An
ore is a type of
rock that contains
minerals with important elements including
metals. The ores are extracted through
mining; these are then refined to extract the valuable element(s).
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 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 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.
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 (e.g. the
kambalda 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 (e.g. MKD-5 is the in-house name for the Mount Keith nickel ).
Classification of ore depositsOre deposits are classified according to various criteria developed via the study of economic geology, or
ore genesis. The classifications below are typical.
Hydrothermal epigenetic depositsGranite related hydrothermalNickel-cobalt-platinum depositsVolcanic-related depositsMetamorphically reworked deposits
Carbonatite-alkaline igneous relatedSedimentary depositsSedimentary hydrothermal depositsAstrobleme-related ores
Sudbury Basin nickel and copper, Ontario, Canada
ExtractionThe basic extraction of ore deposits follows the steps below;
- 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 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 to create 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
A schematic showing the locations of certain ores deposits in the world. A specific focus has been put on metals, and construction materials. Natural resources that are used for energy (fossil oil, gas ...) can be found on another map. Although metals can still be won from regular mining, most metals, ... can now be much more economically won from landfills. This, as landfills require much less labour (less soil needs to be dug off and sieved). In addition, the use of a cradle-to-cradle material recovery can also save a lot of labour and is therefore also more economically attractive. For some materials however, regular mining will still need to continue. In this case, it is best to choose ore sites that are located in biodiversity-poor regions (e.g. mountainous regions, regions outside of the tropical-subtropical zone). As the map is simplified, we can herefore study the maps from the USGS at mrdata.usgs.gov ; the database is also usable with Google Earth, see www.gelib.com/world-mineral-resources.htm The map was made using data from Howstuffworks (maps.howstuffworks.com/world-energy-minerals-map.htm )
Some additional ore deposits in the world. The map was made using data from the book "Future Energy and Resources" by Robin Kerrod and "Working with the oceans" by Lawrence Williams and Alan CollinsonTradeOres (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 USA and Japan.
Important ore mineralsSee alsoConvince yourself of our products for your applications.
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