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By Z. Zhang, M. -Y. Liu, X. -G. Chen, F. Breton

"The microstructures of AlSi10Mg foundry alloy in permanent mould (PM) and high pressure vacuum die (HPVD) castings were analyzed and compared. The as-cast microstructures of two castings mainly consisted of eutectic silicon particles, primary Mg2Si and Fe-rich intermetallic phases. The surface layer in HPVD castings, which has a unique feature and different structures, was carefully characterized. The dimension variation of microstructural phases along the cross section in PM samples is less than that in HPVD samples, although the size of microstructural phases in PM samples was much larger than that in HPVD samples. The mechanical properties of PM and HPVD samples were evaluated on as-cast and T6-treated conditions. The tensile properties of HPVD castings are remarkable better than those of PM castings on the as-cast condition. The T6 heat treatment greatly improves the tensile strength of PM castings while it has limited impact on the tensile strength of HPVD castings.INTRODUCTION The AlSi10Mg alloys are widely applied to the high pressure die casting (HPD) and high pressure vacuum die casting (HPVD). In the HPD process, the melt is injected into the die cavity under a high speed (30–50 m/s in the gate velocity for aluminum alloys), and solidified under a high pressure (up to 200 MPa in the cavity) and with a high cooling rate (up to ~103 Ks–1) (Gourlay, Laukli & Dahle, 2007; Ji, Wang, Watson & Fan, 2013). This results in a unique microstructure feature that is different to other casting processes under gravity. One major concern in HPD castings is porosity due to trapped air in the cavity (Ji et al., 2013), which seriously restricts the application of a heat treatment on the improvement of mechanical prosperities because of the formation of blisters on casting surfaces. For the process improvement, the high pressure vacuum die casting was developed in 1980s (Uchida, 2009). In this process, the melt is injected into the die cavity under reduced pressure (vacuum), which greatly reduces gas porosity in castings due to effectively avoiding the trapped air. Consequently, HPVD castings are heat-treatable without the formation of blisters on castings surface during heat treatment. The HPVD process has been widely applied to produce high quality structural castings in recent years attributed to reliable vacuum system development (Uchida, 2009). However, the microstructure features of HPVD castings are not systemically characterized yet."

Jan 1, 2018

By Gilles Carrière

"The Huntingdon mine of Quebec Copper Corporation is situated 3 miles south of the village of Eastman, in the Eastern Townships of Quebec. The copper deposit consists of several pyrrhotite-chalcopyrite replacement bodies or bands.The first mining operations on the conspicuous surface gossan of the Huntingdon deposit started in 1865. They were suspended in 1883. The .mine was again active from 1890 to 1893 and from 1912 to 1924. These operations were carried to a depth of 500 feet, and it is estimated that some 150,000 tons of ore were extracted, of a grade reported as varying between 3 Yi and 7 per cent copper.In 1950 a program of exploration was initiated in the area of the old mine, and resulted in the finding of 500,000 tons of ore with a grade of 2 per cent copper. A new shaft was sunk to a depth of 1,160 feet, and by February 1954 the mine was extracting 800 tons of ore daily.General Geology and StructureThe mineralized zones are on the west side of a band of altered volcanic rock, locally called andesite, adjacent to a sill-like body of serpentinized peridotite which lies west of the andesite. The bands of andesite and serpentine extend several miles north and south of the mine. Their strike is generally north 15 degrees east, and they dip steeply east. Their widths vary very considerably along the strike, but in the mine area each is about 450 feet wide on surface. They are enclosed in sediments of the Caldwell series, consisting of greywackes, quartzites, slates, and shales. The andesite belongs to the same series, which is thought to be of Cambrian age (1). The ultrabasic intrusive is post-Ordovician.At p\aces along the serpentine contact the andesite shows a pronounced schistosity; it is parallel to the contact and rarely extends farther than a hundred feet from it. No evidence of strong folding or faulting has been found so far in the mine workings. Some apparent distortions and irregularities in the strike of the contact may all be due to the intrusive nature of the serpentine. In the mine area, transgressive tongues of serpentine point southward in the andesite.A few vertical lamprophyre dykes, not more than five feet thick, cut the other formations at right angles."

Jan 1, 1949

By H. H. Claudet

PROBABLY the first flotation mill for treating molybdenite ores was put into operation .in Norway during 1913, when the writer was employed to introduce and apply the Elmore vacuum flotation process at a mine in southern Norway. These operations proved successful and led to other similar installations in that country. It remained, however, for Norwegian engineers themselves to iron out their difficulties and establish the molybdenum industry on a basis which ultimately attained world importance. Just as today, an urgent demand for molybdenum arose during the world war of 1914-18. By 1916, many molybdenite properties were in operation in Canada and several small concentrating mills were under construction. At one of these, in the Ottawa Valley district, the opportunity came for applying the Elmore vacuum flotation process, using a flow-sheet similar to that adopted in Norway. Later, as one of the staff of the General Engineering Company, who had already developed a highly efficient flowsheet for treating molybdenite ores, using the Callow pneumatic flotation process, the writer devoted considerable time to research work and investigations on a number of molybdenite projects and deposits in eastern Canada. The bulk of Canada's production of molybdenite was coming at that time from the Moss mine at Quyon, Que., where concentration of the ore was effected by water-film flotation. It is of interest to note that this process, based on the principle of surface tension, had been developed and introduced by the late Henry E. Wood, of Denver, Colorado- one of the original owners of the Moss mine-at the time he was investigating the Elmore vacuum process in his Denver plant. The process, with certain modifications, was used at several other properties in eastern Canada, and notably in the ore dressing laboratories of the Department of Mines at Ottawa and in a plant at Renfrew, Ont., in both of which ore from deposits in various parts of Canada was treated, with recovery of very appreciable amounts o much needed molybdenite. During the summer of 1917, the water-film flotation mill at the Moss mine was dismantled and the plant was re-modelled by the General Engineering Company to include the Callow system. This installation, using improved flotation methods, was highly successful both as to recovery and grade of concentrate, and proved a decided advance in molybdenite concentration, a recovery of upwards of 90 per cent being obtained, with a concentrate grading over 90 percent MoS2.

