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By K. Yamaguchi

"This Precious metals content copper scrap is treated with a copper smelting process, and copper and precious metals are recovered. The precious metal lost in the slag is increasing with increasing of treated scrap amount. To determine the portion of the precious metals chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. The distribution of precious metals between copper matte and FeOx-SiO2 slag phases is determined at 1300 oC and a fixed partial pressure of SO2 of 0.1 atm for the matte grades from 40 to 70 mass% of copper. The distribution ratios show a tendency to increase when the grade of matte is increased. In addition, the solubility of platinum and rhodium in the FeOx-SiO2-CaO slag under the air and the solubility of platinum in the FeOx-SiO2 slag equilibrated with a pure platinum or the Pt-Cu alloy were determined at 1300oC in the range of oxygen partial pressure from 10-9 to 10-7. The solubility of platinum and rhodium in the slag tends to increase with increasing content of copper in the slag and oxygen partial pressure. INTRODUCTIONThe stringency of the supply and demand of platinum group metal (PGM) intensifies by localization for resources and increase of the demand for PGM, furthermore, smelting and the recycling of PGM in the nonferrous smelting process take an important role. Scrap containing a precious metal for the purpose of collection of PGM is treated by copper smelting recently. With increase of the treatment amounts, loss of PGM in slags is the serious problem.In considering of PGM loss in slags, knowledge of the distribution behavior for PGM between slag and matte phases or slag and copper phases and the PGM solubility in slags is important. The distribution ratios of silver and gold between the FeOx-SiO2 slag and the Fe-Cu matte were reported by Roghani (Roghani et al., 2000), Shinha (Shinha et al., 1985) and Takeda (Takeda et al., 1993) However, there is no data for the PGM distribution ratio. On the other hand, the PGM solubility in slags was reported by Sano (Sano et al., 1997) However, there is very few report for the solubility of PGM in the nonferrous smelting slags."

Jan 1, 2012

By S. R. McCutcheon, D. R. Lentz

"Abstract - The 12.1 Mt Brunswick No. 6 Zn-Pb-Cu-Ag massive sulfide deposit (New Brunswick, Canada) lies between two subaqueous felsic volcanic formations near the base of the Middle Ordovician Tetagouche Group. The footwall comprises rhyodacitic pyroclastic rocks (Nepisiguit Falls Formation), whereas the hanging wall comprises a sequence of rhyolitic flows, breccias, and hyaloclastites (Flat Landing Brook Formation), with an age difference of less than 3 m.y. The Brunswick No. 6 deposit is a proximal autochthonous deposit with a well-zoned massive sulfide body and a basal Cu zone that, at depth, develops into a stockwork stringer sulfide (feeder) system. The massive sulfides are capped sharply by a layered magnetite-chert unit that extends regionally beyond the deposit. The deposit has a keel shape (sheath) formed by the F1F2 interference pattern. The heterogeneous ductile deformation and upper greenschist-grade regional metamorphism has transposed many of the epigenetic stockwork structures and alteration within the host sequence. Hydrothermal alteration is much more extensive, both vertically and laterally, in the footwall (a few 100 m) than in the hanging wall (<100 m). Anomalies farther up in the hanging wall sequence seem to be associated with independent alteration systems related to the rhyolite domes. The least-altered footwall units exhibit keratophyric alteration (albite or adularia) and weak Mg enrichment (chlorite). More intense micaceous (sericite and Mg-rich chlorite) alteration occurs around the footwall sequence. The transposed stockwork stringer sulfides are typically composed of Fe-rich chlorite (± sericite, ± silica) with pyrite, pyrrhotite, chalcopyrite, arsenopyrite, and sphalerite. The (Fe2O3T+MgO)/(Na2O+K2O) and base metal alteration indices are the best practical lithogeochemical vectoring tools at this deposit. Sommaire - Le gîte de 12.1 Mt de sulfures massifs de Zn-Pb-Cu-Ag Brunswick No.6 est localisé entre deux formations volcaniques felsiques sous-marines situées près de la base du Groupe de Tetagouche d’âge Ordovicien Moyen. Le mur consiste en roches pyroclastiques rhyodacitiques (Formation de Nepisiguit Falls) tandis que le toit consiste en une séquence de coulées, de brèches et d’hyaloclastites de composition rhyolitique (Formation de Flat Landing Brook); la différence d’âge entre les deux est de moins de 3 m.y. Le gisement Brunswick No. 6 est un gîte autochtone proximal comprenant un corps de sulfures massifs clairement zoné ainsi qu’une zone cuprifère basale qui passe progressivement à un stockwork de filonnets de sulfure en profondeur (feeder). Les sulfures massifs sont abruptement surmontés d’une unité laminaire de chert et de magnétite dont l’extension par delà le gisement est régionale. Le gisement affecte la forme d’une quille (fourreau) résultant d’un patron d’interférence F1F2. Plusieurs des structures épigénétiques du stockwork et des patrons d’altération de l’encaissant ont été transposés par la déformation ductile hétérogène ainsi que par le métamorphisme régional au faciès des schistes verts. L’altération hydrothermale est beaucoup plus importante, tant verticalement qu’horizontalement, dans le mur (quelques 100 m) que dans le toit (<100 m). Les anomalies situées plus haut dans le mur semblent être reliées à des systèmes d’altération indépendants associés aux dômes de rhyolite. Les unités les moins altérées du mur une altération kératophyrique (en albite ou en adulaire) ainsi qu’un faible enrichissement en Mg (chlorite). Une altération en mica (séricite et chlorite magnésienne) plus intense est présente autour de la séquence du mur. Les sulfures du stockwork de filonnets transposés consistent typiquement en chlorite ferrifère (± séricite, ± silice) accompagnée de pyrite, de pyrrhotite, de chalcopyrite, d’arsénopyrite et de sphalérite. L’indice d’altération (Fe2O3T+MgO)/(Na2O+K2O) et l’indice des métaux usuels sont les outils d’exploration les plus appropriés dans ce gisement."

