Muidu ilus jutt, aga strekk on veoks kasutatav kaeveõõs mille suurus tehakse just nii suur kui vaja, e. et masin või inimene või loom sinna mahuks. Nimetatud suured kaeveõõned on kambrid, kust soola kaevandati. Niipalju siis võõrastest terminitest.

http://www.maaleht.ee/news/uudised/isevarkiteated/article.php?id=27109147

Elust enesest: järve põhja puuritud auk tekitas katastroofi

Louisiana osariigis asuva Peigneur’ järve all oli soolakaevandus.

1980 hakkas Texaco firma järve alt ka naftat otsima. 21. XI 1980 leidsidki puurplatvormi mehed midagi huvitavat — jõudsid 430 m sügavusel puuriga kaevanduse strekki. Niisama hästi võiks öelda, et järve põhjas tõmmati lahti väljavoolukork.

Kaevanduse 30 m laiustesse ja 24 m kõrgustesse strekkidesse mühisev vesi sulatas augu aina suuremaks, tekkis 50m läbimõõduga keeris, mis imes kaasa puurplatvormi, 11 pargast, botaanikaaia ning veel 26 hektarit metsa ja maad järve ümbert.

Imekombel ei saanud surma ükski inimene, vaid kolm koera. Kõik maa all olnud 55 kaevurit pääsesid tänu tõhusale evakueerimisdrillile, naftapuurijad lasksid jalga, kui platvorm juba kahtlaselt viltu vajuma hakkas.

Järvel kala püüdnud Leonce Viator jaksas keerisest välja sõuda. Kui Viator kaldale jõudis, sidus paadi puu külge. Peagi vaatas ta abitult, kuidas puu koos paadiga järvepõhja vajub.

Delcambre’i kanal, mille kaudu vesi järvest muidu Mehhiko lahte voolab, muutis ajutiselt suunda ja tekitas Louisiana osariigi suurima, 50 m kõrguse kose, kui merevesi järveauku jooksis. Mitu päeva töötasid kaevanduse kohal suured geisrid — šahtidest purskas õhupatjade survel vett enam kui 100 m kõrgusele. Kui järv taas vett täis sai ja keeris kadus, hüppas üheksa pargast tagasi veepinnale.

Muidu ilus lugu aga “roomikkopp” peaks olema mingi “Walli” taoline roomikutega kast. Mis on kopp?

http://www.aripaev.ee/3594/new_eri_artiklid_359408.html
Case CX-seeria sai pisiasjadeni läbi mõeldud

Case CX-seeria sai pisiasjadeni läbi mõeldud

Case CX210B nool ulatub pui…

Kunagi tegin fotovõistluse, siis kui internetti alles leiutati, aga vahepeal on spetsiaalsed saidi tehtud

http://www.ene.ttu.ee/maeinstituut/maeselts/minf03.htm

Leidsin juhuslikult aruande veeteemalisest internatsionaalsest koostööst:

http://www.brgm.fr/dcenewsFile?ID=239

Ja oh ime- sealt leidsin võistlusel osaleva pildi

Pilt:

http://community.webshots.com/album/50133657zwmqqg

Album:

http://outdoors.webshots.com/photo/1050134823033176931bWBGxu

Kuna nn. koostöötegijatel pole õrna aimugi kelle, kus ja mida see pilt täpsemalt näitab (minul aga on), siis on sellisest toredast aruandest hästi näha – pseudokoostöö, pseupublitseerimise ja pseudouuringute olulisus meie praeguses teadus- ja uuringuruumis. Ametnik raiub nagu mantrat kolme sõna: ISIweb, rahvusvaheline koostöö ja projektipõhisus – lülitab siis sisse elktrilüliti ja nendib – hea, et kosmoseprogrammile allkirja andsime, nüüd oleme teadlased.

