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Chuquicamata, Chile, site of the largest circumference and second deepest open pit copper mine in the world.
Break time underground, Colorado, ca. 1900
.Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or (coal) seam.^ When the coal seam is fairly close to the surface yet too deep to use surface mining, a slope mine can be built, with the mine entrance being a tunnel which slants down from the surface to the coal seam.

^ A drift mine is a mine in which the entry is directly into a horizontal coal seam exposed at or near the surface.

^ Surface mining is used when a coal seam is located close to the surface.

.Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash.^ The former term is used in metal -mines and the latter in coal-mining.

^ Special methods of mining are dealt with in the separate articles on Coal, Gold , and other minerals and metals.

^ A fire underground speedily becomes formidable, not only in coal but also in metal mines, on account of the large quantity of timber used to support the excavations.

.Any material that cannot be grown through agricultural processes, or created artificially in a laboratory or factory, is usually mined.^ The cost of filling has been greatly reduced by the system of flushing culm , sand , gravel and similar material, through pipes leading from the surface into mine workings.

Mining in a wider sense comprises extraction of any non-renewable resource (e.g., petroleum, natural gas, or even water).
Mining of stone and metal has been done 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 finally reclamation of the land to prepare it for other uses once the mine is closed.^ The valuation of mines then involves the following steps: (1) The sampling of the deposit so far as developed, and assaying of the samples taken; (2) The measurement of the developed ore; (3) estimates of the probable amount of ore in the undeveloped part of the property; (4) estimates of probable profits, life of the mine, and determination of the value of the property.

^ Instead of mining in horizontal floors the filling method permits the ore to be mined in vertical chambers or slices which extend from one level to the next above and from one wall of the deposit to the other.

^ Objective : Students will gain and demonstrate knowledge of the process used in mining coal .

.The nature of mining processes creates a potential negative impact on the environment both during the mining operations and for years after the mine is closed.^ In mining regions where 'water transportation is interrupted during certain months of the year the mineral must be stored underground, or in great stock-piles on the surface.

.This impact has led to most of the world's nations adopting regulations to moderate the negative effects of mining operations.^ This has a serious effect on the health and efficiency of the workmen employed, and in extreme cases may even result in increased cost of mining operations.

.Safety has long been a concern as well, though modern practices have improved safety in mines significantly.^ Man-engines were long used, but are now practically abandoned in both Great Britain and the United States, and few remain in any of the mining regions of the world.

Contents

History

Prehistoric mining

Chalcolithic copper mine in Timna Valley, Negev Desert, Israel.
Since the beginning of civilization, people have used stone, ceramics and, later, metals found on or close to the Earth's surface. These were used to manufacture early tools and weapons, for example, high quality flint found in northern France and southern England were used to create flint tools.[1] .Flint mines have been found in chalk areas where seams of the stone were followed underground by shafts and galleries.^ As soon as it appears reasonably certain that the property is workable the mine will be opened by one or more shafts, drifts or tunnels, and the underground passages for active mining operations will be started.

^ In mines operated through shafts the animals are stabled underground, and when well fed and cared for, thrive notwithstanding their rather abnormal conditions of life.

.The mines at Grimes Graves are especially famous, and like most other flint mines, are Neolithic in origin (ca 4000 BC-ca 3000 BC).^ In other cases the life of the mine, like the value of the mineral, is more or less uncertain.

^ The examination of the air of metal mines has shown that in most cases it is much worse than the air of crowded theatres or other badly ventilated buildings.

^ At Bendigo in Australia are several shafts between 3000 and 4000, and one, the Victoria Quartz mine, 43 00 ft.

.Other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District.^ If rock-filling must be brought from the surface its use will generally be confined to mines in which it is difficult to support the roof in any other way.

^ The shape of the hills and ridges is necessarily influenced by the inclination of the strata, by the relative hardness of different rock-beds, and by the presence of folds and fissures and other lines of weakness.

The oldest known mine on archaeological record is the "Lion Cave" in Swaziland. .At this site, which by radiocarbon dating proves the mine to be about 43,000 years old, paleolithic humans mined mineral hematite, which contained iron and was ground to produce the red pigment ochre.^ In mining regions where 'water transportation is interrupted during certain months of the year the mineral must be stored underground, or in great stock-piles on the surface.

^ Mine law is that branch of the law of real property relating to mineral and mining rights as distinct from rights pertaining to the surface of the ground.

^ The floor containing these old haulage roads now becomes the top slice of the one hundred-foot block of ground below and is mined out as described.

[2][3] Mines of a similar age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons and tools.[citation needed]

Ancient Egypt

Ancient Egyptians mined malachite at Maadi.[4] At first, Egyptians used the bright green malachite stones for ornamentations and pottery. .Later, between 2,613 and 2,494 BC, large building projects required expeditions abroad to the area of Wadi Maghara in order "to secure minerals and other resources not available in Egypt itself."^ In the case of coal, salt , iron ore, pyrite and other homogeneous minerals, boring may give all the information required.

[5] Quarries for turquoise and copper were also found at "Wadi Hamamat, Tura, Aswan and various other Nubian sites"[5] on the Sinai Peninsula and at Timna. .Mining in Egypt occurred in the earliest dynasties, and the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt, and are described by the Greek author Diodorus Siculus.^ From very ancient times deposits of gold and silver have in most countries been held as the property of the crown .

.He mentions that fire-setting was one method used to break down the hard rock holding the gold.^ It is necessary, however, to keep the mine sealed until the burning timbers, or coal, and the red-hot rocks have become cool, or the fire will again break out.

^ The principal item in mining cost is that of labour, which is expended chiefly in breaking down the mineral, either by the use of hand tools or with the aid of powder .

^ In the United States the Nevada square set system of timbering is used in connexion with rock filling (fig.

One of the complexes is shown in one of earliest known maps. .They crushed the ore and ground it to a fine powder before washing the powder for the gold dust.^ Grains of gold or particles of ore may be detected by washing samples of gravel in a prospector's 1 Of doubtful origin.

