Minnesota Development Group Mine (Minnesota Development Gp.), Alleghany, Alleghany Mining District (Forest Mining District), Sierra County, California, USAi
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Latitude & Longitude (WGS84):
39° 27' 27'' North , 120° 49' 25'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Washington | 185 (2011) | 11.1km |
| Downieville | 282 (2011) | 11.3km |
| Pike | 134 (2011) | 15.1km |
| Camptonville | 158 (2011) | 19.3km |
| Sierra City | 221 (2011) | 20.2km |
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Nevada County Gem & Mineral Society | Grass Valley, California | 33km |
A former lode Au occurrence/mine located in sec. 2,T18N, R10E, MDM, (¾ mile SE of Alleghany), in the headwaters area of Hope Ravine, on National Forest land. MRDS database accuracy for this location is not stated.
NOTE: USGS MRDS database file #10103100 references MRDS file #10237848 as a related file; however, that referenced file pertains to a placer deposit/mine stated to be located in Nevada County despite bearing the name of Minnesota Flat. There was apparently a hydraulic placer mine at or near Minnesota Flat, Sierra County, and the referenced file's data regarding geographic coordinates are believed to be in error.
Mineralization is hosted in slate and serpentinite. The ore body is a pinch-and-swell body striking WNW and dipping N at a thickness of 3.05 meters. Several parallel veins follow an intrusion on footwall serpentine. The hanging wall is slate and sometimes both walls. The vein is 2 to 10 feet thick. Gouge, graphitic clay and talc slate casings (castings ?) occur on both sides. Local rocks include Mesozoic gabbroic rocks, unit 2 (undivided).
Workings include surface and underground openings with an overall depth of 86.87 meters, overall length of 1,219.2 meters, overall width of 152.4 meters and comprised of a 200 foot adit and a 50 foot winze.
Production data are found in: Crawford, James John (1896).
No other production record was found.
NOTE: USGS MRDS database file #10103100 references MRDS file #10237848 as a related file; however, that referenced file pertains to a placer deposit/mine stated to be located in Nevada County despite bearing the name of Minnesota Flat. There was apparently a hydraulic placer mine at or near Minnesota Flat, Sierra County, and the referenced file's data regarding geographic coordinates are believed to be in error.
Mineralization is hosted in slate and serpentinite. The ore body is a pinch-and-swell body striking WNW and dipping N at a thickness of 3.05 meters. Several parallel veins follow an intrusion on footwall serpentine. The hanging wall is slate and sometimes both walls. The vein is 2 to 10 feet thick. Gouge, graphitic clay and talc slate casings (castings ?) occur on both sides. Local rocks include Mesozoic gabbroic rocks, unit 2 (undivided).
Workings include surface and underground openings with an overall depth of 86.87 meters, overall length of 1,219.2 meters, overall width of 152.4 meters and comprised of a 200 foot adit and a 50 foot winze.
Production data are found in: Crawford, James John (1896).
No other production record was found.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Graphite Formula: C Description: Present as graphitic clay. |
| ⓘ Native Gold Formula: Au Description: Placer gold. A 266 ounce nugget was found in the 1850's. |
| ⓘ Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| ⓘ | Graphite | 1.CB.05a | C |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
| C | Carbon | |
|---|---|---|
| C | ⓘ Graphite | C |
| O | Oxygen | |
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
Other Databases
| Link to USGS MRDS: | 10103100 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Calaveras-Baker DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- Sierra NevadaMountain Range
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