Sirgala karjäärist veavad 200 tonnised karjäärikallurid tuhandeid tonne raumaaki Kukruse teele, mööda üldkasuatatavaid teid. Sellega seoses on pealelaadimiseks hangitud Eesti suurim 20m3 pöördkoppekskavaator, ning rajatud 100 m sügavune karjäär. Kõike need rekordid on püstitatud vaid selleks, et tasuta liiva müüa. Seda jutustab artiklile lisatud pilt.

Abiks:

http://belaz.minsk.by/production/
http://www.hitachi-c-m.com/global/products/excavator/large/ex3600-6/index.html

 Viidatud lugu:

Kadri Bank, aripaev.ee 20. juuli 2009 05:31

ITAR-TASS     Seaduseaugu tõttu annab riik Eesti Energia käe läbi võileivahinnaga ära ehitusmaterjali Kukruse-Jõhvi teelõigule, jättes aga ennast ilma paarikümnest miljonist kroonist. Juba enam kui kuu sõidavad Ida-Virumaal asuva Sirgala karjääri ja tänavuse kalleima teedeehituse vahet kallurid, kastis tuhanded tonnid liiva. Eesti Energia Kaevandustele kuuluvast karjäärist ostab teedeehituskonsortsium seda materjali hinnaga, mis ei küüni väidetavalt üle paarikümne sendi tonni kohta, kirjutab Äripäev.     Tehingu osapooled — Eesti Energia Kaevandused ja ehitajad eesotsas Talteriga — hinda avalikustama ei soostu, öeldes, et lepingus fikseeritud hinnad sisaldavad konfidentsiaalset infot. Eesti Energia Kaevanduste arendusdirektor Kalmer Sokman lisab, et ehitajale müüakse ühe lepingu raames nii killustikku, aherainet kui ka liiva ja eraldi iga materjali hinna väljatoomine jätaks eksitava mulje.

Vaata lisaks:

aripaev.ee: Kingitud miljonid

New lab designed to study dark matter is now under construction

Construction crews have now started building the deepest underground science laboratory in the world, which scientists will use to study dark matter.

“The fact that we’re going to be in the Davis Cavern just tickles us pink,” Case Western Reserve University researcher Tom Shutt told the Associated Press. The cavern used to be a gold mine that has been abandoned for some time now. The part of the mine called Davis Cavern is named after Ray Davis Jr., a scientists who used the mine to study solar neutrinos in the 1960s.

The research lab, located at a depth equivalent to six Empire State buildings, will be used to help scientists study dark matter. Being almost 5,000 feet under the Earth’s surface is an ideal location as cosmic rays likely won’t interfere with research, but it will be some time before researchers are able to begin working there.

Engineers and construction crews must now stabilize and repair some of the tunnels, and add new safety infrastructure to prevent tunnel collapse. Research already is being conducted at 4,850 feet, with Congress mulling two labs that would go even deeper than the one now being built.

Case Western Reserve University, Brown University, and a couple of other universities and research groups are helping develop the new underground science laboratory. Around a dozen total collaborators plan to research dark matter at the facility.

The Large Underground Xenon (LUX) detector equipment — a project aimed at studying the Big Bang explosion — is expected to be the first dark matter experiment.

Dark matter is a popular topic of research because many astronomers believe galaxies may have never formed without dark matter. Furthermore, the theory behind dark matter and what it is remains a mystery — learning more about dark matter may help physicists finally figure out if the universe is expanding or contracting.

The lab should be fully operational by 2016. http://www.dailytech.com/article.aspx?newsid=15510

Were is the deepest mine in the world?

In: Geology, Engineering [Edit categories]

South Africa is where it’s at for deep mines. And what are they digging for? Gold! AngloGold Ashanti’s Savuka mine near Carletonville is currently the world’s deepest mine at just less than 3.8km below the surface.

Gold Fields mines Driefontein will be the world’s deepest mine at 4.1km below the surface and Kloof will be the second deepest mine at 4km underground when their extensions are complete. They’re digging them now.

At this stage AngloGold Mponeng mine is official the deepest mine in the world and the current project will take it another 300 meters deeper.

