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By Nessetech Consulting, L. A. Cisternas, E. D. Galvez, S. H. Kuan, L. H. Saw

"In Malaysia, there were two rare earths processing plants namely Asian Rare Earth (ARE) and the Malaysian Rare Earth Corporation Plant (MAREC) in Perak, which were operated until 1992 and were subsequently closed due to problems pertaining to disposal of large amount of radioactive waste. Recently, Lynas Advanced Materials Plant (LAMP) has become one of the largest rare earths processing plant in the world producing rare earth elements (REE) in Gebeng, Pahang. The primary raw material is lanthanide concentrate (LC) which is imported from Mount Weld mine in Australia and shipped to Malaysia. LC is produced from lanthanide ore after mining and mineral processing. The ore has a lower impact than Bayan Obo, Mountain Pass and adsorbed clay deposits, given the small footprint of the mine itself and the remoteness of the location. The type of ore being mined (rare earth phosphates: carbonatite, monazite) may have higher thorium content than bastnasite ore from the Chinese or American mines but still far below radiation concerns. This paper was written to review the processing flowsheet at the Lynas Advanced Materials Plant (LAMP), the environmental impact associated with the processing of the said ores and the sustainability of the operation.INTRODUCTIONRare earth minerals are one of a set of 17 minerals or chemical elements which consists of yttrium and scandium, as well as the 15 lanthanide elements (lanthanum, cerium, praseodymium, neodymium, promethium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). Despite their importance, rare earth minerals rarely exist in economically viable concentrations and they are usually difficult to extract. Rare-earth minerals create strong magnets when added to magnetic elements such as iron, and are useful for the production of electronics systems as well as electric cars. They are also used extensively in automotive catalytic converters, fluid cracking catalysts in petroleum refining, wind turbines, phosphors in colour televisions and flat panel screens, displays for mobile phones and laptops, rechargeable batteries, and various medical devices. The elements are typically split into two subgroups: the cerium sub-group of ‘‘Light’’ rare earth elements (LREEs) which includes La to Eu and the yttrium sub-group of ‘‘Heavy’’ rare earth elements (HREEs) which include the remaining lanthanide elements, Gd to Lu, including yttrium (Gupta and Krishnamurthy, 1992; Jordens et al., 2013; Trifonov, 1963). Scandium, however, when it is classified as a rare earth element, is not included in either the LREE or HREE classifications (Gupta and Krishnamurthy, 1992; Jordens et al, 2013). Half of the world’s 110 million tons of reserves exist in China while other sizable deposits are found in Russia, United States, Brazil, India, Australia, Canada, and Greenland. The countries known to be actively mining REE are China, Russia, India, Brazil and Malaysia (Hao et al., 2015). Among these countries, China has the largest REE production, accounting for more than 93% of global supply (Yap, 2015). The critical metal report (Moss et al. 2011) listed 14 economically vital raw materials that are prone to supply disruption and concluded that supply disruption would threaten the goal for cleaner transport and sustainable energy since rare earth metals are used in products using green technology, such as hybrid/electric vehicles, carbon capture systems, wind power generation, low-energy lighting, and energy efficient flat-screen displays."

