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By J. C. White

"During the early development of the Mattabi Mine in 1970, discussions with the Ontario Government revealed their policy of prohibiting, as much as possible, the development of new, isolated, single-industry townsites. Subsequently, Mattabi located its first housing in the Township of Ignace, which is situated 50 miles from the site of the mine and plant. Over 200 employees now commute 100 miles daily to and from work.This paper describes the experience gained and discusses the advantages and disadvantages of a remote townsite."

Jan 1, 1976

By C. M. Kleemann

The paper describes the present milling practice at Western Mining Corporation Limited's new nickel mine at Kambalda in Western Australia. It details the crushing, autogenous grinding, flotation and spray drying circuits for the production of a nickel concentrate. It also indicates some of the metallurgical problems which have been encountered in concentrating this ore.

Jan 1, 1973

By G. E. Norman, A. L. Mckague

"The new smelting process commenced operation in 1978. The pelletizing and sinter plants were replaced with slurry-fed roasters and the blast furnaces with electric furnaces. The existing converter aisle and matte handling facilities remained unchanged.Process DescriptionNickel-copper concentrate is partially roasted in two slurry-fed fluid bed roasters. After gas cleaning, the sulphur dioxide gas is transferred to the acid plant. The roaster product is conveyed to two electric furnaces for smelting to produce a waste slag and furnace matte. The slag goes to the disposal area and furnace matte containing the metal values is processed in the converters for further removal of iron and sulphur.The final matte containing about 75 per cent metal values is shipped to the refinery in Norway.The commercial smelter was designed for 2135 tonnes per day of concentrate, with an availability of 85% . Roasters and electric furnaces were sized at 117 per cent of design, or 1250 tonnes per day on each of two lines. Concentrate storage capacity in the plant is sufficient for two to three days' plant operation.The new smelting process will be discussed under the following headings:Concentrate Slurry HandlingFeed PreparationRoaster OperationRoaster Gas CleaningCalcine TransferElectric Furnace Operation and Process Control Converting and Matte HandlingUnder these headings, process control , equipment changes, and plant performance after three years' operation is reviewed. A brief discussion of accident prevention , and working environment is also included ."

Jan 1, 1984

By Robb. V. M., F. Walraven, L. J. Robb

"Abstract -The old Albert Silver Mine is a polymetallic deposit comprising concentrations of Cu­ Pb-Zn-Ag-U-F within a set of sub-parallel quartz-hematite veins which occur within the fine-grained apical phase of the 2050 Ma old A-type Bushveld granites. Mineralization occurs as an early pyrite­ chalcopyrite-arsenopyrite-galena-sphalerite-(argentiferous) tetrahedrite paragenesis followed by a later, more oxidized assemblage comprising chlorite-hematite-fluorite-pitchblende. Accumulation of metals appears to have taken place at the interface between a coarse-grained porphyritic granite and an overlying fine-grained phase: veins occur in the latter and represent leakage of magmatic fluids from the differentiated, water-saturated, subjacent granite.Mineralization processes in the Bushveld granites are believed to be related to long-lived circulation of dominantly magmatic fluids stimulated by the high heat productive capacity of the host rocks. Endo- and exogranitic tin-tungsten and base metal mineralization formed during an evolving hydrothermal system that lasted for several hundred million years, forming innumerable small- to medium­ scale polymetallic deposits. At the Albert Silver Mine, unroofing of the cover sequences at circa 1600 Mato 1700 Ma resulted in the incursion of lower-temperature, high-f02 meteoric fluids which remobilized the earlier sulfides and introduced the paragenetically late U-F mineralization ."

