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Rosita Hills District

Past Producer in Custer county in Colorado, United States with commodities Gold, Silver, Perlite, Lead, Zinc, Copper, Aluminum, Potassium
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Mineral occurrence model information
  7. Host and associated rocks
  8. Nearby scientific data
  9. Geologic structures
  10. Economic information about the deposit and operations
  11. Mining district
  12. Production statistics
  13. Bibliographic references
  14. Reporter information

Geologic information

Identification information

Deposit ID 10311016
Record type District
Current site name Rosita Hills District
Alternate or previous names Rosita, Querida District

Geographic coordinates

Geographic coordinates: -105.34779, 38.11862 (WGS84)

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

Comments on the location information

  • West side of the Wet Mountains, about 6 miles ESE of Westcliffe; includes about 10 square miles of the Rosita volcanic center, mostly in the SW/4 of T 22 S, R 71 W.

Commodities

Commodity Importance
Gold Primary
Silver Primary
Perlite Primary
Lead Secondary
Zinc Critical Secondary
Copper Secondary
Aluminum Critical Tertiary
Potassium Tertiary

Comments on the commodity information

  • Principally a gold and silver district, plus perlite, and some base metal production. Alunite deposits at Democrat Hill and Mt. Robinson are possible sources of alumina and/or potassium.

Mineral occurrence model information

Model code 105
USGS model code 25a-d
Deposit model name Epithermal vein, generic
Mark3 model number 119

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Stratigraphic age (youngest) Miocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
    Stratigraphic age (youngest) Oligocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Latite
    Stratigraphic age (youngest) Miocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Trachyte
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyodacite
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Trachyandesite
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Volcanic Breccia (Agglomerate)

Nearby scientific data

(1) -105.34779, 38.11862
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Rosita Hills volcanic complex; ring faults; breccia pipes

Comments on the geologic information

  • The Rosita volcanic center consists of andesitic and rhyolitic intrusive and extrusive rocks that represent the remains of a large volcano. Base- and precious-metal ore is hosted in sulfide fissure veins and breccia pipes.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Both

Mining district

District name Rosita Hills District

Production statistics

  • Year 1958
    Period 1872-1958
    Material Approx. ore mined.
    Ore mined 500000mt
    Accuracy Estimate

Comments on the production information

  • Estimated production is for both Rosita Hills and nearby Silver Cliff districts.
  • The Rosita District is credited with about 85,000 oz. of gold, mostly from the Bassick mine.

Comments on the reserve resource information

  • A 1981 report suggested that high-grade vein, or low-grade, bulk-tonnage silver deposits may occur at 13 target areas in the district. (Sunshine files)
  • Estimated 800,000 tons alunite resource @ 16.6% alunite at Democrat Hill and 1,200,000 tons @ 6.5% alunite at Mount Robinson. (Thoenen, 1941)

Comments on development

  • The first discovery, in 1872, was the Senator (now Maverick) mine at Rosita. In 1874, rich silver ore was discovered at the Humboldt-Pocahontas vein nearby, and in 1877, rich gold ore was discovered at the Bassick mine. Many other small deposits were found, and several ore reduction plants were built, but the rich ore soon was mined out and by 1885 activity declined.

Reference information

Bibliographic references

Reporter information

Type Date Name Affiliation Comment
Reporter 24-FEB-2005 Keller, John W. Colorado Geological Survey
Updater 04-APR-2006 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.