American Hill Mining District, Sierra County, California, USAi
| Regional Level Types | |
|---|---|
| American Hill Mining District | Mining District |
| Sierra County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
39° North , 120° West (est.)
Estimate based on other nearby localities or region boundaries.
Margin of Error:
~49km
Type:
Köppen climate type:
NOTE: There is no USGS MRDS database file for this district.
Location: The American Hill district is in southwestern Sierra County about five miles E of the town of Alleghany. It is both a lode and placer district, but the placer deposits have been more important. It includes the Cornish House area.
Geology: The district is chiefly underlain by slate. Serpentine and amphibolite are to the west, and granodiorite is just to the east. Extensive gravel deposits are part of a tributary to the Forest channel of the Tertiary Yuba River, which extends in a southwest direction through the district. The northern part of the district is covered by andesite. Dioritic dikes often are associated with the gold-quartz veins.
Ore deposits: The gravels are quartzitic and contain coarse gold. One of the gravel deposits is as much as 300 feet thick and covered with clay and sand. The quartz veins are lenticular and occur either in the slate or near the slate-granodiorite contact. The ore bodies contain free gold with pyrite, arsenopyrite, and galena. Sometimes carbon is found in cavities in the quartz. Some high-grade pockets have been found, but most of ore averages less than ½ ounce per ton.
Mines: Placer: American Hill, Bear Creek, Excelsior, Mable Mertz, Yellow Jacket. Lode: Comet, Ironsides, Jim Crow, Lonesome Pine, Pilgrim, Von Humboldt.
Location: The American Hill district is in southwestern Sierra County about five miles E of the town of Alleghany. It is both a lode and placer district, but the placer deposits have been more important. It includes the Cornish House area.
Geology: The district is chiefly underlain by slate. Serpentine and amphibolite are to the west, and granodiorite is just to the east. Extensive gravel deposits are part of a tributary to the Forest channel of the Tertiary Yuba River, which extends in a southwest direction through the district. The northern part of the district is covered by andesite. Dioritic dikes often are associated with the gold-quartz veins.
Ore deposits: The gravels are quartzitic and contain coarse gold. One of the gravel deposits is as much as 300 feet thick and covered with clay and sand. The quartz veins are lenticular and occur either in the slate or near the slate-granodiorite contact. The ore bodies contain free gold with pyrite, arsenopyrite, and galena. Sometimes carbon is found in cavities in the quartz. Some high-grade pockets have been found, but most of ore averages less than ½ ounce per ton.
Mines: Placer: American Hill, Bear Creek, Excelsior, Mable Mertz, Yellow Jacket. Lode: Comet, Ironsides, Jim Crow, Lonesome Pine, Pilgrim, Von Humboldt.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded from this region.Mineral List
Mineral list contains entries from the region specified including sub-localities4 valid minerals.
Detailed Mineral List:
| ⓘ Galena Formula: PbS |
| ⓘ Native Gold Formula: Au Localities: Reported from at least 20 localities in this region. |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Quartz Formula: SiO2 Localities: Reported from at least 16 localities in this region. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | 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 | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| Fe | Iron | |
| Fe | ⓘ Pyrite | FeS2 |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Localities in this Region
- California
- Sierra County
- American Hill Mining District
- American Hill
- American Hill Mine
- Bayes Mine (Bayls Mine)
- Excelsior Mine (Excelsior group; Hawkeye; Bell Point Consolidated Gravel Mine; Bell Point Cons. Gravel Mine)
- Mable Hertz Mine (Alaskan Mine [?])
- Mount Moriah Mine (Lawler)
- Nixon Mine
- Pilgrim Mine (English-American Gold Mining Company; English-American Gold Mng Co.)
- Sierra Gold Mining Placer Company prospect (Sierra Gold Mng Placer Co.)
- Talisman Placer Mine
- Urelene Mine
- Von Humboldt Mine
- Yellow Jacket Mine (Bear Creek)
- Cornish House
- American Hill
- American Hill Mining District
- Sierra County
- California
- Sierra County
- American Hill Mining District
- Cornish House
- Columbia Channel
- Comet Mine (Republic group; Alhambra group)
- Eagle Bird Mine
- Elkton claims
- Emerald Mine (Emerald Quartz group; Emerald Quartz Grp.)
- Ironsides Mine
- Isabel placer
- Jim Crow Mine
- Lonesome Pine Mine
- Pliocene Mine
- Republic group
- Unidentified Au mine [12]
- Unnamed Au mine [10]
- Unnamed Au prospect [69]
- Viola group
- Cornish House
- American Hill Mining District
- Sierra County
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
