The Vermilion Range exists between

Tower, Minnesota Tower is a city located in Saint Louis County, Minnesota, United States. As of the 2020 census, the city had a total population of 430. State Highways 1 ( MN 1), 169 ( MN 169), and 135 ( MN 135) are three of the main routes in Tower. Tower is l ...

and

Ely, Minnesota Ely ( ) is a city in Saint Louis County, Minnesota, United States. The population was 3,268 at the 2020 census. Located on the Vermilion iron range, Ely once had several iron ore mines. It is an entry point for campers and canoers into the Bou ...

, and contains significant deposits of

iron ore 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 color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the fo ...

. Together with the

Mesabi The Mesabi Iron Range is a mining district in northeastern Minnesota following an elongate trend containing large deposits of iron ore. It is the largest of four major iron ranges in the region collectively known as the Iron Range of Minnesota ...

and

Cuyuna Range The Cuyuna Range is an inactive iron range to the southwest of the Mesabi Range, largely within Crow Wing County, Minnesota. It lies along a line between Brainerd, Minnesota, and Aitkin, Minnesota. The width ranges from 1 to 10 miles (1.6 to 16 ...

s, these three constitute the

Iron Range The term Iron Range refers collectively or individually to a number of elongated iron-ore mining districts around Lake Superior in the United States and Canada. Much of the ore-bearing region lies alongside the range of granite hills formed by ...

s of northern

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

. While the Mesabi Range had iron ore close enough to the surface to enable pit mining, mines had to be dug deep underground to reach the ore of the Vermilion and Cuyuna ranges. The

Soudan mine The Lake Vermilion-Soudan Underground Mine State Park is a Minnesota state park at the site of the Soudan Underground Mine, on the south shore of Lake Vermilion, in the Vermilion Range (Minnesota). The mine is known as Minnesota's oldest, deep ...

was nearly 1/2 mile underground and required blasting of Precambrian sedimentary bedrock.Jackson, Judy
"Notes from Underground"
''Ferminews'', July 19, 2002. The

banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness a ...

in the range consists of a "interbedded sequence" of

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

and hematite. Eleven mines operated in the range, with five in the Ely area. The Ely

Trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

, a synclinal fold, produced 70 million metric tons from the Chandler, Pioneer, Zenith, Sibley and Savoy mines. The largest mine in the range, Soudan, was closed in 1962, and the last mine in the Ely area closed in 1964. Despite the effort needed for the deep mining Soudan mine, the ore obtained was worth the effort; the quality of the

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

ore was so pure that two pieces could be welded. The bedrock, known as

taconite Taconite () is a variety of iron formation, an iron-bearing (over 15% iron) sedimentary rock, in which the iron minerals are interlayered with quartz, chert, or carbonate. The name "taconyte" was coined by Horace Vaughn Winchell (1865–1923) � ...

, also contained iron, but in a much lower concentration. After more efficient practices for creating

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

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. When the newer blast furnaces came into use, the expensive Vermilion Lump was no longer needed. New processes were developed to extract the iron from the taconite by using

open-pit mining Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mining ...

. This method produced ore at a significantly reduced cost. 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.

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{{Coord, 47, 51, N, 92, 4, W, display=title Geology of Minnesota Iron ore deposits Mountain ranges of Minnesota

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