Jan 1, 2006

By W. Griffith

"While oxalic acid precipitation practices are commonly applied on purified rare earth elements (REEs) pregnant leaching solutions (PLS), few efforts have been reported using oxalic acid (OXA) to recover REEs directly from untreated PLS. High oxalic acid demand is the most significant issue in all these direct oxalic precipitation (DOP) practices. Preliminary research on DOP of REE from a dilute PLS originating from an acid bake followed by water leaching was conducted. At 75°C, the oxalic acid demand was between 12 and 18 times the stoichiometric requirement for complete REE precipitation. Conducting DOP at 25°C had superior REE recovery but the product purity and filterability declined. Between 75°C and 100°C, REE recovery increased with increasing temperature. When sodium hydroxide was used to adjust the pH during DOP, in the range of 0.5 to 1.5, higher pH benefited REE recovery. Using ammonium hydroxide in place of sodium hydroxide, the REE recovery was reduced by close to 5%. Sodium chloride addition to the PLS was also investigated and the results showed that at both 75°C and 25°C, the REE recovery was enhanced substantially. At 25°C, when the oxalic acid addition was controlled at 4.7 times the stoichiometric requirement, the overall REE recovery reached 95% with the addition of 240 g/L NaCl. Other reagents such as KCl, NH4Cl also showed significant enhanced REE recovery at the same oxalic acid addition. The addition of sodium sulphate appeared to largely enhance the precipitation of LREE but inhibited the formation of HREE oxalate. All results indicate the formation of rare earth double salts may play an important role in REE DOP sulphate media.INTRODUCTIONThe conventional routes for recovering rare earth elements (REEs) from a sulphuric acid pregnant leaching solution (PLS) involves an initial purification step for removal of iron, aluminium for example by precipitation through neutralization, followed by precipitation of REEs as hydroxide, oxalate or carbonate salts, or by bulk solvent extraction for REE recovery (Xia, 2013). Another route was used by Bayan Obo in their historical flowsheet, where the PLS was first subjected to double sulphate precipitation, then the remaining REEs, mostly heavy rare earth elements (HREE), were recovered by oxalate precipitation (Li, 2011)."

