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Topic: Gold extraction

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	Resource Investor - Gold & Silver - Gold Extraction Trends in Russia
		Upon analysis of the investment appeal of the gold mining industry, it is necessary to note that the tendency, and the long-term trend of the price for gold, represents a wavy line with rather a number of failures, but also without a lesser number of significant ascensions.
		The market of gold "is closely fixed" at a level of the incomes of the population, and any increase in the market of jewellery (on which about 90% of all extracted precious metal are consumed) quickens, and the consumption of gold by the jewellery industry is in an inverse relationship from its price.
		But gold and exchange currency reserves of the Central Bank are focused to a greater degree on currency (in their volume cost of gold is not stable moving within the limits of 4%).
	www.resourceinvestor.com /pebble.asp?relid=19533 (1831 words)

	Mining Interactive--Gold Extraction
		Gold bearing slurry was introduced at the raised end of the box and pased slowly through the shavings to overflow at the lower end.
		Activated carbon is used to adsorb the gold directly from the cyanided pulp which flows continually from the first vessel to the last in the series, and the carbon is transferred intermittently by pumping in the opposite (countercurrent) direction.
		Flotation concentrates have to be subjected to roasting to render the gold amenable to extraction by cyanidation.
	www.mininginteractive.com /FAQ/gold-extraction.htm (2181 words)

	Gold Smelting and Refining (Site not responding. Last check: )
		Gold mining is carried out on a small scale by individual prospectors (e.g., in China and Brazil) and on a large scale in underground mines (e.g., in South Africa) and in open pit mining (e.g., in the United States).
		Gold is also recovered as a by-product from the smelting of copper, lead and other metals (see the article “Copper, lead and zinc smelting and refining” in this chapter).
		In the mercury extraction of gold, workers may be exposed to high airborne mercury concentrations when mercury is placed in or removed from the sluices, when the amalgam is purified or pressed and when the mercury is distilled off; mercury poisoning has been reported amongst amalgamation and distilling workers.
	www.ilo.org /encyclopedia/?doc&nd=857200677&nh=0 (1452 words)

	Use in Mining
		Gold is one of the noble metals and as such it is not soluble in water.
		Gold recovery from sulfide ore is poor because the cyanide preferentially leaches the sulfide minerals rather than the gold, and cyanide is consumed by the formation of thiocyanate.
		Gold is recovered from the solution first using either cementation on zinc powder or concentrating the gold using adsorption on activated carbon, followed by elution and concluding with either cementation with zinc or electrowinning.
	www.cyanidecode.org /cyanide_use.php (1807 words)

	Citigold Corporation - Gold Extraction
		The CIL plant is fully equipped with crushing and grinding circuits, gravity circuit for coarse gold, gold absorption and desorption leach circuits, electrowinning and gold pouring facilities.
		The team at Charters Towers ensures the processing plant machinery is in satisfactory operational condition for the processing and extraction of gold from the ore. All equipment involved in the extraction process, including crushers, tanks and pumps is continuously being audited and examined for its durability and performance ability.
		The stockpiled ore, comprising the large blasted rock from underground, is crushed to under 12 millimetres, and transported by conveyer to the grinding mill where water and lime are sufficiently added and the ore reduced in size to fine sand particles with a width of 0.1 millimetres.
	www.citigold.com /goldrecovery.asp (726 words)

	Gold (Site not responding. Last check: )
		Gold and diamonds are the two highly valued commodities which were largely instrumental in the development of the country's infrastructure and the establishment of secondary industry during the first half of the twentieth century.
		Gold, in the figurative language of the people, was "the tears wept by the sun" and every part of the interior of the temple glowed with burnished plates and studs of the precious metal.
		Gold usage in dentistry is almost as old as its usage in jewellery, with the result that there is a long experience of the performance and bio-compatibility of gold alloys in dentistry.
	www.bullion.org.za /MiningEducation/Gold.htm (10960 words)

	Gold
		The successful application of heap leaching to the extraction of gold from low-grade deposits has been one of the main factors in higher output since the 1970s, especially in the United States.
		Heap leaching of gold was pioneered in the United States in 1973 at Placer Development's Cortez open pit in Nevada and proved on a larger scale at Pegasus Gold's Zortman Landusky mine in Montana.
		The gold is now in the metal element state with zero charge and appears as fine specks of gold to be precipitated out and the precipitate is then refined.
	www.elmhurst.edu /~chm/vchembook/327gold.html (492 words)

	Lateral Science - Getting Gold - Chapter 6
		The extraction of gold from the soil is an industry so old that its first introduction is lost in the mist of ages.
		As before stated, gold is one of the most widely disseminated of the metals, and man, so soon as he had risen from the lowest forms of savagery, began to be attracted by the kingly metal, which he found to be easily fashioned into articles of ornament and use, and to be practically non- corrodable.
		The mode of extraction longest in vogue, and after all the cheapest and most effective, for free milling ores where the gold is not too fine, is amalgamation with mercury, which metal has a strong affinity for gold, silver, and copper.
	www.lateralscience.co.uk /gold/gg6.html (5636 words)