Ancient Greece and Rome

Agricola, author of De Re Metallica
Drainage wheel from Rio Tinto mines
.Mining in Europe has a very long history, examples including the silver mines of Laurium, which helped support the Greek city state of Athens.^ Man-engines were long used, but are now practically abandoned in both Great Britain and the United States, and few remain in any of the mining regions of the world.

^ These are common in Europe, and are sometimes employed in the United States and elsewhere in mines where the output is large and the shafts deep and of small cross section.

^ In long-wall and in the work of mining pillars the roof will be supported on one side only, the overhanging beds acting as cantilevers.

.However, it is the Romans who developed large scale mining methods, especially the use of large volumes of water brought to the minehead by numerous aqueducts.^ In the case of a developed mine its life may be predicted in many cases with absolute certainty - as when the extent of the mineral deposit and the volume of mineral can be measured.

^ A fire underground speedily becomes formidable, not only in coal but also in metal mines, on account of the large quantity of timber used to support the excavations.

^ This method of mining and filling can be used when the work is done in horizontal floors or in transverse chambers.

.The water was used for a variety of purposes, including using it to remove overburden and rock debris, called hydraulic mining, as well as washing comminuted or crushed ores, and driving simple machinery.^ Rock-filling will be used whenever a large proportion of barren material must be mined with the ore.

^ If rock-filling must be brought from the surface its use will generally be confined to mines in which it is difficult to support the roof in any other way.

^ Siphons are sometimes used to carry the water over an undulating grade and thereby save the expense of a deep rock cutting.

.They used hydraulic mining methods on a large scale to prospect for the veins of ore, especially a now obsolete form of mining known as hushing.^ For coal, iron ore and other cheap minerals, mechanical handling by many different methods is used in loading and unloading railway wagons and vessels, and in forming the stock-piles and reloading the mineral therefrom.

^ Instead of mining in horizontal floors the filling method permits the ore to be mined in vertical chambers or slices which extend from one level to the next above and from one wall of the deposit to the other.

^ A fire underground speedily becomes formidable, not only in coal but also in metal mines, on account of the large quantity of timber used to support the excavations.

.It involved building numerous aqueducts to supply water to the minehead where it was stored in large reservoirs and tanks.^ Where an effective sealing of the mine is impracticable it is sometimes possible to extinguish the fire from the outside of the mine by constructing a large reservoir or tank in the upper part of the mine-shaft and suddenly releasing a large volume of water by opening dischargedoors.

^ For raising large volumes of water from deep shafts pairs of tanks are operated in balance in special shaft compartments by their own hoisting engine.

When a full tank was opened, the wave of water sluiced away the overburden to expose the bedrock underneath and any gold veins. .The rock was then attacked by fire-setting to heat the rock, which would be quenched with a stream of water.^ Underground fires may sometimes be .extinguished by direct attack with water.

The thermal shock cracked the rock, enabling it to be removed, aided by further streams of water from the overhead tanks. .They used similar methods to work cassiterite deposits in Cornwall and lead ore in the Pennines.^ Instead of mining in horizontal floors the filling method permits the ore to be mined in vertical chambers or slices which extend from one level to the next above and from one wall of the deposit to the other.

^ The usual method of working metal-mines is by overhand and underhand stoping, using rock-filling,, or pillars of mineral to support the roof.

^ For deep workings the milling method is usually employed, in which the ore is excavated in funnel -shaped pits, each of which connects with underground haulage roads by a shaft.

.The methods had been developed by the Romans in Spain in 25 AD to exploit large alluvial gold deposits, the largest site being at Las Medulas, where seven long aqueducts were built to tap local rivers and to sluice the deposits.^ The information so gained not only determines the value of the deposit, but also serves to indicate the best methods of development and of working.

^ This is in general a cheaper and quicker method of development for inclined deposits than by a vertical shaft, and it has the added advantage that much information as to the character of the deposit is obtained as the shaft is sunk.

^ The vast majority of mineral deposits are unworkable, and of those that are developed a large proportion prove unprofitable.

.Spain was one of the most important mining regions, but all regions of the Roman Empire were exploited.^ By sinking additional pits or by extending the costeaning trenches and uncovering the outcrop of the deposit more fully it is sometimes possible to obtain all the information required for the most extensive and important mining operations.

.They used reverse overshot water-wheels for dewatering their deep mines such as those at Rio Tinto.^ They can be used only when a supply of water under sufficient pressure is available for power.

^ The efficiency of such ventilating furnaces is low, and they cannot safely be used in mines producing fire-damp.

^ Such cars are in use at a number of deep inclined shafts in the Lake Superior copper district, where the depths range from 3000 to 5000 ft.

.In Great Britain the natives had mined minerals for millennia ,[6] but when the Romans came, the scale of the operations changed dramatically.^ In mining regions where 'water transportation is interrupted during certain months of the year the mineral must be stored underground, or in great stock-piles on the surface.

^ When the development of a mine has advanced sufficiently the operation of working or extracting the mineral begins.

^ To lessen the danger from blasting operations the use of special safety explosives is required in Great Britain and some European countries.

The Romans needed what Britain possessed, especially gold, silver, tin and lead. Roman techniques were not limited to surface mining. .They followed the ore veins underground once opencast mining was no longer feasible.^ When direct attack is no longer practicable, it is possible to extinguish the fire by sealing the mine workings, and exhausting the supply of oxygen.

At Dolaucothi they stoped out the veins, and drove adits through barren rock to drain the stopes. .The same adits were also used to ventilate the workings, especially important when fire-setting was used.^ Either may be used for drainage of the mine workings, in which case it becomes an adit.

^ The efficiency of such ventilating furnaces is low, and they cannot safely be used in mines producing fire-damp.

.At other parts of the site, they penetrated the water table and dewatered the mines using several kinds of machine, especially reverse overshot water-wheels.^ This seems to be due to the dust abundantly produced in mining operations, and especially by machine drills when boring " dry " (rising) blast holes.