3.8Km underground – My experience in the deepest mine in the world

POSTED ON 05 DECEMBER 2008

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The world’s deepest pub

Lucille Davie

26 August 2002

Take your next tipple almost a quarter of a kilometre underground in what used to be a donkey stable in one of the world’s richest and deepest gold mines. That is, of course, if you don’t mind damp, dark places and don’t suffer from claustrophobia.

You can book this pub any day of the week from 5pm to 9pm, and get there by taking a large, clangy lift down 226 metres to spend a few hours where, back in the 1920s, some 300 donkeys stayed for three months while pulling cocopans filled with gold-laden rocks for removal above ground.

The pub is on level 5 of the mine known as Shaft 14 on what used to be Langlaagte, the farm on which the main reef was first discovered in Johannesburg in 1886, some six kilometres south of the city centre. The mine goes down 57 levels or 3 500 metres, and over its 90-year lifespan produced some 1.4 million kilograms of gold, blasted out of the ground by 30 000 miners.

The mine is part of the 100-kilometre reef stretching from Boksburg in the east to Randfontein in the west, and visible from a distance with its impressive head gear protruding above the surrounding mine dumps.

The pub – or the wooden doors of the old stable – is visible in the underground mine tour of Shaft 14 at Gold Reef City, the historical village, casino and pleasureland. The tour takes 35 minutes and will give you a glimpse of what it must have been like to work 12-hour shifts down the mine.

When Shaft 14 was opened in 1897, just 11 years after Johannesburg was established, there was no electricity at the mine. Lighting underground was by means of candles, which posed a risk for explosions caused by methane gas. Combined with the darkness, the wetness, the heat, the closeness and the ear-shattering noise of the drills, it was a tough way to earn a living.

Get ready to block your ears! (Picture: Lucille Davie)

The underground temperatures range from 30 degrees to 50 degrees, but with cooling systems temperatures can be maintained at around 28 degrees. With each drop of 100 metres underground, the temperature increases by one degree.

If you were wondering why the donkeys only stayed below ground for three months, it was because after that time they had invariably gone blind.

As you step out the lift underground, you look ahead to a whitewashed tunnel – to help returning miners adjust from the darkness to the brightness outside – and spend the tour walking down two-metre high tunnels, with the cocopan track down the middle of the tunnel.

Source: City of Johannesburg web site

From Wikipedia, the free encyclopedia

Coordinates: 69°23′46.39″N 30°36′31.20″E

Kola Superdeep Borehole, 2007

The Kola Superdeep Borehole (Russian: Кольская сверхглубокая скважина) is the result of a scientific drilling project of the formerUSSR. The project attempted to drill as deep as possible into the Earth’s crust. Drilling began on 24 May 1970 on the Kola Peninsula, using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. A number of boreholes were drilled by branching from a central hole. The deepest, SG-3, reached 12,261 metres (40,230 ft) in 1989, and remains the deepest hole ever drilled.^[1] The longest hole ever drilled is the 12,290 m (40,300 ft) Maersk Oil BD-04A well at Al-Shaheen field in Qatar.^[2]

Contents [hide] 1 Digging 2 Research 3 Current Status 4 Other projects 5 See also 6 References 6.1 Bibliography 6.2 Notes 7 External links

[edit]Digging

The initial target depth was set at 15,000 m (49,000 ft). On 6 June 1979, the world depth record held by the Bertha Rogers hole in Washita County, Oklahoma at 9,583 m (31,440 ft)^[3] was broken. In 1983, the drill passed 12,000 m (39,000 ft), and drilling was stopped for about a year to celebrate the event.^[4] This idle period may have contributed to a break-down on 27 September 1984: after drilling to 12,066 m (39,590 ft), a 5,000 m (16,000 ft) section of drillpipe twisted off and was left in the hole. Drilling was later restarted from 7,000 m (23,000 ft).^[4] The hole reached 12,262 m (40,230 ft) in 1989. In that year the hole depth was expected to reach 13,500 m (44,000 ft) by the end of 1990 and 15,000 m (49,000 ft) by 1993.^[5] However, due to higher than expected temperatures at this depth and location, 180 °C (356 °F) instead of expected 100 °C (212 °F), drilling deeper was deemed unfeasible and the drilling was stopped in 1992.^[4] With the expected further increase in temperature with increasing depth, drilling to 15,000 m (49,000 ft) would have meant working at a projected 300 °C (570 °F), at which the drill bit would no longer work.