Jan 1, 1944

Heap leaching accounts for around 20% of the global production of copper. In heap leaching coarsely crushed ore particles are contacted with an aqueous lixiviant percolating through large packed beds (heaps) of the ore particles, with the loaded solution collected at the foot of the heap for metal recovery, solution make-up and recycle. While dominant for copper oxide acid leaching, it finds application also in copper sulphide (bio) leaching. Despite their apparent simplicity, heaps are in fact complex chemical reactors in which a number of competing sub-processes determine the overall rate of metal extraction. Therefore, meaningful prediction of copper production rates from heaps, as well as operational optimisation and control, all hinge on a comprehensive and quantitative understanding of these complexities. The paper gives a comprehensive overview of the various sub-processes in copper heap leaching and their interactions, including those relating to mineral-particle-solution-gas phase interactions at the micro-scale bulk transport and distribution of solution in unsaturated dense beds at the macro-scale. On the basis of a more fundamental understanding and modelling, the potential for optimized operation offers new opportunities for the extraction of value from both low-grade and complex polymetallic ores. INTRODUCTION Heap leaching is one of the percolation leaching technologies, which includes in situ leaching, dump leaching, heap leaching and vat leaching (Bartlett, 1998). The common phenomenon in all these technologies is the transport of leach solution through a fixed bed of ore particles, which interacts with the solid as it migrates along its path. The target minerals are released into solution and with its flow are carried out of the bed. The targeted dissolved metal species are recovered from solution through various hydrometallurgical techniques, especially solvent extraction (SX), before the barren solution is returned to the leach process. Heap leaching is practised in three main types of applications: sulphuric acid leaching of copper oxide ores, cyanide leaching of gold ores as well as the oxidative acid leaching of secondary copper sulphide ores, usually with the assistance of certain microorganisms and, more recently, in the presence of chlorides (CaCl2, sea water). While gold heap leaching dates back to the 1960s, large scale copper heap leaching commenced in Chile from the 1980s, and sulphide heap leaching emerged essentially as a consequence of acid leaching from mixed oxide/sulphide ores from the 1990s (Watling, 2006).

Jan 1, 2019

By J. M. Cormie

"The orebodies of the East Malarcic mine are interesting from a geological standpoint because of the very small amount of vein quartz, the occurrence of much of the ore in soft greenstone schist, the presence of innumerable bodies of porphyry and diorite, and their obvious relationship to structural features .The property lies in the northeast part of Fourniere township in western Quebec, and within the important fault zone that geological mapping in recent years has shown is traceable wesrward through the Noranda and Kirkland Lake camps and eastward to beyond the Val d'Or region . The claims included in the property were staked by J.P. Norrie and L. K. Coffin in 1932, but gold was not discovered until i934. Production began late in 1938. The total amount of ore milled up to the end of 1945 was 2,837,091 tons from which gold having the value of $16,631,758 was recovered.The region is underlain by an alternating series of Early Precambrian sediments and volcanics cut by innumerable intrusives. These are more fully described in the works of Gunning, Ambrose, and Norman. The East Malanie property is underlain by three formations, which, named from north· to south, are : the Cadillac sediments, the Blake River volcanics, and the Kewagama sediments. In addition, there are countless intrusions of porphyry and diorite, particularly in the greenstone, occurring in all sizes up to those measurable in hundreds and even thousands of feet . These constitute a large proportion of the greenstone in places. In many parts of the ore zone there is more porphyry and diorite than schist. The greenstone itself is not homogeneous but includes peridotite, andesitic lava, and soft talcose schist.Orebodies have been found in both the Blake River volcanics and the Kewagama sediments. They are not known to occur in the Cadillac group. The ore occurs in a zone of pyrite mineralization in which almost no other metallic minerals and very little vein quartz are present. Generally, the grade varies directly with the amount of pyrite. The mineralization is later than all the rocks of the area. Diorite was a particularly favourable rock for mineralization and contains the highest grade of ore, but any rock in the fault zone may be ore-bearing, whereas the same type away from the zone is not."

