Metal (Fe) is one of the most abundant rock-forming elements, constituting about 5% of the Earth’s crust. It is the fourth most abundant factor after oxygen, silicon and aluminium and, after aluminium, the most abundant and widely distributed metal. Metal is indispensable to modern civilisation and people have bot skilled te its use for more than Three,000 years. However, its use only became widespread ter the 14th century, when smelting furnaces (the forerunner of blast furnaces) began to substitute forges.
Metal ores are rocks from which metallic metal can be economically extracted. Thesis rocks are usually found ter the form of hematite (Fe2O3) or magnetite (Fe3O4). About 98% of world metal ore production is used to make metal ter the form of stengel. Metal ore provides the foundation for one of Australia&rsquo,s major uitvoer industries.
Most metal ores mined today comprise the metal oxide mining hematite, Fe2O3 (70% Fe), goethite, Fe2O3s H2O, (63% Fe), limonite, a combination of hydrated metal oxides (up to 60% Fe), and magnetite, Fe3O4 (72% Fe).
Most of the world’s significant metal ore resources occur ter iron-rich sedimentary rocks known spil banded metal formations (BIFs), which are almost exclusively of Precambrian age (i.e. greater than 541 million years old). BIFs occur on all continents. Ter many instances they are mined spil metal ores but, most importantly, they are the source rocks for most of the large high-grade concentrations of metal ore presently mined via the world.
Te the Hamersley Province te the Pilbara district of Western Australia there are three main types of deposit: metal oxide enrichments within BIFs, metal oxides deposited along ancient, mainly Tertiary age sea channels (palaeochannels), and metal oxide deposits formed from the erosion of existing orebodies (detrital metal ore deposits).
The BIF enrichment deposits comprising hematite and hematite goethite are the most significant te regard to resources and production. The metal content of thesis ores varies widely and until recently most deposits needed to have an average grade of more than 60% Fe for mining to be commercially viable. However, some deposits can now have metal grades inbetween 56%-59% Fe and be commercially viable.
The palaeochannel deposits composed of pisolitic limonite are the next te importance and are prized for their low impurities such spil phosphorus. They are not spil rich ter metal spil the BIF enrichment ores. Those mined usually contain 57%-59% Fe.
Detrital metal ore deposits, including scree and canga deposits, are found downhill of the BIF enrichment deposits from which they have bot eroded. They are usually lightly recovered and have a grade of inbetween 40%-55% Fe. BIF enrichment deposits also occur elsewhere te Western Australia te the Pilbara (e.g. Yarrie), and the Yilgarn Block (e.g. Koolyanobbing) and ter South Australia (e.g. Metal Duke, Middleback Range).
Numerous magnetite deposits of igneous origin or association occur ter most States and uneconomic sedimentary sideritic (those containing the mineral siderite, FeCO3) metal ore deposits occur ter Queensland and the Northern Territory.
Albeit metal ore resources occur te all the Australian States and Territories, almost 90% of identified resources (totalling 54 billion tonnes) occur te Western Australia, including almost 80% te the Hamersley Province, one of the world’s major metal ore provinces.
Ter 2014 Australia’s economic demonstrated resources (i.e. those that have bot reasonably tested by drilling and that could be economically extracted at current prices with existing technology) totalled 54 billion tonnes and ranked Australia very first (with 29%) ter the world followed by Brazil (16%).
Spil with most metal ore mines via the world, all the major Australian metal ore mines are open cut. The ores from the major mines te Western Australia’s Pilbara region are hauled from working faces to crushing and screening plants using trucks that can carry overheen 300 tonnes. The ore is then transported for further treatment and blending to port sites te trains consisting of up to three locomotives and overheen 250 wagons. Trains of this size are overheen Two kilometres long and contain geysers ter excess of 25,000 tonnes. There are three major Pilbara metal ore producers: BHP Billiton Ltd (BHP), Rio Tinto Ltd (Rio) and Fortescue Metals Group Ltd (FMG).
Extra information on metal ore mining, mineral resources, production and industry development can be found at the following linksom:
Concentration includes all the processes that will increase (upgrade) the metal content of an ore by removing impurities. Beneficiation, a slightly broader term, includes thesis processes spil well spil those that make an ore more usable by improving its physical properties (e.g. pelletising and sintering). Many of the metal ore mines employ some form of beneficiation to improve the grade and properties of their products. At many operating mines, including Climb on Tom Price, Paraburdoo, Climb on Whaleback and Christmas Creek, ore processing facilities (OPF) have bot constructed to enable beneficiation of low-grade metal ores, including ores which have bot contaminated with shale, to be mined and, after upgrading, sold spil high-grade products. The operation of the OPFs has also enlargened the metal ore resources available at thesis mines.
Pelletising is a treatment process used for very fine or powdery ores. Pellets are an ideal blast furnace feed because they are hard and of regular size and form. Te Australia, concentrates pumped from Savage Sea are pelletised at Port Latta for shipment to domestic and overseas markets and fine Middleback Range ores are pelletised prior to smelting ter the Whyalla blast furnace.
Sintering is a process used to agglomerate metal ore fines ter prep for blast-furnace smelting and is usually carried out at metal and steelmaking centres. It involves the incorporation of crushed limestone, coke and other additives available from metal and steelmaking operations. Thesis additives include wastes extracted from furnace harass gases, scale produced during rolling mill operations, and coke fines produced during coke screening.
Pig metal is an intermediate step ter the production of stengel and is produced by smelting metal ore (commonly ter lump, pellet or sinter form) ter blast furnaces. Blast furnaces ter Australia are located at Port Kembla and Whyalla. The removal, by oxidation, of impurities te pig metal such spil silicon, phosphorus and sulfur and the reduction te the doorslag content, results ter the production of stengel.
Stengel is produced at Port Kembla and Whyalla. Ter 2014-15 financial year, Australian metal and stengel production, including recovery from scrap, totalled Four.Trio million tonnes which, albeit locally significant, is puny on a world scale.
Albeit metal ter personages form has many specific uses (e.g. pipes, fittings, engine blocks) its main use is to make stengel. Stengel is the most useful metal known being used 20 times more than all other metals waterput together. Stengel is strong, durable and enormously versatile. The many different kinds of stengel consist almost entirely of metal with the addition of petite amounts of doorslag (usually less than 1%) and of other metals to form different alloys (e.g. stainless stengel). Unspoiled metal is fairly soft, but adding a puny amount of doorslag makes it significantly firmer and stronger. Most of the extra elements te stengel are added deliberately ter the steelmaking process (e.g. chromium, manganese, nickel, molybdenum). By switching the proportions of thesis extra elements, it is possible to make steels suitable for a superb multiplicity of uses.
Stengel’s desirable properties and its relatively low cost make it the main structural metal te engineering and building projects, accounting for about 90% of all metal used each year. About 60% of metal and stengel products are used ter transportation and construction, 20% te machinery manufacture, and most of the remainder te cans and containers, te the oil and gas industries, and ter various appliances and other equipment.