Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2021Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of Geology: American Geological Institute, 799 p. Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals. The ''grade'' of ore refers to the concentration of the desired material it contains. The value of the metals or minerals a rock contains must be weighed against the cost of extraction to determine whether it is of sufficiently high grade to be worth mining, and is therefore considered an ore. Minerals of interest are generally

oxides An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

sulfides Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

, silicates, or

native metal A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include aluminium, antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, m ...

s such as copper or gold. Ores must be processed to extract the elements of interest from the waste rock. Ore bodies are formed by a variety of geological processes generally referred to as ore genesis.

Ore, gangue, ore minerals, gangue minerals

In most cases, an ore does not consist entirely of a single ore mineral but it is mixed with other valuable minerals and with unwanted or valueless rocks and minerals. The part of an ore that is not economically desirable and that can not be avoided in mining is known as gangue. The valuable ore minerals are separated from the gangue minerals by froth flotation, gravity concentration, and other operations known collectively as mineral processing or ore dressing.

Ore deposits

An ore deposit is an economically significant accumulation of minerals within a host rock. This is distinct from a mineral resource as defined by the mineral resource classification criteria. An ore deposit is one occurrence of a particular ore type. Most ore deposits are named according to their location, or after a discoverer (e.g. the Kambalda nickel shoots are named after drillers), or after some whimsy, a historical figure, a prominent person, a city or town from which the owner came, something from mythology (such as the name of a god or goddess) or the code name of the resource company which found it (e.g. MKD-5 was the in-house name for the Mount Keith nickel sulphide deposit).

Classification

Ore deposits are classified according to various criteria developed via the study of economic geology, or ore genesis. The classifications below are typical.

Hydrothermal epigenetic deposits

* ''Mesothermal'' lode gold deposits, typified by the Golden Mile,

Kalgoorlie Kalgoorlie is a city in the Goldfields–Esperance region of Western Australia, located east-northeast of Perth at the end of the Great Eastern Highway. It is sometimes referred to as Kalgoorlie–Boulder, as the surrounding urban area includ ...

* Archaean

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

hosted gold-uranium deposits, typified by those at

Elliot Lake Elliot Lake is a city in Algoma District, Ontario, Canada. It is north of Lake Huron, midway between the cities of Sudbury and Sault Ste. Marie in the Northern Ontario region. Once dubbed the "uranium capital of the world," Elliot Lake has since ...

, Ontario, Canada and Witwatersrand, South Africa * Carlin–type gold deposits, including; * ''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 in greisen Greisen is a highly altered granitic rock or pegmatite, usually composed predom ...

vein deposits

Granite related hydrothermal

* IOCG or iron oxide copper gold deposits, typified by the supergiant Olympic Dam Cu-Au-U deposit * Porphyry copper +/- gold +/- molybdenum +/- silver deposits * Intrusive-related copper-gold +/- (tin-tungsten), typified by the Tombstone, Arizona deposits * Hydromagmatic magnetite iron ore deposits and skarns * Skarn ore deposits of copper, lead, zinc, tungsten, etcetera

Magmatic deposits

* Magmatic nickel-copper-iron-PGE deposits including ** Cumulate vanadiferous or platinum-bearing magnetite or

chromite Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can s ...

** Cumulate hard-rock titanium ( ilmenite) deposits ** Komatiite hosted Ni-Cu-PGE deposits **

Subvolcanic A subvolcanic rock, also known as a hypabyssal rock, is an intrusive igneous rock that is emplaced at depths less than within the crust, and has intermediate grain size and often porphyritic texture between that of volcanic rocks and plutonic r ...

feeder subtype, typified by Noril'sk-Talnakh and the Thompson Belt, Canada ** Intrusive-related Ni-Cu-PGE, typified by Voisey's Bay, Canada and Jinchuan, China * Lateritic nickel ore deposits, examples include Goro and Acoje, ( Philippines) and Ravensthorpe, Western Australia.

Volcanic-related deposits

* Volcanic hosted massive sulfide (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 Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...

