An ore is a natural occurrence of rock or sediment that contains sufficient minerals with economically important elements, typically metals, that can be economically extracted from the deposit.[1] The ores are extracted at a profit from the earth through mining; they are then refined (often via smelting) to extract the valuable element, or elements.

The ore 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 weighed against the metal value contained in the rock to determine what ore can be processed and what ore is of too low a grade to be worth mining. Metal ores are generally oxides, sulfides, silicates, or native metals (such as native copper) that are not commonly concentrated in the Earth's crust, or noble metals (not usually forming compounds) such as gold. The ores must be processed to extract the elements of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological processes. The process of ore formation is called ore genesis.

Manganese ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm)
Lead ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm)
Gold ore (size: 7.5 × 6.1 × 4.1 cm)
Cart for carrying ore from a mine on display at the Historic Archive and Museum of Mining in Pachuca, Mexico

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 a particular ore type. Most ore deposits are named according to their location (for example, the Witwatersrand, South Africa), or after a discoverer (e.g. the Kambalda nickel shoots are named after drillers), or after some whimsy, a historical figure, a prominent person, something from mythology (phoenix, kraken, serepentleopard, etc.) 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).


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

Granite related hydrothermal

Magmatic deposits

Volcanic-related deposits

Classic VMS Deposit2
A cross-section of a typical Volcanic hosted massive sulfide|volcanogenic massive sulfide (VMS) ore deposit

Metamorphically reworked deposits

Carbonatite-alkaline igneous related

Sedimentary deposits

Magnified view of banded iron formation specimen from Upper Michigan. Scale bar is 5.0 mm.

Sedimentary hydrothermal deposits

Astrobleme-related ores


Simplified world mining map 1
Some ore deposits in the world
Simplified world mining map 2
Some additional ore deposits in the world

The basic extraction of ore deposits follows these steps:

  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


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 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-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

See also


  1. ^ Guilbert, John M. and Charles F. Park, Jr. (1986) The Geology of Ore Deposits, W. H. Freeman, p. 1. ISBN 0-7167-1456-6

Further reading

DILL, H.G. (2010) The “chessboard” classification scheme of mineral deposits: Mineralogy and geology from aluminum to zirconium, Earth-Science Reviews, Volume 100, Issue 1-4, June 2010, Pages 1-420


Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (Fe2O3), the aluminium clay mineral kaolinite (Al2Si2O5(OH)) and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO.TiO2).In 1821 the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France.

Bulk carrier

A bulk carrier, bulk freighter, or colloquially, bulker is a merchant ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, and cement, in its cargo holds. Since the first specialized bulk carrier was built in 1852, economic forces have led to continued development of these ships, resulting in increased size and sophistication. Today's bulk carriers are specially designed to maximize capacity, safety, efficiency, and durability.

Today, bulk carriers make up 21% of the world's merchant fleets and range in size from single-hold mini-bulk carriers to mammoth ore ships able to carry 400,000 metric tons of deadweight (DWT). A number of specialized designs exist: some can unload their own cargo, some depend on port facilities for unloading, and some even package the cargo as it is loaded. Over half of all bulk carriers have Greek, Japanese, or Chinese owners and more than a quarter are registered in Panama. South Korea is the largest single builder of bulk carriers, and 82% of these ships were built in Asia.

On bulk carriers, crew are involved in operation management and maintenance of the vessel taking care of safety, navigation, maintenance and cargo care, in accordance with international maritime legislation. Cargo loading operations vary in complexity and loading and discharging of cargo can take several days. Bulk carriers can be gearless (dependent upon terminal equipment) or geared (having cranes integral to the vessel). Crews can range in size from three people on the smallest ships to over 30 on the largest.

Bulk cargo can be very dense, corrosive, or abrasive. This can present safety problems: cargo shifting, spontaneous combustion, and cargo saturation can threaten a ship. The use of ships that are old and have corrosion problems has been linked to a spate of bulk carrier sinkings in the 1990s, as have the bulk carrier's large hatchways. While important for efficient cargo handling, these allow the entry of large volumes of water in storms or if a ship is endangered by sinking. New international regulations have since been introduced to improve ship design and inspection, and to streamline the process of a crew's abandoning ship.


Galena, also called lead glance, is the natural mineral form of lead(II) sulfide. 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 crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.


Hematite, also spelled as haematite, is a common iron oxide with the formula Fe2O3 and is widespread in rocks and soils. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above 950 °C (1,740 °F).

Hematite is colored black to steel or silver-gray, brown to reddish brown, or red. It is mined as the main ore of iron. Varieties include kidney ore, martite (pseudomorphs after magnetite), iron rose and specularite (specular hematite). While the forms of hematite vary, they all have a rust-red streak. Hematite is harder than pure iron, but much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral.

Huge deposits of hematite are found in banded iron formations. Gray hematite is typically found in places that can have still standing water or mineral hot springs, such as those in Yellowstone National Park in North America. The mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can also occur without water, however, usually as the result of volcanic activity.

