Dexter Tunnel

Past Producer in Rio Grande county in Colorado, United States with commodities Gold, Silver, Copper
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. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Workings at the site
  17. Links to other databases
  18. Bibliographic references
  19. General comments
  20. Reporter information

Geologic information

Identification information

Deposit ID 10014033
MRDS ID D010647
Record type Site
Current site name Dexter Tunnel
Alternate or previous names Claim: Dexter, Ms 77

Geographic coordinates

Geographic coordinates: -106.59699, 37.42585 (WGS84)
Elevation 3538
Relative position 0.35 MILES S 37 W FROM SUMMITVILLE

Site location context

Political divisions (FIPS codes)

Rio Grande(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Summitville(quadrangle 1:24,000 scale)

Antonito(quadrangle 1:100,000 scale)

Durango(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alamosa-Trinchera(hydrologic unit)

Rio Grande Headwaters(hydrologic accounting unit)

Rio Grande Headwaters(hydrologic subregion)

Rio Grande(hydrologic region)

Federal lands

Rio Grande National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Colorado Rio Grande

Public Land Survey System information

Meridian Township Range Section Fraction State
New Mexico 037N 004E 30 SE OF NW Colorado

Comments on the location information

  • ON NE SLOPE OF SOUTH MTN 1600 FT SE OF CHANDLER PORTAL. PORTAL ELEV FROM STEVEN AND RATTE (1960, PL. 4). ; INFO FROM LAND.ST :1975

Commodities

Commodity Importance
Gold Primary
Silver Primary
Copper Secondary

Alteration

  • (Local) Quartz-Alunite Solfataric Alteration

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
    Rock unit name Quartz Latite Of South Mountain;Summitville Andesite
    Rock description Quartz Latite Of South Mountain;Summitville Andesite
    Stratigraphic age (youngest) Miocene
    Stratigraphic age (youngest) Miocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
    Rock unit name Quartz Latite Of South Mountain;Summitville Andesite
    Rock description Quartz Latite Of South Mountain;Summitville Andesite

Nearby scientific data

(1) -106.59699, 37.42585

Economic information

Geologic structures

Type of structure Regional
Structure description San Juan Volcanic Field
Type of structure Local
Structure description Platoro Caldera, Summitville Caldera, Summitville Fault, South Mountain Dome

Controls for ore emplacement

  • Quartz-Alunite Solfataric Bodies Following Nw-Trending Fractures Near Sw Margin Of South Mountain Feeder Conduit

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1873
Discoverer Josiah Mann, Arthur Burton, John A. Mcdonald

Mining district

District name Summit (Summitville) District

Land status

Ownership category Private

Workings at the site

  • Type of workings Surface/Underground
    Length 402.34M

Comments on the workings information

  • TUNNEL DRIVEN GENERALLY DUE WEST FOR 1120 FT ALONG DEXTER VEIN TO LITTLE ANNIE VEIN AND APPARENTLY JOINING WITH WORKINGS OF IDA TUNNEL. QUEEN OPEN CUT ON SURFACE ABOVE TUNNEL.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit MINE DEVELOPED ON DEXTER (ODIN) VEIN, ONLY SIGNIFICANT VEIN IS DISTRICT TRENDING EAST-WEST. AT SURFACE, BODIES OF VUGGY QUARTZ ROCK IN QUARTZ-ALUNITE ZONE APPEAR TO BE DISCONTINUOUS, BUT TREND IS WELL DEFINEDIN DEXTER AND FRENCH LEVELS. OTHER VEIN ZONE OF COMPACT QUARTZ AND VUGGY QUARTZ ROCK PROJECTS SOUTH FROM DEXTER VEIN AND IS CALLED QUEEN OR HIGHLAND MARY VEIN. NW PROJECTIONS FROM DEXTER VEIN REFERRED TO AS PITTSBURGH AND QUEEN VEINS.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1983 Schwochow, Stephen D. Colorado Geological Survey

Beyond USGS

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

Authoritative Colorado resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.