Jan 1, 2016

By K. Halada

Current trend of the global flow of strategic metals are analyzed to discuss the strategy of the development of recycling technology and alternative technology. In many cases, each global flow of metal is changing from the trilateral structure of U.S., EU and Japan in the later 20th century into the convergence to China as the factory of the world. Scrap flows are also changing dynamically. A long term change of prices of metal has gotten changed since the entrance of this century. The estimation of metal consumption up to 2050, in which the author estimated that many kinds of metal will overshoot the reserve base line, is revised considering these change of current trends.

Jan 1, 2014

By F. T. Mooney

Introduction The Flin Flon mine of the Hudson Bay Mining and Smelting Company, Limited, is on the interprovincial boundary between Manitoba and Saskatchewan, about four hundred miles north of the Canada-United States boundary. The orebodies are gold, silver, zinc, and copper replacement deposits occurring as irregular lenses of massive sulphides, arranged en echelon, and irregular masses of disseminated copper sulphides in chlorite. The country rocks are of Precambrian age, dominantly lava flows. Development of the Mine The mine is opened by two vertical main shafts- the North Main and South Main shafts- 3,800 feet apart. The North Main shaft has a depth of 2,210 feet and the South Main shaft is completed for stoping operations to the 3,250-foot level (see Figure 1). These shafts are connected by main haulages driven, on the footwall side of the orebodies, at 520-foot intervals down to the 2,210-foot level. No. 3 (subsidiary) shaft is on the footwall side of the orebodies at a point between the North Main and South Main shafts, 2,400 feet south of the former. It has a depth of 3,250 feet and connects with all main haulage levels- with both Main shafts down to the 2,210-foot level and with the South Main shaft on the 2,750-, 3,000-, and 3,250-foot levels. Other openings tO the mine include B North fan raise, the opening due to the recovery of the open pit sill pillar, and several back-fill raises.

Jan 1, 1949

By S. R. Stopic

The EU-financed INTREAT Project (Integrated treatment of industrial wastes to¬wards prevention of regional water resources contamination) addresses the environmental pollution associated with solid and liquid wastes/effluents produced by complex sulphide ore mining and metallurgical activities. The results concerning the electrolytic recovery of cop¬per from effluents formed after mixing of streams from Copper Refining, Precious Metals Plant and Electrolyte Regeneration in the Balkan Area will be shown. The waste water is characterized by low pH values and high contents of heavy metals, such as Cu, Ni, Bi, As, Sb. The majority of these waste water flow untreated into the natural water streams and through the network of existing rivers, which end up in the river Danube. The influence of current density and flow rate on the deposition rate, the quality of copper and the process efficiency will be presented. The full continuous process is based on cells with rotating disc cathodes and represents a pre-treatment step before common neutralisation in a cascade line

Jan 1, 2007

By A. R. Sheik, A. A. Baba, M. K. Ghosh, K. Sanjay, R. B. Bale, A. G. F. Alabi, F. A. Adekola, L. Ibrahim

"This paper studies the characterization and dissolution of a Nigerian pyrolusite ore, reporting the results of ore physicochemical analyses and detailed ore characterization before and after leaching at optimal conditions. Ore dissolution rate increased proportional to acid concentration and temperature, but decreased with ore particle size. In a 4 M H2SO4 solution at 80°C with a particle size of –90+75 µm and moderate agitation, ore dissolution rate reached 78.7%. Unleached residue produced under optimal leaching conditions consisted of silica with admixtures of cristobalite and stishovite. The calculated activation energy supported the proposed diffusion control mechanism for the process.RÉSUMÉ Le présent article étudie la caractérisation et la dissolution d’un minerai de pyrolusite du Nigeria, il donne les résultats des analyses physicochimiques du minerai et de la caractérisation détaillée du minerai avant et après la lixiviation sous des conditions optimales. Le taux de dissolution du minerai augmentait proportionnellement à la concentration de l’acide mais décroissait avec la taille des particules. Dans une solution 4 M H2SO4 à 80 °C, avec une granulométrie de –90+75 µm et une agitation modérée, le taux de dissolution du minerai a atteint 78,7 %. Les résidus produits sous des conditions optimales de lixiviation étaient constitués de silice avec un mélange de cristobalite et de stishovite. L’énergie calculée d’activation supportait le mécanisme de contrôle de la diffusion proposé pour le procédé."