Jan 1, 1994

By P. Scinto, P. Hudson

"Modern day ore bodies are becoming increasingly harder, more abrasive and lower grade. The Mako deposit is located in Senegal and consists predominantly of primary mafic and felsic lithology that are both very competent and very abrasive ores (Axb < 30, BWi >20 and Ai >1.0). The deposit was initially discovery in 2010 and the Toro Gold management team fast tracked the Mako Project through development and into production to achieve its first gold pour in January 2018. The comminution circuit comprises primary crushing single stage SAG milling with recycle crusher (1oCR SS-SAC). The mill reached design throughput and grind size seven weeks after first ore. The Mako project marks another successful international application of single stage milling, which represents a simple and easy to operate comminution circuit for small-to-mid size projects with a low capital cost. This paper describes the ore interpretation, comminution modelling, grinding circuit selection and design, as well as an overview of the commissioning and ramp-up of the mill.INTRODUCTION The Mako Gold Project is operated by Toro Gold Ltd., which holds a 90% interest in the project. The project is located in south-eastern Senegal in the Kedougou region, close to the Gambia river and township of Mako. The Mako deposit lies in the “Kenieba Window” of eastern Senegal and western Mali, which hosts a number of gold mining operations and development projects. The Mako Gold Project has an estimated life of 8 years with overall recoverable gold estimated at 924 koz. The process plant is designed to treat 1.8Mt/a of ore and produce 128 – 143 koz of gold per annum. Lycopodium Minerals Pty Ltd (Lycopodium) was appointed to provide feasibility studies and EPCM services for the greenfield project. Forming part of consultancy services provided by Lycopodium, Orway Mineral Consultants (OMC), a subsidiary of Lycopodium, was involved in the design, commissioning, ramp up and ongoing post commissioning support of the comminution circuit."

Jan 1, 2019

By Pingchao Ke, Zhihong Liu

"To overcome the problem that scoroditeis not stable in neutral and alkaline solutions, we proposed and investigated a synthesis method of scorodite coated in-situ with hydrated ferric oxide in the Fe(II)-As(V)-H2O system at the initial Fe(III)/As(V) molar ratios larger than 1.0.The synthesis was carried out at 90?,pH 1.5 under atmospheric pressure. During the synthesis, oxygen gas was conducted and bubbled into the system to oxidize Fe(II) ions into Fe(III)ions, and Na2CO3aqueous solution as neutralizing agent was added controllably into the system for keeping the pH constant at 1.5. In this study, three samples of scorodite were synthesized at the controlled initial Fe(II)/As(V) molar ratios of 1.0, 2.0 and 3.0, respectively. The characterizations of the samples by HRTEM, TEM/EDX, and chemical composition indicated that the particle surfaces of scorodite synthesized at the initial Fe(II)/As(V) molar ratio of 2.0 and 3.0 were coated in situ by a film of hydrated ferric oxide with the thickness of several nanometers, while the sample synthesized at the initial Fe(II)/As(V) molar ratio of 1.0 was uncoated scorodite. The TCLP and long-term leaching for the toxicity characteristic of the samples showed that scorodite coated in situ with hydrated ferric oxide was stable in a wide pH range from 3.0 to 10.0, with the arsenic concentrations in the leaching solutions less than 1.0mg/L. Nevertheless, uncoated scorodite was unstable under the conditions from weak acidity to alkalinity, with the arsenic concentrations in the leaching solutions larger than 5.0 mg/L.INTRODUCTIONArsenic pollution is a challenge for environment and health and has been an important issue for scientists (Hopkin, 1989).Arsenicis commonly associated with ores or concentrates of nonferrous metals, mainly as independent arsenic bearing minerals such as arsenopyrite (FeAsS), tennantite(Cu12As4S13), enargite (Cu3AsS4), cobaltite (CoAsS), and gersdorffite (NiAsS), realgar (As2S2), orpiment(As2S3), etc.(Matschullat, 2000; Mandal & Suzuki, 2002; Long & Peng, 2012). In the nonferrous metallurgical processes, arsenic is enriched mainly in such arsenic bearing materials as various flue dusts, residues, and anode slimes, which results in the accumulation of arsenic in the system owing to the circulation of those arsenic-bearing materials back to the system and the pollution to the environment (Harris, et al, 2003).In addition, the utilization of arsenic is limited and has been decreasing owing to its toxicity and carcinogenicity. Therefore, arsenic has to be removed from those arsenic-bearing materials and discarded safely (Dutrizac & Jambor, 1988; Monhemius & Swash, 1999; Drahota & Fillippi, 2009).In this case, how to immobilize arsenic has become a difficult problem which must be solved. Among the methods of immobilizing arsenic which have been proposed and investigated, immobilizing arsenic into a stable mineral to fix it, has been realized as a promising method and becomes a research focus(Dutrizac et al, 1987; Dutrizac & Jambor, 1988; Demopoulos et al, 1995; Fujita et al, 2008a; 2008b).Scorodite has been known as one of the best minerals for immobilizing arsenic, owing to its high stability under weak acidic condition, the arsenic content as high as 32wt%,and good crystallinity benefiting the separation of solid to liquid(Daivid et al, 1999; Zhu & Merkel, 2001). Scorodite can be synthesized from arsenic containing solutions under both hydrothermal and atmospheric conditions, and a lot of work has been done on the synthesis of scorodite and its leaching stability characterization (Filippou & Demopoulos, 1999; Gomez et al, 2011).Two plants for the immobilization of arsenic as scorodite have been putin to operation in Chile and Japan, respectively (Filippou & Demopoulos, 1999; Amir et al, 2016)."

