Copper Hill Mine (Cosumnes Mine; Hobo Mine; Jackass shaft), Four Corners, Amador County, California, USAi
| Regional Level Types | |
|---|---|
| Copper Hill Mine (Cosumnes Mine; Hobo Mine; Jackass shaft) | Mine |
| Four Corners | - not defined - |
| Amador County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
38° 30' 7'' North , 120° 58' 0'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Plymouth | 960 (2017) | 10.8km |
| Rancho Murieta | 5,488 (2011) | 11.1km |
| Drytown | 167 (2011) | 11.9km |
| Amador City | 189 (2017) | 15.4km |
| Ione | 7,000 (2017) | 16.8km |
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 |
|---|---|---|
| Amador County Gem & Mineral Society | Sutter Creek, California | 19km |
| El Dorado County Mineral and Gem Society | Placerville, California | 29km |
| Gold Country Treasure Seekers | Placerville, California | 29km |
| Roseville Rock Rollers | Roseville, California | 39km |
| Fossils for Fun Society, Inc. | North Highlands, California | 41km |
A former Cu-Au-Zn-Ag mine located in the SE¼ sec. 34, T8N, R9E, MDM, 3.8 km (2.4 miles) NW of Four Corners. MRDS database stated accuracy for this location is 100 meters.
NOTE: There is a third USGS MRDS database file which quite apparently pertains to this locality. That file is also named "Copper Hill" and is #10114448, which also provides a second MAS-MILS file #0060050540, and places it in sec. 3, T7N, R9E, MDM. That T&R section is contiguous to sec. 34, T8N, R9E, on its S. The only additional reference provided is the USGS crib list. The error here is apparently in the latitude value since it is otherwise directly S of the actual Copper Hill Mine location (same longitude).
Mineralization is a massive sulphide deposit (Deposit Model: 184: Massive sulfide, kuroko), hosted in rocks of the (amphibolite, and Late Jurassic schist of the Logtown Ridge Formation). The ore body is lenticular in shape, strikes NW and dips 60NE. Controls for ore emplacement included a shear and brecciated zone in Logtown Ridge metavolcanic rocks. Local rocks include Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains).
Workings include underground openings with an overall depth of 213.36 meters and a length of 1,584.96 meters. There are over 1,200 feet of shafts and over 1,800 feet of drifts. The main shaft is on the Cosumnes.
This mine was a large Cu producer in the past. The U.S. Bureau of Mines disclosed 3 separate lenses of ore in an undeveloped block during 1943, after 2,864 feet of diamond drilling. One drill hole NE of the Jackass shaft assayed 22.37% Zn, 0.43% Cu, 9.31 ounces/ton Ag, and 0.02 ounce Au/ton.
NOTE: There is a third USGS MRDS database file which quite apparently pertains to this locality. That file is also named "Copper Hill" and is #10114448, which also provides a second MAS-MILS file #0060050540, and places it in sec. 3, T7N, R9E, MDM. That T&R section is contiguous to sec. 34, T8N, R9E, on its S. The only additional reference provided is the USGS crib list. The error here is apparently in the latitude value since it is otherwise directly S of the actual Copper Hill Mine location (same longitude).
Mineralization is a massive sulphide deposit (Deposit Model: 184: Massive sulfide, kuroko), hosted in rocks of the (amphibolite, and Late Jurassic schist of the Logtown Ridge Formation). The ore body is lenticular in shape, strikes NW and dips 60NE. Controls for ore emplacement included a shear and brecciated zone in Logtown Ridge metavolcanic rocks. Local rocks include Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains).
Workings include underground openings with an overall depth of 213.36 meters and a length of 1,584.96 meters. There are over 1,200 feet of shafts and over 1,800 feet of drifts. The main shaft is on the Cosumnes.
This mine was a large Cu producer in the past. The U.S. Bureau of Mines disclosed 3 separate lenses of ore in an undeveloped block during 1943, after 2,864 feet of diamond drilling. One drill hole NE of the Jackass shaft assayed 22.37% Zn, 0.43% Cu, 9.31 ounces/ton Ag, and 0.02 ounce Au/ton.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Azurite Formula: Cu3(CO3)2(OH)2 |
| ⓘ Bornite Formula: Cu5FeS4 |
| ⓘ Chalcocite Formula: Cu2S |
| ⓘ Chalcopyrite Formula: CuFeS2 Description: Principal ore mineral here. |
| ⓘ Epsomite Formula: MgSO4 · 7H2O |
| ⓘ Malachite Formula: Cu2(CO3)(OH)2 |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Sphalerite Formula: ZnS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Chalcocite | 2.BA.05 | Cu2S |
| ⓘ | Bornite | 2.BA.15 | Cu5FeS4 |
| ⓘ | Sphalerite | 2.CB.05a | ZnS |
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 5 - Nitrates and Carbonates | |||
| ⓘ | Azurite | 5.BA.05 | Cu3(CO3)2(OH)2 |
| ⓘ | Malachite | 5.BA.10 | Cu2(CO3)(OH)2 |
| Group 7 - Sulphates, Chromates, Molybdates and Tungstates | |||
| ⓘ | Epsomite | 7.CB.40 | MgSO4 · 7H2O |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Azurite | Cu3(CO3)2(OH)2 |
| H | ⓘ Epsomite | MgSO4 · 7H2O |
| H | ⓘ Malachite | Cu2(CO3)(OH)2 |
| C | Carbon | |
| C | ⓘ Azurite | Cu3(CO3)2(OH)2 |
| C | ⓘ Malachite | Cu2(CO3)(OH)2 |
| O | Oxygen | |
| O | ⓘ Azurite | Cu3(CO3)2(OH)2 |
| O | ⓘ Epsomite | MgSO4 · 7H2O |
| O | ⓘ Malachite | Cu2(CO3)(OH)2 |
| Mg | Magnesium | |
| Mg | ⓘ Epsomite | MgSO4 · 7H2O |
| S | Sulfur | |
| S | ⓘ Bornite | Cu5FeS4 |
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Chalcocite | Cu2S |
| S | ⓘ Epsomite | MgSO4 · 7H2O |
| S | ⓘ Pyrite | FeS2 |
| S | ⓘ Sphalerite | ZnS |
| Fe | Iron | |
| Fe | ⓘ Bornite | Cu5FeS4 |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Pyrite | FeS2 |
| Cu | Copper | |
| Cu | ⓘ Azurite | Cu3(CO3)2(OH)2 |
| Cu | ⓘ Bornite | Cu5FeS4 |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
| Cu | ⓘ Chalcocite | Cu2S |
| Cu | ⓘ Malachite | Cu2(CO3)(OH)2 |
| Zn | Zinc | |
| Zn | ⓘ Sphalerite | ZnS |
Other Databases
| Link to USGS MRDS: | 10109409 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Foothills-Wallowa DomainDomain
- Sierra Nevada BatholithVolcanic Arc
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