Jan 1, 2016

By Farzad Khodabakhshi, Adrian P. Gerlich

"In this article, cold spraying process was utilized to coat the surface of AZ31 magnesium alloy with a layer of AA7075 aluminum alloy. Thereafter, friction-stir processing (FSP) was employed to enhance the microstructure and consolidate the deposited layer. The grain structure and phase morphology were studied along with indentation hardness before and after cold spraying and friction stir processing. The magnesium substrate had an initial hardness of 74 HV which increased to 102 HV after FSP due to refinement of grains to <2 µm. The aluminum coating layer, provided improved surface hardness up to 160 HV, which further increased to 173 HV after FSP was applied.INTRODUCTION Cold spray is a material deposition process which can be used for surface modification, since it deposits material on a metallic substrate with little heating by way of high velocity ballistic impacts. Using cold spray technology, it is possible to deposit a wide range of coatings with various thicknesses by controlling the characteristics of the feeding powder and metal substrate, gas temperature, gas pressure, powder feeding rate, nozzle geometry, and gun traverse velocity. This process has been recently employed for surface modification in various aircraft and automobile structural applications. This has led to a broad range of research using this process for production and modification of different metallic and non-metallic systems. In the present study, cold spray process was used to deposit a uniform layer of aluminum-zinc alloy (AA7075) on the surface of AZ31 magnesium alloy. This coating was subsequently treated by way of friction-stir processing (FSP) as a new post-spraying modification technique to enhance the structural homogeneity and densification of the coated aluminum layer. This method utilizes a non-consumable rotating tool with a specially designed shoulder and pin that is plunged into the surface of metal to be modified and then moved along the direction of interest. The localized frictional heating between the rotating tool and workpiece leads to softening of the materials around the pin, and material extrusion through a complex flow of material from the advancing toward the retreating side the tool. To the author’s best knowledge, only a few reports discuss the modification of a cold sprayed deposit by FSP process. The microstructure and mechanical properties of the cold sprayed layer and substrate before and after FSP modification were examined using optical observations (OM) and indentation hardness testing. Furthermore, the AZ31 alloy substrate alone was treated with FSP as well, for the aim of comparison to the processed coating."

Jan 1, 2017

By Jas. E. Thomson

"The Omega mine is in McVittie township in the Larder Lake area, Ontario. Production at the mine commenced in 1936, and, until the end of 1946, ore milled amounted to 1,558,604 tons, from which 207,074 oz. gold and 28,205 oz. silver, valued at $7,585,470, were recovered. The mine workings extend to a depth of 1,975 feet.GEOLOGYThe geology of the mine has been described in detail by C. P. Jenney (l) and the writer (2). The general geology and structure in the vicinity of the mine is discussed on an earlier page in this volume. The rock formations found in the mine workings are indicated on the accompanying plan and section (Figs. 1and2). They consist of an intermingled, south dipping complex of volcanics, sediments, and secondary talc-chlorite schists and carbonates. The carbonatized rocks, which are often referred to as 'dolomite' in the Larder Lake camp, are siliceous-carbonate replacements in the talc-chlorite schist zones. In places they contain green mica, probably fuchsite, and are cut by a stockwork of quartz veinlets and stringers. A stock of syenitic intrusives lies south of the mine workings.STRUCTUREThe main structural features are indicated in Figs. 1 and 2. The formations and orebodies have a pronounced southerly dip, which flattens with depth. The talc-chlorite schist and 'dolomite' zones are part of the Larder Lake fault or 'break' on which there appears to be very large displacement. Evidence throughout the district would indicate that the south side moved up and, in the case of the Omega mine, the thrust may have been distributed throughout the several intensely sheared zones. This slice faulting could account for the repetition of sediments and volcanics. An alternative possibility would be original interbedding of volcanics and sediments."

Jan 1, 1954

By John I. Sharpe

Masses of pyritic copper and zinc ores are entrapped along the contact zone between two volcanic groups in the Matagami area. The upper limits of the sulphide concentrations tend to form concordant contacts against lava or cherty tuffite units of the younger group; the lower extremities tend to either follow transverse structures or merge with zones of dispersed sulphides. The sulphides are deformed and intruded by folded dykes. Close relations between metallization boundaries and volcanic lithology and stratigraphy, and a preliminary investigation of the fabrics and crystallization temperatures of the sulphide masses, suggest that the copper and zinc (but; not necessarily all the iron sulphides) were emplaced at h1gh temperatures during volcanism in near-surface lithological-stratigraphic traps. Introduction T HE Matagami area is centered 120 miles north of the Val d&apos;Or and Noranda camps in north-western Quebec. For the present purpose, it is considered to comprise a 155-square-mile area in Isle-Dieu, Galinee and Daniel townships which encompasses the main sulphide masses. Airborne geophysical surveys within this area in 1956 led to the discovery of a large sulphide body -the.