Jan 1, 2017

By H. M. Woodrooffe

IT IS WELL KNOWN that chrysotile asbestos from various occurrences exhibits varied physical properties and certain differences in chemical corn position, both of which conditions may have an important bearing on the industrial utilization of the fibre. The usefulness of a harsh fibre in the manufacture of asbestos cement products and of low-iron fibre for certain electrical uses are examples. It is also .possible to obtain a fibre with a texture too harsh and brittle to be of economic value. Much research into the structure of the mineral and to a lesser degree observations relating the water of combination to certain physical properties have ?been reported. This paper is an attempt to show that the pyrolysis of ?chrysotile takes place in three stages and that the conditions of pyrolysis are peculiar to the fibre and may afford some clue to the variations in physical properties of asbestos fibres which affect their utilization.

Jan 1, 1956

By G. Capobianco

"The coal industry is an important part of Canada&apos;s economy - as an energy source, employer, and generator of export earnings. Coal comprises 71% of our fossil energy and with rapidly advancing handling and burning technology will clearly play a major role in our national energy mix, eventually as synthetic gases and liquids.International coal markets are very competitive and Canada is disadvantaged by long rail hauls to port, and a heavy tax burden. However, high mine productivity has allowed us to increase our markets.Currently, domestic markets are dominated by coal use for electrical generation, a market with significant growth opportunities.Strong growth is expected in export thermal markets, while metallurgical coal demand is projected to show little or no growth in the medium term. IntroductionThe coal industry is a vital part of the Canadian energy scene .• Coal supplies 17% of Canada&apos;s energy.• On a per capita basis, Albertans use more energy in the form of coal than they do oil and gas.• The value of Canada&apos;s exports of coal last year was equal in value to all the cars we imported from Japan.• Coal is our largest single export to our seco nd largest trading partner, Japan.• The value of coal produced in Canada exceeds the value of any other single mineral produced in thi s country.• In Alberta, the safety record for coal mines is on a par with that of department store clerks.• The coal industry employs about 25% of the total number of people employed in all metal mines in Canada, directly and indirectly accounting for about 50 000 jobs.Coal comprises 71% of Canada&apos; s hydrocarbon energy resources on a crude oil equivalent basis . This is more than double our oil sands resource and dwarfs our conventional crude oil and gas resources (Fig. I). In the short term, coal as a solid fuel plays a significant part in the Canadian energy scene. In the longer term, coal, in the form of electricity and eventually liquids and gases, has a tremendous role to play. In 1986, Canada produced 57.8 million tonnes, slightly down from the record high of 60.8 million tonnes in 1985. Our exports in 1986 were 26.0 million tonnes, a growth of 53% in three years."

