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Democrat Hill deposit

Past Producer in Custer county in Colorado, United States with commodities Aluminum, Potassium, Silver, Lead, Zinc, Gold
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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. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Ore body information
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Production statistics
  17. Reserves and resources
  18. Workings at the site
  19. Links to other databases
  20. Bibliographic references
  21. Reporter information

Geologic information

Identification information

Deposit ID 10009280
MRDS ID D002159
Record type Deposit
Current site name Democrat Hill deposit

Geographic coordinates

Point of reference Pit
Geographic coordinates: -105.36139, 38.10472 (WGS84)
Elevation 2774
Relative position at adit entrance; 5 MI. ESE OF SILVER CLIFF

Site location context

Political divisions (FIPS codes)

Custer(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Rosita(quadrangle 1:24,000 scale)

Canon City(quadrangle 1:100,000 scale)

Pueblo(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Arkansas Headwaters(hydrologic unit)

Upper Arkansas(hydrologic accounting unit)

Upper Arkansas(hydrologic subregion)

Arkansas-White-Red(hydrologic region)

Geographic areas

Country State County
United States Colorado Custer

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 022S 071W 30 Colorado

Comments on the location information

  • S CENTRAL PART OF ROSITA HILLS. S END OF DEMOCRAT RIDGE, ABOUT 1-1/2 MILE WNW OF ROSITA, IN THE E/2 SEC 30, T 22 S, R 71 W.

Commodities

Commodity Importance
Aluminum Critical Primary
Potassium Primary
Silver Primary
Lead Secondary
Zinc Critical Secondary
Gold Primary

Comments on the commodity information

  • PROJECT 9350 - 01393 ALUNITE RESOURCES

Materials information

Materials Type of material
Alunite Ore
Diaspore Ore
Kaolinite Ore
Pyrite Ore
Galena Ore
Sphalerite Ore
Quartz Gangue

Alteration

  • (Local) Alunitization, Silicification, Kaolinization. Alteration Of Rhyolite To Alunite By Solfataric Action

Analytical data

Result 2 ANALYSES ARE 16.6 % AND 32.3 % ALUNITe

Mineral occurrence model information

Model code 154
USGS model code 25e
Deposit model name Epithermal quartz-alunite Au
Mark3 model number 38

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Stratigraphic age (youngest) Pliocene
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Rosita Hills Rhyolite
    Rock description Rosita Hills Rhyolite

Nearby scientific data

Pit (1) -105.36139, 38.10472
ListMap

Economic information

Ore body information

  • General form LARGE CHIMNEY (VOLCANIC CONDUIT)
    Thickness 54.86M
    Length 365.76M
    Width 152.4M

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Both
Deposit size Large
Significant No
Discovery year 1890
Discoverer Whitman Cross, USGS

Mining district

District name Rosita Hills District

Land status

Ownership category Private

Production statistics

  • Year 1886
    Period 1886
    Material silver ore
    Ore mined 180mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 1539g/mt
    Major Gold Gold 27g/mt

Reserves and resources

  • Type In-situ
    Name alunite
    Estimate year 1943
    Inferred 720000mt ore
    Commodity Subtype Grade units Group Importance Year
    Aluminum Alunite 15 wt-pct Aluminum Trace 1943

Comments on the reserve resource information

  • Estimated 800,000 tons alunite resource @ 16.6% alunite. (Thoenen, 1941)
  • A 1981 report suggested that low-grade, bulk-tonnage silver deposits may occur in this area. (Sunshine files)
  • GREATER PART OF RESERVE IS INFERRED
  • ALUNITIZED BODY IS LOW-GRADE

Workings at the site

  • Type of workings Surface/Underground
    Name of workings Democat Tunnel
    Length 150M

Comments on the workings information

  • OLD BEN EATON ( 500 FT ) AND DEMOCRAT ( 435 FT ) ADITS DRIVEN INTO S BASE OF DEMOCRAT HILL IN 1870'S FOR SILVER AND OTHER METALS, NOT ALUNITE. ALSO SEVERAL PROSPECT HOLES AND DRIFTS.

Comments on development

  • ECON.COM: DEPOSIT IS LESS THAN 1 MI. FROM A ROAD AND THERE IS LITTLE OVERBURDEN. ALUNITE IS CLOSELY LOCKED WITH QUARTZ

Reference information

Bibliographic references

  • Analytical Data

    THOENEN, J. R., 1941 , ALUNITE RESOURCES OF THE UNITED STATES: USBM REPT. INV. 3561 , P. 13.

  • Deposit

    CROSS, C. W., 1891 , ON ALUNITE AND DIASPORE FROM THE ROSITA HILLS, COLORADO: AM. JOUR. SCI., 3RD SER., V. 41 , NO. 246 , P. 466 - 475 .

  • Deposit

    CROSS, C. W., 1896 , GEOLOGY OF SILVER CLIFF AND THE ROSITA HILLS, COLORADO: USGS 17TH ANN. REPT., PT. 2 , P. 314 - 315 , 377 - 378 .

  • Deposit

    CROSS, C. W., 1912 , ALUNITE DEPOSITS OF ROSITA HILLS, COLORADO, USGS BULL. 511 , P. 38 - 41 .

  • Deposit

    GARDNER, L. S., 1943 , UNPUB. REPT. IN USGS FILE

  • Reserve-Resource

    THOENEN, J. R., 1941 , ALUNITE RESOURCES OF THE UNITED STATES: USBM REPT. INV. 3561 , P. 13 - 14.

  • Deposit

    1878 DIREXPL UNKNOWN: PROSPECTING WORKS

  • Deposit

    1883 GEOLMAP W. CROSS: PUB. REPTS.

  • Deposit

    THOENEN, J. R., 1941 , ALUNITE RESOURCES OF THE UNITED STATES: USBM REPT. INV. 3561 , P. 13 - 14.

  • Deposit

    1942 RECON L. S. GARDNER: UNPUB. REPT.

  • Reserve-Resource

    Sunshine Mining Co. Colorado exploration files, unpublished data, Colorado Geological Survey.

  • Geology

    SHARP, W.N., 1978, GEOLOGIC MAP OF THE SILVER CLIFF AND ROSITA VOLCANIC CENTERS, CUSTER COUNTY, COLORADO: USGS MAP I-1081, 1:24,000.

Reporter information

Type Date Name Affiliation Comment
Reporter 1975-12-01 Hall, Robert B. U.S. Geological Survey
Updater 1978-08-01 Starritt, Bruce C. U.S. Geological Survey
Reporter 1983-11-17 Intermountain Field Operations Center (IFOC) U.S. Bureau of Mines
Updater 2006-04-05 Beach, Richard A. Colorado Geological Survey
Editor 2011-07-26 Wilson, Anna B U.S. Geological Survey changed from site to deposit and fixed some typos.

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.