Jan 1, 1965

By D. P. McDonald

"IntroductionTHE PURPOSE of this paper is to present .a summary of the evidence given before the Petroleum and Natural Gas Conservation Board in support of applications to it for permits to export natural gas from Alberta.I will attempt to be objective in my statements, despite the fact that my main interest in the hearings before the Board was to advance the interests of my own clients, the Westcoast Transmission Company, Limited.The hearing of the export applications •commenced before the Board in January, 1950, with the .application of the Westcoast Transmission Company. Joint hearings were commenced in September, 1950, and completed on December 14th, 1951. The Board heard evidence in support of six applications for export, one application to build a gathering system in Alberta, and three interveners, the .latter being the City of Calgary, the local gas companies, .and the coal interests, including both operators of coal mines and the Unions.The evidence comprised better than 8,400 pages, over two million words, and occupied 92 days before the Board.The Interest in Natural GasThe natural gas industry is one of the newer industries. It is not yet twenty years •old. In the United States, the expansion •of pipeline facilities has been phenomenal in the last fifteen years, and particularly in the last three years, when a total of over two billion dollars was invested in pipeline facilities. There are approximately 250,000 miles of gas transmission pipelines in the United States at this time, with additional lines constantly being pressed."

Jan 1, 1952

By R. V. Kumar, F. Tailoka

In order to use ZnO laden dust as a possible desulphurization reagent, it is important to evaluate thermodynamics of the Zn-O-S system. At temperatures greater than 1450 K, there is an uncertainty in the thermodynamic data for the reaction of zinc with sulfur to form Zinc sulfide. In this work, the standard free energy has been determined using an electrochemical cell: Pt, Mo, MoO2/YSZ/ZnO, ZnS, S02, Pt., between 1198 and 1602 K. AG° varies from -145,880 to -88,100 J (± 2500) , with a phase change to ZnS (g) by sublimation occurring between 1450 and 1460 K. This is supported by thermogravimetric analysis which shows about 80% weight loss in ZnS from 1273 to 1473 K. Feasibility reactions were also performed and confirmed that ZnS (g) is formed when ZnO reacts with FeS (1473 to 1653 K) or with Fe-Csat-S(1473-1673 K). There is therefore potential for the utilization of ZnO laden waste as an additional or alternative reagent for desulfurisation.

Jan 1, 2004

Cansolv® S02 Scrubbing Technology was described in a paper in Copper/Cobre 03. Four years on, the technology is operating at a full scale production facility.Hindustan Zinc Limited expanded their capacity by installing the AUSMELT process. The process proceeds through smelting, slag reduction, slag cleaning and holding stages sequentially in the same vessel, resulting in widely varying off gas characteristics. The off gas is suitable for treatment is a conventional acid plant for a modest proportion of the day, but at other times produces off gas too high in S02 to be discharged to atmosphere. Cansolv® S02 Scrubbing Technology was identified as a means of effectively removing the S02 down to low levels from the off gas during all stages of the pyrometallurgical process. Furthermore, the Cansolv® S02 Scrubbing System Technology produces high purity S02 that allowed for the captured S02 to be directed to an existing acid plant, avoiding the capital cost of new acid making capacity.

Jan 1, 2007

By F. Rashchi, A. Ghahreman, J. Moghaddam, S. Karimi

"In this work, the kinetics of ferric-ferrous redox reaction on a passivated sphalerite electrode is studied by the application of chronoamperometry method in 0.5 mol L-1 H2SO4 solution. The electrochemical behaviour of ferric and ferrous couple was investigated on two sphalerite minerals acquired from two different geological regions (Iran and Canada). The carbon paste electrode (CPE) of sphalerite was initially prepared and passivated in 0.5 mol L-1 H2SO4 solution and after reaching the steady-state condition, ferric and ferrous sulfate solution was added. The registered current density differences between the current density of the passivated electrode and that of the electrode in the iron salts added solution were interpreted for kinetics of ferric-ferrous reduction-oxidation reaction. The equilibrium potential for ferric-ferrous couple on sphalerites surface was about 500 mV vs. Ag/AgCl. The exchange current density (i0) for ferric-ferrous redox reactions on the sphalerite samples had the same magnitude of 10–6 A cm–2. The electrochemical impedance spectroscopy (EIS) measurements at 550 mV vs. Ag/AgCl illustrated that sphalerite oxidation was controlled by two charge transfer process in both of Fe-free and Fe-containing solutions. The charge transfer resistance remarkably decreased when Fe salts added to the 0.5 mol L-1 H2SO4 solution, owing to the ferric-ferrous redox reactions being the predominant reactions on sphalerite surface.INTRODUCTION Direct atmospheric leaching processes for sphalerite concentrates are performed by reduction of an oxidant (e.g. ferric ion and oxygen) and oxidation of sphalerite to zinc ions. Oxygen could be an oxidizing agent as well, but the concentration of oxygen is very low in the solution. The role of ferric ions is predominate in this oxidation (Babu, Sahu, & Pandey, 2002). The oxidation reaction for sphalerite in the presence of ferric in can be presented as follows (Lampinen, Laari, & Turunen, 2015):"

