An ore is a type of rock In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids that contains minerals A mineral is a naturally occurring solid formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock, by comparison, is an aggregate of minerals and/or mineraloids, and need not have a specific chemical composition. Minerals range in composition such as gemstones A gemstone or gem is a piece of attractive mineral, which—when cut and polished—is used to make jewelry or other adornments. However certain rocks, (such as lapis-lazuli) and organic materials (such as amber or jet) are not minerals, but are still used for jewelry, and are therefore often considered to be gemstones as well. Most gemstones are or metals In chemistry, a metal is an element, compound, or alloy characterized by high electrical conductivity. In a metal, atoms readily lose electrons to form positive ions (cations); those ions are surrounded by delocalized electrons, which are responsible for the conductivity. The thus produced solid is held by electrostatic interactions between the that can be extracted through mining Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or seam. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash. Any material that cannot be grown through agricultural processes, or and refined for use. Samples of ore in the form of exceptionally beautiful crystals A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or crystalline formations of metals such as gold Gold is a chemical element with the symbol Au (Latin: aurum) and an atomic number of 79. It has been a highly sought-after precious metal in jewelry, in sculpture, and for ornamentation since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most or copper Copper is a chemical element with the symbol Cu (Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable and a freshly-exposed surface has a pinkish or peachy color. It is used as a thermal conductor, an electrical conductor, a building material, and a may command a value far beyond their value as mere ore or raw metal for subsequent reduction to utilitarian purposes.

The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighted against the contained metal value of the rock to determine what ore can be profitably extracted and what ore is of too low a grade to be worth mining. Metal ores are generally oxides An oxide is a chemical compound contaning at least one oxygen atom as well as at least one other element. Most of the Earth's crust consists of oxides. Oxides result when elements are oxidized by oxygen in air. Combustion of hydrocarbons affords the two principal oxides of carbon, carbon monoxide and carbon dioxide. Even materials that are, sulfides A sulfide mineral is a mineral containing sulfide as the major anion. Sulfides are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, and the sulfosalts (sulfur and a second anion such as arsenic), silicates The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group. Silicate minerals all contain silicon and oxygen, or "native" metals (such as native copper Copper, as native copper, is one of the few metallic elements to occur in uncombined form as a natural mineral, although most commonly occurs in oxidized states and mixed with other elements. Native copper was an important ore of copper in historic times and was used by pre-historic peoples) that are not commonly concentrated in the Earth's crust In geology, a crust is the outermost solid shell of a rocky planet or moon, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantles or "noble" metals (not usually forming compounds) such as gold Gold is a chemical element with the symbol Au (Latin: aurum) and an atomic number of 79. It has been a highly sought-after precious metal in jewelry, in sculpture, and for ornamentation since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most. The ores must be processed to extract the metals of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological Geology is the science and study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, structure, physical properties, dynamics, and history of Earth materials, and the processes by which they are formed, moved, and changed. The field is a major academic discipline, and is also processes. The process of ore formation is called ore genesis The various theories of ore genesis explain how the various types of mineral deposits form within the Earth's crust. Ore genesis theories are very dependent on the mineral or commodity.

Ore deposits

An ore deposit is an accumulation of ore. This is distinct from a mineral resource as defined by the mineral resource classification criteria. An ore deposit is one occurrence of the particular ore type. Most ore deposits are named according to either their location (for example the Witswatersrand, South Africa), or after a discoverer (eg; the kambalda Kambalda type nickel ore deposits are a class of magmatic nickel-copper ore deposit in which the physical processes of komatiite volcanology serve to enrich, concentrate and deposit nickel-bearing sulfide within the lava flow environment of an erupting komatiite volcano nickel shoots are named after drillers), or after some whimsy, an historical figure, a prominent person, something from mythology (phoenix, kraken, serepentleopard, etc) or the code name of the resource company which found it (eg; MKD-5 is the in-house name for the Mount Keith nickel

Classification of ore deposits

Ore deposits are classified according to various criteria developed via the study of economic geology, or ore genesis The various theories of ore genesis explain how the various types of mineral deposits form within the Earth's crust. Ore genesis theories are very dependent on the mineral or commodity. The classifications below are typical

