Procesamiento de minerales II Tratamento de minerais de ouro e prata

Apresentação em tema: "Procesamiento de minerales II Tratamento de minerais de ouro e prata"— Transcrição da apresentação:

1 Procesamiento de minerales II Tratamento de minerais de ouro e prata
Maria Luiza Souza Montevideo 16-20 Setembro 2013 UNIVERSIDADE DE LA REPUBLICA – URUGUAY UFRGS - DEMIN - BRASIL

2 Capítulo 2 – Minas e métodos
Neste item serão vistas, de modo resumido, os seguintes tópicos: Minas de ouro em produção Fluxograma geral para minerais de ouro - Fluxograma para ouro livre - Fluxograma para ouro refratário Ouro livre Recuperação > 90 % na cianetação direta. Ouro refratário  Recuperação < 90 % na cianetação direta. Existem outras classificações mais detalhadas em função do grau de “refratariedade”: minerais complexos e então refratários. UNIVERSIDADE DE LA REPUBLICA – URUGUAY UFRGS - DEMIN - BRASIL

3 No.10 – Obuasi - Gana, África. Reservas: 29 830 000 Oz. de ouro.
Minas de ouro Fonte: Carlos Andres - Gold Miners Investment Newsletter | August 7, 2013 Today, we present the world's Top 10 producing Gold Mines. Compiling them was not easy because there are a few ways they can be ranked.  A top 10 list can by compiled by annual production, or by the size of proven and probable reserves, or more generally by their measured, indicated & inferred resources (which include reserves). We ultimately decided to rank them based on the overall size of gold resources to give the viewer a truer sense of the deposits size and potential. #10 | Obuasi | 29,830,000 Oz Gold Location: GHANA, western Africa In the #10 spot is Obuasi, owned by major gold producer AngloGold Ashanti. It is primarily a high-grade underground mine with periodic open-pit operations during its long history. It is located in the Ashanti region of southwest Ghana in western Africa; a prolific gold producing region for centuries. The underground operation extends to a depth of 1,500 meters or 4,900 feet (almost a mile). Mining began at Obuasi more than 110 years ago, in 1897 when it was originally known as the Ashanti Mine. Minério Complexo: No.10 – Obuasi - Gana, África. Reservas: Oz. de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

4 No.9 – Cadia East - NSW, Austrália. Reservas: 37 600 000 Oz de ouro.
Minas de ouro #9 | CADIA EAST | 37,600,000 Oz Gold Location: New South Wales, AUSTRALIA In the #9 spot is Cadia East, owned by Australian major Newcrest. The large underground mining operation is part of a trio of gold mines, in close proximity to one another, known collectively as Newcrest's Cadia Valley Operations, roughly 250 kilometers west of Sydney. The other two mines are Cadia Hill and Ridgeway. Cadia Hill is a large open-pit mine nearing the end of its useful life just as the newly developed Cadia East recently began its expected 30 year mine life. Gold was first discovered in the gold and copper bearing Cadia region in 1851 and Cadia East was discovered in 1994. No.9 – Cadia East - NSW, Austrália. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

5 No.8 – Mponeng – África do Sul. Reservas: 39 557 000 Oz de ouro.
Minas de ouro Anglo gold Ashanti. Fonte: site AGA Mponeng comprises a twin-shaft system housing two vertical shafts and two service shafts. Ore mined is treated and smelted at Mponeng's gold plant. The ore is initially ground down by means of semi-autogenous milling after which a conventional gold leach process incorporating liquid oxygen injection is applied. The gold is then extracted by means of carbon-in-pulp technology. The Mponeng gold plant conducts electro-winning and smelting (induction furnaces) on products from Savuka and TauTona as well. No.8 – Mponeng – África do Sul. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

