Holseman Mine, Grass Valley, Grass Valley Mining District, Nevada County, California, USAi
| Regional Level Types | |
|---|---|
| Holseman Mine | Mine |
| Grass Valley | Valley |
| Grass Valley Mining District | Mining District |
| Nevada County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
39° 14' 10'' North , 121° 4' 0'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Grass Valley | 12,944 (2017) | 2.0km |
| Nevada City | 3,152 (2017) | 5.1km |
| Rough and Ready | 963 (2011) | 6.0km |
| Alta Sierra | 6,911 (2011) | 10.6km |
| Lake Wildwood | 4,991 (2011) | 11.5km |
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 | 2km |
| Sutter Buttes Gem & Mineral Society | Marysville, California | 46km |
A former Cr-Fe occurrence/mine located in sec. 22, T16N, R8E, MDM, about 2.3 km NNW of Grass Valley proper, N of the Alta Hill Reaservoir and SW of the Nevada Union High School, on a N-facing slope. Owned by Edna M. Wasley (100%), California (1976). Operated by T.F. Hogan, G.J. Hothersall, et al, California (last 1918). MRDS database stated accuracy for this location is 500 meters.
The ore body strikes N00S and dips 90N at a thickness of 7 meters, width of 7 meters and a length of 7 meters. Ore body No. 1 is disseminated, irregular; No. 2 is tabular; and, No. 3 is lenticular. The primary mode of origin was magmatic differentiation. The primary ore control was lithology. Wallrock alteration is intense (carbonitization). Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) and/or Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range).
Workings include surface and underground openings comprised of open cuts and a 20 foot shaft with a 20 foot drift at the bottom. The underground openings have a length of 14 meters and an overall depth of 7 meters.
Hogan and Hothersall shipped 353 long tons of ore in 1916, 446 tons in 1917 and 80 tons in 1918, with a total of 879 long tons shipped and 161 tons stockpiled. The major part of the ore probably came from this deposit. The state reported 50 to 100 tons of milling grade ore, 10 to 18% Cr2O3 remained in 1918. At least 1,040 long tons of ore were produced by 1918.
The ore averaged 30-33% Cr2O3. This mine has been idel since 1918. Its future does not look good due to the proximity of new housing developments.
Reserves and resources data: Type: In-situ (1918) (estimated): inferred: 100 metric tons; total resources: 200 metric tons. Cr2O3: 32 weight per cent; Fe: 7 weight per cent.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Chromite Formula: Fe2+Cr3+2O4 |
| ⓘ 'Fayalite-Forsterite Series' |
| ⓘ 'Pyroxene Group' Formula: ADSi2O6 |
| ⓘ 'Serpentine Subgroup' Formula: D3[Si2O5](OH)4 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Chromite | 4.BB.05 | Fe2+Cr3+2O4 |
| Unclassified | |||
| ⓘ | 'Fayalite-Forsterite Series' | - | |
| ⓘ | 'Pyroxene Group' | - | ADSi2O6 |
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| O | Oxygen | |
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Fayalite-Forsterite Series | |
| O | ⓘ Pyroxene Group | ADSi2O6 |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Mg | Magnesium | |
| Mg | ⓘ Fayalite-Forsterite Series | |
| Si | Silicon | |
| Si | ⓘ Fayalite-Forsterite Series | |
| Si | ⓘ Pyroxene Group | ADSi2O6 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | Iron | |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | ⓘ Fayalite-Forsterite Series | |
Other Databases
| Link to USGS MRDS: | 10031756 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Foothills-Wallowa DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- Sierra NevadaMountain Range
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References
(n.d.) Minerals Availability System (MAS), U.S. Bureau of Mines.file #0060570310
