Mammoth Bar (Pacific Gold Dredging Company property), Grizzly Bear House, Placer County, California, USAi
| Regional Level Types | |
|---|---|
| Mammoth Bar (Pacific Gold Dredging Company property) | - not defined - |
| Grizzly Bear House | - not defined - |
| Placer County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
38° 55' 14'' North , 121° 0' 16'' West
Latitude & Longitude (decimal):
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Cool | 4,100 (2017) | 3.8km |
| Auburn Lake Trails | 3,426 (2011) | 4.5km |
| North Auburn | 13,022 (2011) | 6.8km |
| Auburn | 13,953 (2017) | 6.8km |
| Meadow Vista | 3,217 (2011) | 9.1km |
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 |
|---|---|---|
| El Dorado County Mineral and Gem Society | Placerville, California | 28km |
| Gold Country Treasure Seekers | Placerville, California | 28km |
| Roseville Rock Rollers | Roseville, California | 31km |
| Nevada County Gem & Mineral Society | Grass Valley, California | 34km |
| Fossils for Fun Society, Inc. | North Highlands, California | 41km |
Mindat Locality ID:
85548
Long-form identifier:
mindat:1:2:85548:5
GUID (UUID V4):
20423d33-bdb4-4112-ba86-1befbc723e2d
A former placer Au-PGE (Os, Ir, Pd, Rh) occurrence/mine located in sec. 5, T12N, R9E, MDM, about 3.4 km SW of Grizzly Bear House, on the N side of the Middle Fork American River at its confluence with Murderers Gulch at Mammoth Bar (about 4 miles NE of Auburn), on private land. Operated by the El Dorado and Placer Counties Gold Mining and Power Co., Pacific Gold Dredging Co. (1910). Operated during the years 1914 to 1927. MRDS database stated accuracy for this location is 500 meters. In the early years of dredging, the PGE were not saved. Gravels probably averaged greater than $0.10 (period values) per cubic yard and bedrock greater than $1.00 (period values) per cubic yard. Dredging was carried out on bars of old hydraulic tailings.
Mineralization is a stream placer deposit (Mineral occurrence model information: Model code: 119; USGS model code: 39a; BC deposit profile: C01. C02; Deposit model name: Placer Au-PGE; Mark3 model number: 54), hosted in Holocene gravel near the base of the Sierra Nevada foothills. The ore body is a stream sediment deposit. The gravels averaged 28 feet deep. Controls for ore emplacement included stream hydraulics. The bedrock is slate decomposed to a depth of 1 foot (0.31 meter). Local rocks include pre-Cenozoic metasedimentary and metavolcanic rocks undivided.
Workings included surface dredging operations.
Analytical data results: PGE sample analyzed: 37.22% Pt, 34.72% Ir, $28.02 (period values) Au, Pd and Rh (Logan (1918), p. 109). Au grades estimated at 0.0048 ounce/cubic yard (80 ppb).
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Gold Formula: Au |
| ⓘ Platinum Formula: Pt Description: Placer material - 37.22% Pt. Commonly alloyed with Fe, 34.72% Os + Ir; 28% Au & traces of Pd & Rh. References: |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Gold | 1.AA.05 | Au |
| ⓘ | Platinum | 1.AF.10 | Pt |
Other Databases
| Link to USGS MRDS: | 10109520 |
|---|
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References
(n.d.) Minerals Availability System (MAS), U.S. Bureau of Mines.file #0060610199