Clay-sized hematite crystals can also occur as a secondary mineral formed by weathering processes in soil, and along with other iron oxides or oxyhydroxides such as goethite, is responsible for the red color of many tropical, ancient, or otherwise highly weathered soils.

Il Sole 24 Ore

Il Sole 24 Ore (Italian pronunciation: [il ˈsoːle ˌventikwatˈtroːre]) is an Italian national daily business newspaper owned by Confindustria, the Italian employers' federation.

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 colour from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe3O4, 72.4% Fe), hematite (Fe2O3, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe) or siderite (FeCO3, 48.2% Fe).

Ores containing very high quantities of hematite or magnetite (greater than about 60% iron) are known as "natural ore" or "direct shipping ore", meaning they can be fed directly into iron-making 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. Indeed, it has been argued that iron ore is "more integral to the global economy than any other commodity, except perhaps oil".


Manganese is a chemical element with the symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. Manganese is a transition metal with important industrial alloy uses, particularly in stainless steels.

Historically, manganese is named for pyrolusite and other black minerals from the region of Magnesia in Greece, which also gave its name to magnesium and the iron ore magnetite. By the mid-18th century, Swedish-German chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite (now known to be manganese dioxide) contained a new element, but they were unable to isolate it. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon.

Manganese phosphating is used for rust and corrosion prevention on steel. Ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers. Manganese dioxide is used as the cathode (electron acceptor) material in zinc-carbon and alkaline batteries.

In biology, manganese(II) ions function as cofactors for a large variety of enzymes with many functions. Manganese enzymes are particularly essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. While the element is a required trace mineral for all known living organisms, it also acts as a neurotoxin in larger amounts. Especially through inhalation, it can cause manganism, a condition in mammals leading to neurological damage that is sometimes irreversible.


A miner is a person who extracts ore, coal, or other mineral from the earth through mining. There are two senses in which the term is used. In its narrowest sense, a miner is someone who works at the rock face; cutting, blasting, or otherwise working and removing the rock. In a broader sense, a "miner" is anyone working within a mine, not just a worker at the rock face.Mining is one of the most dangerous trades in the world. in some countries, miners lack social guarantees and in case of injury may be left to cope without assistance.

In regions with a long mining tradition, many communities have developed cultural traditions and aspects specific to the various regions, in the forms of particular equipment, symbolism, music, and the like.


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. These deposits form a mineralized package that is of economic interest to the miner.

Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.

Mining of stones and metal has been a human activity since pre-historic times. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, and final reclamation of the land after the mine is closed. De Re Metallica, Georgius Agricola, 1550, Book I, Para. 1Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. Hence, most of the world's nations have passed regulations to decrease the impact. Work safety has long been a concern as well, and modern practices have significantly improved safety in mines.

Levels of metals recycling are generally low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products. Due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves.

My Youth Romantic Comedy Is Wrong, As I Expected

My Youth Romantic Comedy Is Wrong, As I Expected (Japanese: やはり俺の青春ラブコメはまちがっている。, Hepburn: Yahari Ore no Seishun Rabukome wa Machigatteiru.), abbreviated as OreGairu (俺ガイル) and Hamachi (はまち), and also known as My Teen Romantic Comedy SNAFU, is a Japanese light novel series written by Wataru Watari and illustrated by Ponkan8. The series follows Hachiman Hikigaya who is forced by his teacher to join the school's service club, working with two girls who have their own personal issues to offer help and advice to others while dealing with their inner conflicts.

There are three manga adaptations and two anthology volumes. It has been adapted into an anime television series, which aired between April 4 and June 27, 2013 and was followed by a second season which aired between April 2 and June 25, 2015, as well as an upcoming third season. A video game, titled Yahari Game demo Ore no Seishun Rabukome wa Machigatteiru. and published by 5pb., for the PlayStation Vita was released on September 19, 2013. A second video game also by 5pb was released on October 27, 2016.

Norwegian krone

The krone [ˈkruːnə] (sign: kr; code: NOK), plural kroner, is the currency of Norway and its dependent territories. It is subdivided into 100 øre, which have existed only electronically since 2012. The name translates into English as crown.

The krone was the thirteenth most traded currency in the world by value in April 2010, down three positions from 2007.

Ore Mountains

The Ore Mountains or Ore Mountain Range ( ) (German: Erzgebirge [ˈeːɐ̯tsɡəˌbɪɐ̯ɡə]; Czech: Krušné hory; both literally "ore mountains") in Central Europe have formed a natural border between Saxony and Bohemia for around 800 years, from the 12th to the 20th centuries. Today, the border between Germany and the Czech Republic runs just north of the main crest of the mountain range. The highest peaks are the Klínovec (German: Keilberg), which rises to 1,244 metres (4,081 ft) above sea level and the Fichtelberg (1,215 metres (3,986 ft)).