Jan 1, 1954

By Alfred W. G. Wilson

MR. F. E. LATHE: In studying any subject whatever, one should at least occasionally stand back from the canvas, as it were, and take a broad view of the picture. It is such a view of the subject of industrial minerals that Dr. Wilson has given us today, and, in consideration of our efforts to utilize Canada's resources to the utmost in the present emergency, it seems most timely. I shall confine my remarks on the subject to the resources of the atmosphere and hydrosphere. We seldom stop to realize our dependence upon the atmosphere, not merely as a source of the oxygen we breathe but also of other indispensable elements. As recently as the beginning of the present century, grave concern was felt lest the rapidly increasing population of the world should ultimately starve for lack of the nitrogen required for crop growth. I recently noticed a reference to the Scientific American for March, 1890-just fifty years ago-in which an account is given of work on the fixation of nitrogen, which, said the article, "leads to the conclusion that while cyanides and ammonia may be thus produced experimentally, there are as yet insuperable difficulties in the way of adapting those methods to industrial purposes". Y et, in the early part of the present century, the development of the arc, cyanamide, and synthetic ammonia processes of nitrogen fixation was such as to remove, for all time to come the possibility of a shortage of nitrogen. Today, the atmosphere is by far our greatest source of nitrogen, and the capacity of the nitrogen fixation plants of the world is at least 4,000,000 tons annually-much more than can at present be utilized. Pure oxygen or oxygen-enriched air offers great possibilities in metallurgy and industrial chemistry, but, so far, little application has been made. In a paper presented to the Institute in 1926, 1 pointed out the theoretical savings which could be effected by the use of oxygen in burning carbon-when the gases pass off at 2,460°F., the fuel saving is no less than 50 percent. The use of oxygen on a commercial scale is intimately tied up with the question of refractories, but we should not forget that the possible changes in metallurgical practice by the use of oxygen are truly of revolutionary character.

Jan 1, 1940

By Roger St. C. Smart, Paul Weber, Joan E. Thomas, William M. Skinner, Warwick Stewart, Stuart Miller

For mine sites affected by acid rock drainage (ARD) or with a potential future ARD issue, the prime consideration is not only the classification of different waste rock as potentially acid forming or non acid forming but also the peak acid (and metal) release rates and expected ARD duration during which effective ARD management and acid neutralisation capacity (ANC) are required. Methods for assessment of this ANC (e.g., Sobek tests) are already available but can be unreliable in ARD containing significant proportions of framboidal pyrite or iron carbonates. The measurement of negative ANC values and the release of S to solution showed that significant sulfide oxidation may occur prior to and during testing in samples containing reactive (particularly framboidal) pyrite resulting in serious underestimation of the original ANC. A simple methodology with dissolution in Ar-purged water before ANC testing, removing ferrous salts, and sulfate assay after ANC testing corrects these effects. Results also showed that a significant lag period (up to 432 h) may be needed for complete hydrolysis of Fe associated with the standard Sobek ANC testing of, for instance, siderite. Hence, the ANC of iron carbonates is usually significantly overestimated. By filtering and the addition of H202 until there was no subsequent pH drop (due to Fe hydrolysis reactions), followed by back titration to pH 7.0, the ANC for siderite was similar to the ANC determined after 432 h lag by the Modified Sobek ANC test and to the mineralogical carbonate ANCcarb determined by calculation based on electron probe micro-analysis. A chemical ANC calculation, based on neutralising cations released to solution, has provided a method to quantify the short-term ANC of carbonates and silicates in simple mixed mineral assemblages and waste rock samples. Results showed that silicate ANC can be more important in short-term neutralisation than carbonate ANC in low carbonate samples. In the longer-term, decreasing sulfate and metal loads with increasing pH values suggests that eventually sulfide acidity generation rates will match the longer-term inherent acid neutralisation rates of the sample derived from silicates. A kinetic ANC measurement for silicates, after steady state dissolution is reached, that indicates the number of hydrogen ions neutralised/m2/yr has been developed. These values can be used in estimates of the net acid production profile from wastes with low (and decreasing) pyrite content after the short-term ANC is exhausted.

Jan 1, 2004

By Scott D. Long

"Abstract-Grass roots exploration has an emphasis on good precision at low (sub-economic) concentrations of an element, in order to identify "anomalies" which may lead to drilling targets. Although it is wise to have well-defined quality controls in place during early stage sampling, the control procedures at this stage tend to be rudimentary. When a deposit warrants detailed delineation, the need for accurate geological characterization and assaying of ore-grade rock must be supported by appropriate quality control procedures.As a project returns more promising results, and the likelihood of the project warranting a prefeasibility study increases, it is time to tighten quality assurance requirements and quality control protocols. Delays in instituting adequate quality control and verification procedures may lead to costly remedial actions that can also delay completion of the prefeasibility or feasibility study. Sometimes, as a project matures, the quality control and quality assurance aspects fail to keep pace with the changing nature of the work: an increasing emphasis on precise and accurate assaying of oregrade rock.A resource model is like a house of cards. The foundation of the house is the geological observations, the sampling methods and the geological interpretations performed upon those samples. Upon the sampling, which includes all the sub-sampling steps of sample preparation, rest the assay results. The quality of the assays can be no better than the quality of the sampling. Good assaying technique will preserve all biases and imprecisions introduced during sampling and sample preparation; it cannot remove them. If the sub-samples and/or assays are bad and must be redone, all the succeeding levels of the house of cards must also be rebuilt, or at least patched up.From geological observations, a geological interpretation is built, the quality of which is critical to the construction of an acceptable resource model. Geological elements are difficult to assess, and are not discussed here; they are dependent upon the expertise of the geologists involved. Geological knowledge contributes essential quality control elements to resource/reserve determinations (Sinclair and Postolski, 1999; Postolski and Sinclair, 1999).This paper consists of five sections: (1) overview of quality control protocols, (2) maintaining quality control of databases, (3) quality control of drill sampling, (4) optimizing crushing and grinding requirements, and (5) quality control of assay data acquisition."

