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Jamestown District

Past Producer in Boulder county in Colorado, United States with commodities Gold, Fluorine-Fluorite, Silver, Lead, Copper, Uranium, Tellurium, Molybdenum, Tungsten
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  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. Production statistics
  15. Links to other databases
  16. Bibliographic references
  17. Reporter information

Geologic information

Identification information

Deposit ID 10008720
MRDS ID D001069
MAS/MILS ID 80137015
Record type District
Current site name Jamestown District
Alternate or previous names Central, Jimtown
Related records 60000013

Geographic coordinates

Geographic coordinates: -105.3875, 40.12722 (WGS84)
Location accuracy 1000(meters)

Site location context

Political divisions (FIPS codes)

Boulder(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Raymond(quadrangle 1:24,000 scale)

Estes Park(quadrangle 1:100,000 scale)

Greeley(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

St. Vrain(hydrologic unit)

South Platte(hydrologic accounting unit)

South Platte(hydrologic subregion)

Missouri(hydrologic region)

Federal lands

Arapaho and Roosevelt National Forests(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Colorado Boulder

Comments on the location information

  • District is centered on the granite-quartz monzonite porphyry stock of Porphyry Mountain one-half mile north of Jamestown and includes deposits within a radius of about 3 miles. It lies mostly in T 2 N R 71-72 W and occupies about 36 square miles.

Commodities

Commodity Importance
Gold Primary
Fluorine-Fluorite Critical Primary
Silver Secondary
Lead Secondary
Copper Secondary
Uranium Secondary
Tellurium Critical Tertiary
Molybdenum Tertiary
Tungsten Critical Tertiary

Comments on the commodity information

  • Gold-silver telluride minerals present.
  • Gold, and later, fluorspar are the main economic products; silver and lead are of secondary importance. Tellurium might be recovered from the gold-silver telluride ores. Molybdenum has been detected by drilling deep under Porphyry Mountain.

Materials information

Materials Type of material
Gold Ore
Fluorite Ore
Telluride Ore
Pyrite Ore
Galena Ore
Tetrahedrite Ore
Quartz Gangue

Alteration

  • (Local) sericitic and silicified wall rocks

Mineral occurrence model information

Model code 84
USGS model code 22b
Deposit model name Alkaline Au-Te (Au-Ag-Te veins)
Mark3 model number 80

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Schist > Mica Schist
    Rock unit name Idaho Springs Formation
    Stratigraphic age (youngest) Precambrian
  • Host or associated Host
    Rock type Metamorphic Rock > Gneiss > Mafic Gneiss
    Rock unit name Swandyke hornblends gneiss
    Stratigraphic age (youngest) Precambrian
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite
    Rock unit name Boulder Creek , Overland Mountain, and Silver Plume granites
    Stratigraphic age (youngest) Precambrian
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granodiorite
    Stratigraphic age (youngest) Paleogene
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Alkali-Granite (Alaskite)
    Rock unit name sodic granite-quartz monzonite porphyry of Porphyry Mtn
    Stratigraphic age (youngest) Paleogene

Nearby scientific data

(1) -105.3875, 40.12722
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description through-going NW-trending faults

Comments on the geologic information

  • The Jamestown district is underlain by igneous and metamorphic rocks of Precambrian age and intrusive rocks of Tertiary (Laramide) age. Major northwest-trending faults (breccia reefs) localize ore deposits that are more locally controlled by vein junctions, irregularity of the veins, and physical (chemical) character of wall rocks. Four ore deposit types are lead-silver deposits, fluorspar veins and breccia zones, pyritic gold veins, and gold-silver telluride veins.

Economic information about the deposit and operations

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

Mining district

District name Jamestown District

Production statistics

  • Year 1944
    Period 1903 through 1944
    Material fluorspar (acid spar)
    Ore mined 33291.54mt
    Accuracy Accurate
  • Year 1944
    Period 1903 through 1944
    Material fluorspar (metallurgical)
    Ore mined 64797.75mt
    Accuracy Accurate

Comments on the production information

  • Total value of production since 1865 (to 1943?) estimated at $7,000,000, mostly in gold but including fluorspar valued at about $1,300,000. District output 1901 to 1943, inclusive, totals 57,614.8 oz gold, 200,925 oz silver, 963,951 lb lead, 144,611 lb copper valued at about $1,880,000. Fluorspar production continued until 1973, and its cumulative value now exceeds $25,000,000. Total production of gold estimated slightly over 200,000 oz. and of fluorspar 1 to 1.5 million tons.

Comments on the reserve resource information

  • Sunshine Mining Co. evaluated the Jamestown project, including mainly the Bueno mine, in 1992, and concluded that no more work be done. Extensive files include various reports, assays and maps dated from 1930 to 1992 that may have dated or optimistic resource estimates.

Reference information

Bibliographic references

  • Deposit

    LEMMON, D.M. AND TWETO, O.L., 1962, TUNGSTEN IN THE U.S., USGS MAP, MR-25

  • Geology

    Lovering, T. S., and Goddard, E. N., 1950, Geology and Ore Deposits of the Front Range, Colorado: U.S. Geological Survey Professional Paper 223, 319 p.

  • Deposit

    Goddard, E. N., 1946, Fluorspar Deposits of the Jamestown District, Boulder County, Colorado: Colorado Scientific Society Proceedings, v. 15, no.1, 47 p.

  • Production

    Brady, B. T., 1975, Map showing fluorspar deposits in Colorado: U.S. Geological Survey Mineral Investigations Resources Map MR-70.

  • Reserve-Resource

    Sunshine Mining Co. Colorado exploration files, file ID 14, Boulder County, Jamestown project, unpublished data, available at Colorado Geological Survey.

  • Deposit

    Vanderwilt, J.W., 1947, Mineral resources of Colorado: State of Colorado Mineral Resources Board, 547 p.

  • Production

    Koschmann, A. H., and Bergendahl, M. H., 1968, Principal gold-producing districts of the United States: U.S. Geological Survey Professional Paper 610, 283 p.

  • Commodity

    Nelson-Moore, J.L., Collins, D.B., and Hornbaker, A.L., 1978, Radioactive mineral occurrences of Colorado: Colorado Geological Survey Bulletin 40, 1054 p., 12 pl.

  • Names

    Dunn, L.G, 2003, Colorado mining districts: A reference: Golden, Colo., Colorado School of Mines Library, 364 p.

Reporter information

Type Date Name Affiliation Comment
Reporter 2005-12-07 Beach, Richard A. Colorado Geological Survey

Beyond USGS

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

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.