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Bigger Mica Mine

Past Producer in Jefferson county in Colorado, United States with commodities Feldspar, Mica, Beryllium, Bismuth, Niobium (Columbium), REE, Uranium, Tin, Tantalum
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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. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Ore body information
  12. Economic information about the deposit and operations
  13. Mining district
  14. Land status
  15. Workings at the site
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10013744
MRDS ID D010204
Record type Site
Current site name Bigger Mica Mine
Alternate or previous names Sweitzer Lode
Related records 10215154

Geographic coordinates

Geographic coordinates: -105.21502, 39.56471 (WGS84)
Elevation 2225
Relative position 6.2 MILES S 10 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

Indian Hills(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 006S 070W 03 NE OF NW Colorado

Comments on the location information

  • WEST OF SWITZERS GULCH 0.6 MILES SE OF FENDERS ; INFO FROM LAND.ST :(1975)

Commodities

Commodity Importance
Feldspar Primary
Mica Primary
Beryllium Critical Primary
Bismuth Critical Tertiary
Niobium (Columbium) Critical Tertiary
REE Critical Tertiary
Uranium Tertiary
Tin Critical Tertiary
Tantalum Critical Tertiary

Materials information

Materials Type of material
Beryl Ore
Bismuthinite Ore
Bismutite Ore
Cassiterite Ore
Columbite Ore
Microcline Ore
Monazite Ore
Muscovite Ore
Albite Gangue
Quartz Gangue
Tourmaline Gangue
Uraninite Unknown

Analytical data

Result HAND-COBBED BERYL CONTAINED 12.1% BEO

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Rock unit name Gneissis Quartz Monzonite And Granodiorite;Coarse-Grained Pegmatite
    Rock description Gneissis Quartz Monzonite And Granodiorite;Coarse-Grained Pegmatite
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Associated
    Rock type Plutonic Rock > Pegmatite
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Rock unit name Gneissic Quartz Monzonite And Granodiorite;Biotite Gneiss
    Rock description Gneissic Quartz Monzonite And Granodiorite;Biotite Gneiss

Nearby scientific data

(1) -105.21502, 39.56471
ListMap

Economic information

Geologic structures

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

Ore body information

  • General form TABULAR

Economic information about the deposit and operations

Development status Past Producer
Commodity type Both
Deposit size Small
Significant No
Discovery year 1884
Discoverer Mr. Switzer
Year of first production 1884
Year of last production 1935

Mining district

District name Clear Creek Pegmatite Province

Land status

Ownership category Private

Workings at the site

  • Type of workings Surface/Underground
    Overall depth 24.38M
    Overall length 65.53M

Comments on the workings information

  • IRREGULAR OPEN CUT, 50-FT ADIT CONNECTING AT DEPTH WITH 80-FT SHAFT

Comments on development

  • SUPPOSEDLY PROSPECTED AND FIRST OPENED FOR SN. MINED FOR MICA IN 1888-1890, THEN FOR FELDSPAR IN 1937. PRODUCTION TO 1937 HAS BEEN AT LEAST 3000 TONS FELDSPAR, 1000 TONS SCRAP MICA, 18.9 TONS BERYL.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit ZONED PEGMATITE TRENDS GENERALLY N 40 W, 75 SW, AND IS CUT BY TWO FAULTS: NORTH FAULT TRENDS N46 E, 30 NW; EAST FAULT TRENDS N85 E, 60 NW, WALL ZONE IS 6 TO 11 FT THICK AND CONTAINS MEDIUM-GRAINED QUARTZ-MICROCLINE-BIOTITE-ALBITE PEGMATITE. AVE. 2-FT-THICK INTERMEDIATE ZONE CONTAINS QUARTZ-ALBITE-MUSCOVITE PEGMATITE. CORE CONTAINS MICROCLINE-QUARTZ PEGMATITE IN VERY COARSE CRYSTALS. INTERMEDIATE ZONE CONTAINS BERYL, BI MINERALS, TOURMALINE, CB, MONAZITE; U REPORTED BUT NOT FOUND BY HANLEY AND OTHERS.
Deposit DUPLICATE D001820 DELETED ; INFO.SRC : 1 PUB LIT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-FEB-1983 Schwochow, Stephen D. Colorado 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.