Sebastapol Mine (Star; Extension; Placer Mine; Last Resort; Hansen Bros), Church Meadows, Sierra City Mining District, Sierra County, California, USAi
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Latitude & Longitude (WGS84):
39° 39' 30'' North , 120° 35' 40'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Whitehawk | 113 (2011) | 7.8km |
| Valley Ranch | 109 (2011) | 9.1km |
| Sierra City | 221 (2011) | 10.8km |
| C-Road | 150 (2011) | 11.6km |
| Graeagle | 737 (2011) | 12.2km |
A former placer/lode Au occurrence/mine located in sec. 23 & 26, T21N, R12E, MDM, 2.9 km (1.8 miles) SE of Church Meadows (coordinates of record), along the W side of Howard Creek, S of Howard Creek Meadows (swamp), on National Forest land. MRDS database stated accuracy for this location is 1,000 meters. This was a rich placer mine prior to 1912 when the vein was discovered.
Mineralization is a vein deposit with ore shoots, hosted in porphyry. The ore body strikes E and dips 70N at a thickness of 6.1 meters. The lode is 12 to 20 feet thick without a well-defined vein. The quartz-augite porphyry footwall is altered near the vein. The hanging wall was said to be the same. The ore shoot is 250 feet wide. Local rocks include Mesozoic volcanic rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) and/or Paleozoic metavolcanic rocks, unit 2 (Northeastern Sierra Nevada).
Workings include surface and underground openings with a length of 1,371.6 meters and an overall depth of 27.43 meters and comprised of a 50 foot crosscut, 250 foot drift, and 1 raise 60 feet to surface.
Production data are found in: MacBoyle, Errol (1920b).
No other production record was found.
Analytical data results: less than 1% sulfides.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Augite Formula: (CaxMgyFez)(Mgy1Fez1)Si2O6 Description: Occurs in a quartz-augite porphyry. |
| ⓘ Native Gold Formula: Au |
| ⓘ Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 9 - Silicates | |||
| ⓘ | Augite | 9.DA.15 | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| O | ⓘ Quartz | SiO2 |
| Mg | Magnesium | |
| Mg | ⓘ Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Si | Silicon | |
| Si | ⓘ Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Si | ⓘ Quartz | SiO2 |
| Ca | Calcium | |
| Ca | ⓘ Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Fe | Iron | |
| Fe | ⓘ Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
Other Databases
| Link to USGS MRDS: | 10086605 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Shoofly-Olds Ferry 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 #0060910558
