Last Chance Mine

The Last Chance Mine is a fluorine-fluorite mine located in Chaffee county, Colorado at an elevation of 7,799 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: Last Chance Mine
Secondary: Kramer Mine
Secondary: Lower Adit
Secondary: Adit No. 1
Secondary: Adit No. 2
Secondary: Commercial Minerals, Inc., claims

Commodity

Primary: Fluorine-Fluorite
Tertiary: Manganese

Location

State: Colorado
County: Chaffee
District: Browns Canyon 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

Owner Name: Commercial Minerals, Inc.
Years: 1969 -

Production

Year: 1944
Time Period: 1942-1944
Mined: 9842.000 mt
Material type: FLUORSPAR CONCENTRATES
Year: 1942
Time Period: BEFORE 1942
Mined: 984.200 mt
Material type: FLUORSPAR CONCENTRATES

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1927
Year Last Production: 1949
Discovery Year: 1923
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: Fluorspar deposits (fluorite veins)

Orebody

Not available

Structure

Type: R
Description: Southern Mosquito Range, Arkansas Valley Graben

Type: L
Description: Folds, Faults; N-Trending Fault Bounding Arkansas Valley

Alterations

Alteration Type: L
Alteration Text: Silicification, Fluoritization

Rocks

Name: Gneiss
Role: Associated
Age Type: Associated Rock Unit
Age Young: Neoproterozoic

Name: Gneiss
Role: Associated
Age Type: Host Rock Unit
Age Young: Neoproterozoic

Name: Gneiss
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic

Name: Gneiss
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Analytical Data

Analytical Data: AVERAGE GRADE OF ORE MINED WAS 30% CAF2
Analytical Data: EARLIER HAND PICKED METALLURGICAL-GRADE PRODUCT CONTAINE 80-95% CAF2 AND 2.5-15% SIO2
Analytical Data: FLOTATION CONCENTRATES AVERAGED 93-98% CAF2 AND 1-5% SIO2
Analytical Data: ONE SAMPLE CONTAINED 59.2% CAF2, 24.6% FE2O3, 9.8% SIO2, 3.8% CACO3, 1.7% H2O-MOST ORE, HOWEVER CONTAINED MORE SILICA AND LT 1% CACO3

Materials

Ore: Fluorite
Gangue: Montmorillonite
Gangue: Goethite
Gangue: Pyrite
Gangue: Manganite
Gangue: Pyrolusite
Gangue: Quartz
Gangue: Chalcedony
Gangue: Hematite
Gangue: Barite
Gangue: Calcite
Gangue: Psilomelane
Gangue: Kaolinite
Gangue: Opal

Comments

Comment (Deposit): IN PLACES FAULT CONSISTS OF SHEETED ZONE CONTAINING MANY VEINS OF FLUORSPAR, SOME 6 IN THICK; TWO MAIN ORE BODIES, EACH ABOUT 460X12X25 FT THICK

Comment (Development): FLOTATION MILL OPERATED 1942-1944

Comment (Geology): NW-TRENDING FAULT LOCALIZED ORE BODIES IN PRECAMBRIAN GNEISSIC QUARTZ MONZONITE.

Comment (Location): NE OF HECLA JUNCTION, EAST OF US HWY 285, WEST OF ARKANSAS RIVER; SE/4 SEC. 22, T 51 N, R 8 E. INFO FROM LAND.ST :(1976)

Comment (Production): FLOTATION MILL PRODUCED CERAMIC-GRADE AND A SMALL QUANTITY OF ACID-GRADE CONCENTRATES BEFORE IT BURNED IN 1944

Comment (Workings): ADITS, PITS, TRENCHES

References

Reference (Deposit): VAN ALSTINE, R.E. AND COX, D.C., 1969, FLUORSPAR MINES AND PROSPECTS, IN, GEOLOGY AND MINERAL DEPOSITS OF THE PONCHA SPRINGS NE QUADRANGLE, CHAFFEE COUNTY, COLORADO: USGS PROFESSIONAL PAPER 626, P. 38-43

Reference (Deposit): BRADY, B.T., 1975, MAP SHOWING FLUORSPAR DEPOSITS IN COLORADO: USGS MAP MR-70, 1:500,000, TEXT

Reference (Deposit): VAN DIVER, B.B., 1957, GEOLOGY OF THE CALUMET MINING DISTRICT, CHAFFEE COUNTY, COLORADO: UNIVERSITY OF COLORADO THESIS, P. 83.

Reference (Deposit): VANDERWILT, 1947, COLO. MINERAL RES. BOARD

Reference (Deposit): ARGALL, 1949, COLO. SCH. MINES QUART., V. 44, NO. 2

Reference (Deposit): CONSV. DIV. COMP. DATE, 1,64

Reference (Deposit): USBM MINERAL EXAM. FILE

Reference (Deposit): MINE MAP REPO 404956

Reference (Deposit): RECK, W. H., 1943, KRAMER MINES, INC.: DECO TREFOIL MAGAZINE, ENGINEERING NOTEBOOK BULL. M4-B28, MAY 1943, 12 PP.

Reference (Deposit): VAN ALSTINE, R.E., 1969, GEOLOGY AND MINERAL DEPOSITS OF THE PONCHA SPRINGS NE QUADRANGLE, CHAFFEE COUNTY, COLORADO: USGS PROFESSIONAL PAPER 626, 52 P.

Colorado Mining Photos

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