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Flintsteel Mine, Mass City, Ontonagon County, Michigan, USAi
| Regional Level Types | |
|---|---|
| Flintsteel Mine | Mine (Abandoned) |
| Mass City | Census-designated Place |
| Ontonagon County | County |
| Michigan | State |
| USA | Country |
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Latitude & Longitude (WGS84):
46° 44' 29'' North , 89° 8' 41'' West
Latitude & Longitude (decimal):
Type:
Mine (Abandoned) - last checked 2025
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Ontonagon | 1,324 (2017) | 19.3km |
| White Pine | 474 (2017) | 33.5km |
| Watersmeet | 428 (2017) | 52.7km |
Other/historical names associated with this locality:
Nassau Mine, Old Flintsteel Mine, Superior Mine
Introduction
An underground copper mine consisting of one shaft (Nassau) and a series of pits (FlintSteel Pits).
History
The company organized in 1853 as the Flint Steel River Mining Company. Work was suspended in 1858 and was dormant until 1863 when the company was reorganized as the Flintsteel Copper Company. The company merged with Caledonia in 1871.
Production
The Flintsteel produced approx. 870,000 pounds of refined copper.
For the collector
The mine today is excellent for copper, datolite, and good for silver.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
6 valid minerals.
Detailed Mineral List:
| ⓘ Calcite Formula: CaCO3 |
| ⓘ 'Chlorite Group' |
| ⓘ Datolite Formula: CaB(SiO4)(OH) |
| ⓘ Epidote Formula: (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| ⓘ 'K Feldspar' |
| ⓘ 'K Feldspar var. Adularia' Formula: KAlSi3O8 |
| ⓘ Native Copper Formula: Cu |
| ⓘ Pumpellyite-(Mg) Formula: Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| ⓘ Quartz Formula: SiO2 |
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Copper | 1.AA.05 | Cu |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 5 - Nitrates and Carbonates | |||
| ⓘ | Calcite | 5.AB.05 | CaCO3 |
| Group 9 - Silicates | |||
| ⓘ | Datolite | 9.AJ.20 | CaB(SiO4)(OH) |
| ⓘ | Epidote | 9.BG.05a | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| ⓘ | Pumpellyite-(Mg) | 9.BG.20 | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| Unclassified | |||
| ⓘ | 'K Feldspar var. Adularia' | - | KAlSi3O8 |
| ⓘ | 'Chlorite Group' | - | |
| ⓘ | 'K Feldspar' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Datolite | CaB(SiO4)(OH) |
| H | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| H | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| B | Boron | |
| B | ⓘ Datolite | CaB(SiO4)(OH) |
| C | Carbon | |
| C | ⓘ Calcite | CaCO3 |
| O | Oxygen | |
| O | ⓘ K Feldspar var. Adularia | KAlSi3O8 |
| O | ⓘ Calcite | CaCO3 |
| O | ⓘ Datolite | CaB(SiO4)(OH) |
| O | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| O | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| O | ⓘ Quartz | SiO2 |
| Mg | Magnesium | |
| Mg | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| Al | Aluminium | |
| Al | ⓘ K Feldspar var. Adularia | KAlSi3O8 |
| Al | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Al | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| Si | Silicon | |
| Si | ⓘ K Feldspar var. Adularia | KAlSi3O8 |
| Si | ⓘ Datolite | CaB(SiO4)(OH) |
| Si | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Si | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| Si | ⓘ Quartz | SiO2 |
| K | Potassium | |
| K | ⓘ K Feldspar var. Adularia | KAlSi3O8 |
| Ca | Calcium | |
| Ca | ⓘ Calcite | CaCO3 |
| Ca | ⓘ Datolite | CaB(SiO4)(OH) |
| Ca | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Ca | ⓘ Pumpellyite-(Mg) | Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) |
| Fe | Iron | |
| Fe | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Cu | Copper | |
| Cu | ⓘ Native Copper | Cu |
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Mid-continent DomainDomain
- Mid-continent RiftNarrow Rift
USA
- Michigan
- Keweenaw PeninsulaPeninsula
- Midcontinent RiftGeologic Province
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Flintsteel Mine, Mass City, Ontonagon County, Michigan, USA