^ When mine water is acid the working parts of the pump must be lined with or made of bronze or other non-corrosive material; or the acid may be neutralized by adding lime in the sump.

^ They can be used only when a supply of water under sufficient pressure is available for power.

.These were used extensively in the copper mines at Rio Tinto in Spain, where one sequence comprised 16 such wheels arranged in pairs, and lifting water about 80 feet (24 m).^ The efficiency of such ventilating furnaces is low, and they cannot safely be used in mines producing fire-damp.

^ Such cars are in use at a number of deep inclined shafts in the Lake Superior copper district, where the depths range from 3000 to 5000 ft.

^ In such mines the mineral was carried out on the backs of men, and the water was laboriously raised by a long line of suction-pumps, operated by hand, each lifting the water a few feet only.

.They were worked as treadmills with miners standing on the top slats.^ Vignette of miners working on top, elk on bottom and 2 different saws in middle with the title of the company over it.
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^ Miners working on top under arched title with ornate letters.
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^ Miners working on lower left and fancy title on top.
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.Many examples of such devices have been found in old Roman mines and some examples are now preserved in the British Museum and the National Museum of Wales.^ For example, carbon dioxide occurs in some mines, and hydrogen sulphide, which is a poisonous gas, in others.

^ In many cases, however, it has been found necessary to reopen the mine through the fallen ground, and even to excavate openings through the solid mineral.

^ Examples of other mining methods will be found under Coal .

[7]

Medieval Europe

Mining as an industry underwent dramatic changes in medieval Europe. The mining industry in the early Middle Ages was mainly focused on the extraction of copper, bronze and iron. .Other precious metals were also used mainly for gilding or coinage.^ In the metal mines of Cornwall and Devon special rules are now in force requiring the use of water in drilling, and other precautions, to lessen this danger from dust.

Initially, many metals were obtained through open-pit mining, and ore was primarily extracted from shallow depths, rather than though the digging of deep mine shafts. Around approximately the 14th century, the demand for weapons, armor, stirrups, and horseshoes greatly increased the demand for iron. Medieval knights for example were often laden with up to 100 pounds of plate or chain link armor in addition to swords, lances and other weapons.[8] The overwhelming dependency on iron for military purposes helped to spur increased iron production and extraction processes.
These new military applications coincided with a population explosion throughout Europe in the 11th-14th centuries which enriched the demand for precious metals in order to fill a currency shortage.[9] .The silver crisis of 1465 occurred when the mines had all reached depths at which the shafts could no longer be pumped dry with the available technology.^ In Austria three shafts in the silver mines at Prizbram have reached the depth of over 1000 metres.

^ When direct attack is no longer practicable, it is possible to extinguish the fire by sealing the mine workings, and exhausting the supply of oxygen.

^ Tamarack mine in Houghton county, Michigan , which has reached a vertical depth of about 5200 ft.

[10] .Although the increased use of bank notes and the use of credit during this period did decrease the dependence and value of precious metals, these forms of currency still remained vital to the story of medieval mining.^ The former term is used in metal -mines and the latter in coal-mining.

^ A fire underground speedily becomes formidable, not only in coal but also in metal mines, on account of the large quantity of timber used to support the excavations.

^ In mines of copper, lead and the precious metals, in which the cars are moved by hand, the usual load is from 1200 to 3000 lb.

Use of water power in the form of water mills was extensive; they were employed in crushing ore, raising ore from shafts and ventilating galleries by powering giant bellows. Black powder was first used in mining in Selmecbánya, Kingdom of Hungary (present-day Banská Štiavnica, Slovakia) in 1627.[11] Black powder allowed blasting of rock and earth to loosen and reveal ore veins, which was much faster than fire-setting, in which rock was exposed to heat and then doused with cold water. Black powder allowed the mining of previously impenetrable metals and ores.[12] In 1762, the world's first mining academy was established in the same town. Prior to this invention much mining was accomplished through firesetting. This method began by exposing the vein to prolonged heat from a fire.
The widespread adoption of agricultural innovations such as the iron plowshare, in addition to the growing usage of metal in architecture and building structure were also driving forces in the tremendous growth of the iron industry during this period. Inventions like the arrastra were often used by the Spanish to pulverize ore after being mined. This device employed animal power and utilized mechanical principles similar to that of the ancient Middle Eastern technology of grain threshing.[13]
Much of our knowledge of Medieval mining techniques comes from books such as Biringuccio’s Pirotechnia and probably most importantly from Georg Agricola's De Re Metallica (1556). These books detail many different mining methods used in German and Saxon mines. One of the prime issues dealt with by medieval miners (and one which Agricola explains in detail) was the removal of water from mining shafts. As miners dug deeper to access new veins, flooding became a very real obstacle. As a result the mining industry became dramatically more efficient and prosperous as the use of various mechanical and animal driven pump systems were implemented.

North and South America

Miners at the Tamarack Mine in Copper Country, Michigan, U.S. in 1905.
.In North America there are ancient, prehistoric copper mines along Lake Superior.^ Stonington Mining Company - Lake Superior.
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^ North Lake Mining Company.
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[14][15] "Indians availed themselves of this copper starting at least 5000 years ago,"[14] and copper tools, arrowheads, and other artifacts that were part of an extensive native trade network have been discovered. .In addition, obsidian, flint, and other minerals were mined, worked, and traded.^ Miners working on left &: right with mine vignette.
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[15] While the early French explorers that encountered the sites made no use of the metals due to the difficulties in transporting it,[15] the copper was eventually traded throughout the continent along major river routes. In Manitoba, Canada, there also are ancient quartz mines near Waddy Lake and surrounding regions.[16]
In the early colonial history of the Americas, "native gold and silver was quickly expropriated and sent back to Spain in fleets of gold- and silver-laden galleons"[17] mostly from mines in Central and South America. Turquoise dated at 700 A.D. was mined in pre-Columbian America; in the Cerillos Mining District in New Mexico, estimates are that "about 15,000 tons of rock had been removed from Mt Chalchihuitl using stone tools before 1700."[18][19]
Mining in the United States became prevalent in the 19th century, and the General Mining Act of 1872 was passed to encourage mining of federal lands.[20] .As with the California Gold Rush in the mid 1800s, mining for minerals and precious metals, along with ranching, was a driving factor in the Westward Expansion to the Pacific coast.^ "For working gold mines in California."
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^ Early California gold rush stock certificate.
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^ California Juneau Gold Mines, Ltd.
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With the exploration of the West, mining camps were established and "expressed a distinctive spirit, an enduring legacy to the new nation;" Gold Rushers would experience the same problems as the Land Rushers of the transient West that preceded them.[21] Aided by railroads, many traveled West for work opportunities in mining. Western cities such as Denver and Sacramento originated as mining towns.

