Ore

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For other uses, see Ore (disambiguation).

Image:Banded iron formation.jpg Image:ManganeseOreUSGOV.jpg Image:LeadOreUSGOV.jpg Image:GoldOreUSGOV.jpg

An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. An ore must contain materials which are:

  • valuable
  • in concentrations which can be profitably mined
  • able to be extracted from waste rock by mineral processing techniques.

Ore deposits are mineral deposits defined as being economically recoverable. Mineral deposits may include those bodies of mineralisation which are uneconomic resources, of too low a grade or tonnage or technically impossible for extraction of the contained metal.

What is valuable to mine is generally considered in terms of purely economic considerations. However, cultural, strategic or social goals of nations, tribes and individuals may render economically unfeasible bodies of rock valuable for extraction, for instance ochre, some clays and ornamental stones which are of religious, cultural or sentimental value to a population. Here, value is placed on the rock in non-economic terms.

Ore is thus an economic entity, not a physical entity. Fluctuations in commodity prices will determine what rock is considered valuable and hence ore, and what rock is not valuable and is considered waste. Similarly, the costs of extraction may fluctuate, for example with fuel costs, rendering mining unprofitable and turning ore into waste.

The grade or contained 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 and a 'cut-off grade' used to define what is ore and what is waste.

Ore minerals are generally oxides, sulfides, silicates, or native metals that are not commonly concentrated in the Earth's crust. 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 processes. The process of ore formation is called ore genesis.

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Important ore minerals

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See also

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da:Malm de:Erze et:Maak eo:Erco fr:Minerai lt:Rūda nl:Erts no:Malm (geologi) nn:Malm pl:Ruda pt:Minério ru:Руда simple:Ore sl:Ruda fi:Malmi sv:Malm

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