Jan 1, 1988

By R. W. Wein, L C. Bliss

Northern ecosystems are dominated by a harsh physical environment which dictates a need for biological adaptation. As yet, it is unknown just how these adapted plants and animals will tolerate industrial development. Our work, sponsored by university, government and industry, is part of an effort to evaluate this developmental impact. Our present studies and the results to date will be discussed. Other problems to which the environmental student may address himself in the future to ensure against environ-mental degradation will be suggested.

Jan 1, 1971

By Neil Campbell

Abstract Following discovery on the Giant property of very promising gold deposits, some of which terminate against the steeply-dipping West Bay fault, a geological study was initiated co locate possible faulted extensions of the ore. Geological mapping revealed that the ore and the shear zones to which the ore is confined are older than the fault and therefore subject co displacement by it. It also disclosed several diabase dykes which seem co provide the best basis for determining the fault movement. After applying various techniques co determine their strikes and dips, the dykes were used as structural markers and it was estimated that, subject co certain possible errors, the movement on the fault was 16,140 feet (3.06 miles) south and 1,570 feet (0.297 miles) down on the west side relative co the ease. Evidence supporting this conclusion was obtained when subsequent deep diamond-drill holes intended to test the hypothesis cut an ore-bearing major shear zone which, so far as can be determined, is nearly identical with its present correlative on the Giant property. Introduction The fault under consideration follows a northerly trend past the west side of the original settlement of Yellowknife, which is situated 600 miles north of Edmonton and 400 miles from the Northern Alberta Railway terminus at Waterways, Alberta. The mining properties chiefly concerned include the southern part of the Giant claims, on the east side of the fault, and the Con-Rycon-Demelt claims, on the west side, 3Y2 miles to the south. Geological data were also obtained from the eastern part of the A. Y.E. property, which lies south of the Giant claims, and from the Negus, Meg, Yellorex, and Kam properties, which are south and southeast of the Con-Rycon-Demelt claims. Recognition of the major faults in the Yellowknife Bay area, including the West Bay fault which appears to be the greatest, resulted from the work of Dr. A. W. Jolliffe (McGill University, formerly of the Geological Survey of Canada) in 1935 and subsequent years. It has been stated with little exaggeration that these faults rank with the largest known steeply-dipping dislocations of the earth&apos;s crust. In the winter of 1939, a mineralized shear zone named the Creek Vein was found on the Giant property. It was noticed that the space relationship between the new shear zone and a body of quartz-feldspar porphyry is roughly the same as that between the Con C-4 shear zone and a body of acidic flows lying north of the Con property. Coupling this relation with the assumption that the movement along the fault is dominantly horizontal, it was postulated that the Giant shear zone represented the faulted extension of the Con C-4 shear.

