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⇱ Hoff Mine (Trio Chrome Company lease; Trio Chrome Company leases), Latrobe, Latrobe Mining District, El Dorado County, California, USA

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Hoff Mine (Trio Chrome Company lease; Trio Chrome Company leases), Latrobe, Latrobe Mining District, El Dorado County, California, USAi
Regional Level Types
Hoff Mine (Trio Chrome Company lease; Trio Chrome Company leases)Mine
LatrobeUnincorporated Community
Latrobe Mining DistrictMining District
El Dorado CountyCounty
CaliforniaState
USACountry

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Latitude & Longitude (WGS84):
38° 31' 22'' North , 120° 55' 17'' West
Latitude & Longitude (decimal):
Type:
Nearest Settlements:
PlacePopulationDistance
Plymouth960 (2017)8.1km
Drytown167 (2011)10.8km
Amador City189 (2017)14.3km
Fiddletown235 (2011)14.6km
Rancho Murieta5,488 (2011)15.2km
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
ClubLocationDistance
Amador County Gem & Mineral SocietySutter Creek, California18km
El Dorado County Mineral and Gem SocietyPlacerville, California25km
Gold Country Treasure SeekersPlacerville, California25km
Roseville Rock RollersRoseville, California41km
Fossils for Fun Society, Inc.North Highlands, California43km
Mindat Locality ID:
77730
Long-form identifier:
mindat:1:2:77730:9
GUID (UUID V4):
0


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 Elements

Mineral List


2 valid minerals.

Detailed 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
ⓘChromite4.BB.05Fe2+Cr3+2O4
Group 9 - Silicates
ⓘClinochlore9.EC.55Mg5Al(AlSi3O10)(OH)8
ⓘvar. Pennine9.EC.55Mg5Al(AlSi3O10)(OH)8
Unclassified
ⓘ'Serpentine Subgroup'-D3[Si2O5](OH)4

List of minerals for each chemical element

HHydrogen
Hⓘ ClinochloreMg5Al(AlSi3O10)(OH)8
Hⓘ Clinochlore var. PennineMg5Al(AlSi3O10)(OH)8
Hⓘ Serpentine SubgroupD3[Si2O5](OH)4
OOxygen
Oⓘ ChromiteFe2+Cr23+O4
Oⓘ ClinochloreMg5Al(AlSi3O10)(OH)8
Oⓘ Clinochlore var. PennineMg5Al(AlSi3O10)(OH)8
Oⓘ Serpentine SubgroupD3[Si2O5](OH)4
MgMagnesium
Mgⓘ ClinochloreMg5Al(AlSi3O10)(OH)8
Mgⓘ Clinochlore var. PennineMg5Al(AlSi3O10)(OH)8
AlAluminium
Alⓘ ClinochloreMg5Al(AlSi3O10)(OH)8
Alⓘ Clinochlore var. PennineMg5Al(AlSi3O10)(OH)8
SiSilicon
Siⓘ ClinochloreMg5Al(AlSi3O10)(OH)8
Siⓘ Clinochlore var. PennineMg5Al(AlSi3O10)(OH)8
Siⓘ Serpentine SubgroupD3[Si2O5](OH)4
CrChromium
Crⓘ ChromiteFe2+Cr23+O4
FeIron
Feⓘ ChromiteFe2+Cr23+O4

Other Databases

Link to USGS MRDS:10029853

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