Mining methods and procedures

Steps of mine development

Simplified world mining map (click to enlarge)
Another simplified world mining map (click to enlarge)
The process of mining from discovery of an ore body through extraction of minerals and finally to returning the land to its natural state consists of several distinct steps. The first is discovery of the ore body, which is carried out through prospecting or exploration to find and then define the extent, location and value of the ore body. This leads to a mathematical resource estimation to estimate the size and grade of the deposit. This estimation is used to 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. The next step is to conduct a feasibility study to evaluate the financial viability, technical and financial risks and robustness of the project. .This is when the mining company makes the decision to develop the mine or to walk away from the project.^ The Fairview Consolidated Mining &: Developing Company.
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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 concerns, milling and infrastructure costs, finance and equity requirements and an analysis of the proposed mine from the initial excavation all the way through to reclamation. Once the analysis determines a given ore body is worth recovering, development begins to create access to the ore body. The mine buildings and processing plants are built and any necessary equipment is obtained. .The operation of the mine to recover the ore begins and continues as long as the company operating the mine finds it economical to do so.^ The Comstock Mining and Milling Company was a Helena, Montana, mining company operating the Comstock Mine near Basin.
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Once all the ore that the mine can produce profitably is recovered, reclamation begins to make the land used by the mine suitable for future use.

Mining techniques

A minecart toilet, used in Bisbee, Arizona.
Mining techniques can be divided into two common excavation types: surface mining and sub-surface (underground) mining. Surface mining is much more common, and produces, for example, 85% of minerals (excluding petroleum and natural gas) in the United States, including 98% of metallic ores.[22] Targets are divided into two general categories of materials: placer deposits, consisting of valuable minerals contained within river gravels, beach sands, and other unconsolidated materials; and lode deposits, where valuable minerals are found in veins, in layers, or in mineral grains generally distributed throughout a mass of actual rock. Both types of ore deposit, placer or lode, are mined by both surface and underground methods.
Processing of placer ore material consists of gravity-dependent methods of separation, such as sluice boxes. Only minor shaking or washing may be necessary to disaggregate (unclump) the sands or gravels before processing. Processing of ore from a lode mine, whether it is a surface or subsurface mine, requires that the rock ore be crushed and pulverized before extraction of the valuable minerals begins. After lode ore is crushed, recovery of the valuable minerals is done by one, or a combination of several, mechanical and chemical techniques.
Some mining, including much of the uranium mining and mining for rare earth elements being done today, is done by less-common methods, such as in-situ leaching: this technique involves digging neither at the surface nor underground. The extraction of target minerals by this teqhnique requires that they be soluble, e.g., potash, potassium chloride, sodium chloride, sodium sulfate and uranium oxide which dissolve in water.[23][24]
.Surface mining is done by removing (stripping) surface vegetation, dirt, and if necessary, layers of bedrock in order to reach buried ore deposits.^ Miners remove the coal by drilling a hole, or shaft, in the ground until they reach the layer of coal.

^ SLOPE MINING IS USED WHEN COAL DEPOSITS ARE FOUND IN HILLSIDES, WITH A SLOPED OPENING THEN CONSTRUCTED TO REACH THE COAL AND CARRY IT OUT. .

.Techniques of surface mining include; Open-pit mining which consists of recovery of materials from an open pit in the ground, quarrying or gathering building materials from an open pit mine, strip mining which consists of stripping surface layers off to reveal ore/seams underneath, and Mountaintop removal, commonly associated with coal mining, which involves taking the top of a mountain off to reach ore deposits at depth.^ Coal is mined by surface mining or underground mining.

^ Surface mining is used when a coal seam is located close to the surface.

^ Miners remove the coal by drilling a hole, or shaft, in the ground until they reach the layer of coal.

Most (but not all) placer deposits, because of their shallowly-buried nature, are mined by surface methods. Landfill mining finally are sites where landfills are excavated and processed.[25]
Open-pit mine near Garzweiler, Germany
.Sub-surface mining consists of digging tunnels or shafts into the earth to reach buried ore deposits.^ Once they reach the coal, they dig tunnels in the coal seam.

^ When the coal seam is fairly close to the surface yet too deep to use surface mining, a slope mine can be built, with the mine entrance being a tunnel which slants down from the surface to the coal seam.

^ A drift mine is a mine in which the entry is directly into a horizontal coal seam exposed at or near the surface.

Ore, for processing, and waste rock, for disposal, are brought to the surface through the tunnels and shafts. .Sub-surface mining can be classified by the type of access shafts used, the extraction method or the technique used to reach the mineral deposit.^ The most common type is the shaft mine.

^ There are three types of underground mines: slope, drift, and shaft.

^ In Kentucky, two types of underground mining are primarily used: room and pillar mining and longwall mining.

.Drift mining utilizes horizontal access tunnels, slope mining uses diagonally sloping access shafts and shaft mining consists of vertical access shafts.^ There are three types of underground mines: slope, drift, and shaft.

^ These tunnels are used for traveling throughout the mine, moving coal from place to place and allowing air to circulate within the mine.