The area played an important role in contributing Bronze Age ore, and as the setting of the earliest stages of the early modern transformation of mining and metallurgy from a craft to a large-scale industry, a process that preceded and enabled the later Industrial Revolution.


Oreimo (俺妹), short for Ore no Imōto ga Konna ni Kawaii Wake ga Nai (俺の妹がこんなに可愛いわけがない, lit. My Little Sister Can't Be This Cute) and also known as Ore no Imōto (俺の妹), is a Japanese light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki. The series includes 12 novels released between August 2008 and June 2013. A manga adaptation drawn by Sakura Ikeda was serialized in ASCII Media Works' Dengeki G's Magazine between 2009 and 2011. AIC produced a 12-episode anime adaptation in 2010, with four additional episodes streamed online in 2011. A-1 Pictures produced a 13-episode second anime season in 2013, with three more episodes streamed online later that year. Bandai Namco Games developed three visual novel video games from 2011 to 2013 for the PlayStation Portable and PlayStation 3 consoles.

Portland, Oregon

Portland is the largest and most populous city in the U.S. state of Oregon and the seat of Multnomah County. It is a major port in the Willamette Valley region of the Pacific Northwest, at the confluence of the Willamette and Columbia rivers. As of 2017, Portland had an estimated population of 647,805, making it the 26th most populated city in the United States, and the second-most populous in the Pacific Northwest (after Seattle). Approximately 2.4 million people live in the Portland metropolitan statistical area (MSA), making it the 25th most populous MSA in the United States. Its Combined Statistical Area (CSA) ranks 18th-largest with a population of around 3.2 million. Approximately 60% of Oregon's population resides within the Portland metropolitan area.Named after Portland, Maine, the Oregon settlement began to be populated in the 1830s near the end of the Oregon Trail. Its water access provided convenient transportation of goods, and the timber industry was a major force in the city's early economy. At the turn of the 20th century, the city had a reputation as one of the most dangerous port cities in the world, a hub for organized crime and racketeering. After the city's economy experienced an industrial boom during World War II, its hard-edged reputation began to dissipate. Beginning in the 1960s, Portland became noted for its growing progressive political values, earning it a reputation as a bastion of counterculture.The city operates with a commission-based government guided by a mayor and four commissioners as well as Metro, the only directly elected metropolitan planning organization in the United States. The city government is notable for its land-use planning and investment in public transportation. Portland is frequently recognized as one of the world's most environmentally conscious cities because of its high walkability, large community of bicyclists, farm-to-table dining, expansive network of public transportation options, and over 10,000 acres (4,000 hectares) of public parks. As a result, Portland consistently ranks highly in quality of life in the United States. Its climate is marked by warm, dry summers and cool, rainy winters. This climate is ideal for growing roses, and Portland has been called the "City of Roses" for over a century.


Smelting is a process of applying heat to ore in order to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal base behind. The reducing agent is commonly a source of carbon, such as coke—or, in earlier times, charcoal.The carbon (or carbon monoxide derived from it) removes oxygen from the ore, leaving the elemental metal. The carbon thus oxidizes in two stages, producing first carbon monoxide and then carbon dioxide. As most ores are impure, it is often necessary to use flux, such as limestone, to remove the accompanying rock gangue as slag.

Plants for the electrolytic reduction of aluminium are also generally referred to as aluminium smelters.

Labourers working in the smelting industry have reported respiratory illnesses inhibiting their ability to perform the physical tasks demanded by their jobs.


Sulfide (British English 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 large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.

Swedish krona

The krona (Swedish: [²kruːna] (listen); plural: kronor; sign: kr; code: SEK) is the official currency of Sweden. Both the ISO code "SEK" and currency sign "kr" are in common use; the former precedes or follows the value, the latter usually follows it but, especially in the past, it sometimes preceded the value. In English, the currency is sometimes referred to as the Swedish crown, as krona literally means "crown" in Swedish. The Swedish krona was the ninth-most traded currency in the world by value in April 2016.One krona is subdivided into 100 öre (singular; plural öre or ören, where the former is always used after a cardinal number, hence "50 öre", but otherwise the latter is often preferred in contemporary speech). However, all öre coins have been discontinued as of 30 September 2010. Goods can still be priced in öre, but all sums are rounded to the nearest krona when paying with cash. The word öre is ultimately derived from the Roman gold coin aureus, which in itself comes from the Latin word aurum, meaning gold.

Øre (lake)

Øre or Ørevatn is a lake in the municipality of Åseral in Vest-Agder county, Norway. The 3.82-square-kilometre (1.47 sq mi) lake is located at the confluence of the rivers Logna and Monn at the village of Kyrkjebygda. Near the southern end of the lake, the river Mandalselva flows southwards. The village of Eikerapen lies along the southwestern shore of the lake.

Ore minerals, mineral mixtures and ore deposits
Deposit types
History of geology
Сomposition and structure
Historical geology

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