	Gold Extraction - Gold Mining - Washing, Amalgamation, Leaching, Smelting
		As before stated, gold is one of the most widely disseminated of the metals, and man, so soon as he had risen from the lowest forms of savagery, began to be attracted by the kingly metal, which he found to be easily fashioned into articles of ornament and use, and to be practically non-corrodable.
		The extraction of reef gold from its matrix is a much more complicated process, and the problem how most effectively to obtain that great desideratum—a complete separating and saving operation—is one which taxes the skill and evokes the ingenuity of scientific men all over the world.
		The mode of extraction longest in vogue, and after all the cheapest and most effective, for free milling ores where the gold is not too fine, is amalgamation with mercury, which metal has a strong affinity for gold, silver, and copper.
	geology.com /publications/getting-gold/gold-extraction.shtml (5691 words)

	Extraction and recovery of gold - Patent 5260040
		A process for the hydrometallurgical recovery of gold from gold-bearing material wherein a gold-bearing material is treated with an acidic lixiviant solution containing thiourea and ferric ion to dissolve gold from said gold-bearing material, the improvement comprising including in the lixiviant solution used in said dissolution step a complexing agent for ferric ions.
		Gold is readily dissolved in acidified solutions containing thiourea, using manganese dioxide, hydrogen peroxide or ferric ions as the oxidant D. Bilston, R. Millet and J. Woodcock (1987) Proc.
		Relates to in situ recovery of gold from the fines on a footwall and in the fissures and cracks therein by passing a solution capable of solubilising the gold across the footwall.
	www.freepatentsonline.com /5260040.html (2577 words)

	Gold Extraction - Secondary Processes and Lixiviation
		Having treated on gold extraction with mercury by amalgamated plates and their accessories, something must be said about secondary modes of saving in connection with the amalgamation process.
		The earlier practical applications of chlorine to gold extraction were known as Mears' and Plattner's processes, and consisted in placing the material to be operated on in vats with water, and introducing chlorine gas at the bottom, the mixture being allowed to stand for a number of hours, the minimum about twelve, the maximum forty-eight.
		The process of extracting gold from lode stuff and tailings by means of cyanide of potassium is now largely used and may be thus briefly described:—It is chiefly applied to tailings, that is, crushed ore that has already passed over the amalgamating and blanket tables.
	geology.com /publications/getting-gold/secondary-gold-extraction.shtml (3473 words)

	BRAZIL GOLD
		Currently, Brazil is the worldßs fourth largest producer of gold and the other countries of the region have begun to increase their investment in discovering and utilizing gold resources.
		The sieves are coated with mercury, which bonds with the gold in the sediment separating it from the rest of the material.
		This gold is being mined by both large scale industry and individual wildcat miners called "garimpeiros." Most of the garimpo mining, which is the least regulated and most mercury polluting component of the gold mining sector, occurs in Brazil.
	www.american.edu /projects/mandala/TED/bragold.htm (3727 words)

	TVX - Gold (A brief history of gold extraction methods)
		The oldest method of gold extraction is gold panning, exploiting the higher density of gold to separate it from the lighter accompanying materials.
		The technical principle of treatment of gold ore in the mining districts of Southern Bohemia in the Middle Ages consisted in heat separation (the ore was first heated and then immediately cooled by water), mechanical crushing and subsequent separation or amalgamation.
		The principle of amalgamation is extraction of gold from the pulverized ore by mercury.
	tvx.dbm.cz /english/zlato/zlato31.htm (761 words)

	Trust In Gold - Production, - Extraction
		Generally once metallic gold or a gold alloy has been produced it can be sold to a precious metals refinery for a price quite close to its gold content.
		Many mines have some free gold and often there is a small gravity circuit that uses gold's great weight relative to the rock in which it is found to extract it early in the treatment plant.
		After cyanide's effectiveness for capturing gold into solution was discovered in the late 19th century, gold extraction was revolutionized and recovery efficiencies greatly improved.
	www.trustingold.com /content/view/58/97 (992 words)

	Protests against expanded gold extraction in Bulgaria
		Protests have followed a decision by Bulgaria's environmental authorities to allow the expanded extraction of gold near the western village of Chelopech.
		The company had submitted a project for the Ada Tepe gold mine near the southern town of Kroumovgrad, which is still awaiting the necessary permits from the Environment Ministry.
		The environmentalists' concerns stem from the fact that the project involves gold extraction by the open-pit method, using cyanides.
	www.minesandcommunities.org /Action/press976.htm (432 words)

	Lateral Science - Getting Gold - Chapter 7
		Having treated on gold extraction with mercury by amalgamated plates and their accessories, something must be said about secondary modes of saving in connection with the amalgamation process.
		The earlier practical applications of chlorine to gold extraction were known as Mears' and Plattner's processes, and consisted in placing the material to be operated on in vats with water, and introducing chlorine gas at the bottom, the mixture being allowed to stand for a number of hours, the minimum about twelve, the maximum forty-eight.
		The process of extracting gold from lode stuff and tailings by means of cyanide of potassium is now largely used and may be thus briefly described:--It is chiefly applied to tailings, that is, crushed ore that has already passed over the amalgamating and blanket tables.
	www.lateralscience.co.uk /gold/gg7.html (3426 words)