Jan 1, 1947

By Jean-Marc Lulin

"Depuis 1906, pres de 130 gisements ont ere decouverts dans la inture archeenne polymetallique (Cu, Zn, Au, Ag) du nord-ouest becois. Une etude regionale du developpement du potentiel inier est presentee puis detaillee pour quatre secteurs: RouynDranda, Val d'Or-Malartic, Bousquet-Cadillac et Matagami.L' analyse est conduite a l' aide des parametres suivants: temps, ethodes de decouverte, profondeur des gisements et poids metal. ~~ courbes cumulatives illustrant le nombre de gisements decouverts fonction du temps montrent une forme generale en ""S"" dont les i'iations de pentes correspondent aux variations dans les taux de ~ouverte. Initiation, realisation et stabilisation des cycles de decourte sont ainsi mis en evidence. Deux ""bourns miniers"", de 1922 a ~5 et de 1955 a 1965, rassemblent 72 % des mines identijiees squ' a present.La plupart des mines sont trouvees en subsurface: 90% ont leur fmet entre 0 et 100 metres de profondeur dont 70 % entre 0 et 10 etres. Dans le temps, il y ad' abord recolte par prospection puis par fphysique et enjin, developpement progressif du potentiel en proeur avec des methodes composites. Environ 80% du poids metal extrait de 4 camps miniers, couvrant 8% de Ia surface regionale quelques gros gisements dominent /a production.Ces donnees permettent de proposer une nouvelle approche pour lysed' une region miniere:La distribution de Ia profondeur des gisements en fonction du temps est indicatricede /amaturite d' uncampminieret peut servir a evaluer son potentiel residue/.L' analyse des courbes en ""S"" permet d' extrapoler les taux de succes relies aux differentes methodes et met en relief le role crucial de I' innovation dans I' exploration.ABSTRACTSince 1906, some 130 deposits have been discovered in the Archean polymetallic belt of northwestern Quebec. In this paper, the development of the mining potential is analyzed at the regional scale and for the following mining camps: Rouyn-Noranda, Val d'OrMalartic, Bousquet-Cadillac and Matagami.The analysis is based on the following parameters: time, discovery method, depth and weight of metal extracted. Curves showing the cumulative number of deposits discovered as a function of time are ""S"" shaped with slope variations corresponding to changing discovery rates. Initiation, realization and stabilization of discovery cycles are thus well represented. Two ""mining booms"", 1922 to 1945 and 1955 to 1965, account for 72% of the mines identified to date.Most exploitable orebodies have been found near the surface: 90 %have their top between 0 and 100 meters, including 70% between 0 and 10 meters. Early discoveries were made by prospecting, followed by geophysics while the progressive development of the depth potential is being realized by a combination of methods. Approximately 80 %of the metal extracted comes from four mining camps which cover 8% of the area, but most of the production can be allributed to only a few large deposits. Based on these data, a new approach to the analysis of a mining region is proposed:1) The distribution showing deposit depth versus time is indicative of the maturity of a mining camp and can serve to evaluate its remaining potential.2) The ""S"" curve analysis can be used to extrapolate the success rate of a specific exploration method and also stresses the crucial role of innovation in exploration."

Jan 1, 1990

By Jean-Marc Lulin

"Depuis 1906, près de 130 gisements ont été découverts dans la inture archéenne polymétallique (Cu, Zn, Au, Ag) du nord-ouest québécois. Une étude régionale du développement du potentiel inier est présentée puis détaillée pour quatre secteurs: Rouyn-Dranda, Val d'Or-Malartic, Bousquet-Cadillac et Matagami.L' analyse est conduite a l' aide des paramètres suivants: temps, méthodes de découverte, profondeur des gisements et poids métal. Les courbes cumulatives illustrant le nombre de gisements découverts fonction du temps montrent une forme générale en ""S"" dont les i'iations de pentes correspondent aux variations dans les taux de couverte. Initiation, réalisation et stabilisation des cycles de décourté sont ainsi mis en évidence. Deux ""bourns miniers"", de 1922 à 1945 et de 1955 à 1965, rassemblent 72 % des mines identifiées sqú à présent.La plupart des mines sont trouvées en subsurface: 90% ont leur mmet entre 0 et 100 mètres de profondeur dont 70 % entre 0 et 10 êtres. Dans le temps, il y a d' abord récolte par prospection puis par ophysique et enfin, développement progressif du potentiel en proeur avec des méthodes composites. Environ 80% du poids métal extrait de 4 camps miniers, couvrant 8% de Ia surface régionale quelques gros gisements dominent /a production.Ces données permettent de proposer une nouvelle approche pour analyse d' une région minière:La distribution de Ia profondeur des gisements en fonction du temps est indicatrice de la maturité d' un camp minier et peut servir a évaluer son potentiel résiduel.L’analyse des courbes en ""S"" permet d’extrapoler les taux de succès relies aux différentes méthodes et met en relief le rôle crucial de I' innovation dans I' exploration.ABSTRACTSince 1906, some 130 deposits have been discovered in the Archean polymetallic belt of northwestern Quebec. In this paper, the development of the mining potential is analyzed at the regional scale and for the following mining camps: Rouyn-Noranda, Val d'OrMalartic, Bousquet-Cadillac and Matagami.The analysis is based on the following parameters: time, discovery method, depth and weight of metal extracted. Curves showing the cumulative number of deposits discovered as a function of time are ""S"" shaped with slope variations corresponding to changing discovery rates. Initiation, realization and stabilization of discovery cycles are thus well represented. Two ""mining booms"", 1922 to 1945 and 1955 to 1965, account for 72% of the mines identified to date.Most exploitable orebodies have been found near the surface: 90 %have their top between 0 and 100 meters, including 70% between 0 and 10 meters. Early discoveries were made by prospecting, followed by geophysics while the progressive development of the depth potential is being realized by a combination of methods. Approximately 80 %of the metal extracted comes from four mining camps which cover 8% of the area, but most of the production can be allributed to only a few large deposits. Based on these data, a new approach to the analysis of a mining region is proposed:1) The distribution showing deposit depth versus time is indicative of the maturity of a mining camp and can serve to evaluate its remaining potential.2) The ""S"" curve analysis can be used to extrapolate the success rate of a specific exploration method and also stresses the crucial role of innovation in exploration."

