Dexter Tunnel

The Dexter Tunnel is a gold and silver mine located in Rio Grande county, Colorado at an elevation of 11,608 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Dexter Tunnel
Secondary: Claim: Dexter
Secondary: Ms 77

Commodity

Primary: Gold
Primary: Silver
Secondary: Copper

Location

State: Colorado
County: Rio Grande
District: Summit (Summitville) District

Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

Holdings

Not available

Workings

Type: Surface/Underground

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Discovery Year: 1873
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Model Name: Polymetallic veins

Orebody

Not available

Structure

Type: R
Description: San Juan Volcanic Field

Type: L
Description: Platoro Caldera, Summitville Caldera, Summitville Fault, South Mountain Dome

Alterations

Alteration Type: L
Alteration Text: Quartz-Alunite Solfataric Alteration

Rocks

Name: Quartz Latite
Role: Associated
Age Type: Host Rock
Age Young: Miocene

Name: Quartz Latite
Role: Associated
Age Type: Associated Rock
Age Young: Miocene

Analytical Data

Not available

Materials

Not available

Comments

Comment (Location): 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

Comment (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.

Comment (Workings): 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.

References

Reference (Deposit): PATTON, H.B., 1917, GEOLOGY AND ORE DEPOSITS OF THE PLATORO-SUMMITVILLE MINING DISTRICT, COLORADO: CGS BULL. 13.

Reference (Deposit): STEVEN, T.A., AND RATTE, J.C., 1960, GEOLOGY AND ORE DEPOSITS OF THE SUMMITVILLE DISTRICT, SAN JUAN MOUNTAINS, COLORADO: USGS PROF. PAPER 343

Reference (Deposit): LIPMAN, P.W., 1974, GEOLOGIC MAP OF THE PLATORO CALDERA AREA, SOUTHEASTERN SAN JUAN MOUNTAINS, SOUTHWESTERN COLORADO: USGS MAP I-828.

Reference (Deposit): BLM MINERAL SURVEY MS 77

Colorado Mining Photos

Check out this collection of Colorado's best historic mining photos: Incredible Photos of Colorado Mining Scenes.