French Tunnel

Past Producer in Rio Grande county in Colorado, United States with commodities Gold, Silver, Copper

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Public Land Survey System information
Commodities
Alteration
Mineral occurrence model information
Host and associated rocks
Nearby scientific data
Geologic structures
Controls for ore emplacement
Economic information about the deposit and operations
Mining district
Land status
Workings at the site
Links to other databases
Bibliographic references
General comments
Reporter information

Geologic information

Identification information

Deposit ID	10014035
MRDS ID	D010649
Record type	Site
Current site name	French Tunnel

Geographic coordinates

Geographic coordinates:	-106.60171, 37.42696 (WGS84)
Elevation	3561
Relative position	0.5 MILES S 66 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	SW OF NW	Colorado

Comments on the location information

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

Commodities

Commodity	Importance
Gold	Primary
Silver	Primary
Copper	Secondary

Alteration

(Local) Qaurtz-Alunite Solfataric Alteration

Analytical data

Result	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)

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	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)	-106.60171, 37.42696	ListMap

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 Replacement 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	1872
Year of first production	1880

Mining district

District name	Summit (Summitville) District

Land status

Ownership category	Private

Workings at the site

Type of workings Underground

Length 1584.96M

Type of workings	Underground
Length	1584.96M

Comments on the workings information

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.

Reference information

Links to other databases

Agency	Database name	Acronym	Record ID	Notes
USGS	Mineral Resources Data System	MRDS	D010649
U.S. Bureau of Mines	Minerals Availability System	MAS	0081050011

Bibliographic references

Deposit

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

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

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

CARPER, A.F., 1914, GEOLOGY AND ORE DEPOSITS OF SOUTH MOUNTAIN, RIO GRANDE COUNTY, COLORADO: COLORADO SCHOOL OF MINES THESIS T-464.

General comments

Subject category	Comment text
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.

Subject category

Comment text

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.

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.

External references

Wikidata: Q49412929 (French Tunnel)

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.