6 Minas de ouro #7 | PUEBLO VIEJO | 40,085,000 Oz Gold Location: DOMINICAN REPUBLIC Coming in at #7 is Pueblo Viejo, owned jointly by majors Barrick (60%) and Goldcorp (40%). This large deposit is located in the Dominican Republic, roughly 100km northwest of the capital of Santo Domingo. It might surprise some that this small island nation is rich in mineral reserves. The open pit mine is very new and began production in January It also has large silver and copper reserves to complement its gold deposit. As it ramps up to full production, it will also be one of the largest producers in the world, but we'll save production figures for a separate Top 10 List. Fonte: Since the previous mine extracted the surface ore, the ore being processed today is refractory and needs special treatment. The process consists of crushing, grinding, pressure oxidation and CIL cyanidation. The gold will be mined by conventional open pit methods. The two pits are Moore and Monte Negro. No.7 – Pueblo Viejo – República Dominicana. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

7 Minas de ouro #6 | OYU TOLGOI | 46,340,000 Oz Gold Location: South Gobi Desert, MONGOLIA At #6 on our list is Oyu Tolgoi, owned jointly by Rio Tinto (34%), Turquoise Hill (32%) and Mongolia (34%). This is another newly developed mammoth deposit located in the remote southern reaches of Mongolia. The mine cost the princely sum of US$6.6B to develop and went into production in January In addition to its 46Moz+ of gold, it also contains over 40 billion pounds of copper worth US$140B. It's really a copper mine masquerading as a gold mine. It will also be one of the largest gold and copper producers on earth as it ramps up to full production. Its a copper mine Oyu Tolgoi operational expectations for 2013  The Oyu Tolgoi mine will progressively ramp up during the second half of 2013 and is expected to produce between 75,000 and 85,000 tonnes of copper in concentrates for the year. The mine is expected to be running atreach full capacity in the second half of 2013.  As of June 30, 2013, Oyu Tolgoi held 50,200 tonnes of concentrate in inventory. Concentrate inventory will build to the equivalent of four to eight weeks of production with shipments of finished product matching production rates by the end of 2013, when up to 36 truck convoys are expected to leave the mine site on a weekly basis. In Q2'13, a total of approximately 14.6 million tonnes of material was moved from the open pit, approximately 3.2 million tonnes of ore was moved to the stockpile, approximately 3.7 million tonnes of ore was delivered to the crusher and approximately 3.9 million tonnes of ore was processed by the concentrator. Open-pit production rates were reduced during Q2'13 using stockpiled (2.4 million tonnes) and in-pit broken ore in order to preserve cash. Open pit mining activities are expected to ramp back up in Q3'13.  Construction of the open pit and concentrator complex were completed during Q1'13 and mine infrastructure is substantially complete. The building of the Oyu Tolgoi-Gashuun Sukhait road to an existing toll road continues and is expected to be complete in January The diversion of the Undai River is progressing and is substantially complete. The final cost for the initial development and construction will be approximately $6.2 billion, excluding foreign-exchange exposures. Long-term sales contracts had been entered into for 75% of the Oyu Tolgoi mine's concentrate production over the first three to six years of production. A further contract was subsequently entered into for up to 25% of production. These contracts were conditional upon the Oyu Tolgoi mine achieving ore throughput of over 70% for 14 consecutive days. Oyu Tolgoi satisfied this production milestone in July Accordingly, contracts for up to 70% of total production are now enforceable, and sales under the terms of these contracts have commenced. However, for the remaining contract, the production condition was not met by the contracted deadline, and discussions are ongoing with the customer about the future of this sales contract. Oyu Tolgoi is currently delivering concentrate under long-term sales contracts and spot market sales. Oyu Tolgoi begins shipping copper concentrate Oyu Tolgoi has started shipping copper concentrate to customers from its copper and gold mine in Mongolia. 9 July 2013 No.6 – Oyu Tolgoi – Deserto de Gobi, Mongólia. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