Jan 1, 1989

By Elaine Ellingham, Francis T. Manns

"Abstract -The Orostar and Scadding were two small gold mines owned and operated by Orofino Resources Limited. Conventional statistical treatment indicates an identical arithmetic mean grade of 0.22 oz/T Au for both mineable reserves. Further, the deposits are both shown to have cut weighted average reserve grade of 0.21 oz/T. Orostar mined out at 0.206 oz/T and Scadding at0.156 oz/TAu . The combined exploration and development database contained 1394 fire assays, more than enough for statistical confidence in a normal distribution. Therefore this study was initiated to determine, if possible, why the mill head grades were lower than the averages and to experiment with several methods to determine whether a reliable statistical mill head grade estimation method would emerge. Despite the identical reserve grades, distinct differences in the grade distribution histograms are present. By studying the arithmetic and log-normal grade distribution s, with some attention to South African practices, this paper reports on those differences which may account for the considerable divergence in the mill head grades. Furthermore, this study casts considerable doubt on the industry standard method of cut weighted averages.The global mill head grades of the two deposits have been derived from the arithmetic average grades by graphic means. This precise method of mill head grade prediction, if applied to complex orebodies, could permit selective grade control and result in direct cost savings by allowing the operator to detect false value stopes, benches or levels and emphasize reliable regions of not only gold mines, but also uranium or base metal deposits."

Jan 1, 1992

By S. Kelebek, E. Yalcin

"Diethylenetriamine (DETA) and/or triethylenetetramine (TETA) are reagents that can generally be categorized under ""flotation modifiers"". These polyamines are known to be effective for the deactivation/depression of pyrrhotite that is present in Canadian nickel-copper sulphide ores in large quantities. Recent bench scale testing on some of these complex ores indicated that chalcopyrite flotation can also be adversely affected under certain conditions involving polyamines, which may be taken to be an evidence of their specific affinity towards chalcopyrite. In general, DETA shows no significant depressant action on chalcopyrite while TETA&apos;s promotion of hydrophilicity for this mineral has been observed even in the presence of xanthate. This prompted an investigation on thermodynamic equilibria involving these polyamines and copper ions. Results serve a useful purpose to identify conditions for deactivation phenomena. CuDETA2+ and CuTETA2+ chelates as products of sequestration have large predominance areas covering a wide range of redox and pH conditions, where copper xanthate species are not stable, especially in the presence of TETA."

