Hoff Mine (Trio Chrome Company lease; Trio Chrome Company leases), Latrobe, Latrobe Mining District, El Dorado County, California, USAi
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Latitude & Longitude (WGS84):
38° 31' 22'' North , 120° 55' 17'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Plymouth | 960 (2017) | 8.1km |
| Drytown | 167 (2011) | 10.8km |
| Amador City | 189 (2017) | 14.3km |
| Fiddletown | 235 (2011) | 14.6km |
| Rancho Murieta | 5,488 (2011) | 15.2km |
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 |
|---|---|---|
| Amador County Gem & Mineral Society | Sutter Creek, California | 18km |
| El Dorado County Mineral and Gem Society | Placerville, California | 25km |
| Gold Country Treasure Seekers | Placerville, California | 25km |
| Roseville Rock Rollers | Roseville, California | 41km |
| Fossils for Fun Society, Inc. | North Highlands, California | 43km |
Mindat Locality ID:
77730
Long-form identifier:
mindat:1:2:77730:9
GUID (UUID V4):
7c737647-f770-49cc-b3e4-d1c1d0304749
A former Cr-Fe occurrence/mine located in the W½ (NW¼ ?) sec. 30, T8N, R10E, MDM, about 7 km SE of Latrobe, just N of the Cosumnes River, on private land. Owned by Robert Haddock and R. H. Chaix, California (1976). Operated by the Trio Chrome Co. under lease from Haddock and Chaix, California (1976). Operated by Theresa Garibaldi (timeframe unstated). MRDS database stated accuracy for this location is 500 meters.
The ore body strikes N60W and dips 70N at a thickness of 3 meters and a length of 19 meters. The ore body is disseminated and lenticular in form. The primary mode of origin is magmatic differentiation. The wallrock alteration is intense (carbonitization). The ore is coarse-grained and ranges from a medium-grade disseminated ore to nearly pure chromite. Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) and/or Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains).
Workings include surface openings comprised of an open cut.
According to Taliaferro and Bradley, about 200 long tons were produced during WWI, but federal records list only 107 long tons. The average minable grade of chromite is 28 to 33%. About 20 long tons of ore remain on the dump and unmined reserves are nearly exhausted.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Chromite Formula: Fe2+Cr3+2O4 |
| ⓘ Clinochlore Formula: Mg5Al(AlSi3O10)(OH)8 |
| ⓘ Clinochlore var. Pennine Formula: Mg5Al(AlSi3O10)(OH)8 |
| ⓘ '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 |
| Group 9 - Silicates | |||
| ⓘ | Clinochlore | 9.EC.55 | Mg5Al(AlSi3O10)(OH)8 |
| ⓘ | var. Pennine | 9.EC.55 | Mg5Al(AlSi3O10)(OH)8 |
| Unclassified | |||
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| H | ⓘ Clinochlore var. Pennine | Mg5Al(AlSi3O10)(OH)8 |
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| O | Oxygen | |
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| O | ⓘ Clinochlore var. Pennine | Mg5Al(AlSi3O10)(OH)8 |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Mg | Magnesium | |
| Mg | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Mg | ⓘ Clinochlore var. Pennine | Mg5Al(AlSi3O10)(OH)8 |
| Al | Aluminium | |
| Al | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Al | ⓘ Clinochlore var. Pennine | Mg5Al(AlSi3O10)(OH)8 |
| Si | Silicon | |
| Si | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Si | ⓘ Clinochlore var. Pennine | Mg5Al(AlSi3O10)(OH)8 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | Iron | |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
Other Databases
| Link to USGS MRDS: | 10029853 |
|---|
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Foothills-Wallowa DomainDomain
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References
(n.d.) Minerals Availability System (MAS), U.S. Bureau of Mines.file #0060170244
