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32-426: In Europe in former times, before he could become a hewer, the miner had to learn to be a "sorter boy" ( Scheidejunge ), identifying ores and separating the ore from the gangue . After that he would continue his training in the pit itself. Here, he had to learn further skills, initially as a putter ( Hundtstößer literally "truck pusher"), transporting material around the mine in wagons. Only afterwards could he learn

64-454: A centimeter over several million years. The average diameter of a polymetallic nodule is between 3 and 10 cm (1 and 4 in) in diameter and are characterized by enrichment in iron, manganese, heavy metals , and rare earth element content when compared to the Earth's crust and surrounding sediment. The proposed mining of these nodules via remotely operated ocean floor trawling robots has raised

96-421: A direct result of metamorphism. These are the leading source of copper ore. Porphyry copper deposits form along convergent boundaries and are thought to originate from the partial melting of subducted oceanic plates and subsequent concentration of Cu, driven by oxidation. These are large, round, disseminated deposits containing on average 0.8% copper by weight. Hydrothermal Hydrothermal deposits are

128-449: A large source of ore. They form as a result of the precipitation of dissolved ore constituents out of fluids. Laterites form from the weathering of highly mafic rock near the equator. They can form in as little as one million years and are a source of iron (Fe), manganese (Mn), and aluminum (Al). They may also be a source of nickel and cobalt when the parent rock is enriched in these elements. Banded iron formations (BIFs) are

160-644: A number of ecological concerns. The extraction of ore deposits generally follows these steps. Progression from stages 1–3 will see a continuous disqualification of potential ore bodies as more information is obtained on their viability: With rates of ore discovery in a steady decline since the mid 20th century, it is thought that most surface level, easily accessible sources have been exhausted. This means progressively lower grade deposits must be turned to, and new methods of extraction must be developed. Some ores contain heavy metals , toxins, radioactive isotopes and other potentially negative compounds which may pose

192-399: A preparatory course, which culminated with an in-house examination. Master hewers reported to the mining authority. A particularly experienced hewer who had worked for over 10 years and was at least 35 years old, could, if suitable, be appointed as a "leading hewer" ( Fahrhauer ). In order to achieve this he had to be deemed professionally suitable. His professional suitability was assessed on

224-824: A risk to the environment or health. The exact effects an ore and its tailings have is dependent on the minerals present. Tailings of particular concern are those of older mines, as containment and remediation methods in the past were next to non-existent, leading to high levels of leaching into the surrounding environment. Mercury and arsenic are two ore related elements of particular concern. Additional elements found in ore which may have adverse health affects in organisms include iron, lead, uranium, zinc, silicon, titanium, sulfur, nitrogen, platinum, and chromium. Exposure to these elements may result in respiratory and cardiovascular problems and neurological issues. These are of particular danger to aquatic life if dissolved in water. Ores such as those of sulphide minerals may severely increase

256-513: A single 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 cannot be avoided in mining is known as gangue . The valuable ore minerals are separated from the gangue minerals by froth flotation , gravity concentration, electric or magnetic methods, and other operations known collectively as mineral processing or ore dressing . Mineral processing consists of first liberation, to free

288-539: 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

320-468: A so-called leading hewer's course ( Fahrhauerkurs ), which also acted as a certificate of proficiency. Leading hewers were responsible persons in the sense of the Federal Mining Law ( Bundesberggesetz ) and were given a written order of authority ( Bestellschreiben ). The working hours of the hewers varied from region to region and ranged between 10–12 hours, but the time taking entering and leaving

352-486: A variety of geological processes generally referred to as ore genesis and can be classified based on their deposit type. Ore is extracted from the earth through mining and treated or refined , often via smelting , to extract the valuable metals or minerals. Some ores, depending on their composition, may pose threats to health or surrounding ecosystems. The word ore is of Anglo-Saxon origin, meaning lump of metal . In most cases, an ore does not consist entirely of

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384-478: Is a mineral deposit occurring in high enough concentration to be economically viable. 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

416-410: Is considered alluvial if formed via river, colluvial if by gravity, and eluvial when close to their parent rock. Polymetallic nodules , also called manganese nodules, are mineral concretions on the sea floor formed of concentric layers of iron and manganese hydroxides around a core. They are formed by a combination of diagenetic and sedimentary precipitation at the estimated rate of about

448-547: Is economically viable to mine and process. 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. A complex ore is one containing more than one valuable mineral. Minerals of interest are generally oxides , sulfides , silicates , or native metals such as copper or gold . Ore bodies are formed by

480-511: The US and Japan. For detailed petrographic descriptions of ore minerals see Tables for the Determination of Common Opaque Minerals by Spry and Gedlinske (1987). Below are the major economic ore minerals and their deposits, grouped by primary elements. [REDACTED] Media related to Ores at Wikimedia Commons Oxide mineral The oxide mineral class includes those minerals in which

512-730: The United States and the Shanghai Futures Exchange in China. The global Chromium market is currently dominated by the United States and 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

544-553: The acidity of their immediate surroundings and of water, with numerous, long lasting impacts on ecosystems. When water becomes contaminated it may transport these compounds far from the tailings site, greatly increasing the affected range. Uranium ores and those containing other radioactive elements may pose a significant threat if leaving occurs and isotope concentration increases above background levels. Radiation can have severe, long lasting environmental impacts and cause irreversible damage to living organisms. Metallurgy began with

