In the late 19th century, prospectors searching for gold in northern Minnesota discovered extremely rich veins of hematite at this site, often containing more than 65% iron. An open pit mine began operation in 1882, and moved to underground mining by 1900 for safety reasons. The mine is on the shore of Lake Vermillion in Minnesota. It is operated under the Department of National Resources. The surface is open to the public and during the summer there are tours of the mine.