Soudan Iron Formation

October 02, 2005

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Provided by: Lawrence Judy
Summary authors & editors: Lawrence Judy

The picture above showing a close-up view of a glacially polished outcrop known as the Soudan Iron Formation was taken in the Soudan Underground Mine State Park in Minnesota. This banded iron formation, including hematite, jasper, and chert, is part of the Vermillion Range -- the dime is included for scale. Iron deposits found here were first mined from open pits in the late 1800s, and the first ore was actually shipped in 1884. The nearly vertical orientation of the ore body led to underground mining of the ore by 1890. United States Steel operated this mine near the southern shore of Lake Vermillion in Minnesota until 1962, when the availability of Mesabi taconite mining made underground mining less economical, despite the fact that ore reserves are estimated at 1.5 million tons. The mine yielded 17.9 million tons of ore, specular hematite, some of which, on display at the visitors center, had an iron content of 65%.

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