8 Minas de ouro #5 | OLYMPIADA | 47,500,000 Oz Gold Location: Central Siberia, RUSSIA In the #5 spot is Olympiada, owned solely by Russian major Polyus. This large open-pit mine is located in the country's most prolific gold bearing region; the Krasnoyarsk krai in central Siberia. In fact this area is at the heart Russian natural resource production in general. Olympiada was discovered in 1970 and finally went into production in 1996 and despite its age it has plenty of resource life left. Russia is the 4th largest gold producer in the world, and as Russia's biggest producer, Olympiada was responsible for 9% of the total in 2012. Located in one of Russia’s most prolific gold mining provinces, Olimpiada is Polyus Gold’s largest operation. The mine began production in 1996 and currently accounts for over a third of the Company’s total gold output. The ore mined at the site is processed at two plants with a combined capacity of 8 mln tonnes of ore annually. To treat Olimpiada’s sulphide ores, Polyus Gold employs BIONORD, the Company’s proprietary bio-oxidation technology. Successful exploration activities in the area indicate the potential for substantial extension of the life of this unique mine. Biooxidation of Refractory Gold Sulfide Concentrate of Olympiada Deposit. Advanced Materials Research (Volumes ). P May, 2009 No.5 – Olympiada – Sibéria Central, Rússia. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

9 Minas de ouro #4 | MURUNTAU | 50,000,000 Oz Gold Location: Kyzyl Kum Desert, UZBEKISTAN At #4, Muruntau is physically the largest open pit gold mine on earth, measuring 3.5km x 2.5km across (2.2mi x 1.6mi) at the surface. This megalith of a mine is currently owned by the Uzbek government. Like its cousins, Oyu Tolgoi and Olympiada, this mine is located on the remote fringes of the Asian steppe. Production began in the late 60's, as modern larger scale production ramped up in the 1990's with Newmont's involvement. Although large, the deposits true size is hard to ascertain due to a less than transparent owner. CIANETAÇÃO-RIP-ELUIÇÃO COMPLEXA EM TRÊS ESTÁGIOS: AC. SULFURICO. AMONIACAL E O ÚLTIMO COM TIOUREIA. No.4 – Muruntau – Deserto de Kyzyl Kum, Uzbequistão. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

10 Minas de ouro #3 | LIHIR | 64,100,000 Oz Gold Location: Niolam (aka Lihir) Island, PAPUA NEW GUINEA Now we're entering rarified air. In the #3 spot is Lihir at a whopping 64Moz+. This large tropical open pit mine began production in 1997 and is currently owned by Australian major Newcrest who acquired it in 2010 for a cool US$22B. It's another remote mine, located on the small island of Lihir, over 900km (560mi) east of Port Moresby, Papua New Guinea. The pit is actually in the caldera of an extinct volcano that is geothermically active. Retrofitting is currently underway to dramatically increase production, which will likely make it one of the largest gold producers as well. Most of the ore is refractory and is treated using pressure oxidation before the gold is recovered by a conventional leach process. No.3 – Lihir – Niolam Island, Papua Nova Guiné. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

11 Minas de ouro #2 | SOUTH DEEP | 81,413,000 Oz Gold Location: Near Johannesburg, SOUTH AFRICA #2 South Deep is also located in the Witwatersrand Basin, very near to 8th place Mponeng. Similarly, it is a high-grade deep underground mine, just southwest of Johannesburg. The mine is in the early stages of ramping up to full production. Mining began at the site in 1961 and Gold Fields bought the operation in The mine produced 273,000 ounces in 2012 and is expected to produce 770,000 ounces annually by Amazingly, it is estimated that the mine will maintain this high rate of production until 2057 with mine life lasting until 2080. Fonte: Technical Report – 31dez12. The milling circuit includes a semi-autogenous grinding (SAG) mill for primary and secondary milling, which is conducted in two overflow ball mills. Classification is done using a cluster of cyclones. Four Knelson concentrators facilitate the recovery of free gold and the concentrate is tabled in the smelthouse using a Gemini Table. The cyclone overflow is thickened before the slurry reports to the leach circuit, which has 10 mechanically agitated tanks, each with a 3,000 cubic metres volume. Cyanide is used for gold dissolution and lime is added to ensure protective alkalinity. An eight-stage, carousel-type carbon-in-pulp (CIP) circuit is used for gold adsorption. Each tank in the train is 200 cubic metres. Carbon stripping is achieved using the AARL elution system, while carbon regeneration is carried out in a rotary kiln at a rate of 500 kg/hr. Gold is recovered from the solution by using electro-winning “Sludge Reactors”, and then dried. This is followed by smelting in an induction furnace to produce gold bullion. Concentrates from the Gemini Table are calcined and smelted in the induction furnace. The gold bars are marked and dispatched to the Rand Refinery. No.2 – South Deep – Johannesburg, África do Sul. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