Jan 1, 2009

M INE production requires the coordination of the talents of men and the use of equipment. Mine operators maintain a continual surveillance of equipment, looking for improvements and modifications that will benefit them. Few give similar attention to the advances made in the education of mining engineers since they themselves graduated. That is not surprising. Education lacks the advertising budget available to manufacturers. A modification to improve a mechanical contrivance is advertised, and an advertiser&apos;s press releases get attention by publishers. The whole program for mining engineering education could be revolutionized and no one, except a few professors, would know about it. The Canadian Institute of Mining and Metallurgy&apos;s newly established General Commit-tee on Education can improve that situation. Nine groups of engineers in Canadian universities are trying to give undergraduates an education that will make them useful to the mineral industry as mining engineers. The tabulation offered here (Table I) is an analysis of the distribution of the undergraduate-teacher contact time.

Jan 1, 1963

By L. V. Chugaev, Y. M. Shneerson, P. V. Zaytsev, I. V. Fomenko, M. A. Pleshkov

"Pressure oxidation (POX) is one of the most common and reliable methods of processing gold-bearing sulfide concentrates. However, when processing concentrates that contain natural carbonaceous matter, substantial gold losses occur due to autoclave preg-robbing. The latter involves formation of gold chloride complexes under typical POX conditions (high temperatures, high acidity and high ORP) and subsequent sorption of these complexes by carbonaceous matter. Naturally, chloride ion plays a significant role in the process of autoclave preg-robbing; its concentration in POX solution has a well-marked effect on subsequent gold recovery during cyanidation of POX residue. The previous research done by SRC Hydrometallurgy showed that autoclave preg-robbing of gold could be significantly inhibited by the addition of mercury(II) compounds to POX slurry. The positive effect of mercury(II) was well pronounced both at high (>20 mg/L) and low (<5 mg/L) Cl concentrations in POX solution. The successful bench-scale laboratory testing was followed by pilot plant trials at Ore Test Facility in Blagoveshchensk, Russia. The present paper provides the results of these trials. The bench-scale testing results were verified; the optimum oxidizing parameters and reagent dosage were specified. The behavior of mercury (II) at POX pilot plant was found to be in good consistency with industrial practice described in the literature.INTRODUCTION Pressure oxidation (POX) is one of the most common, reliable, and commercially proven methods of processing gold-bearing sulfide ores and concentrates. However, when processing double refractory materials that contain natural carbonaceous matter, POX technology advantages are compromised by autoclave preg-robbing of gold. The latter occurs when natural organic carbon and soluble halides are both present in autoclave feed. Strongly oxidizing conditions of POX (high temperature, oxidation-reduction potential or ORP, and acidity) favor formation of gold-halide (mostly, gold-chloride) complexes, which tend to bond with carbonaceous matter. The exact nature and mechanism of this bonding is unknown, but as the result of this, cyanide is unable to leach gold from POX residue and the precious metal is lost to the tails (Axenov et al., 2014; Dimov, Chryssoulis, & Sodhi, 2003; Fomenko, Zaytsev, Pleshkov, Chugaev, & Shneerson, 2013)."

