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low-grade iron ore, a flintlike rock usually containing less than 30% iron. Resistant to drilling and to the extraction of its contained metal, the rock was long considered worthless. Experiments begun in 1912 by the American scientist Edward W. Davis and continued by him for nearly 40 years produced the pelletizing method for upgrading the ore. The development of the jet piercer (a high-temperature flame thrower) provided penetration speeds of up to 40 ft (12 m) an hour for blasting holes in the rock. In 1956 exploitation of the vast reserves of taconite in the Mesabi range of Minnesota was begun by some of the largest steel companies in the United States.



metamorphosed, stratified, ferruginous rock of Precambrian age consisting of metalliferous and nonmetalliferous quartzites and schists alternating with and passing into one another many times. Taconite’s composition may include quartz, hematite, magnetite, biotite, chlorites, amphiboles, and carbonates. In the USSR, Precambrian ferruginous rocks, including ta-conite, are usually referred to as ferruginous quartzites. Taconites, especially magnetite forms, are mined as iron ores, for example, in the Labrador Iron Ore Belt.


The siliceous iron formation from which high-grade iron ores of the Lake Superior district have been derived; consists chiefly of fine-grained silica mixed with magnetite and hematite.
References in periodicals archive ?
Caption: After nine months of construction, United Taconite is churning out Mustang pellets.
And since the taconite is mixed with other minerals in the ore body, it must be extracted onsite in a pelletizing plant, itself a massive industrial plant that will require a lot of power to run.
That's exactly what Paul Plesha did after LTV Steel announced that the taconite mine on Minnesota's Iron Range, where he had worked for twenty-eight years, would shut down.
However, recent cases at the Aberdeen Proving Grounds, Mitsubishi, Texaco, the Eveleth Taconite Mine in the Mesabi Iron Range and elsewhere show that sexism and racism run rampant in US workplaces in 1996.
About half of MP's electric revenue comes from its large industrial customers, including forestry, product mills and the taconite mining industry, the domestic steel industry's main supplier of pelletized iron ore.
The group succeeded in convincing a federal judge to order Reserve to stop dumping its taconite tailings--finely ground particles which contained asbestoslike fibers--into the lake.
That guaranteed mining companies tax parity with other industries when high-grade hematite ore ran out and firms had to reinvest in equipment to process lower-grade taconite.
I was surprised, however, when the article's last paragraph mistakenly credited another utility for the work my company has been doing to help Minnesota's taconite industry improve its efficiency and productivity.
Whole industries, especially those based on natural resources, have risen, declined (or departed), and occasionally repeated the cycle (as with shifts from iron ore to taconite, from lumber milling to paper milling, and from beef to turkey processing).
The 4-year accord covers 11,000 employees at the company's mill in East Chicago, IN, a taconite mine in Virginia, MN, and a lime and stone operation in Gulliver, MI.
The new deal will cover nearly 2,000 USW-represented employees at Cliffs' Tilden and Empire mines in Michigan, and its United Taconite and Hibbing Taconite mines in Minnesota.
The SKF Three-Barrier Solution, consisting of sealed SKF Explorer spherical roller bearings, housings and SKF Taconite Seals, also has been deployed for the mine's overland conveyor belts, with shafts measuring between 500 mm and 700 mm.