Montroy Tunnel

The Montroy Tunnel is a gold and silver mine located in Rio Grande county, Colorado at an elevation of 11,765 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: Montroy Tunnel

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: Underground

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1880
Discovery Year: 1879
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

Not available

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: Associated Rock
Age Young: Miocene

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

Analytical Data

Not available

Materials

Not available

Comments

Comment (Deposit): MINE DEVELOPED PRINCIPALLY ON LITTLE ANNIE VEIN ZONE, MOST EXTENSIVELY DEVELOPED VEIN AND RICHEST AU PRODUCER IN DISTRICT. DEPOSIT IS NW-SE-TRENDING, NEARLY VERTICAL, IRREGULARLY TABULAR MASS OF LIMONITE-STAINED, HIGHLY SILICIFIED ROCK, ALMOST ENTIRELY VUGGY QUARTZ WITH LOCAL SELVAGES OR INCLUSIONS OF QUARTZ-ALUNITE ROCK. ZONE APPARENTLY ENDS ON SE NEAR WINCHESTER PORTAL. NE-TRENDING CROSS-FRACTURES REFLECTED BY PROJECTIONS OF SILICIFIED ROCK AND ELONGATED PIPES, SUCH AS ANNIE BELLE VEIN EXTENDING SW FROM ANNIE OPEN CUT. HIGHLY OXIDIZED ORE (AURIFEROUS LIMONITE) STOPED ABOVE IDA LEVEL, SOME MINED BETWEEN IDA AND CHANDLER LEVELS. UNOXIDIZED AU-CU SULFIDE ORE ON CHANDLER LEVEL AND AS DEEP AS REYNOLDS LEVEL BUT CONTINUITY UNKNOWN. MONTROY WORKINGS ALSO EXTEND SW INTO ONE OR TWO SW-PROJECTING VEINS.

Comment (Workings): TUNNEL DRIVEN S 18 W FOR 170 FT INTO LITTLE ANNIE VEIN ZONE. AT LEAST 200 FT OF DRIFT ON VEIN. STOPES ABOVE MONTROY LEVEL AND BETWEEN MONTROY AND FRENCH LEVELS. CRAWFORD RAISE CONNECTS MONTROY AND FRENCH LEVEL. IDA SHAFT FROM SURFACE DRIVEN THROUGH MONTROY LEVEL JUST NORTH OF IDA CUT AND APPROX 150 SOUTH OF MONTROY PORTAL. 640 FT OF WORKINGS ON ONE OR TWO SW-PROJECTING VEINS.

Comment (Location): ON NORTH SLOPE OF SOUTH MTN 850 FT SSE OF CHANDLER PORTAL. PORTAL ELEV FROM STEVEN AND RATTE (1960, PL. 4). ; INFO FROM LAND.ST :1975

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.

Colorado Mining Photos

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