Jan 1, 1998

By R. P. Viljoen, A. L. Sokolov

"The distribution of mineralized provinces is analyzed on the basis of their genetic link with specific blocks of the earth's crust including ancient platforms, mobile belts and zones of tectonicmagmatic activation. Mobile and fold belts surround the Siberian platform in Russia and the Kaapvaal craton in South Africa, with decreasing age zoning away from ancient platform margins. The main differences in the geological development of the two cratonic areas are: (1) the long period before the final stabilization of the Siberian platform (3600 Ma to 1600 Ma) and the comparatively short period of time for the stabilization of the Kaapvaal craton (3600 Ma to 3050 Ma) and (2) the intensive multiple activation of the marginal zones of the Siberian platform and the tectonicallycontrolled, magmatic sedimentary, intracratonic activity, typical of the Kaapvaal craton. Mineralization of the Siberian platform is largely characterized by marginal reactivation zones of differing ages although mineralized intracratonic Cu-bearing basins of Proterozoic age are also known. Mineralization of the Kaapvaal craton is mainly related to the formation of the intracratonic basins i.e., Witwatersrand (Au, U) and Transvaal (Au). The latter is characterized by multi-age volcanic-intrusive activity including the emplacement of Bushveld Complex (Cu, Ni, Pt, Cr, Au, V). The Siberian platform is characterized by the prolonged development of inherited mineralization from Archean until the late Mesozoic. The main period of mineralization in the Kaapvaal craton is restricted to the middle Proterozoic.The Baykal-Patomskaya and Namaqua-Natal mobile zones occupy similar positions adjacent to the Siberian and Kaapvaal cratons, respectively, and demonstrate similar modes of metallogenic development: i.e., the early formation of exhalative Pb-Zn-Cu deposits during the early stage and magmatic Cu deposits during the late stage. The more remote mobile belt near the Siberian platform, the Trans-Baykal, is characterized by intensive multi-age mineralization (Wo, Mo, Sn, fluorite), related to a period of tectonic-magmatic activation. The Saldania Belt occupies a similar position near the Kaapvaal craton but is known for its poor Au, and Cu mineralization. It does, however, have some similarities with Trans-Baykal Belt in regard to Mo-W bearing granitoids.The phenomenon of interference of geosynclinal, orogenic, platform, and tectono-magmatic activation regimes is known for the Russian section of the Pacific Ocean Volcanic Belt."

Jan 1, 1994

By Ki-Bok Min, Bona Park

"In spite of the applications of DEM models to emulate the elastic modulus, Poisson’s ratio and strengths of isotropic rock in laboratory scale, extensions to anisotropic rock and larger engineering scale still have many challenges to overcome such as robust verification and validation against observed field case. In this study, a discrete element modeling was performed in order to represent a transversely isotropic rock such as shale, and the upscaled model was applied to foundation and borehole problems using PFC2D. The applicability of the upscaled rock mass model was verified by an analytical solution. The DEM modeling of stress redistribution induced by an applied surface line load compares well with Boussinesq’s isotropic solution and anisotropic solution given by Bray. The borehole model with a circular opening under biaxial stress was compared with both isotropic and anisotropic solutions resulting in good agreement. The abilities of DEM model to investigate the micromechanisms accounting for complex macroscopic behaviors and to predict the macroscopic behavior are discussed.The results demonstrate that DEM modeling has the potential to be applied to anisotropic rock mechanics problems on larger engineering scales such as wellbore stability problems especially in shale formations. Furthermore, the effect of anisotropy modeled through this study may be able to explain failure behavior of anisotropic rock encountered frequently in real cases.INTRODUCTIONAnisotropy is prevalent in various types of rocks, especially in shale that contain a set of parallel bedding planes. These weak planes in various forms are sources of large deformation and low shear strength and contribute significantly to the anisotropic behavior of rocks (Amadei, 1996; Cho et al., 2012; Kim et al., 2012). As elastic and strength behavior of anisotropic rock is substantially different from that of isotropic rock, proper consideration of anisotropy is of great importance. There is extensive of experimental evidence showing the anisotropy of shale. Niandou et al. (Niandou et al., 1997) analyzed the plastic deformation and failure mechanisms of Tournemire shale were highly dependent on the orientation of bedding planes. Cho et al. (Cho et al., 2012) presented various deformations and strengths of Boryeong shale obtained from laboratory experiments. Fjaer and Nes (Fjaer and Nes, 2013) performed uniaxial and triaxial compressive strength tests using Mancos shale, and they observed that the shear sliding along the planes of weakness before the occurrence of a major failure can reduce the strength of anisotropic rock. The recent research has demonstrated that the anisotropy of rock is an important consideration in rock engineering."