^ When the coal seam is fairly close to the surface yet too deep to use surface mining, a slope mine can be built, with the mine entrance being a tunnel which slants down from the surface to the coal seam.

Other methods include shrinkage stope mining which is mining upward creating a sloping underground room, long wall mining which is grinding a long ore surface underground and room and pillar which is removing ore from rooms while leaving pillars in place to support the roof of the room. Room and pillar mining often leads to retreat mining which is removing the pillars which support rooms, allowing the room to cave in, loosening more ore. Additional sub-surface mining methods include Hard rock mining which is mining of hard materials, bore hole mining, drift and fill mining, long hole slope mining, sub level caving and block caving

Machinery

Gold-bearing gravels are shoveled into a trommel at the Blue Ribbon placer mine, Alaska.
Heavy machinery is needed in mining for exploration and development, to remove and stockpile overburden, to break and remove rocks of various hardness and toughness, to process the ore and for reclamation efforts after the mine is closed. Bulldozers, drills, explosives and trucks are all necessary for excavating the land. In the case of placer mining, unconsolidated gravel, or alluvium, is fed into machinery consisting of a hopper and a shaking screen or trommel which frees the desired minerals from the waste gravel. The minerals are then concentrated using sluices or jigs. Large drills are used to sink shafts, excavate stopes and obtain samples for analysis. Trams are used to transport miners, minerals and waste. Lifts carry miners into and out of mines, as well as moving rock and ore out, and machinery in and out of underground mines. Huge trucks, shovels and cranes are employed in surface mining to move large quantities of overburden and ore. Processing plants can utilize large crushers, mills, reactors, roasters and other equipment to consolidate the mineral-rich material and extract the desired compounds and metals from the ore.

Extractive metallurgy

The science of extractive metallurgy is a specialized area in the science of metallurgy that studies the extraction of valuable metals from their ores, especially through chemical or mechanical means. Mineral processing (or mineral dressing) is a specialized area in the science of metallurgy that studies the mechanical means of crushing, grinding, and washing that enable the separation (extractive metallurgy) of valuable metals or minerals from their gangue (waste material). Since most metals are present in ores as oxides or sulfides, the metal needs to be reduced to its metallic form. This can be accomplished through chemical means such as smelting or through electrolytic reduction, as in the case of aluminum. Geometallurgy combines the geologic sciences with extractive metallurgy and mining.

Environmental effects

Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.
Environmental issues can include erosion, formation of sinkholes, loss of biodiversity, and contamination of soil, groundwater and surface water by chemicals from mining processes. In some cases, additional forest logging is done in the vicinity of mines to increase the available room for the storage of the created debris and soil.[26] Besides creating environmental damage, the contamination resulting from leakage of chemicals also affect the health of the local population.[27] Mining companies in many countries may be required to follow environmental and rehabilitation codes; however, in many areas regulation is not enforced, and mining companies have encouraged self-policing.[28] In 1992 a Draft Code of Conduct for Transnational Corporations was proposed at the Rio Earth Summit by the UN Centre for Transnational Corporations (UNCTC), but the Business Council for Sustainable Development (BCSD) together with the International Chamber of Commerce (ICC) argued successfully for self-regulation instead.[29] This was followed up by the Global Mining Initiative which created of the International Council on Mining and Metals, an industry organization which works to self-regulate the mining industry internationally.[28] The mining industry has provided funding to various nonprofit groups, which have been subsequently less inclined to fight for the rights of indigenous people.[30]
Ore mills generate large amounts of waste, called tailings, which are perhaps their largest environmental burden. For example, 99 tonnes of waste are generated per tonne of copper, with even higher ratios in gold mining. These tailings can be toxic. Tailings, which are usually produced as a slurry, are most commonly dumped into ponds made from naturally-existing valleys.[31] These ponds are secured by impoundments (dams or embankment dams).[31] In 2000 it was estimated that 3,500 tailings impoundments existed, and that every year, 2 to 5 major failures and 35 minor failures occurred; for example, in the Marcopper mining disaster at least 2 million tons of tailings were released into a local river.[32] Subaqueous tailings disposal is another option.[31] The mining industry has argued that submarine tailings disposal (STD), which disposes of tailings in the sea, is ideal because it avoids the risks of tailings ponds; although the practice is illegal in the United States and Canada, it is used in the developing world.[33]
Certification of mines with good practices occurs through the International Organization for Standardization (ISO) such as ISO 9000 and ISO 14001, which certifies an 'auditable environmental management system'; this certification involves short inspections, although it has been accused of lacking rigor.[28]:183-4 Certification is also available through Ceres' Global Reporting Initiative, but these reports are voluntary and unverified. Miscellaneous other certification programs exist for various projects, typically through nonprofit groups.[28]:185-6

Regulations and World Bank relationship

.The World Bank has been involved in mining since 1955, mainly through grants from its International Bank for Reconstruction and Development, with the Bank's Multilateral Investment Guarantee Agency offering political risk insurance.^ Alaska Mining , Development, Transportation and Investment Co.
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[34] Between 1955 and 1990 it provided about $2 billion to fifty mining projects, broadly categorized as reform and rehabilitation, greenfield mine construction, mineral processing, technical assistance, and engineering. These projects have been criticized, particularly the Ferro Carajas project of Brazil, began in 1981.[35] The bank established mining codes intended to increase foreign investment, in 1988 solicited feedback from 45 mining companies on how to increase their involvement.[28]:20
.In 1992 the bank began to push for privatization of government-owned mining companies with a new set of codes, beginning with its report The Strategy for African Mining.^ This company and Miller Gold Mining company were owned by the same people.
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^ This company and Oriental Gold Mining company were owned by the same people.
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^ The Colorado &: New England Mining Company.
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In 1997, Latin America's largest miner Companhia Vale do Rio Doce (CVRD) was privatized. These and other movements such as the Philippines 1995 Mining Act led the World Bank to publish a third report (Assistance for Minerals Sector Development and Reform in Member Countries) which endorsed mandatory environment impact assessments and attention to the locals. The codes based on this report are influential in the legislation of developing nations. The new codes are intended to encourage development through tax holidays, zero custom duties, reduced income taxes, and related measures.[28]:22 The results of these codes were analyzed by a group from the University of Quebec, which concluded that the codes promote foreign investment but "fall very short of permitting sustainable development".[36] The observed negative effect of natural resources on economic development is known as the resource curse.