	Ore processing & gold extraction @ Martha Mine
		Carbon is heated to 600 degrees C and fed into the circuit in the opposite direction to the slurry flow, moving from the last adsorption tank to the first.
		This is because the gold and silver move towards the carbon via a diffusive process.
		The gold and silver migrates and attaches itself to the stainless steel cathodes.
	www.marthamine.co.nz /ore_process.html (1154 words)

	Gold extraction (Overview - Research)
		Gold is commonly extracted from ore using the carbon in pulp (CIP) process.
		The gold adsorbs to the carbon and the carbon is moved up the leach circuit achieving gold loadings of approximately 2 500 grams per tonne.
		Gold is electrowon from the concentrated gold solution onto steel wool with the steel wool being dissolved away by hydrochloric acid, leaving a gold doré which is smelted into bars for shipment to the mint.
	www.csiro.au /science/Gold.html (545 words)

	Gold Extraction Methods
		Process selection is the systematic development of the optimum metal extraction route for a particular ore using the most appropriate technology.
		Process selection is an iterative procedure which usually starts as soon as exploration has established the presence of gold mineralization in sufficient grade and tonnage for the orebody to be considered a potentially economic reserve.
		The risk associated with the development of gold projects can be minimized planning a good work metallurgical program, and considering aspects that have been considered in the project: capital, profitability, risk and environmental factors
	www.e-goldprospecting.com /html/gold_extraction.html (162 words)

	YES TECHNOLOGIES: Cyanide-free biocatalyzed leaching of gold and silver ore
		Gold dissolves in the bisulfide solution and is recovered with activated carbon or zinc dust.
		Since its invention in 1899, cyanidation and its variants have been the processes of choice for extraction of gold and silver from oxidized ores.
		A second application of the process is recovery of gold and silver from scrap.
	www.yestech.com /tech/gold1.htm (678 words)

	Gold extraction company could pull out of Bulgaria - Business news
		Canada’s Dundee Precious Metals said on March 23 it would pull out of Bulgaria if their gold extraction project in Chelopech is not allowed to expand.
		The Chelopech copper and gold mine in western Bulgaria will be closed if the Environment and Water Affairs Ministry delays any further the project for the upgrading of the mining facilities, Dundee Precious Metals president Jonathan Goodman told the media.
		The Supreme Expert Environmental Council (SEEC) with the Ministry of Environment and Water Affairs approved on March 10 the positive environmental impact assessment of a Dundee project to dig for more gold in the area.
	www.sofiaecho.com /article/gold-extraction-company-could-pull-out-of-bulgaria/id_14345/catid_23 (709 words)

	Peru gold mine company is looking for loan or joint venture partner
		Our core business will be the extraction of gold ore but the potential in the rare earths; titanium and zirconium of the identified (modified) concessions are under evaluation in our area.
		The gold and mineral content of the Urubamba Valley is exceptionally high due to its location at the foothills of the Andes Mountains.
		Gold is one of the soundest investments in the known world.
	www.goldandsilvermines.com /igold.htm (1375 words)

	Gold n Gem Grubbin: Family fun, gold and gem panning, jewelry, fishing, camping, mini golf (Site not responding. Last check: )
		The ore is dumped onto this large grizzly where the larger pieces are dumped off allowing the sand (where the gold is) and the gravel to fall through and be processed through the plant.
		Placer mining is a form of gold mining associated with the streams and rivers where they run today and where they ran in the past.
		Placer is gold that has been washed away by natural erosion from the main vein in the hills.
	www.goldngem.com /who.htm (656 words)

	The Hindu : Biotechnology in gold extraction
		The Hutti Gold Mines Company Limited established a research collaboration with the Indian Institute of Science at Bangalore to assess the amenability of bioprocessing of refractory gold ores of Karnataka.
		Refractory gold ores from the G.R. Halli mines were chosen for the research work since they contained both gold and silver besides the presence of base metals such as lead, zinc, copper and cobalt.
		Refractory gold concentrates and process water are added to a mixing vessel to yield a slurry at 10-15 per cent pulp density which is then fed to reactors 1 and 2 on a continuous mode at acidic pH.
	www.hinduonnet.com /thehindu/seta/2002/02/21/stories/2002022100060300.htm (513 words)

	UNIDO - FEATURE: Artisanal Gold Mining without Mercury Pollution
		Since the modern "gold rush" in developing countries began in the 1980s, millions of people have become artisanal miners, despite the risks of working in small tunnels or on steep hills and being exposed to mercury spilling mills, toxic vapours and explosives.
		Gold in the ore sludge is mixed with mercury into an amalgam, which is then separated by heating into mercury vapour and gold.
		As a follow-up, a full project will be developed designed to help the governments of the six countries, where gold mining activities affect international waters with mercury emissions from artisanal mining, design regulations, institutional structures and a legal framework of the mining sector.
	www.unido.org /doc/4571 (993 words)

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