IRON ORE MINING

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, deep purple, to rusty red. The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite, limonite or siderite. Hematite is also known as "natural ore". The name refers to the early years of mining, when certain hematite ores contained 66% iron and could be fed directly into blast furnaces. Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel. 98% of the mined iron ore is used to make steel.
Minnesota's iron ore was actually discovered while prospectors were searching for gold. Since the object of their search was gold, the iron was ignored. It turned out the iron would become much more valuable to northern Minnesota than the small amount of gold found.Iron ore was discovered on the three iron ranges at different times. The first ore shipped from the Vermilion Range was in 1884, the Mesabi Range in 1892, and the Cuyuna Range in 1911.
World consumption of iron ore grows 10% per annum on average with the main consumers being China, Japan, Korea, the United States and the European Union.Iron ore mining methods vary by the type of ore being mined. There are four main types of iron ore deposits worked currently, depending on the mineralogy and geology of the ore deposits. These are magnetite, titanomagnetite, massive hematite and pisolitic ironstone deposits.
Hematite ore
Hematite iron ore deposits are currently exploited on all continents, with the largest intensity of exploitation in South America, Australia and Asia. Most large hematite iron ore deposits are sourced from metasomatically altered banded iron formations and rarely igneous accumulations.Hematite iron is typically rarer than magnetite bearing banded iron formations or other rocks which form its main source or protolith rock, but it is considerably cheaper and easier to beneficiate the hematite ores and requires considerably less energy to crush and grind. Hematite ores however can contain significantly higher concentrations of penalty elements, typically being higher in phosphorus, water content (especially pisolite sedimentary accumulations) and aluminium (clays within pisolites).