Jan 1, 2015

By A. Nielsen

"The Polaris mining operation (Fig. I) is located on Little Cornwallis Island in the Canadian Arctic, an area with a very limited shipping season and a hostile climate. The operation consists of the underground works, barge-mounted concentrator facilities, concentrate storage and shipping facilities, a personnel accommodation complex and an airstrip.The electrical energy for the operation is provided by four 2.3 MW diesel-generators installed on the barge. The power is distributed through a 4.16 KV system connected directly to the generators and to the large motors. All other loads are supplied at 600 V or 120 V.The power plant has been designed as a Total Energy System with maximum energy efficiency and thus designed for maximum heat recovery. The waste heat recovered on a year 'round basis is expected to be sufficient for the process heating and drying as well as the space heating for offices and accommodations. The engine cooling system consists of two glycol-water loops, a "" cold"" loop for charge air and lube oil cooling and a ""warm"" loop for jacket water cooling. Each loop is complete with heat exchangers f or heat recovery and out-door forced air radiators to dispose of excess heat. A water loop in the concentrator area transfers the heat from the jacket water loop and the exhaust gas boiler to the space heating equipment, the process and the heating system for the accommodations. Part of the exhaust gas is diverted to the concentrate dryers.IntroductionThe Polaris Mine is a highly mechanized, trackless mine with access through a decline. Drill equipment is electrically powered to minimize fumes and heat. Dry development and production drilling eliminates the need for an underground water supply system.The concentrator, power generators, work shops and auxiliary facilities are located on a barge which is beached in a prepared berth on the shore of Crozier Strait. Oil storage tanks, concentrate storage and accommodation buildings are built on shore. The concentrate storage building ha s a 12-month capacity and is fed from the concentrator by a conveyor system.The accommodation building houses up to 240 people, includes administration office, dining and recreation facilities. The complex is housed in on e interconnected building with public use areas alternating with accommodation units.At full production annual concentrate shipments will amount to about 220,000 wet tonnes. This will be accommodated by about 8 shipments during the regular shipping period-August 15 to October 15. Re-supply of general cargo and fuel will be carried out annually in about 3 shipments within the same period."

Jan 1, 1984

By S. D. Normani

A Deep Geologic Repository (DGR) for Low and Intermediate Level radioactive waste has been proposed by Ontario Power Generation for the Bruce Nuclear site in Ontario, Canada. The DGR is to be constructed at a depth of about 680m below ground surface within the argillaceous Ordovician limestone of the Cobourg Formation. The objective of this paper is to apply paleoclimate boundary conditions to a regional-scale groundwater flow model for the DGR site and to describe the influence of glacial loading and unloading on flow system evolution using the FRAC3DVS-OPG flow and transport model. The regional-scale domain encompasses an area of 18,775km2 extending from Lake Huron to Georgian Bay in southwestern Ontario, Canada. From a hydrogeologic perspective, the domain can be subdivided into a shallow zone, an intermediate zone, and a deep zone comprised of the low-permeability units of Ordovician and the more permeable Cambrian where present. The deep groundwater zone is characterized by units containing stagnant water having high concentrations of total dissolved solids (TDS) that can exceed 300g=L. The high TDS values at depth require density-dependent coupled flow and transport calculations within FRAC3DVS-OPG. The computational sequence involves the calculation of steady-state density independent flow that is used as the initial condition for the determination of pseudo-equilibrium for a density-dependent flow system that has an initial TDS distribution. The 1,000,000 year pseudo-equilibrium heads and brine concentrations are used as the initial condition for the paleoclimate simulations. Over the past 900,000 years, the Canadian Shield has experienced approximately nine episodes of complete glaciation. During the glaciation cycles, the entire Canadian land mass has been covered by a series of continental ice-sheets whose maximum thickness reached 4 km and whose southern extents reached, in some cases, beyond the present-day Canada-U.S. border. The glaciation phase of a single glaciation-deglaciation episode is typically 90,000 years in duration, while the deglaciation portion proceeds relatively rapidly and has an average duration of approximately 10,000 years. Output from the University of Toronto Glacial Systems Model, a continental scale North American glacial reconstruction of the most recent 120,000 year glaciation event developed by W. R. Peltier, is used to supply the paleoclimate boundary conditions used in this paper. Permeabilty reductions due to the presence of permafrost are also considered in the paleoclimate simulations. This paper will demonstrate that the choice of rock properties can significantly affect residual pore water pressures within the rock matrix, as well as the migration of glacial meltwater.

May 1, 2009

By A. Abadías Llamas, N. Bartie, M. Stelter

Evaluating the economic viability as well as the sustainability of the Circular Economy (CE) system requires a deep understanding of the distribution of all elements, compounds, alloys, materials etc. in flows. In this paper, the circularity of the copper value chain, including primary and secondary processing, is rigorously evaluated. The studied system comprises the metallic copper production from primary sources (from mineral to metal), copper-containing commodity production (copper is mixed with other metals) and copper recycling through secondary smelting to close the loop. This is linked to photovoltaic (PV) panels and battery storage. A simulation model of this system is created using HSC Sim, considering more than 30 elements (and its various compounds), 180 unit operations and 800 flows. From the mass and energy balances obtained through the simulation, an exergy analysis is conducted to evaluate the resource consumption from a second law (entropy) perspective. Additionally, these results are complemented through a Life Cycle Assessment (LCA), the recovery of technology elements and by-products is discussed, while quantifying the losses through the value chain. Through the digitalization of the complete system, a better CAPEX and OPEX understanding of the metal recovery and losses can be obtained, as well as the associated resource consumption and environmental impacts. New flowsheets and technologies can be evaluated. Several scenarios show how the resource consumption and the environmental impacts are affected by the recovery of different materials to produce different products. INTRODUCTION A key challenge of the circular economy (CE) is the linkage and optimization of both resource and energy efficiency of the (renewable) energy infrastructure and the resource cycle depicted by Figure 1 simultaneously. In addition, the CE requires the linkage of all stakeholders as shown by Figure 1. This has been discussed in some detail by Reuter and Bartie (2019) and Reuter et al. (2019). Copper and all its associated technology elements is one of the key enabling metals that is an economical copper colored thread through CE society (Reuter & Kojo, 2014). The Metal Wheel (Figure 2) shows the linkage of and recovery of various elements associated with copper and other carrier metals. This reveals that copper acts as an important carrier metal because of its properties i.e. the wealth of technology elements it carries from geological ores, but also its capacity to act as solvent of valuable elements and thence a key closer of various complexly connected element and material cycles when these technology elements are released during copper refining. The same applies to all other carrier metals of modern CE society as shown for example recently in a lead policy brief (Blanpain, Reuter & Malfliet, 2019).