Jan 1, 2017

By T G. Callcott

Australian coking coals are either class 434<tlj534<2l, at Port Kembla, or 634<3> at Newcastle. The former yield good blast-furnace cokes; the latter yield poor ones. However, increases in conventional strength indices, by methods applicable with normal coking ovens, seem unlikely to be economically attractive. Characterization of the coals has enabled an "economic" blend to be developed in the Newcastle area, and this has affected mining, preparation and handling operations. Coking studies have led to a specification for the making of strong coke, especially from the high-volatile Newcastle coals. Continuous coking studies, developed from the efforts to make very strong coke, have taken two directions. Firstly, coking thin layers of coal on strands; secondly, coking, in various types of vessels, compacts of coals with or with-out the inclusion of non-coking coals, iron ores or other inert materials. Gas, "sand" and hot metal coking have been tested for use in compact coking. Particular attention has been paid to pellets of coal and ore. The probable industrial problems in adopting any of the ideas are presently being examined.

Jan 1, 1963

By Junto Nishiwaki, Shinji Kumai

"Mechanical and physical properties of the impact welded dissimilar metal joints are controlled by joint interface morphology. An intermediate layer (IML) is often formed at the joint interface and this deteriorates the interface quality in some metal combinations. Numerical and experimental studies were performed in order to examine the formation mechanism of the wavy interface and intermediate layer for explosive welded Al/Cu dissimilar metal joints. The impact welding process consists of (1) high-speed oblique collision of metal plates, (2) metal jet emission and large deformation and temperature increase at collision point and (3) rapid cooling at the joint interface. Euler-Lagrange coupling method, smooth particle hydrodynamic (SPH) method and modified laplacianFoam (LF) method were linked together to simulate a series of processes from (1) to (3), and the final interface morphology including the formation of IML was reproduced. The wavy morphology (wave-height, wavelength) and the position and composition of IML formed at the joint interface of Al/Cu joints were quantitatively in good agreement with those reproduced by numerical analysis. Our simulation results are useful for the control of the interface morphology, reduction of the amount of IML, and improvement of the mechanical properties of the impact welded dissimilar metal joints.INTRODUCTIONImpact welding is a kind of solid state joining method providing extremely high joint strength for both similar-and dissimilar metal combinations. Explosive welding and magnetic pulse welding are representative methods to achieve the impact welding. By a high-speed oblique collision between two metal plates, a metal jet is emitted from the collision point. The metal jet can remove any oxide films and contaminations on the plates and produce an active refreshed surface. Consequently, good metallurgical bonding can be achieved even for dissimilar metals (Crossland, 1982). Solid metals deform like fluids under the high pressure condition at the collision point and characteristic wavy interface is formed. In addition to the wavy interface, an intermediate layer (IML) is often formed at the joint interface in some metal combinations. Elimination or reduction of the amount of IML at the joint interface is desired since the excessive IML formation along the joint interface causes a large reduction in physical and mechanical properties. Formation of IML is considered to result from characteristic thermal history at the joint interface including partial melting due to the local temperature increase and successive rapid cooling behavior at the joint interface. In order to control the IML formation at the joint interface, it is necessary to reveal both heating and cooling processes at the joint interface. However, it is impossible to observe the phenomenon occurring at the joint interface and also difficult to investigate the temperature change at the joint interface directly during the impact welding. Therefore, simulation or numerical analysis is indispensable to overcome this problem. In the present study, the explosive welded Al/Cu joint, which is prone to form IML at the joint interface, was selected for the research. By using a newly developed numerical analysis method, not only the formation process of wavy interface, but also the local temperature increase and successive temperature decrease at the joint interface were reproduced. The formation process of IML was investigated by using both numerical analytic and experimental results."

