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- Le gisement du Vermilion Range (Minnesota), situé entre la Tour et Ely, Minnesota, contient d'importants gisements de minerai de fer exploités à grande échelle à partir de 1884, et fait partie de l'ensemble minier de l'Iron Range du nord du Minnesota, à l'intérieur de la chaîne de montagne américaine de l'Iron Range, avec le gisement de Mesabi Range exploité à partir de 1892 et le gisement du Cuyuna Range mis en service vers 1911. Alors que les monts Mesabi avaient du minerai de fer assez près de la surface pour permettre l'exploitation à ciel ouvert, des mines ont été creusées profondément sous terre pour atteindre le minerai du Vermilion Range et du gisement du Cuyuna Range. La plus grande mine du Vermilion Range, Soudan, a été fermée en 1962, et la dernière mine, dans la zone Ely, fermée en 1964. La qualité de l'hématite était si pure que deux morceaux pouvaient être soudés. (fr)
- The Vermilion Range exists between Tower, Minnesota and Ely, Minnesota, and contains significant deposits of iron ore. Together with the Mesabi and Cuyuna Ranges, these three constitute the Iron Ranges of northern Minnesota. 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 was nearly 1/2 mile underground and required blasting of Precambrian sedimentary bedrock. The banded iron formation in the range consists of a "interbedded sequence" of chert, magnetite and hematite. Eleven mines operated in the range, with five in the Ely area. The Ely Trough, 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 ore was so pure that two pieces could be welded. The bedrock, known as taconite, also contained iron, but in a much lower concentration. 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. 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. 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. (en)
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- The Vermilion Range exists between Tower, Minnesota and Ely, Minnesota, and contains significant deposits of iron ore. Together with the Mesabi and Cuyuna Ranges, these three constitute the Iron Ranges of northern Minnesota. 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 was nearly 1/2 mile underground and required blasting of Precambrian sedimentary bedrock. (en)
- Le gisement du Vermilion Range (Minnesota), situé entre la Tour et Ely, Minnesota, contient d'importants gisements de minerai de fer exploités à grande échelle à partir de 1884, et fait partie de l'ensemble minier de l'Iron Range du nord du Minnesota, à l'intérieur de la chaîne de montagne américaine de l'Iron Range, avec le gisement de Mesabi Range exploité à partir de 1892 et le gisement du Cuyuna Range mis en service vers 1911. La plus grande mine du Vermilion Range, Soudan, a été fermée en 1962, et la dernière mine, dans la zone Ely, fermée en 1964. (fr)
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