Mining industry

While exploration and mining can sometimes be conducted by individual entrepreneurs or small business, most modern-day mines are large enterprises requiring large amounts of capital to establish. Consequently, the mining sector of the industry is dominated by large, often multinational, mostly publicly-listed companies. See Mining Companies for a list. However, what is referred to as the 'mining industry' is actually two sectors, one specializing in exploration for new resources, the other specializing in mining those resources. The exploration sector is typically made up of individuals and small mineral resource companies dependent on public investment. .The mining sector is typically large and multi-national companies sustained by mineral production from their mining operations.^ The Comstock Mining and Milling Company was a Helena, Montana, mining company operating the Comstock Mine near Basin.
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^ Paradise Mining Company - Miners - Bullfrog, Nevada.
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In addition to these two sectors, various other industries such as equipment manufacture, environmental testing and metallurgy analysis also rely on and support the mining industry throughout the world.
Mining operations can be grouped into five major categories in terms of their respective resources. These are, oil and gas extraction, coal mining, metal ore mining, nonmetallic mineral mining and quarrying, and support activities for mining[37]. Out of all these categories oil and gas extraction remains one of the largest in terms of its global economic importance. Prospecting potential mining sites, a vital area of concern for the mining industry is now done using sophisticated new technologies such as seismic prospecting and remote-sensing satellites.

Corporate classifications

Mining companies can be classified based on their size and financial capabilities:
.
  • Major companies are considered to have an adjusted annual mining-related revenue of more than US$500 million, with the financial capability to develop a major mine on its own.
  • Intermediate companies have at least $50 million in annual revenue but less than $500 million.
  • Junior companies rely on equity financing as their principal means of funding exploration.^ Rare mining related company.
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    ^ Scarce Michigan mining related company.
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    ^ This company and Miller Gold Mining company were owned by the same people.
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    Juniors are mainly pure exploration companies, but may also produce minimally, and do not have a revenue of US$50 million.[38]

Safety

Danger sign at an old Arizona mine.
Abandoned mine entrance in Yorkshire, England
Safety has long been a controversial issue in the mining business especially with sub-surface mining. While mining today is substantially safer than it was in the previous decades, mining accidents are often very high profile, such as the Quecreek Mine Rescue saving 9 trapped Pennsylvania coal miners in 2002. Mining ventilation is a significant safety concern for many miners. Poor ventilation of the mines causes exposure to harmful gases, heat and dust inside sub-surface mines. These can cause harmful physiological effects, including death. The concentration of methane and other airborne contaminants underground can generally be controlled by dilution (ventilation), capture before entering the host air stream (methane drainage), or isolation (seals and stoppings).[39] Ignited methane gas is a common source of explosions in coal mines, or, the more violent coal dust explosions. Gases in mines can also poison the workers or displace the oxygen in the mine, causing asphixiation.[39] For this reason, the MHSA requires that workers have gas detection equipment in groups of miners. It must be able to detect common gases, such as CO, O2, H2S, and % Lower Explosive Limit. Additionally, further regulation is being requested for more gas detection as newer technology such as nanotechnology is introduced. High temperatures and humidity may result in heat-related illnesses, including heat stroke which can be fatal. Dusts can cause lung problems, including silicosis, asbestosis and pneumoconiosis (also known as miners lung or black lung disease). A ventilation system is set up to force a stream of air through the working areas of the mine. The air circulation necessary for the effective ventilation of a mine is generated by one or more large mine fans, usually located above ground. Air flows in one direction only, making circuits through the mine such that each main work area constantly receives a supply of fresh air.
Since mining entails removing dirt and rock from its natural location creating large empty pits, rooms and tunnels, cave-ins are a major concern within mines. Modern techniques for timbering and bracing walls and ceilings within sub-surface mines have reduced the number of fatalities due to cave-ins, but accidents still occur.[citation needed] The presence of heavy equipment in confined spaces also poses a risk to miners, and despite modern improvements to safety practices, mining remains dangerous throughout the world.

Abandoned mines

Abandoned mine in Nevada.
There are upwards of 560,000 abandoned mines on public and privately owned lands in the United States alone.[40][41] Abandoned mines pose a threat to anyone who may attempt to explore them without proper knowledge and safety training. Old mines are often dangerous and can contain deadly gases. Standing water in mines from seepage or infiltration poses a significant hazard as the water can hide deep pits and trap gases below the water. Additionally, since weather may have eroded the earth and rock surrounding it, the entrance to an old mine in particular can be very dangerous. Old mine workings, caves, etc. are commonly hazardous simply due to the lack of oxygen in the air, a condition in mines known as blackdamp.

Hearing loss

Miners utilize equipment strong enough to break through extremely hard layers of the Earth's crust. This equipment, combined with the closed workspace that underground miners work in, can cause hearing loss.[42] For example, a roof bolter (commonly used by mine roof bolter operators) can reach sound power levels of up to 115 dB.[42] Combined with the reverberant effects of underground mines, a miner without proper hearing protection is not only at a high risk for hearing loss,[42] but is also going against OSHA standards[43].