Hydrothermal epigenetic deposits

• Mesothermal lode In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fissure in a rock formation or a vein of ore that is deposited or embedded between layers of rock gold deposits, typified by the Golden Mile Kalgoorlie, alternatively known as Kalgoorlie-Boulder, is a city in the Goldfields-Esperance region of Western Australia, and is located 595 kilometres east-northeast of Perth, the state capital. The city was founded in 1893 during the Yilgarn-Goldfields gold rush, and is located close to the so-called "Golden Mile", Kalgoorlie Kalgoorlie, alternatively known as Kalgoorlie-Boulder, is a city in the Goldfields-Esperance region of Western Australia, and is located 595 kilometres east-northeast of Perth, the state capital. The city was founded in 1893 during the Yilgarn-Goldfields gold rush, and is located close to the so-called "Golden Mile"
• Archaean The Archean (pronounced /ɑrˈkiːən/, also spelled Archaean, formerly called the Archaeozoic , also spelled Archeozoic or Archæozoic) is a geologic eon before the Proterozoic and Paleoproterozoic, before 2.5 Ga (billion years ago, or 2,500 Ma). Instead of being based on stratigraphy, this date is defined chronometrically. The lower boundary ( conglomerate A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts. Both conglomerates and breccias are characterized by clasts larger than sand (>2 hosted gold-uranium deposits, typified by Elliot Lake Elliot Lake is a city in northern Ontario, Canada, north of Lake Huron in the Algoma District, midway between the cities of Sudbury and Sault Ste. Marie, Canada Canada is a country occupying most of upper North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean. It is the world's second largest country by total area and shares the world's longest common border with the United States to the south and northwest and Witwatersrand The Witwatersrand is a low, sedimentary range of hills, at an elevation of 1700-1800 metres above sea-level, which runs in an east-west direction through Gauteng in South Africa. The word in Afrikaans means "the ridge of white waters". Geologically it is complex, but the principal formations are quartzites, conglomerates and shales of, South Africa The Republic of South Africa, also known by other official names, is a country located at the southern tip of the continent of Africa. The South African coast stretches 2,798 kilometres and borders both the Atlantic and Indian oceans. To the north of South Africa lie Namibia, Botswana and Zimbabwe, to the east are Mozambique and Swaziland, while
• Carlin type gold deposits, including;
  • Dolomite-hosted jasperoid Jasperoid is a rare, peculiar type of metasomatic alteration and occurs in two main forms; sulfidic jasperoids and hematitic jasperoids. True jasperoids are different from jaspillite, which is a form of metamorphosed chemical sedimentary rock, and from jasper which is a chemical sediment replacement subtype
• Epithermal stockwork In geology, a stockwork is a complex system of structurally controlled or randomly oriented veins. Stockworks are common in many ore deposit types and especially notable in greisens. They are also referred to as stringer zones vein deposits

Granite related hydrothermal

• IOCG or iron oxide copper gold deposits Iron oxide copper gold ore deposits are important and highly valuable concentrations of copper, gold and uranium ores hosted within iron oxide dominant gangue assemblages which share a common genetic origin, typified by the supergiant Olympic Dam The deposit was discovered by Western Mining Corporation in 1975 and started production in 1987. It now belongs to BHP Billiton, which acquired WMC Resources in 2005. The mine currently operates by an underground mining method called sublevel open stoping, using modern and highly productive mining equipment. The March 2005 mine production rate is Cu-Au-U deposit
• Porphyry copper Porphyry copper deposits are copper orebodies which are associated with porphyritic intrusive rocks. The ore occurs as disseminations along hairline fractures as well as within larger veins, which often form a stockwork. The orebodies typically contain between 0.4 and 1 % copper with smaller amounts of other metals such as molybdenum, silver and +/- gold +/- molybdenum +/- silver deposits
• Intrusive-related copper-gold +/- (tin-tungsten), typified by the Tombstone, Arizona Tombstone is a city in Cochise County, Arizona, United States, founded in 1879 by Ed Schieffelin in what was then the Arizona Territory. According to 2006 Census Bureau estimates, the population of the city was 1,569 deposits
• Hydromagmatic magnetite Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part wüstite (FeO) and one part hematite (Fe2O3). This iron ore deposits and skarns
• Skarn It usually forms by chemical metasomatism of rocks during metamorphism and in the contact zone of magmatic intrusions like granites with carbonate-rich rocks such as limestone or dolostone ore deposits of copper, lead, zinc, tungsten, etcetera