Jan 1, 2016

By Rénard Chaigneau

Quality during induration Drying ??40% of energy ??Drying velocity = f(1/radius2) ??Size versus risk of condensation ??Flow is important (minimise fines)Oxidation ??IOC Fe2+ typically 0.04% ??Important to minimise Fe2+forLow Temperature Disintegration ??Tight size distribution is key13

May 1, 2011

By O. Herstad, J. M. Toguri, K. Grjotheim

DURING the last three years, investigations on the aluminum reduction of magnesium-bearing compounds have been initiated at the Institute of Inorganic Chemistry, The Technical University of Norway. The results of these investigations are reported in this paper. Very little information exists in the literature on the reaction between magnesium compounds and metallic aluminum. The available information itself is conflicting, and, to clarify the existing discrepancy, the reactions between aluminum and magnesium oxide (MgO), caJcined dolomite (CaO . MgO) and olivine (Mg2SiO.) were studied. The logical approach for the study of these reactions between condensed states with the formation of a gaseous phase is, ( 1) the measurement of the equilibrium vapour pressure of the gas, in this case magnesium, associated with the respective reactions and, (2) the identification of the end products of the reaction in order to establish the re-action scheme.

Jan 1, 1962

By G. W. Smith

"The adsorption of dehydroabietylamine acetate on quartz, hematite, rutile and baddeleyite has been deter-mined for concentrations ranging from 0.3 to 5,600 µ. moles/I and for pH values ranging from 2.5 to 10.5.The surface tension, UV and IR spectra, equivalent conductance and ion concentrations for dehydroabiety lamine acetate solutions have been determined.Contact-angle and flotability studies have established that good collection may be obtained with this amine but that selectivity depends on the suitable use of depressants for some of the minerals."

Jan 1, 1971

By Sean McClenaghan

Significance Setting Size Production Value History of Discovery Zn and Pb at Austin Brook Brunswick Belt Exploration Discovery Hole Geology Structure Metal Zonation Directed Research Incremental Ores Precious metals Closure and Beyond Mining Remnants Tailings

May 1, 2013

By Dharmendr Kumar, Pradip, Sivakumar Subramanian, Beena Rai, Venugopal Tammishetti

The separation efficiency in a mineral processing plant is generally assessed and reported in terms of elemental assays constituting the minerals of interest. However, different minerals comprising of same elements behave differently under similar process conditions. Thus, it is imperative to track the mineral composition thank elemental composition of different streams in a processing plant. The availability of automated mineral analyzers such as QEMSCAN and TESCAN in recent times has made it possible. However, due to the high cost and expertise required, their adaptation in day to day monitoring of operations is not yet a common place. X-ray diffraction (XRD) profile fitting (Rietveld Refinement) is another technique which can provide estimates of mineral proportions in a sample. The results of Rietveld Refinement however are affected by coating of fines on coarse particles, method of sample preparation, particle size distribution of sample, elemental substitution in mineral crystal lattice. In the present work, we propose a simple and efficient method for quantitative estimation of minerals in iron ores using elemental assays and thermo-gravimetry analysis data. The minerals (hematite, goethite, gibbsite, kaolin and quartz) are identified using powder XRD analysis. It is also observed that goethite contains Al substitution in the crystal lattice. The samples were analyzed for %Fe, %Al2O3 and %Silica using chemical analysis. The measured Loss on Ignition (LOI) in the sample is contributed from goethite, gibbsite and kaolinite phases. LOI from gibbsite and goethite occur in temperature range 250–350°C and LOI from kaolinite occur in temperature range 400–700°C. According, LOI are determined in two different temperature ranges that are 100–400°C and 400–850°C. We have used the data to successfully determine the mineral compositions of iron ore samples. We have also employed a data reconciliation algorithm on the calculated data for further improvement and consistency of our results. Our method is very convenient for quick estimation of mineral proportions in a sample. The proposed method can also be used for quantitative phase estimation in bauxite ores and red muds.