[edit]Research

The Kola borehole penetrated about a third through the Baltic continental crust, presumed to be around 35 kilometres (22 mi), exposing rocks 2.7 billion years old at the bottom.^{[citation needed]} The project has been a site of extensive geophysical studies. The stated areas of study were the deep structure of the Baltic Shield; seismic discontinuities and the thermal regime in the Earth’s crust; the physical and chemical composition of the deep crust and the transition from upper to lower crust; lithospheric geophysics; and to create and develop technologies for deep geophysical study.

To scientists, one of the more fascinating findings to emerge from this well is that the change in seismic velocities was not found at a boundary marking Jeffreys’ hypothetical transition fromgranite to basalt; it was at the bottom of a layer of metamorphic rock that extended from about 5 to 10 kilometers beneath the surface. The rock there had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer ofimpermeable rock.^[6]

Another unexpected discovery was the large quantity of hydrogen gas, with the mud flowing out of the hole described as “boiling” with hydrogen.^[7]

[edit]Current Status

Kola Superdeep Borehole, commemorated on the 1987 USSRstamp

The site is currently controlled by the State Scientific Enterprise on Superdeep Drilling and Complex Investigations in the Earth’s Interior (GNPP Nedra) as the Deep Geolaboratory. As of 2003, the deepest active bore, SG-5, is 8,578 m (28,140 ft) and with a 214 mm (8.4 in) diameter.^{[citation needed]}

[edit]Other projects

The United States embarked on a similar project in 1957, dubbed Project Mohole, which was intended to penetrate the shallow crust under the Pacific Ocean off Mexico. However, after some initial drilling, the project was abandoned in 1966 due to lack of funding. This “failure” inspired great successes of the Deep Sea Drilling Project, Ocean Drilling Program, and the present Integrated Ocean Drilling Program.

[edit]See also

• Mohorovičić discontinuity
• Project Mohole
• Chikyu Hakken, deep oceanic drilling program
• Integrated Ocean Drilling Program
• San Andreas Fault Observatory at Depth
• Earthscope
• USARRAY
• Well to Hell hoax

[edit]References

[edit]Bibliography

• Fuchs, K., Kozlovsky, E.A., Krivtsov, A.I., and Zoback, M.D. (Eds.) (1990) Super-Deep Continental Drilling and Deep Geophysical Sounding. Springer Verlag, Berlin, 436 pp.
• Kozlovsky, Ye.A. (Ed.) (1987) The Superdeep Well of the Kola Peninsula. Springer Verlag, Berlin, 558 pp.

[edit]Notes

[edit]External links

• Official Kola Superdeep Borehole website (in Russian)
• The World’s Deepest Hole – Alaska Science Forum – July 1985
• Cassino, Adam (2003). “Depth of the Deepest Drilling“. The Physics Factbook.
• The Deepest Hole June 20, 2006

From Wikipedia, the free encyclopedia

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. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash. Any material that cannot be grown through agricultural processes, or created artificially in a laboratory or factory, is usually mined. 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 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. This impact has led to most of the world’s nations adopting regulations to moderate the negative effects of mining operations. Safety has long been a concern as well, though modern practices have improved safety in mines significantly. Mining today is able to profitably and safely recover minerals with little negative impact to the environment.

[edit]History

[edit]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. The mines at Grimes Gravesare especially famous, and like most other flint mines, are Neolithic in origin (ca 4000 BC-ca 3000 BC). Other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District.

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

[edit]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.”^[5] Quarries for turqoise and copperwere 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. He mentions that fire-setting was one method used to break down the hard rock holding the gold. 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.

