|Location:||Republic. The observation stand is located only 800m off M-95. Turn east south of the Michigamme River bridge, right at the yield sign, then 400m to the stand.|
|Classification:||Iron Mine, open cast mine.|
|Guided tours:||self guided|
|Address:||Republic Iron Mine|
|Last update:||$Date: 2011/12/13 09:10:39 $|
|1872||iron mining started.|
|1982||iron mining ended.|
|1996||mine permanently closed.|
At Republic Iron Mine first a high-grade hard ore and later hematitic taconite was mined. The ores were formed by several processes, including deposition of the iron-formation and later alteration by paleo-weathering and metamorphism. Republic iron mine lies within the Upper Jaspilite Unit of the Negaunee Iron Formation, which ranges in thickness from 100m to 160m. This jaspilite facies looks very impressive, because of the dark red bands in black rock. The ore is 88% pure iron oxide.
This opencast mine is now closed, and the groundwater filled the huge pit to a certain level. Above this level, the mined ore is easy to see. The pit is 200m deep and has an area of 100ha. It is the only open pit mine in Michigan open for free public viewing. There is an observation stand near the pit's edge. The mine is owned by Cleveland Cliffs Iron Company, who also own Tilden Mine, which is still operating.
The old mine dumps are full of specular hematite and magnetite. You may also find crystallized quartz in openings in the specularite, good specimens of feldspar, beryl, red jasper, jaspilite and tourmaline.
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