12 Minas de ouro #1 | GRASBERG | 106,231,000 Oz Gold Location: Papua, INDONESIA At #1, Grasberg is the granddaddy of them all containing a whopping 100Moz+ of gold. The massive mine is owned by Freeport McMoRan but includes a sizeable sharing agreement with miner Rio Tinto. The site is located in the mountains at an altitude of 4,300 meters or 14,000 feet. In truth, Grasberg produces far more copper, by value, than gold and thus represents one of the world’s largest copper and gold mines. The operations consist of both open pit and underground mines, and have been in operation since the 1980's and the pit forms an enormous mile wide crater. Grasberg mine Operated by Arizona-based miner Freeport-McMoRan Copper & Gold (NYSE:FCX), the Grasberg mine is considered by most experts to be the biggest gold mine in the world. It is also one of the largest copper mines. Grasberg is located in the province of Papua in Indonesia. Open-pit operations at the mine began in 1990 and the company expects that they will continue through As of December 31, 2012, the Grasberg open pit’s recoverable proven and probable gold reserves sat at 6.5 million ounces. The mine’s targeted gold output for 2013 is 1.25 million ounces, but recent setbacks may cause it to only produce 80 percent of that estimate. A mine tunnel collapsed May 14, forcing Freeport to shut down operations, and production did not resume until July 9. There are still expansion projects in progress in the Grasberg mineral district, including the development of large-scale, high-grade underground ore bodies, according to the company’s 2012 annual report. No.1 – Grasberg – Província de Papua, Indonésia. Reservas: Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

13 Mina de ouro da América do Sul - Yanacocha
Yanacocha mine Located in the Andes Mountains in Peru, the Yanacocha mine is the largest gold mine in Latin America. It opened in 1993 and contains three active pits. Since its inception, the mine has produced more than 26 million ounces of gold. Yanacocha is owned and operated by Colorado-based gold producer Newmont Mining (NYSE:NEM,TSX:NMC). The company holds a percent interest in the property and the rest is claimed by Compania de Minas Buenaventura (NYSE:BVN). In 2012, Yanacocha produced 1.346 million ounces of gold. As of December 31, 2012, the asset had 3 million attributable ounces of gold reserves. It is part of a joint venture with Newmont’s Conga Project in Peru. Together they are known as Minera Yanacocha. The Yanacocha area has recently seen a number of protests from Peruvian residents who do not want the Conga project to proceed, as reported by The Peruvian Times. The opposition is due to the fact that the new mine will require Newmont to drain three lakes in the Cajamarca region. Yanacocha no Peru é a maior mina de ouro da América Latina e em 2012 produziu Oz de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

14 Mina de ouro da América do Sul - Yanacocha
Minério só era desmontado e transportado para os PADS de lixiviação. No início das operações, em 1993, o minério apresentava ouro livre em rochas porosas e teores de Au da ordem de 1 g/t. O mineral, após desmonte, era transportado para os “PADS” onde ocorria a lixiviação em pilhas (cianetação). UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

