The French Tunnel is a gold and silver mine located in Rio Grande county, Colorado at an elevation of 11,683 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
Elevation: 11,683 Feet (3,561 Meters)
Commodity: Gold, Silver
Lat, Long: 37.42694, -106.60111
Map: View on Google Maps
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French Tunnel MRDS details
Site Name
Primary: French 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: 1872
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: Qaurtz-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
Analytical Data: ASSAYS TABULATED BY CARPER (1914) RANGED FROM 0.32 TO 2.35 OZ/TON AU AND 1.2 TO 3.75 OZ/TON AG (AT $20.65/OZ AU AND $0.60/OZ AG)
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, IRREGULARY 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 CONTINUTY UNKNOWN. FRENCH LEVEL ALSO DEVELOPS DEXTER (ODIN)VEIN ZONE AND BRANCHES (PITTSBURG-QUEEN AND QUEEN VEINS), ANNIE BELLE AND OTHER SW-PROJECTING VEINS, AND NW END OF COPPER HILL-ESMOND VEIN ZONE.
Comment (Workings): TUNNEL DRIVEN S 25 E INTO NW END OF LITTLE ANNIE VEIN ZONE FOR TOTAL HORIZONTAL DISTANCE OF 1100 FT. BRANCH TUNNELS DRIVEN (1) WEST AND SW TO DEVELOP ANNIE BELLE AND OTHER SW-PROJECTING VEINS (600 FT OF WORKINGS); (2) EAST TO DEVELOP DEXTER (ODIN) VEIN ABOVE DEXTER TUNNEL (700 FT OF WORKINGS); (3) NORTH FROM DEXTER (ODIN) VEIN INTO PITTSBURG-QUEEN VEINS (200 FT OF WORKINGS); (4) SOUTH FROM DEXTER (ODIN) VEIN TO DEVELOP QUEEN VEIN ZONE (560 FT OF WORKINGS); (5) SW INTO NW END OF COPPER HILL-ESMOND VEIN ZONE BENEATH WICHESTER AND DEL NORTE LEVELS (520 FT OF WORKINGS). IDA SHAFT FROM SURFACE DRIVEN THROUGH FRENCH LEVEL ABOUT 360 FT SE OF PORTAL. NEW FRENCH PORTAL LOCATED 100 FT SE OF FRENCH PORTAL AND DRIVEN PARALLEL TO FRENCH TUNNEL.
Comment (Location): ON NORTH SLOPE OF SOUTH MOUNTAIN 650 FT SOUTH OF CHANDLER PORTAL. PORTAL ELEV FROM STEVEN AND RATTE (1960, PL. 4) ; INFO FROM LAND.ST :1975
References
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): CARPER, A.F., 1914, GEOLOGY AND ORE DEPOSITS OF SOUTH MOUNTAIN, RIO GRANDE COUNTY, COLORADO: COLORADO SCHOOL OF MINES THESIS T-464.
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 THESUMMITVILLE DISTRICT. SAN JUAN MOUNTAINS. COLORADO: USGS PROF. PAPER 343
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