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Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite, and the mineral pair forms a buffer that can control how oxidizing its environment is (the oxygen fugacity). This buffer is known as the hematite-magnetite or HM buffer.
Sand used for mining typically had anywhere from 19% magnetite to as low as 2%. The ironsand typically had to be separated from the sand mixture. Because the magnetite is usually heavier than quartz, feldspar, or other minerals, separation was usually done by washing it in sluice boxes (a method similar to gold panning but on a larger scale).
Horizons containing magnetite as the dominant mineral have been extensively mined since 1955 to produce iron ore pellets; the term 'taconite' has consequently been colloquially adapted to describe the magnetite iron-formation ores (taconite iron ore), the mining, milling, magnetic separation, and agglomerating process (taconite process), and ...
Iron mining operations on the Mesabi and Cuyuna Ranges evolved into enormous open pit mines, where steam shovels and other industrial machines could remove massive amounts of ore. Initially the mines exploited large beds of hematite and goethite weathered out of the banded iron formations, and some 2,500,000,000 t (2.5 × 10 9 long tons; 2.8 × ...
As of 2019, magnetite iron ore is mined in Minnesota and Michigan in the United States, eastern Canada, and northern Sweden. [8] Magnetite-bearing banded iron formation is mined extensively in Brazil as of 2019, which exports significant quantities to Asia , and there is a nascent and large magnetite iron ore industry in Australia .
Shaft furnace magnetization roasting is a metallurgical process, mainly used to treat iron ore, so that in a high temperature environment by reacting with reducing agents (such as coal, coke or gas), the iron oxides (such as hematite, limonite, etc.) to reduce to magnetic iron minerals (mainly magnetite).
In June 2011, Richmond Mining LTD, an Australian mining company (RHM:ASX), received a special use permit to develop the Buena Vista Iron Ore Mine in Churchill County, Nevada. The permit includes a 25 miles (40 km) slurry pipeline north to Colado Siding [ 6 ] near Interstate 80 and annual use of up to 1,750 acre-feet (570,000,000 US gal) of water.
Even after improved smelting technology made mined ores viable during the Middle Ages, bog ore remained important into modern times, particularly in peasant iron production. [10] In Russia, bog ore was the principal source of iron until the 16th century, when the superior ores of the Ural Mountains became available. [citation needed]