Records

As of 2008, the deepest mine in the world is TauTona in Carletonville, South Africa at 3.9 kilometers,[44] replacing Savuka Mine in the North West Province of South Africa at 3,774 meters.[45] East Rand Mine in Boksburg, South Africa briefly held the record at 3,585 meters, and the first mine declared the deepest in the world was also TauTona when it was at 3,581 meters. The deepest mine in Europe is Pyhäsalmi Mine in Pyhäjärvi, Finland at 1,444 meters. The second deepest mine in Europe is Boulby Mine England at 1,400 meters (shaft depth 1,100 meters).
The deepest open pit mine in the world is Bingham Canyon Mine in Bingham Canyon, Utah, United States at over 1,200 meters. The largest and second deepest open pit copper mine in the world is Chuquicamata in Chuquicamata, Chile at 900 meters, 940,600 tons of copper and 17,700 tons of molybdenum produced annually.[citation needed]
The deepest open pit mine with respect to sea level is Tagebau Hambach in Germany, the ground of the pit is 293 meters below sea level.
The largest underground mine: El Teniente, in Rancagua, Chile, 2,400 kilometers of underground drifts, 418,000 tons of copper yearly. The deepest borehole in the world is Kola Superdeep Borehole at 12,262 meters. This, however, is not a matter of mining but rather related to scientific drilling.

See also

References

  1. ^ Hartman, Howard L. SME Mining Engineering Handbook, Society for Mining, Metallurgy, and Exploration Inc, 1992, p3.
  2. ^ Swaziland Natural Trust Commission, "Cultural Resources - Malolotja Archaeology, Lion Cavern," Retrieved August 27, 2007, [1].
  3. ^ Peace Parks Foundation, "Major Features: Cultural Importance." Republic of South Africa: Author. Retrieved August 27, 2007, [2].
  4. ^ Shaw, I. (2000). The Oxford History of Ancient Egypt. New York: Oxford University Press, pp. 57-59.
  5. ^ a b Shaw, I. (2000). The Oxford History of Ancient Egypt. New York: Oxford University Press, p. 108.
  6. ^ The Independent, 20 Jan. 2007: The end of a Celtic tradition: the last gold miner in Wales
  7. ^ The Romans in Britain: mining
  8. ^ A culture of Improvement. Robert Friedel. MIT Press. 2007. Pg.81
  9. ^ Medieval Science and Technology: Original Essays.Medieval Iron and Steel – Simplified Hall, Bert http://www.the-orb.net/encyclop/culture/scitech/iron_steel.html
  10. ^ http://mygeologypage.ucdavis.edu/cowen/~GEL115/115CH7.html
  11. ^ Heiss, A.G. & Oeggl, K. (2008). Analysis of the fuel wood used in Late Bronze Age and Early Iron Age copper mining sites of the Schwaz and Brixlegg area (Tyrol, Austria). Vegetation History and Archaeobotany 17(2):211-221, Springer Berlin / Heidelberg, [3].
  12. ^ The use of Firesetting in the Granite Quarries of South India Paul T. Craddock The Bulletin of the Peak District Mines Historical Society, Vol. 13 Number 1. 1996
  13. ^ "The Spanish Tradition in Gold and Silver Mining." Otis E. Young Arizona and the West, Vol. 7, No. 4 (Winter, 1965), pp. 299-314 (Journal of the Southwest) Stable URL: http://www.jstor.org/stable/40167137.
  14. ^ a b Lankton, L. (1991). Cradle to Grave: Life, Work, and Death at the Lake Superior Copper Mines. New York: Oxford University Press, p. 5-6.
  15. ^ a b c West, G.A. (1970). Copper: its mining and use by the aborigines of the Lake Superior Region. Westport, Conn: Greenwood Press.
  16. ^ Bruno, L. & Heaman, L.M. (2004). Structural controls on hypozonal oroganic gold mineralization in the La Rouge Domain, Trans-Hudson Orogen, Saskatchewan. The Canadian Journal of Earth Sciences, Vol. 41, Issue 12, pp. 1453-1471.
  17. ^ Vaden, H.E. & Prevost. G. (2002). Politics of Latin America: The Power Game. New York: Oxford University Press, p. 34.
  18. ^ Maynard, S.R., Lisenbee, A.L. & Rogers, J. (2002). Preliminary Geologic Map of the Picture Rock 7.5 - Minute Quadrangle Sante Fe County, Central New Mexico. New Mexico Bureau of Geology and Mineral Resources, Open-File Report DM-49.
  19. ^ The Cerrillos Hills Park Coalition, (2000). Cerrillos Hills Historic Park Vision Statement. Public documents: Author. Retrieved August 27, 2007, [4].
  20. ^ McClure R, Schneider A. The General Mining Act of 1872 has left a legacy of riches and ruin. Seattle PI.
  21. ^ Boorstin, D.J. (1965). The Americans: The National Experience. New York: Vintage Books, pp. 78-81.
  22. ^ Hartmann HL. Introductory Mining Engineering, p. 11. First chapter.
  23. ^ http://world-nuclear.org/info/inf27.html
  24. ^ http://www.kazatomprom.kz/cgi-bin/index.cgi?p27&version=en
  25. ^ Landfill Mining Landfill Mining, Preserving Resources through Integrated Sustainable Management of Waste, Technical Brief from the World Resource Foundation
  26. ^ Logging of forests and debris dumping
  27. ^ Larmer, Brook (2009-01). "The Real Price of Gold". National Geographic. http://ngm.nationalgeographic.com/2009/01/gold/larmer-text/12. 
  28. ^ a b c d e f Moody R. (2007). Rocks and Hard Places. Zed Books.
  29. ^ Abrahams D. (2005). Regulations for Corporations: A historical account of TNC regulation, p. 6. UNRISD.
  30. ^ Chapin, Mac (2004-10-15). "A Challenge to Conservationists: Can we protect natural habitats without abusing the people who live in them?". World Watch Magazine. 6 17. http://www.worldwatch.org/node/565. Retrieved 2010-02-18. 
  31. ^ a b c US EPA. (1994). Technical Report: Design and Evaluation of Tailings Dams.
  32. ^ TE Martin, MP Davies. (2000). Trends in the stewardship of tailings dams.
  33. ^ Coumans C. (2002). Mining’s Problem with Waste. MiningWatch Canada.
  34. ^ For an overview of the Bank and mining, see Mining, Sustainability and Risk:World Bank Group Experiences.
  35. ^ See the 1995 World Development 23(3) pp. 385-400.
  36. ^ GRAMA. (2003). The Challenges of Development, Mining Codes in Africa And Corporate Responsibility. In: International and Comparative Mineral Law and Policy: Trends and Prospects. Summarized in the African Mining Codes Questioned.
  37. ^ United States Bureau of Labor http://www.bls.gov/oco/cg/cgs004.htm#nature
  38. ^ "Metals Economics Group World Exploration Trends Report". Metals Economics Group Inc.. http://www.metalseconomics.com/pdf/PDAC%202009%20World%20Exploration%20Trends.pdf. Retrieved 2009-05-05. 
  39. ^ a b "NIOSH Mining Safety and Health Ventilation". United States National Institute for Occupational Safety and Health. http://www.cdc.gov/niosh/mining/topics/topicpage30.htm. Retrieved 2007-10-29. 
  40. ^ Kertes, N., (March, 1996). US abandoned mine count still a mystery - General Accounting Office report. American Metal Market, Retrieved August 27, 2007, [5]
  41. ^ People, Land, and Water (March, 2007). KEEP OUT! Old Mines Are Dangerous. Office of Surface Mining: U.S. Department of the Interior. Retrieved Aug, 27, 2007, [6]
  42. ^ a b c Peterson, J.S.; P.G. Kovalchik, R.J. Matetic (2006). "Sound power level study of a roof bolter" (PDF). Trans Soc Min Metal Explor (320): 171–7. http://www.cdc.gov/niosh/mining/pubs/pdfs/splso.pdf. Retrieved 2009-06-16. 
  43. ^ Franks, John R., ed (1996). "Appendix A: OSHA Noise Standard Compliance Checklist". Preventing Occupational Hearing Loss: A Practical Guide. U.S. Department of Health and Human Services. pp. 60. http://origin.cdc.gov/niosh/docs/96-110/pdfs/96-110.pdf. 
  44. ^ "TauTona, Anglo Gold - Mining Technology". SPG Media Group PLC. 2009-01-01. http://www.mining-technology.com/projects/tautona_goldmine/. Retrieved 2009-03-02. 
  45. ^ Naidoo, Brindaveni (2006-12-15). "TauTona to take ‘deepest mine’ accolade". Creamer Media's Mining Weekly Online. http://www.miningweekly.co.za/article.php?a_id=98516. Retrieved 2007-07-19. 

