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How taconite became a viable commercial product

Identified in the late 19th century, it took the depletion of natural iron ores in Minnesota for low-iron taconite to come to the fore.

historical aerial photo of taconite plant
United States Steel’s Extaca plant, 1960. The Oliver Mining Division of USS built the Extaca plant to accompany the Pilotac plant in the development of feasible taconite processing methods.

Though taconite was identified as an iron-bearing rock on the Iron Ranges of northern Minnesota long before the 1950s, it wasn’t until then that it was profitably extracted, processed, and shipped to steel mills on the Great Lakes. As natural ore reserves were diminished, taconite became an alternative source of iron that allowed the Iron Range to continue mining operations in a changing global economy.

The word taconite is derived from the Taconic Mountains of New England, with “taconic” coming from an Eastern Algonquian language — probably Mohican or Lenape. Newton Horace Winchell, Minnesota’s state geologist, created the name in 1892 after he noticed that the rocks in New England looked like the rocks plentiful throughout the Iron Range in Minnesota. The geological structure of taconite, however, is different from the rocks of the Taconics. Taconite has a very low iron content — at best, only 32.5 percent of the rock is iron ore. Since there were many accessible deposits of natural ore with iron contents closer to 60 percent of the rock, taconite was at first passed over in favor of ore that could be shipped directly to smelters without processing.

Taconite was officially documented on the Mesabi Iron Range years before mineable natural ore was found near Mountain Iron. In 1870, prospectors Christian Wieland and Peter Mitchell traveled to the Mesabi Range and found a massive deposit of taconite near current-day Babbitt. They bought the land and incorporated the Mesaba Iron Company in 1882. After the Merritt brothers began mining natural ore on other parts of the Mesabi, Mesaba Iron faded into obscurity until the Mesabi Syndicate was formed in 1915.

A key member of the Mesabi Syndicate was Edward W. Davis—a researcher at the University of Minnesota’s Mines Experiment Station, which was founded in 1914. Researchers at the Minnesota Experiment Station found that the iron in taconite can be accessed by grinding the rock into fine particles and then running them through magnets to separate the iron from the waste rock. Using this information, Davis and the Mesabi Syndicate made an existing camp, the Sulphur Camp, as their headquarters.

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The Syndicate mined the taconite and tested it to see if it could consolidate the iron into pieces suitable for smelting. The first product they created was called sinter, which was a rock-like product that had higher iron content than raw taconite. This research led to the incorporation of the Mesabi Iron Company in 1919, which opened the first commercial taconite facility on the Iron Range.

The Mesabi Iron Company was largely unsuccessful. The sinter product couldn’t compete with the natural ore mined elsewhere on the Mesabi Range. In 1924, only two years after shipping its first load of sinter, the Mesabi Iron Company suspended mining. The cost of processing the ore was too high and their main customer — the Ford Motor Company — was dissatisfied with the low-iron product.

In the years that followed, heightened production for the war effort depleted natural ore reserves. The Mines Experiment Station continued to refine the process for taconite production, introducing methods that reduced lost iron in waste rock. As taconite became a viable replacement for natural ore mining, advocates throughout the state pushed for favorable taxation for taconite mining. In 1964, the Minnesota Legislature passed a bill and a statewide referendum was approved, placing the taconite amendment into the Minnesota Constitution.

The first taconite mine was run by the Reserve Mining Company, which shipped its first load in 1955. The pit was located near Babbitt, and the processing facilities were on Lake Superior. Reserve Mining faced controversy when fishermen and conservationists questioned whether depositing tailings into Lake Superior was healthy for fish and humans. This led to a lawsuit that gave the new Environmental Protection Agency regulatory powers in the 1970s.

In the 1980s, the steel industry slowed its production due to global competition. As a result, taconite plants on the Mesabi Range idled, plants were sold to competitors, and some closed for good. Even with a changing steel industry, however, taconite continued to play a major role in sustaining the Iron Range economy.

For more information on this topic, check out the original entry on MNopedia.