Colfax Mining District (Illinois Mining District), Placer County, California, USAi
| Regional Level Types | |
|---|---|
| Colfax Mining District (Illinois Mining District) | Mining District |
| Placer 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:
~76km
Type:
Köppen climate type:
There is no USGS MRDS database file for this mining district.
Location: The Colfax district is in southwestern Placer County in the vicinity of the town of that name. It includes the deposits in the Weimar-New England Mills area and placer-mining areas along the American and the Bear Rivers. The Colfax district also has been known as the Illinois district.
History: Placer mining began here soon after the beginning of the gold rush. The locality was first known as Alder Gulch and later Ilinoistown. The Rising Sun Mine was discovered in 1866. Colfax, which was named for U. S. Senator Schuyler Colfax who visited the place in 1865, was an important center during the construction of the Central Pacific Railroad. Considerable mining continued in the district until about 1900. Small-scale placer mining, some done by skindivers, has continued until the present time.
Geology: Slates of the Mariposa Formation (Upper Jurassic) are found in the central portion of the district, and slate of the Cape Horn Formation (Carboniferous) crops out to the east. A gabbro intrusion lies to the north and northwest, a diabase body to west, and serpentine lenses and amphibolite to the east and southeast. A fairly extensive patch of Tertiary
channel gravel is exposed on the north side of Colfax Hill. The extensive quartz gravels in the Bear River are hydraulic mine tailings from the You Bet and Lowell Hill districts.
Ore deposits: The ore bodies occur in a number of northeast-striking quartz veins that usually range from two to five feet in thickness. The ore contains free gold and often abundant sulfides. Considerable highgrade ore was found near the surface during the early days.
Mines: Lode: Annie Laurie, Big Oak Tree ($100,000), Bauer, Black Oak, Brushy Creek, Chubb, Hinchy, Last Chance, Live Oak Ravine, Rising Sun ($2 miliion), Victory, and the Whiskey Tunnel. Placer: Bear River Extension, Bear River Tunnel, Burnt Flat, Collins, and the Rocky Bar.
Location: The Colfax district is in southwestern Placer County in the vicinity of the town of that name. It includes the deposits in the Weimar-New England Mills area and placer-mining areas along the American and the Bear Rivers. The Colfax district also has been known as the Illinois district.
History: Placer mining began here soon after the beginning of the gold rush. The locality was first known as Alder Gulch and later Ilinoistown. The Rising Sun Mine was discovered in 1866. Colfax, which was named for U. S. Senator Schuyler Colfax who visited the place in 1865, was an important center during the construction of the Central Pacific Railroad. Considerable mining continued in the district until about 1900. Small-scale placer mining, some done by skindivers, has continued until the present time.
Geology: Slates of the Mariposa Formation (Upper Jurassic) are found in the central portion of the district, and slate of the Cape Horn Formation (Carboniferous) crops out to the east. A gabbro intrusion lies to the north and northwest, a diabase body to west, and serpentine lenses and amphibolite to the east and southeast. A fairly extensive patch of Tertiary
channel gravel is exposed on the north side of Colfax Hill. The extensive quartz gravels in the Bear River are hydraulic mine tailings from the You Bet and Lowell Hill districts.
Ore deposits: The ore bodies occur in a number of northeast-striking quartz veins that usually range from two to five feet in thickness. The ore contains free gold and often abundant sulfides. Considerable highgrade ore was found near the surface during the early days.
Mines: Lode: Annie Laurie, Big Oak Tree ($100,000), Bauer, Black Oak, Brushy Creek, Chubb, Hinchy, Last Chance, Live Oak Ravine, Rising Sun ($2 miliion), Victory, and the Whiskey Tunnel. Placer: Bear River Extension, Bear River Tunnel, Burnt Flat, Collins, and the Rocky Bar.
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-localities8 valid minerals.
Rock Types Recorded
Rock list contains entries from the region specified including sub-localities
Select Rock List Type
Alphabetical List Tree DiagramDetailed Mineral List:
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| ⓘ | 'Tetrahedrite Subgroup' | 2.GB.05 | Cu6(Cu4C2+2)Sb4S12S |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Chromite | 4.BB.05 | Fe2+Cr3+2O4 |
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| ⓘ | Pyrolusite | 4.DB.05 | Mn4+O2 |
| Group 9 - Silicates | |||
| ⓘ | Talc | 9.EC.05 | Mg3Si4O10(OH)2 |
| Unclassified | |||
| ⓘ | 'Psilomelane' | - | |
| ⓘ | 'Tourmaline' | - | AD3G6(T6O18)(BO3)3X3Z |
| ⓘ | 'Soapstone' | - | |
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
| ⓘ | 'Manganese Oxides' | - | |
| ⓘ | 'Amphibole Asbestos' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Talc | Mg3Si4O10(OH)2 |
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| B | Boron | |
| B | ⓘ Tourmaline | AD3G6(T6O18)(BO3)3X3Z |
| O | Oxygen | |
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Pyrolusite | Mn4+O2 |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Talc | Mg3Si4O10(OH)2 |
| O | ⓘ Tourmaline | AD3G6(T6O18)(BO3)3X3Z |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Mg | Magnesium | |
| Mg | ⓘ Talc | Mg3Si4O10(OH)2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| Si | ⓘ Talc | Mg3Si4O10(OH)2 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| S | Sulfur | |
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| S | ⓘ Tetrahedrite Subgroup | Cu6(Cu4C22+)Sb4S12S |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Mn | Manganese | |
| Mn | ⓘ Pyrolusite | Mn4+O2 |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | ⓘ Pyrite | FeS2 |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
| Cu | ⓘ Tetrahedrite Subgroup | Cu6(Cu4C22+)Sb4S12S |
| Sb | Antimony | |
| Sb | ⓘ Tetrahedrite Subgroup | Cu6(Cu4C22+)Sb4S12S |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Localities in this Region
- California
- Placer County
- Colfax Mining District (Illinois Mining District)
- Placer County
- California
- Placer County
- Colfax Mining District (Illinois Mining District)
- Colfax
- Last Chance Mine
- New England Mills
- Annie Laurie Mine
- Bauer Mine (Big Shady group)
- Bear River Mine (Unnamed mine)
- Big John Mine (Tigar claim; Buena Vista claim; Ruby claim; Blue Bell claim)
- Brushy Creek Mine
- Buena Vista Mine
- Bugg prospect (Meyer property)
- Colfax Shale Quarry
- Devon Mine
- Hinchy Mine
- Live Oak Ravine Mine
- Major prospect
- Red Bird Consolidated Mine (Red Bird Cons.)
- Specimen Gulch prospects
- Unnamed Au occurrence [52]
- Weimar deposit
- Zelma Bell placer
- Shady Glen
- Weimar
- Colfax Mining District (Illinois Mining District)
- Placer County
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Calaveras-Baker DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- Sierra NevadaMountain Range
This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to
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for access and that you are aware of all safety precautions necessary.
References
Lindgren, Waldemar (1900) Colfax folio, California. Folios of the Geologic Atlas 66. US Geological Survey doi:10.3133/gf66