Jan 1, 2019

By Euler M. De Souza

"This paper presents a study developed to assess the potential use of salt tailings as backfill to control surface subsidence and as a mine bulkhead used to isolate areas of potential brine inflows. A series of index tests, centrifuge model tests and quasi-static creep consolidation tests were performed to evaluate the creep and consolidation properties of salt backfl1l and to evaluate the effect of brine inflow and brine infiltration on backfill behaviour. The centrifuge models were specifically designed to study the mechanical behaviour of salt backfill under the influence of brine inflow and long-term creep. Test results indicated that salt tailings could be applied underground as a bulkhead to seal off areas of potential inflow with the additional advantage of controlling room closure and local back instability. It is hoped that this study will assist mine planners to develop contingency plans to control brine inflow occurrences. IntroductionThe use of salt tailings as backfill is a technique that would assist in the control of potential brine inflows and surface subsidence, and would have a very positive impact on the long term adverse environmental effects associated with surface salt tailings disposal. A centrifuge testing program was designed to evaluate the behaviour of salt tailings as backfill; the effectiveness of salt backfill as a bulkhead used to isolate areas of potential brine inflow and the potential use of salt backfill to control surface subsidence. The testing program was also used to evaluate the creep-consolidation properties of salt backfill and to evaluate the effect of brine inflow and brine infiltration on backfill behaviour. This paper presents the results of the experimental centrifuge testing program and a comparison of results with models tested under I g using an electrohydraulic servo-controlled loading frame (MTS) and a creep consolidation cell. Applicability of the results to practical underground soft rock mining is also discussed.The centrifuge model tests indicated that salt tailings could be applied underground as bulkheads to seal off areas of potential inflow with the additional advantage of controlling room closure and local back instability. Because the applied stresses (1.2 MPa) and fill consolidation were relatively low, the centrifuge simulated bulkhead did not retain all of the inflow brine. At typical field stresses it is expected that the fill would be able to seal off panels with brine inflows. Further testing at higher stresses are suggested to determine the consolidation and stress levels at which the fill would completely retain any potential brine inflow head and positively act as mine bulkhead."

Jan 1, 1994

By P. I. Laforest, M. S. Moats

"Antimony in smelted copper anodes has been shown to cause problems in electrorefining including brittleness of starter sheets. In order to improve deposit properties, a study was conducted examining the effect of anode chemistry on cathode ductility and electrolyte chemistry. Two industrial anodes with different molar ratios of As/(Sb+Bi) were used in laboratory electrorefining experiments with commercial electrolyte, and the addition of commercial glue and Avitone. The ductility of 21-hr copper deposits was evaluated by a 180° bend test. X-ray diffraction (XRD) and metallography were performed on unbent specimens to characterize the deposit structure. Increasing the anode As/(Sb+Bi) molar ratio from 0.54 to 3.8 resulted in an increase, on average, from four to eight bends to failure in cathode material produced. Significantly lower concentration of antimony (V) in the electrolyte was detected when operating with the higher molar ratio anode. The presence of (111) and (200) planes was noted in cathode material produced from the higher molar ratio anode suggesting that mixed growth character could be responsible for the observed increase in bend test results. The ductility of the starter sheet materials was improved by a higher anode molar ratio.INTRODUCTIONThe presence of antimony in copper electrorefining electrolyte has been reported to cause problems in cathode production (Hiskey, 2012; Peng, Zheng & Chen, 2012; Wang, Chen, Zhou-Lan & Lian-Sheng, 2006; Wang, Chen, Zhou-Lan, Wang, Xiao & Zhang, 2010; Wang, Chen, Zhou-Lan, Wang, Xiao & Tang, 2011; Wesstrom, 2014). To better understand the impact of antimony, laboratory scale electrorefining experiments were conducted using industrial inputs (anodes, cathodes and electrolyte). The influences of anode chemistry on the valences of antimony and arsenic in the electrolyte were monitored and correlated to physical cathode characteristics, such as a bend test to failure and crystallographic orientation.Commercially, starter sheets are produced by electrorefining impure cast copper anodes onto titanium blanks. The starter sheets are then hung in an electrorefining or electrowinning cell using loops of bent starter sheet material. These loops, in the absence of sufficient ductility, fail resulting in cathodes falling into the electrolysis cells. It is thought that the reduction in ductility can be related to anode composition; in particular, the molar ratio of arsenic to antimony plus bismuth As/(Sb+Bi). It has been stated that maintaining this ratio above 2:1 results in numerous improvements to electrorefining operations (Baltazar, Claessens & Thiriar, 1987; Kamath, Mitra, Radhakrishnan & Shetty, 2003; Krusmark, Young & Faro, 1995; Noguchi, Itoh & Nakamura, 1995; Wenzl, 2008)."