576-417: The direct working of native metals such as gold, lead and copper. Placer deposits, for example, would have been the first source of native gold. The first exploited ores were copper oxides such as malachite and azurite, over 7000 years ago at Çatalhöyük . These were the easiest to work, with relatively limited mining and basic requirements for smelting. It is believed they were once much more abundant on

608-561: The hewer's exam there was a "graduation" event ( Lossprechung ). An apprentice hewer was placed under a hewer and had to work under his direction. In the dressing area of the mine, old, former hewers were responsible for supervising the sorter boys. The hewer reported to the mine foreman or supervisor, the Steiger , also called the Dinghauer in some mines, or in smaller pits, the Hutmann . The hewer

640-458: The highest concentration of any single metal available. They are composed of chert beds alternating between high and low iron concentrations. Their deposition occurred early in Earth's history when the atmospheric composition was significantly different from today. Iron rich water is thought to have upwelled where it oxidized to Fe (III) in the presence of early photosynthetic plankton producing oxygen. This iron then precipitated out and deposited on

672-620: The main tin source, began. Some 3000 years ago, the smelting of iron ores began in Mesopotamia . Iron oxide is quite abundant on the surface and forms from a variety of processes. Until the 18th century gold, copper, lead, iron, silver, tin, arsenic and mercury were the only metals mined and used. In recent decades, Rare Earth Elements have been increasingly exploited for various high-tech applications. This has led to an ever-growing search for REE ore and novel ways of extracting said elements. Ores (metals) are traded internationally and comprise

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704-505: The mine was not counted. For one week of hired work in 1617 a hewer was paid just 18 Mariengroschen . This week's wages would not even buy a pound of butter at that time. Until the beginning of the 1950s, they worked 5½ days a week comprising 50 hours. Today, the hewer works 7 hours a day without coming to the surface. Ore Ore is natural rock or sediment that contains one or more valuable minerals , typically including metals , concentrated above background levels, and that

736-520: 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 ). Ore deposits are classified according to various criteria developed via the study of economic geology, or ore genesis . The following is a general categorization of the main ore deposit types: Magmatic deposits are ones who originate directly from magma These are ore deposits which form as

768-582: The ocean floor. The banding is thought to be a result of changing plankton population. Sediment Hosted Copper forms from the precipitation of a copper rich oxidized brine into sedimentary rocks. These are a source of copper primarily in the form of copper-sulfide minerals. Placer deposits are the result of weathering, transport, and subsequent concentration of a valuable mineral via water or wind. They are typically sources of gold (Au), platinum group elements (PGE), sulfide minerals , tin (Sn), tungsten (W), and rare-earth elements (REEs). A placer deposit

800-403: The ore from the gangue, and concentration to separate the desired mineral(s) from it. Once processed, the gangue is known as tailings , which are useless but potentially harmful materials produced in great quantity, especially from lower grade deposits. An ore deposit is an economically significant accumulation of minerals within a host rock. This is distinct from a mineral resource in that it

832-447: The pits: initially metalworkers and, later, electricians. Following training and passing exams, the craftsman had to gain practical experience in order to sit for his hewer examination. This comprised a theoretical and a practical element. The hewer exam could be taken once the miner was 20 years old. Between his apprenticeship as a sorter boy and the exam, the trainee hewer thus had at least two years of practical experience. After passing

864-431: 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. China is currently leading in world production of Rare Earth Elements. The World Bank reports that China was the top importer of ores and metals in 2005 followed by

896-406: The rank of supervisor ( Aufsichtshauer ) or senior hewer ( Oberhauer ). They were not, however, supervisory staff in the mining legal sense, but had the role of a team foreman. If a hewer proved to be particularly expert, he would be appointed as a "master hewer" ( Meisterhauer ). He was then responsible for the technical training of junior miners. For this, the master hewer, was specially trained in

928-479: The skills, as an apprentice hewer ( Lehrhäuer ), that he would later need as a hewer. This form of training, the acquisition of knowledge by experience, was practised in mining until the First World War . From the 1920s, the training of hewers was legally regulated as a result of union demands. Because, in the meantime, many skills required special knowledge, other tradesmen were gradually employed in mining and in

960-465: The surface than today. After this, copper sulphides would have been turned to as oxide resources depleted and the Bronze Age progressed. Lead production from galena smelting may have been occurring at this time as well. The smelting of arsenic-copper sulphides would have produced the first bronze alloys. The majority of bronze creation however required tin, and thus the exploitation of cassiterite,

992-485: Was held in particular esteem, by the other miners in the pit, even though he actually had no authority over them. The Steiger , who were important officials in the early days of state mining, later became just ordinary employees. Depending on diligence, skill and suitability, a hewer could be promoted to Hutmann or Steiger . Even an appointment as shift foreman ( Schichtmeister ), to the council of aldermen or jurats ( Berggeschworenen ) or as mine manager ( Bergmeister )

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1024-418: Was possible. At the end of the 18th century, pit and operational officials were legally required to undertake engineering training at a mining academy or mining school. For this reason, the training of a Steiger could no longer be carried out simply through on the job training. Hewers with many years of experience, the ability to lead men and who had sufficient mining and technical skills, could be promoted to

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