15 Mina de ouro da América do Sul - Yanacocha
Minério só era desmontado e transportado para os PADS de lixiviação. Entre 2006 e 2008 foi construída uma planta de cianetação por agitação com capacidade de processamento de 5 milhões de t/ano. O processo envolve tanto adsorção em carvão ativado para concentração da lixívia rica em ouro como Merrill Crowe para precipitação do Au metálico. O doré pesa cerca de 22 kg contendo 40% de Au e 58% de Ag. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

16 Mina de ouro da Ásia - Muruntau
Newmont Mining's announcement in July 2007 of an agreement which was to see it receive US$80m from the government of Uzbekistan to settle the ongoing dispute over the seizure of assets brings to an end the largest direct foreign investment in the country. With the company's 50% stake in the Zarafshan-Newmont operation transferred, full control of the resources at the Muruntau mine – one of the world's largest open-pit gold mines – reverts to Uzbek hands. Located in the Kyzylkum Desert area of Uzbekistan, about 400km west of Tashkent, the US$250m Zarafshan-Newmont Joint Venture gold operation at Muruntau was the first significant joint venture investment by a Western mining company in the Former Soviet Union (FSU). From its inception until early 2006, the venture had enjoyed good relations with the Uzbek government for nearly 13 years – including tax privileges and a "regime of special favour" – employing around 800 and making more than $500m in payments. In March 2006, however, the situation changed abruptly when the authorities informed Newmont of impending changes to the tax laws – leading to the arrival in June of a demand for $48m in back taxes to cover the period 2002–2005. The company mounted a legal challenge in the Uzbek courts which led to a ruling against Newmont in August, the seizure of the company's assets and the cessation of gold exports. Whether the expropriation of Newmont's assets resulted from the wider worsening of relations between Uzbekistan and the West after the bloody put-down of the uprising in Andijon in May 2005 or low tax receipts and a need for hard currency, the dispute spiralled. In September 2006, Newmont wrote off the book value of its Uzbek stake and in October, filed two international arbitration claims against Uzbekistan – in Washington and Stockholm. The recently reached settlement brings the outstanding claims to a close and ends the involvement of the world's second largest gold mining company in the operations. Newmont's involvement at Muruntau dated from 1990, when a Newmont geologist attending a conference in Moscow joined the first team of Western experts to visit the mine, which extracts about 21Mt/y of gold ore that is processed and refined to 99.99% gold on site. In February 1992, only six months after Uzbekistan became an independent republic, Newmont Gold (Newmont Mining 91%) signed a 50/50 joint venture agreement to treat the stockpiled ore. The Uzbek partners are the State Committee for Geology and Mineral Resources (Goskomgeologia) and the Navoi Mining and Metallurgical Combine. Ground was broken in October 1993 and the first gold was poured in May The European Bank for Reconstruction and Development (EBRD) arranged a $135m debt facility, together with Barclays and other banks. GEOLOGY AND RESOURCES "Full control of the resources at the Muruntau mine – one of the world's largest open-pit gold mines – now reverts to Uzbek hands." The project's resource consists of low-grade gold-bearing material that was mined from the Muruntau quartz-stockwork system, hosted in metamorphosed sediments, over a 25-year period. Ore production during this time has exceeded 350Mt, with a further 600Mt of reserves. Of seven ore types occurring in the Muruntau pit, three have traditionally been stockpiled as untreatable using former Soviet technology. Newmont's heap-leaching technology was used to treat the sub-economic ore which had been stockpiled since the Navoi combine started production in mid About 90% of the Muruntau gold is free and associated with silicification. When operations started this stockpile comprised approximately 245Mt of material, estimated to contain 8.2Moz of gold. In January 2001, the company acquirethe rights to a further 150Mt resource grading 1.44g/t, which was planned to extend the project life to 2013 and the EBRD provided a further $30m for related leach pad expansions. Newmont's equity gold reserves were 1.7Moz at the end of 2005 – written off during the dispute. ORE PROCESSING No mining as such was required, since feed material is loaded directly from the stockpiles. The $225m plant engineering and construction contract was awarded to the Bateman Group. The plant was designed to yield 400,000oz/y or better from higher-grade feed in the first phase, with output later dropping to 250,000oz/y. Material is reclaimed from the stockpile in 25m-high slices by Caterpillar 992 loaders and fed to the 2,000t/h-capacity primary Nordberg Lokotrack 160 mobile jaw crusher. This is linked to a mobile apron feeder that discharges to an intermediate stockpile. From here, Nordberg and MAN Takraf conveyors feed the stationary plant. Four Master Magnets overband tramp metal separators are fitted. The one secondary and two tertiary crushers are Nordberg MP1000 cones and the 16 quaternary units are Cemco Vertical Shaft Impactors. Crushing capacity is 37,800t/d and the final product is 100% –3.7mm. The single leach pad is loaded in eight, 10m-high lifts by a series of conveyors and stackers supplied by Laurel Engineering. Leaching takes 49 days and a conventional Merrill-Crowe process recovers 65% of the gold contained in the ore. The precipitate is melted on site to produce gold-silver doré, which is refined to 99.99% purity at Muruntau for export. In the first half of 2003, the joint venture placed 3.6Mt on the leach pads, averaging 1.5g/t gold. PRODUCTION Gold output improved steadily after leaching started, while costs fell. In 1996, the first full year, 12.74Mt on the leach pad yielded 326,500oz of gold at a cash operating cost of $225/oz, but in the following year 14.6Mt of ore was leached, yielding 430,100oz at $204/oz. Recent outputs have been lower – 391,300oz in 2003 and 309,800oz in 2004 (from 7.46Mt processed ore) – while cash operating costs have risen since 2002, to $134/oz in 2003 and $162/oz in On the other hand, cost increases have been offset by better mill recovery – 95.4% in 2004 compared with 92.9% in Gold sales in 2005 totalled 245,000oz, with production scheduled to continue until 2011. A operação aqui descrita é com a Newmont (USA) e se refere apenas às imensas pilhas de rejeitos de lavra que foram estocadas em mais de 25 anos de operação da mina. A JV Zarafshan-Newmont operou de 1992 a 2006, quando o contrato foi rompido e a mina retornou ao Estado. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