Jan 1, 2016

By G. Dodbiba, A. Otsuki, T. Fujita, J. Ponou, A. Shibayama

"The different types of nano to submicron particles, which are well-dispersed nano particles, coagulated nano particles or settled submicron particles, have been measured by the interactive force apparatus (IFA). The information is very useful for mineral processing treatment. The IFA can measure the particle size distribution in low to high concentration of particles in liquids and non-light transparent liquids. Here, mainly the emulsion and bubble size measurements are described.Emulsion (w/o type) is prepared with oil and water mixture. The nano to micro emulsion particle size is usually measured by light scattering method. The particle size distribution of emulsion of light oil measured by IFA agreed well with the one by the dynamic light scattering (DLS) method. The water size distribution in emulsions of gasoline is difficult for the small reflection index and C heavy oil is difficult for the black color by DLS method. The IFA can measure both emulsions.There are many methods to measure fine air bubbles, however, the finer nano size measurement apparatuses are DLS method and IFA. A “ghost” peak appeared in the large particle micron meter size in DLS method. The mean diameter in IFA is similar with DLS for the nano meter size. INTRODUCTIONParticle size distribution measurement of nano to submicron particle, emulsion and bubble size distribution are very useful for ultrafine particle separation and characterization of fine particles by the necessity of recent fine minerals separation (For example, Li et al.2016, Mikhlin et al.2016, Wang et al.2013). As for the size measurement of solid particles in liquids, three different types of nano to submicron particles, that are well-dispersed nano particles, coagulated nano particles or settled submicron particles, have been measured by the interactive force apparatus (IFA). The particle size distributions are compared with the one of dried particles measured by TEM or SEM. The well-dispersed nano particle size distribution by IFA is influenced by the nano size surfactant micelles and becomes smaller, when compared with the TEM result. The size distribution of nano size of magnetite particles in water is influenced by the isoelectric point and the mean diameter of coagulation becomes larger. The particle coagulation in diluted suspension is about 2nm smaller when compared with the higher concentration. The submicron nickel particle size distribution is well agreed the result by SEM. The coagulation effect is small in the submicron size of nickel powder in water (Fujita et al., 2013). In this paper, the emulsion and bubble size measurements are mainly described."

Jan 1, 2016

By N. Sarmady, Mei Li, N. C. Parson, W. J. Poole

"The mechanical behaviour of AA6082 is a function of the extrusion conditions and in particular, the quench rate after extrusion. It is well known that precipitation of Mg-Si phases on grain boundaries during quenching can negatively affect the ductility of the alloy. In this study, AA6082 alloys containing 0.5 wt. % Mn and 0.15 wt. % Cr were direct chill (DC) cast, homogenized and then extruded to produce 3 mm x 42 mm strips. The microstructure in the as-extruded strips was unrecrystallized due to the Zener-Smith drag from the Mn/Cr dispersoids. It was shown that a solution treatment of 5 minutes at 560°C did not significantly affecting the as-extruded microstructure but if the as-extruded strip was cold rolled prior to heating, recrystallization occurred concurrently with the solution treatment. As such, 3 initial microstructures were produced, i.e. unrecrystallized and recrystallized with a grain size of 9 and 40 µm. After the solution treatment, controlled cooling experiments were conducted using the Gleeble 3500 thermomechanical simulator with cooling rates of 10, 25, 80°C/s as well as water quenched. The mechanical properties (e.g. yield stress, fracture stress and fracture strain) were determined from tensile tests for the different combinations of initial microstructure and cooling rate. The relationship between the quench rate and precipitation of Mg-Si phases on grain boundaries was examined by FEG-SEM. It was found that the yield stress decreased as the cooling rate decreased and that there was complex relationship between the fracture properties and the microstructure.INTRODUCTION As the automotive industry strives to reduce fuel consumption and CO2 emissions with the goal of reducing the environmental impact, there is a need for lighter vehicles. As a result, aluminum alloys are gaining popularity to replace steel parts as structural components. An exemplar of this is the Ford F-150 pickup truck which has an aluminum body and is ˜750 pounds lighter than the previous steel version of the vehicle. The structure includes a mix of aluminum sheet, extrusions and cast alloys. The current research is concerned with the performance of aluminum extrusions in applications such as side rails, crash tubes and other structural parts. These components experience a combination of bending, stretching and folding both during the forming of the part and in service, e.g. crash of a vehicle. There is a need to have detailed information on the influence of processing on final material performance, in particular the cooling rate after extrusion."

Jan 1, 2018

By P. Hansman

"Place Dome Canada's Detour Lake Mine is a low-grade gold producer located in northeastern Ontario. Production is targeted for 2850 tonnes of ore per day. As reserves and mining areas continued to be found below and far to the west of the shaft (Fig. 1), it became necessary to review and upgrade the materials handling facilities. This paper deals with the selection, design and construction of an underground crusher and conveyor system capable of handling up to 450 tonnes per hour from the lowest existing level in the mine.BackgroundThe Detour Lake mine site is accessed via secondary Highway 652 which runs northeast out of Cochrane, Ontario. The road consists of 200 Ian of hard top followed by 100 Ian of well maintained gravel to the mine site. A 1500 m airstrip is maintained at the mine site for emergency use. Prior to 1991, the workforce was flown to and from the mine site. Crews were now bused to the site from Timmins. Remnants of a winter road exist to the southeast which at one time ended in La Sarre, Quebec. This was the route used to haul bulk items during the construction period and early production years.A town site has not been established at the site for the current operations. Instead, a rotational scheme is being utilized whereby most personnel will work seven days on site followed by seven days off site. For some employees, however, the work week is termed as a four/three schedule where they work 42 hours between Monday at 10:00 a.m. and Thursday at 4:00 p.m. with the following three days off. All surface employees and maintenance employees underground work 12-hour shifts. All underground employees work a lOV2-hour shift. Supervisors work a similar schedule as their crews, however, other staff may overlap their rotation during the week.A five-compartment shaft was sunk in 1984 from surface to the 610 m elevation. Shaft stations were established at the 120 m, 260 m, 360 m, 460 m, and 560 m levels. The cage compartment consists of a single deck, 4O-man cage in balance with a counterweight. The cage hoist is an Ingersoll-Rand 10H and is regulated to travel at 4.1 m/s. Two 9 t skips operate in balance at a travel speed of 7.1 mls. The skip hoist is a 3.05 m drum Nordberg. Both hoists are automated to function without a hoistman during normal skipping and cage service runs."

