Leonard Mine

The Leonard Mine is a manganese mine located in Douglas county, Colorado at an elevation of 6,099 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: Leonard Mine  

State:  Colorado

County:  Douglas

Elevation: 6,099 Feet (1,859 Meters)

Commodity: Manganese

Lat, Long: 39.39056, -104.75222

Map: View on Google Maps

Satelite View

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Satelite image of the Leonard Mine

Leonard Mine MRDS details

Site Name

Primary: Leonard Mine


Commodity

Primary: Manganese


Location

State: Colorado
County: Douglas
District: Castle Rock Area


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

Not available


Ownership

Not available


Production

Not available


Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S


Physiography

General Physiographic Area: Interior Plains
Physiographic Province: Great Plains Province
Physiographic Section: Colorado Piedmont


Mineral Deposit Model

Not available


Orebody

Form: IRREGULAR


Structure

Type: R
Description: Denver Basin, Front Range Uplift

Type: L
Description: Denver Basin


Alterations

Not available


Rocks

Name: Sandstone
Role: Host
Age Type: Host Rock
Age Young: Paleocene

Name: Sandstone
Role: Host
Age Type: Host Rock Unit
Age Young: Paleocene


Analytical Data

Analytical Data: STAGE CRUSHING TEST ON 0.5-INCH ORE YIELDED MN DISTRIBUTION OF 60.0 % IN TABLE CONCENTRATE, 5.0 % IN TAILING, 12.5 % IN TABLE SLIME, 22.5 % IN MINUS 10-MESH REJECT
Analytical Data: SINTERING TEST YIELDED 48.4 % MN, 1.9 % FE, 9.2 % SIO2, 3.4 % AL203, 1.2 % CAO, 0.1 % ZN, 0.056 % P, 11.0 % BA.
Analytical Data: COMPOSITE SAMPLE CRUSHED TO MINUS 10-MESH, STAGE-GROUND THRU 48 MESH, SIZED AND TABLED GAVE MN DISTRIBUTION OF 57.2 % IN FIRST CONCENTRATE (14.0 WT % ASSAYING 42.8 % MN AND 7.6 % SIO2), 15.7 % IN SECOND CONCENTRATE (4.1 WT % ASSAYING 40.1 % MN AND 10.2 % SIO2), 9.9 % IN MIDDLING (6.9 WT % ASSAYING ING 15.0 % MN AND 53.3 % SIO2), 4.9 % IN SLIMES (7.4 WT % ASSAYING 7.0 % MN AND 50.2 % SIO2), 12.3 % IN TAILING (67.6 WT % ASSAYING 1.9 % MN AND 73.0 % SIO2).
Analytical Data: SIZING OF CRUSHED COMPOSITE SAMPLE GAVE MN DISTRIBUTION OF 77.7 % IN PLUS 10-MESH AND 22.3 % IN MINUS 10-MESH.
Analytical Data: COMPOSITE OF LEONARD MINE SAMPLE AND TWO BUCKLEY FIELD (ARAPAHOE CO.) SAMPLES ASSAYED 11.1 % MN, 71.4 % INSOL, 56.7 % SIO2, 1.2 % FE, 1.3 % CAO, LT 0.05 % S, 3.0 % BA, 8.0 % AL203, 0.23 % ZN, 0.03 % P.
Analytical Data: LEONARD MINE SAMPLE ASSAYED 10.8 % MN, 72.2 % INSOL, 55.9 % SIO2, 1.2 % FE, 1.7 % CAO, LT 0.05 % S, 2.6 % BA, 9.2 % AL203, 0.25 % ZN, 0.03 % P.


Materials

Ore: Psilomelane
Gangue: Barite
Gangue: Limonite


Comments

Comment (Location): LOCATION CITED AS FRANKTOWN BUT EXACT POSITION UNKNOWN. LAT-LONG GIVEN IS FOR FRANKTOWN ; INFO FROM LAND.ST :(1974)

Comment (Commodity): OTHER UNSPECIFIED MN OXIDES PRESENT IN SMALL AMOUNTS

Comment (Development): ONE OF SEVERAL DENVER BASIN DEPOSITS INVESTIGATED BY USBM AND USGS FOR MN POTENTIAL AS RESULT OF STRATEGIC MINERALS ACT AND WW II NEEDS. NO COMMERCIAL QUANTITIES DISCLOSED AT THAT TIME

Comment (Deposit): MN OXIDES OCCUR AS IRREGULAR MASSES 20 TO 200 MESH IN SIZE FILLING INTERSTICES OF ARKOSIC SANDSTONE IN DAWSON FM

Comment (Deposit): DENVER BASIN MN OCCURRENCES WERE CONSIDERED TOO LOW GRADE FOR COMMERCIAL FERROMANGANESE MANUFACTURE BUT USBM ORE-DRESSING TESTS INDICATED SOME DEGREE OF CONCENTRATION POSSIBLE BY SIZING METHODS AND BY SIMPLE TABLING AND SINTERING. FLOTATION INCREASED MN RECOVERY BUT LOWERED GRADE DUE TO EXCESS SILICA AND BARIUM ; INFO.SRC : 1 PUB LIT


References

Reference (Deposit): TRAVER, W.M., JR., 1947, INVESTIGATIONS OF STRATEGIC MINERAL RESOURCES, IN VANDERWILT, J.W., MINERAL RESOURCES OF COLORADO: COLORADO STATE MINERAL RESOURCES BOARD, P. 490-491.

Reference (Deposit): TRIMBLE, D.E., AND MACHETTE, M.N., 1979, GEOLOGIC MAP OF THE GREATER DENVER AREA, FRONT RANGE URBAN CORRIDOR, COLORADO: USGS MAP I-856-H

Reference (Deposit): WELLS, R.R., AND OTHERS, 1952, BENEFICIATION OF OXIDE MANGANESE ORES FROM ARAPAHOE, DOUGLAS, SAGUACHE, CUSTER, CHAFFEE, AND PARK COUNTIES, COLORADO: USBM RI-4845, P. 3-6.


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