Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, deep purple, to rusty red. The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite, limonite or siderite. Hematite is also known as “natural ore”. The name refers to the early years of mining, when certain hematite ores contained 66% iron and could be fed directly into blast furnaces. Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel. 98% of the mined iron ore is used to make steel.

Minnesota’s iron ore was actually discovered while prospectors were searching for gold. Since the object of their search was gold, the iron was ignored. It turned out the iron would become much more valuable to northern Minnesota than the small amount of gold found.

Iron ore was discovered on the three iron ranges at different times. The first ore shipped from the Vermilion Range was in 1884, the Mesabi Range in 1892, and the Cuyuna Range in 1911.