Jan 1, 1995

By Q. Ricoux, F. Goettmann, A. Maihatchi

"Electrodeposition processes are widely used in the metallurgical industry to produce, extract and refine metals from various feed materials. However, raw materials used to provide non-ferrous metals often contain high amounts of iron. In the presence of iron, while metals are plated at the cathode, electrowinning processes produce corrosive and highly oxidative ferric ions at the anode that are harmful for the process sustainability. In fact, these ferric ions cause dramatic current efficiency loss, induce high maintenance expenditures to limit the corrosion of devices and it results in the formation of impure and dendritic deposits on the cathode. Consequently, the management of iron in electrodeposition process became a major issue in non-ferrous metals production. Actually, numerous methods have been developed to limit the ferric ion concentration in the electrolyte or, at least, to limit its harmful effect. Many methods aim to limit the iron(III) concentration in the electrolyte, generally by coupling electrowinning to extraction process such as solvent extraction (SX) (Bender & Emmerich, 2015), ion exchange (IX) (Gula, Dreisinger, & Horwitz, 1996) or cementation (Kust, 1979) processes to remove ferric ions. Other routes consist of (i) using the ferric ions oxidant properties to leach raw materials, either directly in the electrolytic cell (Fanta & Tributsch, 1975) or through a secondary circuit (Cain, 1950), or (ii) reducing ferric ions through periodic reversal of direct current to enhance the formation of Fe2+ (Loutfy & Bharucha, 1980). On the other side of the spectrum, papers discuss methods to valorize the iron from by-products of the non-ferrous metal industry, that generates vast quantities of iron containing wastes (A. Agrawal, Sahu, & Pandey, 2004). Many studies on iron electroplating and electrolytic iron production from ores have been carried out (Cain, 1950; Mostad, Rolseth, & Thonstad, 2008), but very few have been conducted on waste or by-products. Therefore, we propose to build on the previous literature review to develop a process for the production of electrolytic iron from by-products.INTRODUCTIONNon-ferrous metals and their alloys are used in a large variety of applications. Aluminum and titanium are used for their strength, light weight and corrosion resistant properties in structural applications. Copper has been used in various applications requiring high thermal and electrical conductivity, as kitchen products and electrical wires. Nickel and zinc are commonly used as plating materials; nickel offers a wide range of working temperature and zinc is used for steel plating. Gold, silver, and platinum group metals are used in electrical/electronic applications, jewelry and chemistry as catalysts."

Jan 1, 2016

By P. C. Holloway, M. J. Collins, K. R. Buban

Historically, there has been little incentive to process copper-arsenic concentrates by leaching, rather than via established smelting operations. However, with ever tightening environmental emission standards and more arseniferous concentrates being produced, increasingly sophisticated and upgraded off- gas handling facilities are required in smelting operations, generating greater quantities of challenging metallurgical dust. In this context, oxidative pressure leaching offers distinct advantages. The current state of pressure leach technology delivers high extractions from copper concentrates, while producing an environmentally stable process residue, without atmospheric emissions of sulphur dioxide or arsenic. However, as was shown in an earlier study, copper extractions and environmental leach residue stability are impacted negatively by arsenic levels above 2.5 to 3.0 wt%. In further studies on pressure leaching of copper concentrates, Sherritt has developed process conditions that allow even highly arseniferous (> 7 wt% As) feed materials to be converted into environmentally stable residues, with excellent copper extractions. At the same time, pressure leach residues can be generated that are amenable to silver recovery via direct cyanidation, without pre-treatment by lime boiling or hot curing. The results of pilot plant test work are discussed. INTRODUCTION As the production of copper has expanded over the years, resource exploitation has extended beyond relatively clean, high grade and easily accessible ores, and copper sulphide concentrates increasingly come with higher levels of contaminants, such as As, Hg, Sb and Bi, and lower copper and sulphide sulphur concentrations. However, as concerns on the impact of the emission of such contaminants into the natural environment have mounted, import/export restrictions have made the trading of copper concentrate more difficult, and, in particular, the export of concentrates with greater than 0.5 wt% As; under ever tightening environmental emission standards, these lower quality concentrates can be a significant strain on the off-gas handling facilities in smelting operations. The processing of arsenic bearing copper concentrates is, therefore, an increasing challenge as copper producers seek to exploit more complex mineralization and to extend the life of their operations. In this environment, processing arsenical copper concentrates with high temperature pressure leaching (>200°C) must be considered as an alternative to pyrometallurgical processing. Leaching kinetics for copper minerals at these temperatures are rapid and acid is generated for potential use in heap leach operations. Pressure leaching of copper concentrates eliminates gaseous emissions of arsenic and sulphur, while generating environmentally stable residues, as measured by the Toxicity Characteristic Leach Procedure (TCLP) (Kalanchey et al., 2007). Both medium and high temperature pressure leaching of copper concentrates have also proven themselves technically on an industrial scale (Marsden et al., 2004) with high copper recoveries.

Jan 1, 2019