Ore is natural rock or

sediment Sediment is a naturally occurring material that is broken down by processes of weathering Weathering is the deterioration of rocks, soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, ...

that contains one or more valuable

mineral In geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly ove ...

s, typically containing

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat In thermodynamics, heat i ...

s, 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 Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econ ...

and treated or refined, often via

smelting Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver Silver is a chemical element A chemical element ...

, 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 A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atom Every atom is composed of a nucleus and one or more electrons bound to th ...

, sulfides, silicates, or native metals such as

copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal and electrical conductivity. A fre ...

gold Gold is a chemical element with the Symbol (chemistry), symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a Brightness, bright, slightly orange-yellow, dense, s ...

. Ores must be processed to extract the elements of interest from the waste rock. Ore bodies are formed by a variety of

geological Geology () is a branch of natural science concerned with Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System ...

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 In mining, gangue () is the commercially worthless material that surrounds, or is closely mixed with, a wanted mineral In geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the feat ...

. The valuable ore minerals are separated from the gangue minerals by

froth flotation Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Sc ...

, gravity concentration, and other operations known collectively as

mineral processing In the field of extractive metallurgy, mineral processing, also known as ore dressing, is the process of separating commercially valuable minerals from their ores. History Before the advent of heavy machinery the raw ore was broken up usi ...

ore dressing In the field of extractive metallurgy, mineral processing, also known as ore dressing, is the process of separating commercially valuable minerals from their ores. History Before the advent of heavy machinery the raw ore was broken up usi ...

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 In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fissure (or crack) in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning (ore vein) dates from th ...

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 Perth is the list of Australian capital cities, capital and largest city of the Australian states and territories of Austr ...

* Archaean conglomerate hosted gold-uranium deposits, typified by those at Elliot Lake, Ontario, Canada and Witwatersrand,

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

* Carlin–type gold deposits, including; * ''Epithermal'' stockwork 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 Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet A magnet is a material or object that produces a magnetic ...

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

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 The oxide mineral class includes those minerals in wh ...

** Cumulate hard-rock titanium ( ilmenite) deposits ** Komatiite hosted Ni-Cu-PGE deposits ** Subvolcanic 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 The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

) and Ravensthorpe,

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

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-

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

) * Rare-earth elements – Mount Weld,

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country b ...

and

Bayan Obo Bayan'obo Mining District, ( Mongolian: ''Bayan Oboɣ-a Aɣurqai-yin toɣoriɣ'', Баян-Овоо Уурхайн тойрог ( mn, italic=yes, "rich" + ovoo Ovoo, oboo, or obo ( mn, овоо, bua, обоо, kjh, обаа, Tradition ...

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Easter ...

* Diatreme hosted diamond in kimberlite, lamproite or lamprophyre

Sedimentary deposits

Banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thicknes ...

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 t ...

deposits, including ** Channel-iron deposits or pisolite type iron ore * Heavy mineral sands ore deposits and other

sand dune A dune is a landform A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topo ...

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

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

Lead Lead is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cann ...

zinc Zinc is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cann ...

silver Silver is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements ...

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 Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are ...

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 nickel and copper, Ontario, Canada

Extraction

The basic extraction of ore deposits follows these steps: # Prospecting or

exploration Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians. Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most ...

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 ...

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 feed ...

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 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 Lithium (from el, λίθος, lithos, lit=stone) is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unli ...

niobium Niobium is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements c ...

- 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 The World Bank is an international financial institution that provides loans and grants to the governments of low- and middle-income countries for the purpose of pursuing capital projects. The World Bank is the collective name for the Int ...

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

* Barite: BaSO₄ *

Bauxite Bauxite is a sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name fo ...

Al(OH)₃ and AlOOH, dried to Al₂O₃ for production of

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that speci ...

Beryl Beryl ( ) is a mineral composed of beryllium aluminium Aluminium (aluminum in American and Canadian English) is a chemical element A chemical element is a species of atoms that have a given number of protons in their nucl ...

: Be₃Al₂(SiO₃)₆ * Bornite: Cu₅FeS₄ * Cassiterite: SnO₂ * Chalcocite: Cu₂S for production of

* 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 The oxide mineral class includes those minerals in wh ...

: (Fe, Mg)Cr₂O₄ for production of

chromium Chromium is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements c ...

Cinnabar Cinnabar (), or cinnabarite (), from the grc, κιννάβαρι (), is the bright scarlet to brick-red form of Mercury sulfide, mercury(II) sulfide (HgS). It is the most common source ore for refining mercury (element), elemental mercury and ...

: HgS for production of mercury * Cobaltite: (Co, Fe)AsS * Columbite- Tantalite or Coltan: (Fe, Mn)(Nb, Ta)₂O₆ * Galena: PbS * Native gold: Au, typically associated with

quartz Quartz is a hard, crystalline mineral In geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they chang ...

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 soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gase ...

: Fe₂O₃ * Ilmenite: FeTiO₃ *

Magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet A magnet is a material or object that produces a magnetic ...

: Fe₃O₄ *

Malachite Malachite is a copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal and e ...

: Cu₂CO₃(OH)₂ * Molybdenite: MoS₂ * Pentlandite: (Fe, Ni)₉S₈ * Pollucite: *

Pyrolusite Pyrolusite is a mineral In geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern ...

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

platinum Platinum is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical element ...

* Sphalerite: ZnS * Uraninite (pitchblende): UO₂ for production of metallic

uranium Uranium is a chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements c ...

* Wolframite: (Fe, Mn)WO₄

References

External links

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