[edit]Ancient Greece and Rome

Agricola, author of De Re Metallica

Drainage wheel from Rio Tinto mines

Mining in Europe has a very long pedigree, examples including the silver mines of Laurium, which helped support the Greek city state of Athens. 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. The water was used for a variety of purposes, including using it to remove overburden and rock debris, called hydraulic mining, as well as washingcomminuted or crushed ores, and driving simple machinery. 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. It involved building numerous aqueducts to supply water to the minehead where it was stored in large reservoirs and tanks. 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. 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. The methods had been developed by the Romans in Spain in 25 AD to exploit large alluvial gold deposits, the largest site being atLas Medulas, where seven long aqueducts were built to tap local rivers and to sluice the deposits. Spain was one of the most important mining regions, but all regions of the Roman Empire were exploited. They used reverse overshot water-wheels for dewatering their deep mines such as those at Rio Tinto. In Great Britain the natives had minedminerals for millennia ,^[6] but when the Romans came, the scale of the operations changed dramatically. 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. 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. At other parts of the site, they penetrated the water table and dewatered the mines using several kinds of machine, especiallyreverse overshot water-wheels. 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). They were worked as treadmills with miners standing on the top slats. 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.^[7]

[edit]Medieval Europe

Mining in the Medieval period is best known through the work De Re Metallica (1556) of Georg Agricola, who described many different mining methods then used in German and Saxon mines. 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.^[8] This allowed blasting of rock and earth to loosen and reveal ore veins, which was much faster than fire setting. In 1762, the world’s first mining academy was established in the same town.

[edit]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.^[9][10] “Indians availed themselves of this copper starting at least 5000 years ago,”^[9] 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.^[10] While the early French explorers that encountered the sites made no use of the metals due to the difficulties in transporting it,^[10] 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.^[11]

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”^[12] mostly from mines in Central and South America. Turquoise dated at 700 A.D. was mined in pre-ColumbianAmerica; 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.”^[13][14]

Mining in the United States became prevalent in the 19th century. 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. 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.^[15] Aided by railroads, many traveled West for work opportunities in mining. Western cities such as Denver and Sacramento originated as mining towns.

[edit]Mining methods and procedures

[edit]Steps of mine development

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. 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. 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.

[edit]Mining techniques

A minecart toilet, used inBisbee, Arizona.

Mining techniques can be divided into two common excavation types: surface mining and sub-surface (underground) mining. Mining 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 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.^[16][17]

Surface mining is done by removing (stripping) surface vegetation, dirt, and if necessary, layers of bedrock in order to reach buried ore deposits. 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. Most (but not all) placer deposits, because of their shallowly-buried nature, are mined by surface methods. Landfill miningfinally are sites where landfills are excavated and processed.^[18]

Open-pit mine near Garzweiler, Germany

Sub-surface mining consists of digging tunnels or shafts into the earth to reach buried ore deposits. 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. Drift mining utilizes horizontal access tunnels, slope mining uses diagonally sloping access shafts and shaft mining consists of vertical access shafts. 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

[edit]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 drillsare 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.

[edit]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. Geometallurgycombines the geologic sciences with extractive metallurgy and mining.

[edit]Environmental effects

This section needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2008)

House in Gladbeck, Germany, with fissures caused by gravity erosion due to 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. ^[19] Besides creating environmental damage, the contamination resulting from leakage of chemicals also affect the health of the local population. ^[20] Mining companies in some countries are required to follow environmental and rehabilitation codes, ensuring the area mined is returned to close to its original state. Some mining methods may have significant environmental and public health effects.

Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.

