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
Elevation: 6,099 Feet (1,859 Meters)
Commodity: Manganese
Lat, Long: 39.39056, -104.75222
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.
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.
Colorado Mining Photos
Check out this collection of Colorado's best historic mining photos: Incredible Photos of Colorado Mining Scenes.
