Eldorado Bar deposit (Eldorado Strip Mine), Eldorado Bar, East Helena, Lewis and Clark County, Montana, USAi
| Regional Level Types | |
|---|---|
| Eldorado Bar deposit (Eldorado Strip Mine) | Deposit |
| Eldorado Bar | - not defined - |
| East Helena | - not defined - |
| Lewis and Clark County | County |
| Montana | State |
| USA | Country |
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Latitude & Longitude (WGS84):
46° 44' 10'' North , 111° 51' 6'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Helena Valley Northeast | 2,995 (2011) | 8.7km |
| Helena Valley Southeast | 8,227 (2011) | 14.4km |
| Helena Valley Northwest | 3,482 (2011) | 16.1km |
| East Helena | 2,057 (2017) | 17.0km |
| Helena Valley West Central | 7,883 (2011) | 17.9km |
Mindat Locality ID:
122777
Long-form identifier:
mindat:1:2:122777:5
GUID (UUID V4):
5241c8c4-6d0c-4bc7-bbb0-3faaadcdedc1
A former placer Au-Ag-PGE (Pt-Os-Ir-Pd)-gemstone-corundum deposit/mine located in secs. 9 & 10, T11N, R2W, MPM, 17.0 km (10.6 miles) NNE of East Helena, along Hanser Lake, on the Missouri River (on the N bank of the Missouri River, 7.75 miles NW of Canyon Ferry), on National Forest land. Property is 1,200 acres. Operated by Sam Speerstra, Montana (1990); and, Watts, Griffis and Mcouat (WGM) Toronto, Canada (1994). Owned by American Gem (1994). MRDS database stated accuracy for this location is 100 meters.
Mineralization is a Au-PGE-gemstone deposit hosted in Holocene gravels. The ore body is river sands and gravels with a depth-to-top of 4.57 meters. Local rocks include Mississippian, undifferentiated (Greyson shale).
Workings included surface alluvial mining operations. 10 million cubic yards of material were handled in 6.5 years. WGM was conducting initial tests for renewed sapphire mining in this area in September 1994.
Production data are found in: Mertie (1951): 80.
Production statistics: Year 1944; Period 1938 - 1944; Material: gravel: ore mined: more than 10,000,000 cubic yards: at $0.20/cubic yard (period values).
Comments on the production information: 0.006 ounces Au/ton.
Reserve-Resource data are found in: The Northern Miner (1994).
Analytical data results: Per 100 pounds of concentrates: Pt = 7.86 ounces; Os - Ir = 0.56 ounces and Pd = 0.42 ounces.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| β Almandine Formula: Fe2+3Al2(SiO4)3 |
| β Cassiterite Formula: SnO2 |
| β Corundum Formula: Al2O3 |
| β Corundum var. Sapphire Formula: Al2O3 Description: The sapphires are naturally pale, but can be heat-treated to achieve a deeper blue color (MRDS file note).
|
| β 'Garnet Group' Formula: X3Z2(SiO4)3 References: |
| β Gold Formula: Au |
| β Hematite Formula: Fe2O3 References: |
| β Kyanite Formula: Al2(SiO4)O |
| β Quartz Formula: SiO2 |
| β Quartz var. Chalcedony Formula: SiO2 |
| β Topaz Formula: Al2(SiO4)(F,OH)2 |
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| β | Gold | 1.AA.05 | Au |
| Group 4 - Oxides and Hydroxides | |||
| β | Corundum | 4.CB.05 | Al2O3 |
| β | Hematite | 4.CB.05 | Fe2O3 |
| β | Corundum var. Sapphire | 4.CB.05 | Al2O3 |
| β | Quartz var. Chalcedony | 4.DA.05 | SiO2 |
| β | 4.DA.05 | SiO2 | |
| β | Cassiterite | 4.DB.05 | SnO2 |
| Group 9 - Silicates | |||
| β | Almandine | 9.AD.25 | Fe2+3Al2(SiO4)3 |
| β | Kyanite | 9.AF.15 | Al2(SiO4)O |
| β | Topaz | 9.AF.35 | Al2(SiO4)(F,OH)2 |
| Unclassified | |||
| β | 'Garnet Group' | - | X3Z2(SiO4)3 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | β Topaz | Al2(SiO4)(F,OH)2 |
| O | Oxygen | |
| O | β Almandine | Fe32+Al2(SiO4)3 |
| O | β Cassiterite | SnO2 |
| O | β Quartz var. Chalcedony | SiO2 |
| O | β Corundum | Al2O3 |
| O | β Hematite | Fe2O3 |
| O | β Kyanite | Al2(SiO4)O |
| O | β Quartz | SiO2 |
| O | β Corundum var. Sapphire | Al2O3 |
| O | β Topaz | Al2(SiO4)(F,OH)2 |
| O | β Garnet Group | X3Z2(SiO4)3 |
| F | Fluorine | |
| F | β Topaz | Al2(SiO4)(F,OH)2 |
| Al | Aluminium | |
| Al | β Almandine | Fe32+Al2(SiO4)3 |
| Al | β Corundum | Al2O3 |
| Al | β Kyanite | Al2(SiO4)O |
| Al | β Corundum var. Sapphire | Al2O3 |
| Al | β Topaz | Al2(SiO4)(F,OH)2 |
| Si | Silicon | |
| Si | β Almandine | Fe32+Al2(SiO4)3 |
| Si | β Quartz var. Chalcedony | SiO2 |
| Si | β Kyanite | Al2(SiO4)O |
| Si | β Quartz | SiO2 |
| Si | β Topaz | Al2(SiO4)(F,OH)2 |
| Si | β Garnet Group | X3Z2(SiO4)3 |
| Fe | Iron | |
| Fe | β Almandine | Fe32+Al2(SiO4)3 |
| Fe | β Hematite | Fe2O3 |
| Sn | Tin | |
| Sn | β Cassiterite | SnO2 |
| Au | Gold | |
| Au | β Gold | Au |
Other Databases
| Link to USGS MRDS: | 10038144 |
|---|
Other Regions, Features and Areas containing this locality
North America
- Rocky MountainsMountain Range
North America PlateTectonic Plate
- Great Falls DomainDomain
USA
- Montana
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References
(n.d.) Minerals Availability System (MAS), U.S. Bureau of Mines.file ID #0300490227