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 Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and Bayan Obo, Mongolia * Diatreme hosted diamond in kimberlite, lamproite or lamprophyre

Sedimentary deposits

* Banded iron formation

iron ore 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 color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the fo ...

deposits, including **

Channel-iron deposits Channel iron deposits (CID) are iron-rich fluvial sedimentary deposits of possible Miocene age occupying meandering palaeochannels in the Early to Mid-Cenozoic Hamerlsey palaeosurface of Western Australia. Examples are also known from Kazakhstan. T ...

or pisolite type iron ore * Heavy mineral sands ore deposits and other

sand dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...

hosted deposits * Alluvial gold, diamond, tin, platinum or black sand deposits * Alluvial oxide zinc deposit type: sole example

Skorpion Zinc Skorpion Zinc is a zinc mine in the ǁKaras Region of southern Namibia, producing Special High Grade (SHG) zinc. The mine is situated near Rosh Pinah. It was established at a cost of US$450 million by Anglo American in 2003. It is the tenth-l ...

Hydrothermal deposits formed largely from basinal brines

Hydrothermal deposits formed by basinal saline fluids, include the following main groups:Arndt, N. and others (2017) Future mineral resources, Chap. 2, Formation of mineral resources
Geochemical Perspectives, v6-1, p. 18-51
* Clastic hosted or

SEDEX Sedimentary exhalative deposits (SEDEX or SedEx deposits) are zinc-lead deposits originally interpreted to have been formed by discharge of metal-bearing basinal fluids onto the seafloor resulting in the precipitation of mainly stratiform ore, ...

Lead- zinc- silver deposits. They are typified, among others, by Red Dog, McArthur River, Mount Isa, Rammelsberg.Leach, D. and others (2010) Sediment-hosted lead-zinc deposits in Earth history. Economic Geology, v. 105, p. 593-625. * Mississippi valley type (MVT) zinc-lead deposits * Sediment-hosted stratiform Cu-Co-(Ag) deposit, typified by the Copperbelt of Zambia and DRC.Sillitoe, R.H., Perello, J., Creaser, R.A., Wilton, J., Wilson, A.J., and Dawborn, T., 2017, Reply to discussions of "Age of the Zambian Copperbelt" by Hitzman and Broughton and Muchez et al.:, p. 1–5, doi: 10.1007/s00126-017-0769-x.

Astrobleme-related ores

Sudbury Basin The Sudbury Basin (), also known as Sudbury Structure or the Sudbury Nickel Irruptive, is a major geological structure in Ontario, Canada. It is the third-largest known impact crater or astrobleme on Earth, as well as one of the oldest. The cra ...

nickel and copper, Ontario, Canada

Extraction

The basic extraction of ore deposits follows these steps: # Prospecting or exploration to find and then define the extent and value of ore where it is located ("ore body"). # Conduct resource estimation to mathematically estimate the size and grade of the deposit. # 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. # 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 Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sc ...

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. # Development of access to an ore body and building of mine plant and equipment. # The operation of the mine in an active sense. # 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 material A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...

s 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 The New York Mercantile Exchange (NYMEX) is a commodity futures exchange owned and operated by CME Group of Chicago. NYMEX is located at One North End Avenue in Brookfield Place in the Battery Park City section of Manhattan, New York City. ...

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 quarterly 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 Niobium is a chemical element with chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has sim ...

- 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 US and Japan.

Important ore minerals

* Acanthite (cooled polymorph of Argentite): Ag₂S for production of silver *

Barite Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

: BaSO₄ * Bauxite Al(OH)₃ and AlOOH, dried to Al₂O₃ for production of aluminium * Beryl: Be₃Al₂(SiO₃)₆ * Bornite: Cu₅FeS₄ *

Cassiterite Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains t ...

: SnO₂ * Chalcocite: Cu₂S for production of copper * Chalcopyrite: CuFeS₂ *

Chromite Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can s ...

: (Fe, Mg)Cr₂O₄ for production of

chromium Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium metal is valued for its high corrosion resistance and hardne ...

* Cinnabar: HgS for production of

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

* Cobaltite: (Co, Fe)AsS * Columbite- Tantalite or Coltan: (Fe, Mn)(Nb, Ta)₂O₆ *

Galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

: PbS * Native gold: Au, typically associated with quartz or as placer deposits *

Hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

: Fe₂O₃ * Ilmenite: FeTiO₃ * Magnetite: Fe₃O₄ * Malachite: Cu₂CO₃(OH)₂ * Molybdenite: MoS₂ * Pentlandite: (Fe, Ni)₉S₈ * Pollucite: *

Pyrolusite Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...

: MnO₂ * Scheelite: CaWO₄ * Smithsonite: ZnCO₃ * Sperrylite: PtAs₂ for production of platinum *

Sphalerite Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimen ...

: ZnS * Uraninite (pitchblende): UO₂ for production of metallic uranium * Wolframite: (Fe, Mn)WO₄

References

External links

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