The Cotopaxi Mine is a zinc and copper mine located in Fremont county, Colorado at an elevation of 6,781 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: 6,781 Feet (2,067 Meters)
Commodity: Zinc, Copper
Lat, Long: 38.38, -105.69778
Map: View on Google Maps
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Cotopaxi Mine MRDS details
Site Name
Primary: Cotopaxi Mine
Secondary: Gumaer Mine
Secondary: Cotopaxi Lode
Secondary: Fannie Lode
Secondary: Fannie Mill
Commodity
Primary: Zinc
Primary: Copper
Secondary: Gold
Secondary: Silver
Secondary: Lead
Tertiary: Tungsten
Tertiary: Molybdenum
Tertiary: Iron
Location
State: Colorado
County: Fremont
District: Cotopaxi 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: Unknown
Ownership
Owner Name: Brown Mineral Research, Inc.
Home Office: Box 491, Canon City, Co
Years: 1975 -
Owner Name: Tombstone Mining Co.
Home Office: Box 491, Canon City, Co
Years: 1975 -
Production
Year: 1950
Time Period: 1915-1950
Mined: 15747.200 mt
Material type: ore
Description: Cp_Grade: ^1.11% Cu, 0.58% Pb, 10.41% Zn, 0.97 Oz/Ton Ag, 0.01 Oz/Ton Au
Deposit
Record Type: Site
Operation Category: Past Producer
Operation Type: Surface-Underground
Year First Production: 1875
Year Last Production: 1967
Discovery Year: 1875
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: Stratabound Precambrian sulfide, Colorado and Wyoming
Orebody
Form: LENSOID
Structure
Type: L
Description: Cotopaxi Fault; Subsidiary North-, Nne-, And Ew-Trending Faults
Type: R
Description: Thirtynine Mile Volcanic Field
Alterations
Alteration Type: L
Alteration Text: gahnite mineralization present (zinc spinel)
Alteration Type: L
Alteration Text: Surficial Oxidation
Rocks
Name: Granodiorite
Role: Associated
Age Type: Associated Rock
Age Young: Paleoproterozoic
Name: Granodiorite
Role: Associated
Age Type: Associated Rock
Age Young: Paleoproterozoic
Name: Amphibolite
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Schist
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Skarn (Tactite)
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Gneiss
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Gneiss
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Schist
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Biotite Gneiss
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Name: Amphibolite
Role: Host
Age Type: Host Rock
Age Young: Paleoproterozoic
Analytical Data
Analytical Data: SORTED ORE (1883) 58 % ZN, 4.6 % CU, 10 OZ/TON AG
Materials
Ore: Malachite
Ore: Scheelite
Ore: Pyrrhotite
Ore: Bornite
Ore: Covellite
Ore: Cuprite
Ore: Galena
Ore: Tetrahedrite
Ore: Magnetite
Ore: Goethite
Ore: Limonite
Ore: Hematite
Ore: Molybdenite
Ore: Pyrite
Ore: Chalcopyrite
Ore: Chrysocolla
Ore: Sphalerite
Ore: Gahnite
Ore: Anglesite
Ore: Silver
Ore: Gold
Gangue: Clinohumite
Gangue: Thulite
Gangue: Cordierite
Gangue: Hornblende
Gangue: Gypsum
Gangue: Quartz
Gangue: Garnet
Gangue: Calcite
Gangue: Biotite
Gangue: Actinolite
Gangue: Diopside
Gangue: Amazonstone
Gangue: Phlogopite
Gangue: Anthophyllite
Comments
Comment (Geology): Heinrich (1981) described the Cotopaxi deposit and the Sedalia deposit as skarns.
Comment (Geology): Maps indicate that the strike of the deposit is generally north-northeast and the dip is about 45 degrees to the SE (Heinrich, 1981).
Comment (Location): Located about 0.5 mi northwest of the bridge across the Arkansas River at Cotopaxi, in the E1/2 SE1/4 sec. 25, T. 48 N., R. 11 E.
Comment (Production): Workings consist of lower adit, upper adit, and an open cut. The adits access several hundred feet of drifts and stopes (Heinrich, 1981).