Further reading

  • Ali, Saleem H. (2003) Mining, the Environment and Indigenous Development Conflicts. Tucson AZ: University of Arizona Press.
  • Ali, Saleem H. (2009) Treasures of the Earth: need, greed and a sustainable future. .New Haven and London: Yale University Press
  • Even-Zohar, Chaim (2007) From Mine to Mistress: Corporate Strategies and Government Policies in the International Diamond Industry (ISBN 0953733610)
  • Geobacter Project: Gold mines may owe their origins to bacteria (in PDF format)
  • Garrett, Dennis Alaska Placer Mining
  • Jayanta, Bhattacharya (2003) Principles of Mine Planning.^ Alaska Gold Mining Association..
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    ^ Alaska-Klondyke Gold Mining and Development Co.
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    ^ Alaska-Ebner Gold Mines Co.
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    New Delhi: Allied Publishers. 454 pages
  • Morrison, Tom (1992) Hardrock Gold: a miner's tale. ISBN 0-8061-2442-3

External links


Study guide

Up to date as of January 14, 2010

From Wikiversity

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.This list includes only those large open-pit mines for which an article exists in Wikipedia.^ A fire underground speedily becomes formidable, not only in coal but also in metal mines, on account of the large quantity of timber used to support the excavations.

^ The latter includes not only the actual excavation of the mineral, but also haulage and hoisting by which it is brought to the surface, timbering and other means of supporting the excavations, and the drainage and ventilation of mines.

Resources

Wikipedia

See also

The Udachnaya pipe in Russia.

1911 encyclopedia

Up to date as of January 14, 2010
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From LoveToKnow 1911

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Gaming

Up to date as of February 01, 2010

.From Wikia Gaming, your source for walkthroughs, games, guides, and more!^ Mining trainers - WoWWiki - Your guide to the World of Warcraft Wikia Gaming Create a new wiki Log in Create an account WoWWiki View source (log in to edit) History Share this article Article Discussion .
  • Mining trainers - WoWWiki - Your guide to the World of Warcraft 11 January 2010 15:52 UTC www.wowwiki.com [Source type: FILTERED WITH BAYES]

^ This'll probably be the easiest stretch in the game If you're lucky, otherwise it's one of the more painful times in your mining life.
  • World of Warcraft Mining guide 11 January 2010 15:52 UTC www.gotwarcraft.com [Source type: General]

These quests are gain from any alliance master in most cities.

Athen


This article uses material from the "Mining" article on the Gaming wiki at Wikia and is licensed under the Creative Commons Attribution-Share Alike License.

Simple English

File:Wurfschaufellader
Miner machine with a mine worker

Mining is the process of taking things from the ground. Any material that cannot be grown must be mined. Mining things from the ground is called extraction. Mining can include extraction of metals and minerals, like coal, gold, silver, platinum, copper, and iron. Mining can also include other things like oil and natural gas.

Some mining is done by scraping away the soil (dirt) from the top of the ground. This is called strip mining. Some mining is done by going deep underground into a mine shaft. This is called underground mining. Some mining, such as gold mining, is done in other ways. Gold can be mined by searching in the bed of a river or other stream of water to remove the flakes of gold. This is called panning or placer mining.

Mining is the only way to extract coal, a vital source of energy. These mines can be strip mines, or they can be hundreds of feet in the ground.

A person who works in a mine is called a miner.

Underground mining is a dangerous job. Many coal and copper mines have accidents. Several coal miners die every year from accidents. Safety rules and special safety equipment is used to try and protect miners from accidents.

pcd:Mine


Citable sentences

Up to date as of December 22, 2010

Here are sentences from other pages on Mining, which are similar to those in the above article.








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