17 Mina de ouro da Ásia - Muruntau
OURO LIVRE ou associado a quartzo (~ 90%) Teor: 1,5 g/t Capacidade nominal da operação: oz de Au/ano The single leach pad is loaded in eight, 10m-high lifts by a series of conveyors and stackers supplied by Laurel Engineering. Leaching takes 49 days and a conventional Merrill-Crowe process recovers 65% of the gold contained in the ore. The precipitate is melted on site to produce gold-silver doré, which is refined to 99.99% purity at Muruntau for export. In the first half of 2003, the joint venture placed 3.6Mt on the leach pads, averaging 1.5g/t gold. Newmont forneceu a tecnologia de lixiviação em pilhas. Não havia lavra. Mais de 90 % do mineral era ouro livre associado a quartzo, com um teor de 1,5 g/t. Ciclo de lixiviação era de 49 dias e a recuperação de cerca de 655 do Au se dava por processo Merrill-Crowe. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

18 Minas de ouro – Região de Witwatersrand - África do Sul
Silver and iridium are recovered as gold-refining byproducts, and the basin also has coal mines, although they are bit players in the overall mining of the Basin. On the East Rand, Ergo is run by DRDGold Limited, a company involved in the extraction of gold and uranium residue from slimes dams and sand dumps on the Central, East and Far East Rand, and to produce sulphuric acid. On the West Rand, Mponeng, Savuka and TauTona, formerly known as Western Deep Levels, are managed by AngloGold Ashanti, and Kusasalethu (previously Elandsrand) and Doornkop Mines are managed by Harmony Gold.  South Deep, Kloof and Driefontein mines are operated by Goldfields and Mintails Limited. In the Vaal River area, AngloGold Ashanti operate Great Noligwa, Kopanang, Tau Lekoa and Moab Khotsong. In the Free State Province, Harmony Gold runs Bambanani, Tshepong, Phakisa, Target, Masimong and Joel mines. Espécime de 10,5 cm (9,5 Oz.) Mina: Old Vogelstruisbult UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