Comment (Production): Lindgren (1908) visited the property in 1907 and noted that the cotopaxi Mine had been idle for many years, but at one time was a "considerable shipper of ore".
Comment (Workings): OPEN PIT, DRILLING
Comment (Geology): Cotopaxi is thought to be a metamorphosed massive sulfide deposit similar to the Sedalia mine near Salida and the Betty (Lone Chimney) mine near Guffey (Sheridan and Raymond, 1984). Gahnite, a zinc spinel, is present in large quantities. Zinc spinels are indicative of metamorphosed massive sulfide deposits (Heimann, 2002).
Comment (Commodity): Zinc occurs mainly as sphalerite and gahnite, a zinc spinel mineral. Copper occurs as chalcopyrite. Minor galena and molybdenite are present. Pyrite, pyrhotite, and magnetite are locally common.
Comment (Deposit): DEPOSIT LIES ON WEST SIDE OF ANTICLINE
References
Reference (Deposit): HEINRICH, E.W., 1981, PRECAMBRIAN TUNGSTEN AND COPPER-ZINC SKARN DEPOSITS OF SOUTH-CENTRAL COLORADO: CGS RESOURCE SERIES 21, 115 P.
Reference (Geology): Heimann, Adriana, 2002, The composition of zinc-rich spinels associated with metamorphosed massive sulfide deposits - a reexamination: Society of Economic Geologists Abstracts, 2002 Denver Annual Meeting.
Reference (Production): COLORADO DIVISION MINES INSPECTION RECORDS; COKER, 1982
Reference (Deposit): 6) HARRER, C.M. AND TESCH, W.J., JR., 1959, RECONNAISSANCE OF IRON OCCURRENCES IN COLORADO: USBM INFORMATION CIRCULAR 7918, 82 P.
Reference (Deposit): SALOTTI, C.A., 1965, MINERALOGY AND PARAGENESIS OF THE COTOPAXI, COLORADO COPPER-ZINC SKARN DEPOSIT: AMERICAN MINERALOGIST, V. 50, NO. 9, P. 1179-1212.
Reference (Deposit): COKER, R.J., 1982, MINERAL RESOURCES OF THE ARKANSAS CANYON PLANNING UNIT WITH SPECIAL EMPHASIS ON THE FORMER GRAPE CREEK WILDERNESS STUDY AREAS AND THE MCINTYRE HILLS WILDERNESS STUDY AREA: US BLM MINERAL REPORT, P. 50-52.
Reference (Deposit): Sheridan, D.M., and Raymond, W.H., 1984. Preliminary report on the geology of the Sedalia mine are and its Proterozoic deposits of base-metal sulfides and gahnite, Chaffee County, Colorado: U.S. Geological Survey Open-File Report 84-0800, 27 p., 1 plate.
Reference (Deposit): Sheridan, D.M., and Raymond, W.H., 1984, Precambrian deposits of zinc-copper-lead sulfides and zinc spinel (gahnite) in Colorado: U.S. Geological Survey Bulletin 1550, 31 p.
Reference (Deposit): TAYLOR, R.B., SCOTT, G.R., WOBUS, R.A., EPIS, R.C., 1975, RECONNAISSANCE GEOLOGIC MAP OF THE COTOPAXI 15-MINUTE QUADRANGLE, FREMONT AND CUSTER COUNTIES, COLORADO: USGS MAP I-900, 1:62,500.
Reference (Deposit): LINDGREN, W., 1908, NOTES ON COPPER DEPOSITS IN CHAFFEE, FREMONT, AND JEFFERSON COUNTIES, COLORADO: USGS BULLETIN 340, P. 157-174.
Reference (Deposit): VANDERWILT, J.W., 1947, MINERAL RESOURCES OF COLORADO: COLORADO MINERAL RESOURCES BOARD, P. 83-85.
Reference (Deposit): Sheridan, D.M., Raymond, W.H., Taylor, R.B., and Hasler, J.W., 1990, Metallogenic map of stratabound exhalative and related occurrences in Colorado: U.S. Geological Survey Miscellaneous Investigations Series Map I-1971, scale 1:1,000,000
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