Jan 1, 2016

By D. R. Lentz, C. J. Beaumont-Smith, S. H. Mcclenaghan

"Abstract - The Louvicourt Au-Ag-Cu-Zn-Pb sulfide deposit is hosted by a Middle Ordovician calc-alkaline sequence of aphyric rhyolite flows and associated fragmental rocks at the top of the Flat Landing Brook Formation. The Zr/TiO2 (average = 0.110) and Y/TiO2 (average = 0.021) ratios in the footwall felsic volcanic rocks are consistent with known values for the Reids Brook member. The deposit consists of two concordant lenses of semi-massive to massive sulfides, approximately 150 m long and up to 9 m thick, which represent a fold repetition of a single exhalative horizon. The deposit contains a geologic resource of 136 000 tonnes grading 1.2% Pb, 1.0% Zn, 0.4% Cu, 90.9 g/t Ag, and 0.96 g/t Au; the deposit locally contains elevated Au (2.9 ppm) and Ag (320 ppm) contents. A laterally continuous iron formation that contains barite caps the deposit, and is gradational vertically and laterally into laminated siltstone. The exhalite confirms the stratiform nature of this deposit, but a large percentage of sulfides occur as late replacements of altered felsic fragmental rocks in the footwall. Abundant examples of colloform pyrite and perlitic and spherulitic textures in volcanic clasts are well preserved. The base- and precious-metal content of the Louvicourt deposit is atypical of the Bathurst Mining Camp (BMC). Reported assay data (n = 27) indicate an average Pb/Zn ratio of 2.6, the highest in the BMC (average = 0.39). Lead exhibits a strong Spearman Rank correlation (r&apos; = 0.92) with base metals throughout the sequence, indicating a preponderance of galena in both the stockwork and stratiform zones. The Ag and Au contents in this deposit are among the highest in the BMC and exhibit a Au-Ag- Cu-Pb association. Barite-rich exhalative pyrite exhibits a moderate Au correlation with Ag (r&apos; = 0.77; n = 10) and Cu (r&apos; = 0.76) and occurs in portions of the exhalative sulfides that are enriched in Pb. Chemical exhalative rocks are conformably overlain by trachy-andesitic volcaniclastic (possibly pyroclastic) rocks that are assigned to the Little River Formation. These are enriched in Nb (average = 38.4 ppm) and P2O5 (average = 0.17 wt.%), and have much lower Zr/TiO2 (average = 0.056) and Y/TiO2 (average = 0.0062) relative to rocks higher in the hanging wall. The intermediate volcanic rocks are conformably overlain by massive to pillowed basalt flows and related hyaloclastite that have Nb/Y = 0.60 and high TiO2 contents (average = 2.8 wt.%). This chemistry is consistent with rocks of the Brunswick Mines member (Little River Formation), except that these rocks are considerably enriched in P2O5 (average = 0.82 wt.%). This syngenetic exhalative deposit is unique for the BMC with a high Pb/Zn and elevated Au and Ag contents, as well as an epithermal signature (Sb-Ag-Au-Tl-Hg), analogous to high sulfidation volcanogenic massive sulfide deposits. Its intimate relationship with an emergent felsic dome (Flat Landing Brook Formation), chlorite-silicate-oxide-sulfide exhalite (locally hematitic), and the abundance of barite are classical features of many of the Kuroko deposits."

Jan 1, 2006

By D. B. Smith

DURING the summer of 1953, test work commenced at the Sullivan Concentrator with a view to the modification of filtration practice by the inclusion of wet cyclone classification of the lead concentrates, with separate filtration of the underflow and overflow products. Formerly, practice was conventional and the equipment employed comprised one 50-foot diameter thickener ?with the underflow routed via a 20-foot stock tank to two 8-foot by 12-foot Oliver filters. Heating of the filter feeds to 40° C. and the use of mechanical slappers on the filter drums ?have both been standard features of Sullivan practice for years. Both of these have been retained. Currently (February, 1956), lead concentrates are being classified into sands and slimes by 12-inch cyclones with the underflow, at 75 per cent solids, being fed to No. 1 Oliver filter. The overflow is thickened to 75 per cent solids and filtered separately by a No. 2 Oliver filter . The tonnage split is approximately two of underflow to one of overflow. The overflow contains 75 to 80 per cent of the total minus I 500 mesh slimes in the feed.