Nickel-cobalt-platinum deposits

• Magmatic nickel-copper-iron-PGE deposits including
  • Cumulate Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group of igneous rocks vanadiferous Vanadium is the chemical element with the symbol V and atomic number 23. It is a soft, silvery grey, ductile transition metal. The formation of an oxide layer stabilizes the metal against oxidation. Andrés Manuel del Río discovered vanadium in 1801 by analyzing the mineral vanadinite, and named it erythronium. Four years later, however, he was or platinum-bearing magnetite Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part wüstite (FeO) and one part hematite (Fe2O3). This or chromite Chromite is iron magnesium chromium oxide: Cr2O4. It is an oxide mineral belonging to the spinel group. Magnesium can substitute for iron in variable amounts; also, aluminium and ferric iron commonly substitute for chromium
  • Cumulate hard-rock titanium (ilmenite Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite) deposits
  • Komatiite hosted Ni-Cu-PGE deposits Kambalda type nickel ore deposits are a class of magmatic nickel-copper ore deposit in which the physical processes of komatiite volcanology serve to enrich, concentrate and deposit nickel-bearing sulfide within the lava flow environment of an erupting komatiite volcano
  • Subvolcanic feeder subtype, typified by Noril'sk-Talnakh Norilsk is a major city in Krasnoyarsk Krai, Russia. It was granted city status in 1953. It is the northernmost city in Siberia and the world's second largest city (after Murmansk) above the Arctic Circle. Norilsk with Yakutsk and Vorkuta are the only large cities in the continuous permafrost zone. Norilsk is also the northernmost city on the and the Thompson Belt, Canada Canada is a country occupying most of upper North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean. It is the world's second largest country by total area and shares the world's longest common border with the United States to the south and northwest
  • Intrusive-related Ni-Cu-PGE, typified by Voisey's Bay Voisey's Bay is a Canadian bay in the province of Newfoundland and Labrador, Canada and Jinchuan, China

• Lateritic nickel ore deposits Lateritic nickel ore deposits are surficial, weathered rinds formed on ultramafic rocks. They comprise 73% of the continental world nickel resources and will be in the future the dominant source for the winning of nickel, examples include Goro and Acoje, (Philippines The Philippines, officially known as the Republic of the Philippines, is a country in Southeast Asia with Manila as its capital city. It comprises 7,107 islands in the western Pacific Ocean) and Ravensthorpe, Western Australia Western Australia is a state of Australia, occupying the entire western third of the Australian continent. Australia's largest state and the second largest subnational entity in the world, it has 2.1 million inhabitants , 85% of whom live in the south-west corner of the state. The state's capital city is Perth. The people of Western Australia are.

Volcanic-related deposits

• Volcanic hosted massive sulfide Volcanogenic massive sulfide ore deposits or VMS are a type of metal sulfide ore deposit, mainly Cu-Zn-Pb which are associated with and created by volcanic-associated hydrothermal events in submarine environments (VHMS) Cu-Pb-Zn including;
  • Examples include Teutonic Bore and Golden Grove, Western Australia
    • Besshi type
    • Kuroko type

Metamorphically reworked deposits

• Podiform serpentinite-hosted paramagmatic iron oxide-chromite deposits, typified by Savage River, Tasmania iron ore, Coobina chromite deposit
• Broken Hill Type Pb-Zn-Ag, considered to be a class of reworked SEDEX deposits

Carbonatite - alkaline igneous related

• Phosphorus-tantalite-vermiculite (Phalaborwa South Africa)
• Rare earth elements - Mount Weld, Australia and Bayan Obo, Mongolia
• Diatreme hosted diamond in kimberlite, lamproite or lamprophyre

