
Reporter 2010-12-10 Wilson, Anna B. U.S. Geological Survey Added mentions from DMEA Docket 3992 on 17-jan-2012.

Beyond USGS

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

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