Jan 1, 2018

By Marlin E. Sandlin

NORTH-CENTRAL United States is now, and will continue to be, a natural market for Canadian crude oil. This area is a natural market for many basic reasons. There are no physical barriers along the border of our countries. This market is in dose proximity to Canadian production. This market is already joined by crude oil pipe-1,ines to numerous producing areas of Canada. The tariff barriers are reasonable. We are not handicapped by mandatory quota restrictions. There are many of us who desire lo sell Canadian crude oil in this market. Further, and what is really important, there are many of us who desire to buy Canadian crude oil for this market. It is fundamental that for crude oil to be sold in the world market, it must ?be sold at competitive prices. At the same time, it is important that such competitive price must result in a fair price for the crude oil at the we1lhead. The factors of nearness to market, cheap pipe line transportation, and reasonable United States tariffs, all tend to make ?possible a competitive market and a fair wellhead price.

Jan 1, 1958

By P. J. van Staden

Several differences exist between the columns used for laboratory simulations of heap leaching and commercial heaps. Column walls support part of the weight of the ore and restrict the particle packing arrangements. Columns are typically of a diameter that is smaller than the dripper spacing to be used on the commercial heaps. The stacking practices that cause segregation and stratification on heaps are absent from columns. Intuitively, these physical differences would be expected to be the reasons behind the observed differences between column and heap leaching performance. But how can they be quantified, and what is the magnitude of the differences? Could some of these differences be built into column leaching experiments in order to better simulate commercial-scale heap leaching performance to ease the scale-up calculations from column leaching data? Alternatively, could heap construction practices be improved so that the ideal performance obtained in columns could be emulated on heaps? Data from a few heap leaching cases studies that permit direct comparisons between column and heap leaching performance is analysed, to reveal the extent of the differences in resistance to mass transfer. Discussion is provided on the implications for column and heap leaching practice, and for scale-up design procedures. INTRODUCTION Differences have been known to exist between leaching performance observed in laboratory columns and that of commercial-scale heaps. Both the heap leaching kinetics and finally achievable extent of extraction are generally found to be inferior in heaps compared to that achieved in columns. Heap leaching design engineers extrapolate the anticipated heap leaching performance by multiplying the time-axis of a column-leaching curve by a factor of about 2 and the extraction-axis by a factor of about 0.8, as explained by Jansen and Taylor (2002), Scheffel (2002), John (2011) and Scheffel, Guzmán, and Dreier (2016). The procedure is illustrated in Figure 1 by means of a hypothetical example. The solid line represents the leaching performance observed in a laboratory column, and the dashed line represents the anticipated leaching performance of a heap, extrapolated from the column leaching data using these empirical scale-up factors.

Jan 1, 2019

By M. Epiney, A. Ghahreman, R. Kim1and

"In the presence of sulfidic refractory ores, increasing the dissolved oxygen (DO) concentration can positively affect the gold leaching rate. To identify the role of DO in gold cyanidation, electrochemical behavior was studied in the presence of 3 different ores. Sample 1 was a low sulfide pyrite ore, contained 5.14% pyrite, 0.19% galena and 3.09% S. Sample 2 was a pyriticore as well, contained more sulfide as 8.35% S, and 12.4% of pyrite. Sample 3 was a tailing of silicate gold ore, still containing75 g/tAu, 0.13% Pb and 0.18% S. Gold cyanidation kinetics were studied by cyclic voltammetry (CV) and chronoamperometry tests. With sample 1, the gold oxidation peak current density from CV curve was increased to 1.38mA/cm2under oxygen injection, while it was only 0.66 mA/cm2with air injection. From chronoamperometry test, the reaction rate was also faster under oxygen injection. Sample 2 showed similar behavior with sample 1, but the gold oxidation peaks higher than sample 1, i.e. 1.75 and 2.27 mA/cm2, under air and oxygen injection, respectively. However, it seemed that the gold oxidation was impeded by sulfide ions for a longer period. In the presence of sample 3, the gold oxidation peak was the highest among three ores –2.75mA/cm2under oxygen injection, because of its lowest sulfide content. However, from chronoamperometry test, it was also shown that the gold oxidation was impeded because of a significant amount of Pb in the ore sample.INTRODUCTIONIt is well known that gold is leached under oxidative condition (Marsden &House, 2006). Through the most representative and oldest gold leaching technique, cyanidation, more than 90% of gold can be selectively leached from an ore. According to Elsner’s equation, gold is leached in cyanide solution by forming cyanide complex [Au (CN)2–], and oxygen is consumed as an oxidant(Eq. 1)."

