is a variety of iron formation, an iron-bearing sedimentary rock, in which the iron minerals are mixed with quartz, chert, or carbonate. The iron content of taconite ore, is generally 25 to 30%. In the late 19th and early 20th centuries, available iron ore was of such high quality that taconite was considered an uneconomic waste product. After much of the high grade iron ore in the United States had been mined out, taconite became a new source of iron.

To process taconite, the ore is ground into a fine powder, the iron is separated from the waste rock by strong magnets, the powdered iron is combined with clay and rolled into ball about one centimeter in diameter. The pellets are heated hardened to make them durable. Since the commercial development of this process, the term taconite has been used globally to refer to iron ores amenable to upgrading by similar processes.

These processed taconite ore pellets are also referred to as "taconite". Because this is the form that is typically transported by rail and ship, and cargo of these is often discussed, this usage of the term is very common.


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