The Soudan Underground Mine is described as Minnesota's oldest, deepest, and richest iron mine. It began operation as an open pit mine in 1884, and moved to undergroung mining by 1900 for reasons of safety. From 1901 until the end of active mining in 1962, the Soudan Mine was owned by the United States Steel Corporation's Oliver Iron Mining division. It was known for the high oxygen content of its ore, a valuable feature in producing steel. For this reason, a small amount of valuable Soudan ore was often mixed with ore from other mines. Advances in steelmaking eventually allowed oxygen to be injected artificially, and it was no longer profitable to extract the expensive ore from the Soudan Mine. The mine was also known as a very desirable place to work, with a better safety record than many, and a relatively dry, clean, and stable environment. For these reasons, the Soudan Mine has sometimes been called the "Cadillac of iron mines."

The Soudan Mine is in Breitung Township, on the shore of Lake Vermilion in northern Minnesota's Vermilion Range. The mine is close to Highway 169, about 20 miles east of Virginia and 20 miles west of Ely, or about one mile from Tower. It has become a popular tourist site, often visited on the way to and from Ely and the Boundary Waters Canoe Area Wilderness.

Today the mine is a Minnesota state park under the Department of Natural Resources. The surface buildings are open to the public, and during the summer months there are daily tours of the mine. Visitors are lowered in an 80-year-old electric mine hoist to level 27, the mine's lowest level at 2,341 feet below ground, where they explore the historic mining facilities or the currently active underground physics laboratory.

Underground Laboratory

The Soudan Mine was home to the Soudan proton decay experiment and its successor, Soudan-II. The University of Minnesota and the Department of Natural Resources have expanded the laboratory to accommodate other physics projects, such as the currently active MINOS -- a neutrino detector -- and CDMS-II -- a dark matter search experiment. Low-background materials screening facilities are in use and continuing development, and the mine has been proposed as one possible site for a U.S. Deep Underground Science and Engineering Laboratory. Parts of the laboratory are open for daily tours, and there is an annual open house with more access to the facilities and representatives of the experiments to help with the tours and answer questions.

External Links

• Soudan Underground Mine State park (http://www.dnr.state.mn.us/state_parks/soudan_underground_mine/index.html)
• National Register of Historic Places: Mines: Soudan Mine (http://nrhp.mnhs.org/property_overview.cfm?propertyID=1)
• Deep Underground Science and Engineering Laboratory (http://int.phys.washington.edu/NUSEL/) (proposed)