Jan 1, 2017

By L Tafaghodi Khajavi, M. Barati

The distribution of phosphorus between solid silicon and iron-silicon melt was determined to investigate the degree of phosphorus removal from silicon by solvent refining with iron-silicon alloys. The distribution coefficient which is the ratio of the mole fraction of phosphorus in solid to that of liquid is as follows: 0.22±0.02 (1310°C), 0.29±0.02 (1260°C) and 0.33±0.02 (1210°C). The removal percentage of phosphorus is: 84.2% (1310°C), 72.5% (1260°C), and 63.7% (1210°C). The average phosphorus content of produced silicon in the proposed solvent refining process would be over two times less than that of the conventional directional solidification. The values of interaction coefficient of phosphorus on iron at different temperatures were obtained as -3460±155 (1310°C), -3595±159 (1260°C) and -3694±119 (1210°C). Self interaction parameter of phosphorus at different temperatures are as follows: 68±4 (1310 ?C), 78±10 (1260 ?C) and 103±19 (1210 ?C). The calculated values for distribution coefficient of phosphorus at infinite dilution are: 0.22±0.00 (1310°C), 0.30±0.00 (1260°C) and 0.34±0.00 (1210 °C).

Jan 1, 2015

By A. A. Rogozhin, E. G. Likhnikevich, S. I. Anufrieva, A. V. Kurkov

The Beloziminskoe deposit in Siberia is a large, potentially productive deposit of rare metals contained in ochreous apatite pyrochlore ores formed by weathering of a carbonatite. The ores are composed of pyrochlore, columbitized pyrochlore, monazite, apatite, magnetite, ferric and manganese hydroxide, titanic iron ore, zircon, hydromica, quartz, feldspar, and carbonates. A gravity-flotation enrichment flowsheet with application of cationic and anionic collectors has been developed. This flowsheet allows for obtaining a pyrochlore concentrate containing 44.3% Nb2O5 and 1.89% P2O5 with recovery of 55.83% Nb2O5 as well as an apatite concentrate containing 39.2% P2O5 and 1.05% TR2O3 with recovery of 62% P2O5 and 43.23% TR2O3 from ores containing 0.92% Nb2O5, 16.9% P2O5 and 0.6% TR2O3. Rare-earth concentrate containing 40% TR2O3 with recovery of approximately 10% TR2O3 was obtained at the same time. Major losses of valuable elements are related to slimes, which make up more than 50% of the ground ore. The niobium concentrate does not meet the phosphorus and radionuclide concentrations needed for the production of ferro-niobium. Acid leaching and sulfatization provided a high level of phosphorous and radionuclide removal. Conditions include hydrochloric acid pre-leaching at 75- 80°C with an 18% HCl solution for four hours and low-temperature sulfatization of acid-leached concentrate at 160-180°C for one hour followed by water leaching of the residue. The apatite concentrate could potentially be processed using nitric acid leaching. This technology is based on decomposition of apatite concentrate with 55-57% strength nitric acid with transfer of rare-earth metals into solution in the form of ammonium phosphate. This technology recovers a rare-earth concentrate containing 95% TR2O3 with extraction of 86%, and highly concentrated polynutrient fertilizer (ammophos) with phosphorus extraction of 95%. The completed research shows how complex multicomponent ores of residual soil may be processed for the extraction of niobium, phosphorus, and rare-earth products.