Jan 1, 1956

By H. Bannach

"This paper focusses on what seem to be the leading indicators of prosperity in the minerals industry during this decade: the geographical distribution of deposits, environmental impact, capital allocation and acid consumption. There is a potential for meeting environmental criteria at a reasonable profit margin, but those with limited acid demand within economic range will face hard times to meet growing environmental concerns, resulting in additional mine closures. At the other end, those with old waste dumps who are thinking about smelting capacity additions will need capital influx at a much larger rate than ever before. All things considered, a change should be made in the way the world&apos;s copper reserves are computed, because there is a growing need to internalize these effects back to the ore blocks before a meaningful estimate of reserves becomes available.IntroductionThe copper industry has undergone several changes during the past decade, many of which were expected to take place because they rel1ect the economics of ageing mines. However, many others took place that shocked the industry because they were not completely under control. The focus of this paper is to rel1ect on those changes, and on market expectations for this decade that somehow depend on their impact.To review the prospects for new mine developments and expansions from an industry perspective to a full extent, it would be necessary to consider not only the deposits themselves, but also geographical constraints, environmental constraints, labour composition, technology development and use, the availability of capital, ownership issues, and integration within the industry. This paper, however, will concentrate on only some of the key elements that are believed to playa major role in shaping the market in the decade that has just begun. These elements, all interconnected, are:"

Jan 1, 1992

By P. Dauphin

"CANMET’s Mining and Mineral Sciences Laboratories have developed the Canadian Mining Technology Network (CMT-Net), a website to provide industry with up to date information on technologies in several areas. This paper gives background on the Mineral and Metal Processing sector, describes the steps leading to the development of the websites strategy and gives a tour of CMT-Net. IntroductionThe government of Canada is developing a strategy aimed at fostering the development of value-added activities in the area of mineral and metal processing (MMP). Natural Resources Canada (NRCan) and Industry Canada will partner in delivering on this strategy. Instrumental in defining the main thrusts of the value-added strategy was a series of consultations held across Canada with representatives of companies and organizations active in the sector. The objective of the consultations was to identify barriers to the development of activities which add value in the sector, as well as point to positive factors.Following the consultations, a discussion paper was produced, “From Mineral Resources to Manufactured Products: Towards a Value- Added Mineral and Metal Strategy for Canada” (Natural Resources Canada, 1998). The paper reviews the sector’s structure and main statistical information, lists some of the positive factors and barriers to value-added activities and defines a new partnership between industry and government that will lead to more valueadded activities. The main objective of the paper is to serve as a discussion document between stakeholders during the development of the strategy."

Jan 1, 1999

By J. O'Leary, R. Cannell, D. Honsberger

"The Scully Mine deposit lies within the group of metasediments that together comprise the rocks of the Labrador Trough. The ore itself still retains the bedding characteristics of the parent rocks and on this basis has been divided into three main members, namely: Upper, Middle and Lower. The Upper and Lower both show many of the bedding characteristics of the cherty taconites of the northern U.S.A.; the Middle member is a coarse-grained friable specularite rock. The ore minerals are hematite (normally present in the specular variety) and magnetite, although the latter rarely occurs in concentrations greater than 20 per cent. Gangue minerals are quartz and the hydrated iron oxides. Manganese oxides also occur as accessory minerals. The outcrop area of the orebody is in excess of 2 square miles, displaying a complex pattern of faulting and folding, which has been formed as a result of at least two orogenic periods."