19 Minas de ouro – Região de Witwatersrand - África do Sul
Geologic map of the Witwatersrand basin and location of goldfields (Frimmel et al., 2005, Econ Geol 100th Anniv Vol, p. 772) = Mapa geológico da região de Witwatersrand e localização dos depósitos de ouro. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

20 Mineral típico do “Rand” – África do Sul
Minas de ouro – Região de Witwatersrand - África do Sul Mineral típico do “Rand” – África do Sul Ouro electrum contendo zinco, mercúrio, prata, Cu, associados a sulfetos de ferro finamente disseminados em matriz de conglomerados (Pebbles). Elementos traços em uraninita: Th, W, Bi, Mo, Ta,Y e elementos de terras raras. Dependendo da Região da África teremos ouro livre ou refratário. Mineralium Deposita April 2013, Volume 48, Issue 4, pp Trace element distribution in uraninite from Mesoarchaean Witwatersrand conglomerates (South Africa) supports placer model and magmatogenic source. M. Depiné, H. E. Frimmel, P. Emsbo, A. E. Koenig, M. Kern. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

21 Mineração de ouro na Europa
“De Re Metallica Libri XII” 1550, por Georgius Agricola. Mineral ouro livre: Au-Ag com pirita em quartzo. 17.1m oz of gold and 81.1m oz of silver (measured and indicated), including 10.1m oz of gold and 47.6m oz of silver (proven and probable) The Rosia Montana deposits are epithermal, low to intermediate sulphidation systems with relatively simple metallurgy. The mineralization does not contain deleterious antimony, mercury, arsenic or tellurium. Gold occurs as electrum (gold-silver), associated with sulphides (predominantly pyrite) and in the native form. Mineralization is associated with quartz-adularia alteration and later carbonate-clay-sulphides and occurs as disseminations throughout the host rocks. The bulk of the known reserves are localized within the two adjacent dacitic bodies, Cetate (in the west) and Cirnic (in the east). The surrounding breccia units host the Orlea, Cirnicel and Igre deposits and much of the breccia hosted mineralization remains open. The Slovak Republic has a long and abundant history of goldmining. In spite of the rather small extent of km², the geological building is wealth of forms, and a long time ago the inhabitants already knew how to make use of the natural ressources.The eldest proof of mining on the territory of today's Slovak Republic can be found in the area of "Spania Dolina" (Central Slovakia), up to 3500 BC. In his work "De Re Metallica Libri XII" from 1550, Georgius Agricola mentions in the chapter about gold- and silvermining that mining of those metals has a longer tradition in this part of Europe than in Freiburg in Germany. Gold has alredy been mined by Celts and Romans in Slovakia. At the end of the 13 th century, the first mining company was founded, and by 1570 already 300 companies existed. This rapid development caused migration of miners from Germany and Tyrol to Slovakia. In the mines of Banska Stiavnica, black gunpowder has been used for the first time in mining on Feb.8 th , 1627 by Caspar Weindl. The significance of mining in Slovakia is also shown by the number of names of towns which are derived from mining terminology. In the year 1735, the first school for miners was founded in Banska Stiavnica. In 1765 it became the first mining academy. In modern history of goldmining in Slovakia, the extraction of gold from the sediments of the Danube during the years is interesting. The AUREA  corp., founded by Dr. B. Sto?es, extracted the gold by using dredgers. The end of  these mining activities is in relation to the economiy crisis at the end of the Thirties. The mining was not continued after the Second World War, but today you can still find some goldpanners at the Danube. But not only the Danube is interesting for goldpanners. Almost every stream and river in Slovakia contains gold. Source of this gold is not only the region in Central Slovakia around Kremnica and Banska Stiavnica, but also the Vysoké Tatry (High Tatra) and many other mountain ranges. Today goldpanning has a meaning as entertainment and recreational sport, where you can connect your stay in free nature with unforgettable experiences. With a little bit of luck and dexterity, your effort will be rewarded by finding glittering pieces of gold in your pan. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