Jan 1, 2016

By C. Prévost, V. Leclerc, R. Pinto, M. Ruel

"A buffer’s ability to dampen production variations is directly related to its size. Small buffers cannot handle large variations in production, resulting in production losses when their inventory is depleted or saturated. This paper presents a predictive control algorithm used to regulate the inventory in a buffer of limited size, subject to large production variations caused by an upstream batch process. The algorithm was designed to manage the acid flow rates in an acid regeneration process, servicing batch leach reactors at Rio Tinto Fer et Titane, in Sorel-Tracy, Québec. The objective was to increase production by reducing equipment downtime caused by imbalances in the acid tanks servicing the leach reactors. The controller attempts to maintain acceptable acid tank volumes by optimizing the leach reactors acid/slag ratio and reaction time as a function of anticipated acid needs, all while maintaining product quality.INTRODUCTION Some beneficiation processes in extractive metallurgy require processing bulk material in batches. Typical examples of metallurgical beneficiation batch processes are smelting, leaching, electrowinning, elution and carbon-in-pulp. These processes are often situated midstream in an ore beneficiation flow sheet and either receive or transfer ore to continuous processes. Batch processes, by their very nature, introduce large variability in the flow sheet, because they process large finite quantities of material at nearly periodic time intervals. In order to dampen variations in production, various buffers–tanks and stockpiles–are utilized to accumulate ore upstream and downstream of batch processes. A buffer’s ability to dampen production variations is directly related to its size (Phillis & Gumede, 2011). Small buffers cannot handle large production variations, resulting in equipment downtime when their inventory is depleted or saturated (Everett, 2010, Berton et al., 2013). Consequently, the batch equipment production rates must be adequately managed to minimize production losses, attributed to depleted or saturated inventories, while maintaining product quality. Algorithms that anticipate or predict future production variations are often utilized to regulate buffer inventories, subject to large flow rate variations (Salvo et al., 2002; Bonvin, 2013). This paper presents a predictive control algorithm used to maintain an acceptable volume in a spent acid tank servicing several batch leach reactors. The algorithm is implemented at the acid leach plant of Rio Tinto Fer et Titane, in Sorel-Tracy, Québec."

Jan 1, 2017

By I. Filzwieser, M. B. Hanel, A. Filzwieser

The paper describes the current density increase within the last 150 years. From the beginning in 1885 at 30 A/m² up to the highest used current densities nowadays at 420 A/m² towards future pathways were even 1000 A/m² can be achievable. A short tour through history will highlight the milestones of the process of electrolytic refining of copper. Besides the improvement of the existing technology, the biggest changes leading to higher possible current densities are linked to the introduction of the ISA stainless steel plates and the introduction of the parallel flow principle. Furthermore, the parameters influencing the limitations regarding current density and therefore the practical used current density as well as the influence from the chemical composition of the electrolyte is discussed. Finally, the possibility of further increasing the current densities by enhancing the relative movement between electrolyte and electrode will give an outlook about the future of the copper electrolysis process. INTRODUCTION The current density is the most important characteristic to describe the productivity of a copper refining electrolysis besides the characteristic number for the electrical efficiency. Over the last 150 years, current density has risen from a few amperes per square meter to over 400 A/m² without any significant change in the principle of electrolytic refining. This increase in current density is documented exemplary by the electrolysis of Montanwerke Brixlegg in Austria (Brixlegg, 1963, 2013). The very beginning of the technology of electrolytic refining of copper was first patented in England by James Elkington in 1865 and the first electrolytic copper refinery was built in Newark, New Jersey, in 1883 (Armstrong, 1999). The secondary smelter Montanwerke Brixlegg, Austria, has been operating an electrolysis plant since 1884. In 1988, the third "Mount Isa" electrolysis plant worldwide and the first in Europe was put into operation in Brixlegg. Since 2010, the so-called high-current electrolysis (parallel flow METTOP-BRX Technology) with a current density of approx. 400 A/m² has been operated in half of the electrolysis process.

Jan 1, 2019

By Y. Zedan

Cutting fluids play important roles during machining, including the reduction of friction and temperature. Using a cutting fluid, however, degrades the quality of the environment and increases machining costs. The aim of the present research work is to study the effect of cutting fluids and their interactions with cutting parameters on the quality of holes during the drilling of 6061-T6 aluminum alloys. The lubrication types and modes investigated are dry machining, flood lubricant machining and minimum quantity lubrication machining (MQL), while the part quality criteria include the surface finish, the dimensional accuracy, and burr forms and sizes. A scanning electron microscope (SEM) was used to investigate the formation of built-up edges (BUE) in the drill flutes as well as the surface texture of drilled holes. It was found that dry machining and MQL machining can produce parts having quality levels comparable to those obtained in wet machining, when using the optimal cutting conditions.