Mining can have adverse effects on surrounding surface and ground water if protective measures are not taken. The result can be unnaturally high concentrations of some chemicals, such as arsenic, sulfuric acid, and mercury over a significant area of surface or subsurface. ^[21] Runoff of mere soil or rock debris -although non-toxic- also devastates the surrounding vegetation. The dumping of the runoff in surface waters or in forests is the worst otion here.Submarine tailings disposal is regarded as a better option (if the soil is pumped to a great depth.^[22] Mere land storage and refilling of the mine after it has been depleted is, of course, even better; if no forests need to be cleared for the storage of the debris. There is potential for massive contamination of the area surrounding mines due to the various chemicals used in the mining process as well as the potentially damaging compounds and metals removed from the ground with the ore. Large amounts of water produced from mine drainage, mine cooling, aqueous extraction and other mining processes increases the potential for these chemicals to contaminate ground and surface water. In well-regulated mines, hydrologists and geologists take careful measurements of water and soil to exclude any type of water contamination that could be caused by the mine’s operations. The reducing or eliminating of environmental degradation is enforced in modern American mining by federal and state law, by restricting operators to meet standards for protecting surface and ground water from contamination. This is best done trough the use of non-toxic extraction processes as Bioleaching. If the project site besomes nonetheless polluted, mitigation techniques such as acid mine drainage (AMD) need to be performed.

The five principal technologies used to monitor and control water flow at mine sites are diversion systems, containment ponds, groundwater pumping systems, subsurface drainage systems, and subsurface barriers. In the case of AMD, contaminated water is generally pumped to a treatment facility that neutralizes the contaminants.^[23] Some examples of areas affected by acid mine drainage are the Berkeley Pit, and the Wheal Jane Mines.

Dissolution and transport of metals and heavy metals by run-off and ground water is another example of environmental problems with mining, such as the Britannia Mine, a former copper mine near Vancouver, British Columbia. Tar Creek, an abandoned mining area in Picher, Oklahoma that is now an Environmental Protection Agencysuperfund site, also suffers from heavy metal contamination. Water in the mine containing dissolved heavy metals such as lead and cadmium leaked into local groundwater, contaminating it.^[24] Long-term storage of tailings and dust can lead to additional problems, as they can be easily blown off site by wind, as occurred at Scouriotissa, an abandoned copper mine inCyprus. Erosion of exposed hillsides, mine dumps, tailings dams and resultant siltation of drainages, creeks and rivers can significantly impact the surrounding areas, a prime example being the giant Ok Tedi Mine in Papua New Guinea. In areas of wilderness mining may cause destruction and disturbance of ecosystems and habitats, and in areas of farming it may disturb or destroy productive grazing and croplands. In urbanised environments mining may produce noise pollution, dust pollution and visual pollution.

To ensure completion of reclamation, or restoring mine land for future use, many governments and regulatory authorities around the world require that mining companies post a bond to be held in escrow until productivity of reclaimed land has been convincingly demonstrated, although if cleanup procedures are more expensive than the size of the bond, the bond may simply be abandoned. Since 1978 the mining industry has reclaimed more than 2 million acres (8,000 km²) of land in the United States alone. This reclaimed land has renewed vegetation and wildlife in previous mining lands and can even be used for farming and ranching. For further reading on reclamation of former mining sites, please see Restoration ecology.

[edit]Mining industry

This section requires expansion.

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. 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.

[edit]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. Juniors are mainly pure exploration companies, but may also produce minimally, and do not have a revenue of US$50 million.^[25]

[edit]Safety

Danger sign at an old Arizona mine.

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).^[26] 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.^[26] 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, includingsilicosis, 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 in spite of modern improvements to safety practices, mining remains dangerous throughout the world.

[edit]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.^[27][28] 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. 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.

[edit]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.^[29] For example, a roof bolter (commonly used by mine roof bolter operators) can reach sound power levels of up to 115 dB.^[29] Combined with the reverberant effects of underground mines, a miner without proper hearing protection is not only at a high risk for hearing loss,^[29] but is also going against OSHA standards^[30].

[edit]Records

As of 2008, the deepest mine in the world is TauTona in Carletonville, South Africa at 3.9 kilometers^[31], replacing Savuka Mine in the North West Province of South Africa at 3,774 meters^[32]. 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 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.

[edit]See also

• Outline of mining
• Landfill mining
• List of uranium mines
• Canadian Mining Hall of Fame
• Exposure action value

[edit]References

[edit]External links

Look up mining in Wiktionary, the free dictionary.

• Glossary of terms
• Introduction to Mining
• What is mining?
• Mining