Sedimentary deposits

• Banded iron formation iron ore deposits, including
  • Channel-iron deposits or pisolite type iron ore
• Heavy mineral sands ore deposits and other sand dune hosted deposits
• Alluvial gold, diamond, tin, platinum or black sand deposits
• Alluvial oxide zinc deposit type: sole example Skorpion Zinc

Sedimentary hydrothermal deposits

• SEDEX
  • Lead-zinc-silver, typified by Red Dog, McArthur River, Mount Isa, etc
  • Stratiform arkose-hosted and shale-hosted copper, typified by the Zambian copperbelt.
  • Stratiform tungsten, typified by the Erzgebirge deposits, Czechoslovakia
  • Exhalative spilite-chert hosted gold deposits
• Mississippi valley type (MVT) zinc-lead deposits
• Hematite iron ore deposits of altered banded iron formation

Astrobleme-related ores

• • Sudbury Basin nickel and copper, Ontario, Canada

Extraction

The basic extraction of ore deposits follows the steps below;

1. Prospecting or Exploration to find and then define the extent and value of ore where it is located ("ore body")
2. Conduct resource estimation to mathematically estimate the size and grade of the deposit
3. Conduct a pre-feasibility study to determine the theoretical economics of the ore deposit. This identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work.
4. Conduct a feasibility study to evaluate the financial viability, technical and financial risks and robustness of the project and make a decision as whether to develop or walk away from a proposed mine project. This includes mine planning to evaluate the economically recoverable portion of the deposit, the metallurgy and ore recoverability, marketability and payability of the ore concentrates, engineering, milling and infrastructure costs, finance and equity requirements and a cradle to grave analysis of the possible mine, from the initial excavation all the way through to reclamation.
5. Development to create access to an ore body and building of mine plant and equipment
6. The operation of the mine in an active sense
7. Reclamation to make land where a mine had been suitable for future use

Trade

Ores (metals) are traded internationally and comprise a sizeable portion of international trade in raw materials both in value and volume. This is because the worldwide distribution of ores is unequal and dislocated from locations of peak demand and from smelting infrastructure.

Most base metals (copper, lead, zinc, nickel) are traded internationally on the London Metal Exchange, with smaller stockpiles and metals exchanges monitored by the COMEX and NYMEX exchanges in the United States and the Shanghai Futures Exchange in China.

Iron ore is traded between customer and producer, though various benchmark prices are set yearly between the major mining conglomerates and the major consumers, and this sets the stage for smaller participants.

Other, lesser, commodities do not have international clearing houses and benchmark prices, with most prices negotiated between suppliers and customers one-on-one. This generally makes determining the price of ores of this nature opaque and difficult. Such metals include lithium, niobium-tantalum, bismuth, antimony and rare earths. Most of these commodities are also dominated by one or two major suppliers with >60% of the world's reserves. The London Metal Exchange aims to add uranium to its list of metals on warrant.

The World Bank reports that China was the top importer of ores and metals in 2005 followed by the USA and Japan.

Important ore minerals

• Acanthite: Ag₂S for production of silver
• Barite: BaSO₄
• Bauxite Al₂O₃ for production of aluminium
• Beryl: Be₃Al₂(SiO₃)₆
• Bornite: Cu₅FeS₄
• Cassiterite: SnO₂
• Chalcocite: Cu₂S for production of copper
• Chalcopyrite: CuFeS₂
• Chromite: (Fe, Mg)Cr₂O₄ for production of chromium
• Cinnabar: HgS for production of mercury
• Cobaltite: (Co, Fe)AsS
• Columbite-Tantalite or Coltan: (Fe, Mn)(Nb, Ta)₂O₆
• Galena: PbS
• Gold: Au, typically associated with quartz or as placer deposits
• Hematite: Fe₂O₃
• Ilmenite: FeTiO₃
• Magnetite: Fe₃O₄
• Molybdenite: MoS₂
• Pentlandite:(Fe, Ni)₉S₈
• Pyrolusite:MnO₂
• Scheelite: CaWO₄
• Sphalerite: ZnS
• Uraninite (pitchblende): UO₂ for production of metallic uranium

• Wolframite: (Fe, Mn)WO₄

See also

• Mineral resource classification
• Economic geology
• Ore genesis

Categories: Economic geology

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