22 Classificação / Concentração Tratamentos oxidativos
Fluxograma geral para minérios de ouro Cominuição Classificação / Concentração Cianetação Cementação Adsorção Tratamentos oxidativos ROM (2g/t Au) DORÉ (40 a 90 % Au) UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

23 Cominuição/Classificação Concentração Gravimétrica
Fluxograma para minérios de ouro livre Cominuição/Classificação Concentração Gravimétrica Cianetação Cementação Adsorção Au grosso ROM (2g/t Au) DORÉ (40 a 90 % Au) Au fino Apenas tenho ouro grosso e ouro fino. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

24 Fluxograma para minérios de ouro livre
Cominuição/Classificação Cianetação: em tanques com agitação, em bateladas (intensiva), em “VAT” ou piscina estacionária, em pilhas Cementação com Zno (clarificação/desaeração) Adsorção/ Dessorção em CA (CIP,CIL,CIC) ROM (2g/t Au) DORÉ (40 a 90 % Au) Só temosouro fino. Zno: pó de zinco metálico. Processo Merril-Crowe UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

25 Tratamentos oxidativos para minério de ouro refratário
Em relação à cianetação os minerais de ouro são classificados em dois grupos: - Minerais de ouro livre e/ou oxidados; - Minerais de ouro refratários (ouro ocluso em sulfetos, minerais de ouro, etc). Os tratamentos oxidativos são usados para minerais de ouro refratários à cianetação direta. Os tratamentos oxidativos são realizados antes da cianetação. Os principais métodos de oxidação empregados na indústria do ouro são: - Pré-aeração da polpa antes da cianetação; - Bio-oxidação ou lixiviação ácida dos minerais sulfetados; - Oxidação ou lixiviação sob pressão dos minerais sulfetados; - Ustulação ou tostação dos minerais sulfetados. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

26 Classificação / Concentração gravimétrica Tratamentos oxidativos
Fluxograma para minério de ouro complexo Cominuição Classificação / Concentração gravimétrica Cianetação Cementação Adsorção Tratamentos oxidativos ROM (2g/t Au) DORÉ (40 a 90 % Au) Sulfetos Leves/mistos Concentrado gravimétrico sofre tratamento oxidativo. Finos podem ser cianetados ou não. UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

27 Cominuição/Classificação Gravimetria/Flotação Tratamentos oxidativos
Fluxograma para minério de ouro complexo Cominuição/Classificação Gravimetria/Flotação Cianetação Cementação Adsorção Tratamentos oxidativos ROM (2g/t Au) Sulfetos Rejeito Concentrado gravimétrico pode ir direto para fundição se for ouro livre. Finos podem ser cianetados ou não; depende de diversos fatores. Mostras Circuito Cuiabá DORÉ (40 a 90 % Au) UDELAR – URUGUAY UFRGS – DEMIN - BRASIL

28 Fluxograma para minério de ouro complexo
Flotação Filtragem Ustulação Regeneração do Carvão Ativado Cianetação CCD Cementação-MC Barragem Calcinado Barragem Rapaunha Fábrica de H2SO4 Transporte Armazenagem Moagem Gravimetria Fundição Doré (Au-Ag) ROM - Refratário (Mina Cuiabá) CIP Eluição CN- C.A. Ar Cal Tratamento de Efluentes Circuito Cuiabá Circuito simples é o de Raposos. AGA – MG - Brasil UDELAR – URUGUAY UFRGS – DEMIN - BRASIL