An underground copper mine consisting of 7 incline shafts near the community of Centennial, just north of Calumet. The Schoolcraft Mining Co. was organized in 1863 and worked the Calumet Conglomerate in a small scale operation until it went bankrupt in 1873. In 1876, the Centennial Mining Co. organized on the previously owned Schoolcraft property and worked the Osceola Amygdaloid until 1896, at which time the company re-organized as the Centennial Copper Co. Work was discontinued on the Calumet Conglomerate and the Osceola Amygdaloid and two new incline shafts were driven on the Kearsarge Amygdaloid. In 1923, Calumet and Hecla took control of the mine and operated it until 1931 when it closed. In 1944, shaft #2 was reopened and operated until 1966 when the mine closed for good. Before C&H took control, the Centennial Mine produced approximately 37 million lbs. of refined copper. The mine today offers the collector a wide range of minerals. A visit to #3 or #6 can produce copper "skulls" and an occasional greenstone (Chlorastrolite). Shafts #1 and #2 can yield copper crystals, silver, datolite, and incredible quartz/epidote crystals. A note about #1 and #2, the county owns these piles and uses them for their activities; at last check these piles were almost gone!

Regions containing this locality

North America Plate	Tectonic Plate
Keweenaw Peninsula, Michigan, USA	Peninsula

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Stenian 1000 - 1200 Ma ID: 3184728

Mesoproterozoic volcanic rocks Age: Stenian (1000 - 1200 Ma) Comments: Mid-Continent Rift Lithology: Bimodal volcanic rocks Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Stenian 1000 - 1200 Ma ID: 2928161

Portage Lake Volcanics Age: Stenian (1000 - 1200 Ma) Stratigraphic Name: Portage Lake Volcanics Description: Lava flows, mostly basalt, andesite and felsite flows and subordinate interflow sedimentary rocks. Comments: This unit is the same as unit Yp on paper map of Sims (1992). Description is taken from that unit description. Original map source: Cannon, W.F., Kress, T.H., Sutphin, D.M., Morey, G.B., Meints, Joyce, and Barber-Delach, Robert, 1997, Digital Geologic Map and mineral deposits of the Lake Superior Region, Minnesota, Wisconsin, Michigan: USGS Open-File Report 97-455 (version 3, Nov. 19 Lithology: Major:{basalt}, Minor:{basaltic andesite}, Incidental:{rhyolite, sandstone mudstone} Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

References

Localities in this Region

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