Vermilion Range (Minnesota)

[1] The banded iron formation in the range consists of a "interbedded sequence" of chert, magnetite and hematite.

The Ely Trough, a synclinal fold, produced 70 million metric tons from the Chandler, Pioneer, Zenith, Sibley and Savoy mines.

After more efficient practices for creating steel were discovered, the use of this high-quality ore was abandoned due to its more costly mining expense.

The Soudan hematite was used in the open hearth furnace, where the density of the ore, called Vermilion Lump, was needed to break through the floating slag to cause the molten charge to roil and burn off the impurities.

Once proven successful, the technical change resulted in Minnesota's iron industry centering on the Mesabi Range, where the taconite was much easier to access.