Jan 1, 2017

By D. L. Koch, J. W. Tester, L. K. Sinclair

"In this study, hydraulic conductivity (K) geostatistics were used to predict residence time distribution of well-to-well flow. Flow profiles, fracture density measurements, and pumping tests were available from the highly fractured Florence Copper in situ leaching site. The flow profiles were used to establish the statistical distribution and spatial autocorrelation of K. Two tests were used for validation. The first test confirmed that fracture density and K are autocorrelated over similar length scales. In the second test, Monte Carlo flow simulations successfully recreated the results of pumping tests. Flow sim¬ulations were used to stochastically model well-to-well residence time distribution. RÉSUMÉ Dans cette étude, nous utilisons la géostatistique de la conductivité hydraulique (K) pour prévoir la distribution des temps de séjour (DTS) de l’écoulement entre les puits. Des profils de l’écoulement, des mesures de la densité des fractures et des essais de pompage existaient pour le site fortement fracturé de lixiviation in situ de Florence Copper. Les profils de l’écoulement ont permis d’établir la distribution statistique et l’autocorrélation spatiale de K. Deux essais ont servi à la validation ; le premier a confirmé que la densité des fractures et K sont autocorrélés sur des échelles de longueur similaires ; quant au second, des simulations d’écoulements de type Monte Carlo sont parvenues à reproduire les résultats des essais de pompage. Les simulations d’écoulement ont servi à établir un modèle stochastique de la DTS de l’écoulement entre les puits.INTRODUCTION In situ leaching is the circulation of a dilute acid or base solution in the subsurface, via a series of injection and recovery wells, to dissolve a target metal. In situ leach modelling requires forecasting the residence time distribution (RTD) of flow between wells. In fractured formations such as copper porphyry deposits, order-of-magnitude variations in hydraulic conductivity (K) can result in highly channeled flow, resulting in a heavy tailed RTD (Becker & Shapiro, 2003; Kang, Le Borgne, Dentz, Bour, & Juanes, 2015). Channeling through preferential pathways has impacted copper recovery at several past in situ leaching field tests (Cathles, Glenn, Lenzi, Nigrini, Deans, & Huff, 1978; Ahlness & Pojar, 1983; Schmidt, Earley, & Friedel, 1994; Sinclair & Thompson, 2015). The aim of this work is to combine multiple types of hydrogeological measurements to stochastically forecast the well-to-well RTD in fractured rock for the purposes of copper in situ leach modelling."

Jan 1, 2018

By A. M. S. Hussein, B. E. Rogers

Progressively more stringent emission limits and advances in regulations and enforcement have made air compliance more difficult for metallurgical facilities. This has historically required improved collection and treatment of stack sources. Fugitive emission reductions are now increasingly required to achieve compliance. Typically small in magnitude, fugitive emissions have a disproportionate impact on ground level concentrations, can be visible to the public and can influence workplace health and safety. Moreover, these emissions are complex, as they are spread over multiple sources, distance and time and are affected by various activities and conditions. As such it is difficult to find, define and monitor these emissions and their impacts. This difficulty translates to the design of emission reduction measures and operational requirements. This paper presents an overview or ‘heuristic’ of fugitive emissions management for compliance in existing operations. This includes aspects such as the impact of regulations on project scope, approaches to developing a comprehensive emission inventory, considerations for solution development and the plant’s role in sustaining compliance once achieved. Case studies are presented to demonstrate how portions of this approach have been applied.

Jan 1, 2015

By M. Laframboise, M. Buarzaiga

High-pressure acid leaching (HPAL) of nickel laterites has received considerable attention in recent years. High paymetals extraction, good selectivity, and advances in pressure hydrometallurgical technology are some of the reasons for this interest. Falconbridge Limited (Sudbury. Ontario) investigated the HPAL process using both fresh water and seawater for ore processing. The use of seawater resulted in a chloride concentration of 7.8 g/L in the autoclave feed. A test program was developed to study the effect of process water and leach temperature on the leaching behaviour of different ore compositions from the Koniambo deposit in New Caledonia. The work showed that salinity has a major effect on autoclave chemistry. This paper explores the results.

Jan 1, 2004

By M. Kreuh

Crystalline Mg(OH)Cl and amorphous Mg2(OH)3C1 were successfully isolated from a hydrolyzed molten salt electrolyte sample in this work, It was found that the chemical form and crystallinity of the hydroxylchloride were controlled by the cooling rate of the molten sample when it was taken. Crystalline Mg(OH)Cl could only be obtained by cooling the molten electrolyte sample at a rate not faster than 0.6 °C/min, Upon more rapid cooling, the hydroxylchloride species precipitated as Mg2(OH)3Cl, The behavior of these solid hydroxylchlorides when contacted with fresh and non-hydrolyzed molten electrolyte at 550°C was also examined, It was found that the Mg(OH)Cl rapidly dissolved in the hot electrolyte and did not decompose into MgO at that temperature as would be expected from the literature, The dissolution rate of solid Mg2(OH)3Cl was found to be so slow by comparison that it resulted in the complete decomposition into MgO which thereafter was incorporated into the electrolyte as a suspended solid phase rather than dissolution.

Jan 1, 2004