IRON ORE

The major rock types mined for the production of metallic iron are massive hematite, pisolitic goethite/limonite, which provide a 'high-grade' ore, and banded metasedimentary ironstone, magnetite-rich metasomatite, to a much lesser degree, rocks rich in siderite, rocks rich in chamosite and taconite which provide a 'low-grade' ore.

Hematite is named from the Greek word for blood, haima, because of its reddish colour. The ore has very high iron content, and although the iron content of hematite itself is lower than that of magnetite, the mineral sometimes occurs in higher-grade deposits, often referred to as direct-shipping ore (DSO). This means that, due to its high iron content, such hematite ores may be mined and extracted with a fairly simple crushing and screening process prior to shipping for further industrial uses.

Magnetite ore’s most distinctive property is its magnetism. It is the most magnetic mineral in the world. Additionally, obtaining iron from hematite ore can produce a great deal of carbon emissions, and the process for magnetite ore is much less harmful. End products made from this type of iron ore are also of higher quality than that produced from hematite ore. The former has fewer impurities, making it a premium product that can be sold to steelmakers for higher prices. In this way, the elevated cost of processing magnetite ore can be balanced out.

Ore bearing rock is reduced by blasting into product which, through a sequential crushing process in ball mills, is reduced to powder fine consistency. Magnetic rollers extract the iron concentrate and the waste is transferred to a tailings facility.

Coal, cleaned of impurities in a coking furnace into almost pure carbon, is mixed with fine grained iron ore in a blast furnace to produce pig iron for use in industrial processes like steel making.

Iron ore process