taconite Britannica ConciseLow-grade iron formation (e.g., in Minnesota). Recovery of the iron requires fine grinding and concentration of iron-bearing phases (see mineral processing), which are then formed into pellets suitable for blast furnaces. As high-grade deposits of iron ore have become depleted, taconite deposits have increased in importance. More on "taconite" from the 32 Volume Encyclopædia Britannica:
taconite - a low-grade siliceous iron formation in Minnesota, U.S., from which high-grade iron ore is derived. The iron formation consists of fine-grained silica with variable ratios of hematite and magnetite totaling less than 30 percent iron. Recovery of the iron requires fine grinding and concentration of iron-bearing phases, which in turn are formed into pellets suitable for blast furnaces. As ...
Minnesota - Iron ore accounts for more than 90 percent of the value of all minerals produced in Minnesota. The Mesabi Range, the largest of three iron ranges in the state, began production in 1892 and at its peak produced one-fourth of the world's iron ore. By the late 1950s, however, most of the high-grade natural ores of the Mesabi had been depleted. A process was developed at the University of Minnesota ...
Mesabi Range - largest of three iron ranges in northern Minnesota, U.S. (the others are Vermilion and Cuyuna). It extends 110 miles (180 km) from Babbitt (northeast) to Grand Rapids (southwest) at heights varying from 200 to 500 feet (60 to 150 metres), with a high point of 2,000 feet (610 metres). The great bulk of its iron-ore formation is hard magnetic taconite, which exists in thick layers up to 3 miles (5 ...
iron processing - Crushing and screening are straightforward mechanical operations that do not alter an ore's composition, but some ores need to be upgraded before smelting. Concentration refers to the methods of producing ore fractions richer in iron and lower in silica than the original material. Most processes rely on density differences to separate light minerals from heavier ones, so the ore is crushed and ...
Virginia - city, St. Louis county, northeastern Minnesota, U.S. It lies in the Mesabi Range, about 60 miles (95 km) northwest of Duluth. Iron ore was discovered in 1890 by Leonidas Merritt at the site of the nearby city of Mountain Iron. Two years later ore was found at the site of Virginia, which was then laid out as a mining centre and named for the home state of an area lumberman. The city burned down in ...
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