Jan 1, 1972

By Gabriel Voicu, Marc Bardoux, Ross Stevenson, Nuno Machado, Jean Lafrance

"Abstract - Paleoproterozoic gold is found in two different volcano-sedimentary sequences and intrusive bodies separated by 600 km within the Guiana Shield. The 2148 Ma St-Élie granite intruded volcanic-arc sequences of the Paramaca Group, whereas the 2096 Ma Omai stock penetrated backarc/ island-arc sequences of the Barama-Mazaruni Group. Positive ?Nd values suggest that both suites lack Archean crustal contaminants, which is consistent with an origin in an oceanic arc setting.The St-Élie deposit is characterized by quartz-dominant vein systems with minor metallic minerals, represented chiefly by pyrrhotite and pyrite. Biotite, calcite, and chlorite are the main gangue minerals. The alteration haloes at St-Élie feature a strong potassic zone, which is absent at Omai. The ore-controlling structures are ductile and the vein emplacement is related mainly to contemporaneous, high-angle ductile shear zones. The St-Élie deposit formed at temperatures >350°C. The stable isotopes values are compatible with a magmatic or metamorphic source.The Omai deposit is characterized by quartz-dominant vein systems with minor metallic minerals, represented mainly by pyrite. Ankerite, scheelite, albite, and chlorite are common gangue minerals. The vein emplacement is syn- to post-deformation and it is related mainly to brittle shear zones with low-angle, stockwork networks and breccia zones. The Omai deposit formed in a temperature range between 250°C and 170°C, much lower than the St-Élie deposit. The stable isotope values are compatible with mixing between deep-seated fluids of metamorphic or magmatic origin with surface- derived fluids.These differences between St-Élie and Omai are interpreted in terms of their depth of formation. Alteration patterns, structural elements, and paragenetic assemblages indicate that the gold at St-Élie was most probably emplaced at a mesozonal depth, whereas the Omai setting yields evidence for epizonal conditions."

Jan 1, 1999

Induced microseismicity monitoring is: ?Essential tool in improving the geotechnical understanding about a mine and its inaccessible surrounding rock masses. It helps to determine: -Event timing, location, and magnitude - identification of highly stressed areas -Event source mechanism - the physics of fracturing in its seismic source region -Seismic strain-rate distribution in 5D - identification of stress concentration or migration patterns -Geomechanical interpretation - identification of hidden geological structures or weaknesses in the ground -Strategy for mining e.g. by a block caving method - maximization of mine production and to optimize ground support design -Potential of future seismic hazards -Large event re-entry protocol, to improve mine safety ?The norm as part of mine safety maintenance and long-term mine design practices

Aug 1, 2013

By Francisco Tamargo

"This paper refers to a new process for the full recovery (above 98%) of zinc and other valuable metals (Pb, Ag, Au) accompanying zinc in its concentrates while iron is separated as a marketable product free of any harmful impurities and suitable for sale to the cement industry. The process has been especially designed to achieve the following goals: maximizing the recovery of zinc and those valuable metals that are present in most zinc concentrates (lead, silver, gold); allowing the recovery of other valuable metals such as indium or germanium that could be present in some zinc concentrates; avoiding or minimizing the need for residue disposal in safe areas as it is the common practice nowadays in the zinc industry. Finally, the process achieves the previously related goals at a competitive cost, in line with the existing more efficient operations while using conventional equipment working under atmospheric conditions. The new process can be easily implemented in those smelters using the jarosite or goethite processes as well as in those smelters using direct leaching as a part of the processing facilities. A study has already been conducted on the use of jarosite in the cement manufacturing process, in the raw mix preparation as well as for a set controller. It shows that use of clean jarosite in the manufacture of ordinary Portland cement can result in improved quality of the clinker. Jarosite showed compatibility to influence the burning characteristics of the cement raw mixes. The presence of SO3 bearing mineral phases such as natrojarosite showed the suitability of clean jarosite for use as a set controller in cement production.INTRODUCTION Iron is by far the most abundant impurity accompanying zinc in its concentrates, and consequently, iron residue disposal is a major environmental concern for many zinc smelters in the world. This is especially true during the last 30 years when environmental restrictions became more and more strict. Much research work has been carried out during the last 30 years to try to find a solution for this important issue, but with little success. Only the jarofix process represents a partial solution to this problem as jarofix is stored nearby the smelters with certain limitations as a non-contaminant residue. However, it does not avoid the need to dispose of an important amount of residues every year, representing an environmental liability. Meanwhile, the number of countries limiting or banning the disposal of iron residues generated by the zinc smelters is growing, so that the solution to this problem is becoming an urgent matter right now. At the same time, the lack of appropriate available land for iron disposal is also a major concern in many cases."

Jan 1, 2016