Big Oak Tree Quartz Mine (Big Oak Tree Mine; Milford), Colfax, Colfax Mining District (Illinois Mining District), Placer County, California, USAi
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Latitude & Longitude (WGS84):
39° 6' 9'' North , 120° 58' 47'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Colfax | 2,005 (2017) | 2.3km |
| Alta Sierra | 6,911 (2011) | 7.7km |
| Lake of the Pines | 3,917 (2011) | 9.6km |
| Meadow Vista | 3,217 (2011) | 11.9km |
| Grass Valley | 12,944 (2017) | 14.7km |
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 | 15km |
| El Dorado County Mineral and Gem Society | Placerville, California | 44km |
| Gold Country Treasure Seekers | Placerville, California | 44km |
| Roseville Rock Rollers | Roseville, California | 47km |
A former lode Au occurrence/mine located in the SE¼ (estimated) sec. 33, T15N, R9E, MDM, 2.4 km (1.5 miles) W of Colfax, on the divide between the Bear River and Campbell Creek. The property comprises 10 acres. Operated during the period 1883 to 1887, in 1924 & 1926. MRDS database stated accuracy for this location is 500 meters. This locality is presented simply as "Big Oak Tree" Mine in Clark (1970a). Adjoins the Rising Sun Mine on the S.
Mineralization is a vein deposit hosted in diabase and gabbro. The ore body strikes N80E and dips 80N at a thickness of 0.46 meters. The vein averages 18 inches in thickness. Local rocks include Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains).
Workings include underground openings with a length of 304.8 meters and an overall depth of 87.48 meters and comprised of 2 inclined shafts, 5 drifts and a winze.
Production data are found in: Logan, Clarence August (1936).
Some production occurred during the period 1883 to 1887, 1924 & 1926.
Ore averaged $28 (period values) Au/ton.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsGallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Pyrite | FeS2 |
| Fe | Iron | |
| Fe | ⓘ Pyrite | FeS2 |
| Au | Gold | |
| Au | ⓘ Gold | Au |
Other Databases
| Link to USGS MRDS: | 10007742 |
|---|
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 #0060610379
Lindgren, Waldemar (1900) Colfax folio, California. Folios of the Geologic Atlas 66. US Geological Survey doi:10.3133/gf66