Jan 1, 2011

By Frank D. Shepherd

THE Gunnar Gold Mines property is on the west shore of Beresford lake, in the Rice Lake mining division, southeastern Manitoba. Gold was first discovered in place in the Rice-Beresford Lakes area in 1911 on the Gabrielle claim, now included in the San Antonio Mines property at Rice lake. Following an eastward trend of favourable prospecting ground, promising showings were next staked in the vicinity of Long lake during the years 1915 and 1916. At that time, William Walton and associates, among them Gilbert LaBine, staked the Eldorado vein, north of Long lake, and Eldorado Gold Mines, Limited, was formed to develop the property a Company that, later, was to become widely known through successful operation of its radium-silver mine at Great Bear lake, Northwest Territories. Continuing eastward from Long lake, Walton and his partners, Gunnar Berg, Leo Seaberg, and Wm. Quesnel, staked claims during the years 1920-24 in the vicinity of Beresford lake which, later, were to become incorporated into the Gunnar Gold Mines property. The presence of gold-bearing quartz on these claims had been known from the time they were staked, but an opportunity to consolidate them into a group was not forth-coming until early in the year 1933. Although promising gold showings had been disclosed during the performance of assessment work on individual claims, no continuous mineralization having mine-making possibilities was discovered until after the consolidation of the entire group. From this stage onward, progress was rapid. Active exploration was begun on August 1st, 1933, and late in October James Houston reported favourably on the property. On October 27th, Gunnar Gold Mines, Limited, was incorporated in the Province of Ontario to develop and operate the property. The Company is also registered in Manitoba. The authorized capitalization is 3,000,000 shares of $1.00 par value. Gilbert LaBine was appointed president of the Company, with James Houston as mine manager. Following completion of a diamond-drilling programme, planned in 1933, it was decided to install a mine plant capable of carrying development to a depth of 1,000 feet. A transmission line, 5 miles in length, was built to the Great Falls-Central Manitoba line of the Manitoba Power Company, Limited.

Jan 1, 1939

"SART technology is a useful tool for improving the economics of gold recovery from certain types of complex gold ores. SART liberates cyanide consumed by base metals such as copper, zinc and nickel, and enables the newly freed cyanide to be recycled to precious metals leaching while producing high-grade base metal sulphide concentrates for sale. The benefits of SART include the reduction in cyanide consumption, avoidance of cyanide destruction costs, minimization of risks of environmental non-compliance due to residues of cyanide destruction reporting to mine effluents, and generation of extra revenue from the sale of base metal concentrates. Concerns with SART typically include uncertainties around capital and operating costs and proper integration of SART into the overall metallurgical flowsheet. This paper presents two case studies addressing these concerns. The first involves actual costs of the full scale SART integrated into a gold heap leach operation and treating up to 500 m3/hr of leach solution at a mine in Mexico. The second involves field pilot testing and a preliminary cost estimate for integrating SART into a silver mine in Peru using Merrill Crowe.INTRODUCTION One of the current trends in the gold industry globally is the increasing importance of complex polymetallic gold deposits as discoveries of large Carlin type gold deposits become increasingly rare (Sceresini, 2005). The presence of cyanide soluble copper and zinc in complex gold deposits necessitates changes in traditional gold extraction metallurgical flowsheets. One of the tools available to the industry to help deal with interferences of cyanide-soluble base metals in gold extraction is the SART (sulphidization-acidification-recycling-thickening) process. SART breaks the weak acid dissociable (WAD) base metal-cyanide complexes, precipitates the metals as high-grade sulphide concentrates and makes the freed cyanide available for recycle. Although SART is a commercially available technology, it is still relatively new to the industry. Fewer than ten (10) full scale plants have been constructed in the past couple of decades. Some of these SART plants are small, most are located at remote sites, and the majority have not operated on a continuous basis. This has resulted in a general lack of information in the industry about the true costs, operability and metallurgical performance of SART. BQE Water has been involved in the design, construction, commissioning and operation of large scale SART plants in Mexico, Turkey and Chile and has conducted field testing programs as part of the technical assessment of SART integration into various metallurgical circuits. Having built and operated numerous plants utilizing selective sulphide precipitation of heavy metals, BQE Water has gained unique insight into the design and control of the sulphidization stage of SART to minimize costs and ensure high efficiency in cyanide recovery."

Jan 1, 2017