Little Johnnie Mine

The Little Johnnie Mine is a thorium mine located in Gunnison county, Colorado at an elevation of 8,921 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

Name: Little Johnnie Mine  

State:  Colorado

County:  Gunnison

Elevation: 8,921 Feet (2,719 Meters)

Commodity: Thorium

Lat, Long: 38.32167, -107.08611

Map: View on Google Maps

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.


Satelite image of the Little Johnnie Mine

Little Johnnie Mine MRDS details

Site Name

Primary: Little Johnnie Mine
Secondary: Unpatented Claims: Little Johnnie Nos. 1-2
Secondary: Little Johnnie Extension
Secondary: Cathey Nos. 1-5
Secondary: Charley Nos. 1-5


Commodity

Primary: Thorium
Tertiary: REE


Location

State: Colorado
County: Gunnison
District: Goose Creek District


Land Status

Land ownership: BLM Administrative Area
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

Not available


Ownership

Owner Name: John A. Mcgregor
Home Office: Powderhorn
Years: 1962 -


Production

Not available


Deposit

Record Type: Site
Operation Category: Occurrence
Deposit Type: Vein
Operation Type: Unknown
Discovery Year: 1949
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

Form: TABULAR


Structure

Type: R
Description: Gunnison Uplift, San Juan Volcanic Field

Type: L
Description: Gunnison Gold Belt, Iron Hill Alkalic Complex, Tolvar Peak Stock


Alterations

Not available


Rocks

Name: Syenite
Role: Associated
Age Type: Associated Rock
Age Young: Late Ordovician

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


Analytical Data

Analytical Data: 0.009, 0.05
Analytical Data: 0.15, 0.84
Analytical Data: 0.031, 0.17
Analytical Data: 0.034, 0.19
Analytical Data: 0.019, 0.10
Analytical Data: 0.88, 4.9
Analytical Data: 0.11, 0.61
Analytical Data: 0.12, 0.67
Analytical Data: 0.045, 0.25
Analytical Data: ADAMS AND MOORE (1951) GIVE CHEMICAL ANALYSIS OF VEIN MATERIAL AS 2.29% TH02 AND 0.50% RARE-EARTH OXIDE. RADIOMETRIC ANALYSES TABULATED BY OLSON AND WALLACE (1956) (EACH SET OF VALUES IS % EQUIV URANIUM AND CALCULATED % TH02 ASSUMING THAT ALL RADIOACTIVITY IS DUE TO TH): 0.13, 0.73
Analytical Data: 0.014, 0.08
Analytical Data: 0.20, 1.12


Materials

Ore: Thorite
Gangue: Xenotime
Gangue: Quartz
Gangue: Goethite
Gangue: Chlorite
Gangue: Clinozoisite
Gangue: Allophane
Gangue: Rutile
Gangue: Hematite
Gangue: Tourmaline
Gangue: Barite
Gangue: Apatite


Comments

Comment (Location): ON NORTH SIDE OF MILKRANCH GULCH DRAINAGE BASIN AND EAST OF OLD LOT MINE. ; INFO FROM LAND.ST :1976

Comment (Deposit): THORIUM VEINS IN THIS AREA ARE ONE OF FOUR ENVIRONMENTS OF TH OCCURRENCE KNOWN IN POWDERHORN-IRON HILL AREA AND ARE PROBABLY RELATED TO EMPLACEMENT OF LATE PRECAMBRIAN SYENITES NORTH AND WEST OF IRON HILL AND OF YOUNGER LATE PRECAMBRIAN OR CAMBRIAN CARBONATITES AT IRON HILL. FOLIATION OF DUBOIS GREENSTONE FELSITE AND SEVERAL LAYERS OF HORNBLENDE SCHIST AND AMPHIBOLITE COUNTRY ROCK TREND GENERALLY N 55 TO 60 E, 80 TO 90 NW. OLSON AND WALLACE (1956) DESCRIBE SEQUENCE AS QUARTZ-BIOTITE SCHIST AND QUARTZITE, METARHYOLITE PORPHYRY, AMPHIBOLITE DIKES AND BODIES ALL CUT BY SMALL FAULTS, BY SYENITE DIKES AND LARGE NW-TRENDING GABBRO DIKE, AND BY QUARTZ, CARBONATE, SODA-AMPHIBOLE, AND BRECCIA VEINS. POORLY EXPOSED VEIN IS MINERALIZED FAULT TRENDING N 65 E, DIPPING WITHIN 10 DEG OF VERTICAL. VEIN RANGES FROM UNDER 6 INCHES TO 5 FT WIDE, WITH AVERAGE NOT EXCEEDING 2 FT. VEIN MAY EXTEND FARTHER NE REAPPEARING AS TRACHYTE PORPHYRY DIKE BUT IS SEPARATED FROM IT BY TWO NW-TRENDING CAMBRO-ORDOVICIAN

Comment (Deposit): DIABASE DIKES. MINERALOGY CHARACTERIZED BY SUBHEDRAL TO ANHEDRAL MASSES OF THORITE OR THOROGUMMITE, EUHEDRAL CRYSTALS OF HEMATITE PARTLY ALTERED TO GOETHITE, COARSE-GRAINED BARITE, AND POSSIBLE ACCESSORY XENOTIME (Y RARE EARTH).

Comment (Workings): 40-FT LITTLE JOHNNIE NO. 1 TUNNEL; 389-FT LITTLE JOHNNIE NO. 2 TUNNEL; SMALL PROSPECT SHAFT; SURFACE CUTS.


References

Reference (Deposit): HEDLUND, D.C., AND OLSON, J.C., 1975, GEOLOGIC MAP OF THE POWDERHORN QUADRANGLE, GUNNISON AND SAGUACHE COUNTIES, COLORADO: USGS MAP GQ-1178.

Reference (Deposit): HEDLUND, D.C., AND OLSON, J.C., 1961, FOUR ENVIRONMENTS OF THORIUM-, NIOBIUM-, AND RARE-EARTH-BEARING MINERALS IN THE POWDERHORN DISTRICT OF SOUTHWESTERN COLORADO: USGS PROF. PAPER 424-B, P. B283-B286.

Reference (Deposit): OLSON, J.C., AND HEDLUND, D.C., 1981, ALKALIC ROCKS AND RESOURCES OF THORIUM AND ASSOCIATED ELEMENTS IN THE POWDERHORN DISTRICT, GUNNISON COUNTY, COLORADO: USGS PROF. PAPER 1049-C.

Reference (Deposit): OLSON, J.C., AND WALLACE, S.R., 1956, THORIUM AND RARE-EARTH MINERALS IN POWDERHORN DISTRICT, GUNNISON COUNTY, COLORADO: USGS BULL. 1027-0.

Reference (Deposit): NELSON-MOORE, J.L., AND OTHERS, 1978, RADIOACTIVE MINERAL OCCURRENCES OF COLORADO AND BIBLIOGRAPHY: CGS BULL. 40, P. 175.

Reference (Deposit): ADAMS, J.W., AND MOORE, F.B., 1951, AEC PRELIM. RECON. REPT. RR-95.

Reference (Deposit): COLORADO DIV. MINES INF. REPTS.


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