Milton claim (Redmayne and McGonigal prospect), Sierra City, Sierra City Mining District, Sierra County, California, USAi
| Regional Level Types | |
|---|---|
| Milton claim (Redmayne and McGonigal prospect) | Claim |
| Sierra City | City |
| Sierra City Mining District | Mining District |
| Sierra County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
39° 31' 48'' North , 120° 36' 58'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Sierra City | 221 (2011) | 4.3km |
| Downieville | 282 (2011) | 18.4km |
| Calpine | 205 (2011) | 21.4km |
| Whitehawk | 113 (2011) | 21.9km |
| Sierraville | 200 (2011) | 22.3km |
Mindat Locality ID:
93430
Long-form identifier:
mindat:1:2:93430:2
GUID (UUID V4):
ed45da9f-94fa-482d-a437-c6d2a80db843
A former Cr occurrence/mine located in sec. 10, T19N, R12E, MDM, 4.2 km (2.6 miles) SSE of Sierra City, along the N ridge of the Middle Yuba River, on private land in a National Forest area. Discovered in 1918 by R.C. Zaring. Owned/operated by R.C. Zaring. Owned by Mrs. Jean Hartley, Sacramento, California. Produced only in 1941. MRDS database accuracy for this location is not stated.
Mineralization is hosted in dunite of the Calaveras Formation. The ore body is lenticular in form, strikes N50-55W and dips 60-70N with a plunge of 15-20SE, a width of 1 meter and a length of 5 meters. The deposit occurs in a linear mass of ultramafic rock exposed in the northern Sierra Nevada Mountains. Ore occurs as discontinuous lenses of the above dimensions, enclosed in larger, lens-shaped dunite bodies. Two dominant directions of shearing are found in the deposit, one trending N70-75W, and the other trending N10-20E. Local alteration includes moderate to complete serpentinization of the host rock. Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains).
Tectonic Structure: Sierra Nevada Batholith
Workings include surface and underground openings comprised of an upper cut, 65 feet long and 10 to 15 feet wide, and a smaller open cut with an adit driven in the W wall, 45 to 50 feet lower and 100 feet E of the upper cut.
Production data are found in: Averill, Charles V. (1942a).
Production statistics: Year: 1941: Lump ore (accurate): averaged 40.60% Cr2O3 (41 weight percent).
Analytical data results: Ore contains 40.6% Cr2O3, Cr:Fe = 2.36. Analysis made by the Smith Emery Company (1941).
Reserve-Resource data are found in: Stinson, Melvin Clarence (1975).
Reserves and resources: Type: in-situ: estimate year: 1975: Total resources = 223,000 metric tons of ore at 30 weight percent Cr2O3 (1975).
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Chromite Formula: Fe2+Cr3+2O4 |
| ⓘ 'Serpentine Subgroup' Formula: D3[Si2O5](OH)4 Description: Occurs as an alteration product. |
| ⓘ Uvarovite Formula: Ca3Cr2(SiO4)3 |
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 | |||
| ⓘ | Uvarovite | 9.AD.25 | Ca3Cr2(SiO4)3 |
| Unclassified | |||
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| O | Oxygen | |
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Si | Silicon | |
| Si | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Ca | Calcium | |
| Ca | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Cr | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Fe | Iron | |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
Other Databases
| Link to USGS MRDS: | 10043627 |
|---|
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References
