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By Denis Bois

La Bolivie est un pays en développement qui compte une tradition minière qui précède même l?établissement espagnol en Amérique. Pendant toutes ces années, l?exploitation minière s?est faite sans grands égards pour l?environnement. Au cours des dernières années cependant, le gouvernement bolivien a modifié ses lois afin de rendre nécessaire la prise en compte de l?environnement dans le processus d?exploitation d?une mine. Dans le cadre d?un projet MRN-ACDI1 visant à renforcer le secteur minier en Bolivie et ses retombées pour la population, l?URSTM2 a été mandaté pour développer et mettre en place un programme académique de gestion environnementale minière, basée sur l?expertise canadienne. Ce programme vise à renforcer les institutions académiques boliviennes responsables de la formation en environnement minier en Bolivie ainsi que les ministères et agences gouvernementales concernées.

May 1, 2001

By Lee W. T. Weitzel

This paper reviews the Falconbridge- SMRQ?s Raglan project in northern Quebec and the process that was used in developing its current long-term mine plan. Challenges were many and not only limited to the longevity of the project, numerous ore deposits (both underground and open pit), and a 40km property strike length. As a result of its remote northern location other factors such as progressive reclamation, leachable mine waste, water treatment, and waste management were also part of the plan. A combination of modern planning tools were used to formulate the plan including DataMine, Mine 2-4D, AutoMod Simulation, and an Excel based financial spreadsheet to bring the total plan together. The focus of this paper is to show the complexity of modern mine planning and associated economic modeling of mine processes.

May 1, 2002

By B. Oraee-Mirzamani

One the most important tasks after excavation of tunnels is the implementation and installation of a support system. Tunnel collapse poses a safety hazard and can cause worker injuries. In addition, it may have a severe economic impact because tunnel collapse can stop production and ore transportation. Therefore, an appropriate and well-designed support system is necessary for collapse prevention and to help stabilize the tunnels. In this research, we suggest a support system for the Parvade1 underground coal mine. The study case is a common mining roadway tunnel in the E1 longwall panel in this mine. To design an appropriate support system, we used the finite element method (Phase2 software). The results of this research can be used to design support systems for future tunnels in this mine and any coal mine that has similar conditions.

Aug 1, 2013

By W. Beres, R. E. Miller, B. Shiari, L. R. Zhao

A dynamic multiscale simulation method has been developed to study the material scratching processes on nanoscale single crystals. The model simultaneously captures the atomistic mechanisms near the free surface and the long range mobility of dislocations and their interactions, without the computational cost of full atomistic simulations. The method also permits the simulation of system sizes that are approaching experimentally accessible systems, albeit in 2D. Simulations are performed on single crystal aluminum to study the atomistic details, surface evolution, and generation and propagation of dislocations for a variety of scratching depths at room temperature. Simulations demonstrate the power of the developed method in capturing both long-range dislocation plasticity and short-range atomistic phenomena during tool advance. Variations of scratching normal and tangential forces are investigated and related to plastic deformation and dislocations generation during the simulation process.

Jan 1, 2006

By N. Verbaan, Ph. Henry, S. Lamotte

Hydrometal(lurgy) provides an adequate technology to reintroduce otherwise lost metal units into the industrial cycle, thereby saving resources and energy, while keeping the environment cleaner. Three case studies at an integrated hydrometallurgical recycling facility (Hydrométal) in Belgium are discussed. (1) Non-ferrous leach residues are treated by a leach-SX process to recover their minor metals (Ge) contents. The remaining acid waste solution is used by the fertilizer industry nearby. (2) Residual low quality acid and caustic are used in the processing of zinc industry cements to produce copper, nickel, cobalt and zinc concentrates by several consecutive selective leach - precipitation processes. (3) Copper anode slimes are treated and their precious metal contents are recovered. Depending on the composition of the slimes, separate or combined concentrates of copper, bismuth, tellurium/selenium and silver/precious metals can be produced.

Jan 1, 2004

During industrial copper electrowinning, a fraction of the electrolyte becomes entrained with the oxygen gas bubbles that are evolved at the anodes. The fraction of entrained bubbles increases from the bottom of the anode to the top, resulting in a bubble distribution that appears as an inverted wedge between the cathode and anode. Since the bubbles act as insulating spheres, electrolyte resistance increases from the bottom of the electrodes to the top resulting in correspondingly higher local current densities and uneven copper growth along the cathode. To counter-act the inherent tendency toward excessive copper growth near the bottom of the cathodes, the use of tapered anodes was examined. The potential improvement in cathode current distribution was evaluated by comparing the primary current distributions for 2-D computer models of a copper electrowinning cell with plate shaped anodes against one with tapered anodes.

Jan 1, 2007

By S. Kawai

Natural convective flow of the electrolyte solution plays an important role in several electrochemical systems. Copper refining electrolysis is the most important industrial process to produce high purity copper on large scale. Turbulent natural convection develops along vertical plane copper electrodes installed in an unstirred electrolyte accompanying with the electrochemical deposition and dissolution of copper during the electrolysis. It introduces the electrolyte stratification phenomenon. Thus, the electrolyte is circulated in a special way depending on each electrorefining tankhouse. The theoretical discussion is indispensable to understand the coupling phenomenon between the ionic mass transfer rate and the morphological variations of electrodeposited copper. In present study, the mass transfer rate of both Cu2+ and H+ ions as well as the momentum transfer rate is numerically analyzed accompanying with the turbulent natural convection along 1 m high Cu metal electrode surface.

Jan 1, 2007

By T. Takahashi, K. Oyamada, Y. Miyata, T. Isoo

The carbonation reaction of steelmaking slag has been known for many years. However, the size of blocks manufactured from this by-product material has been limited due to the difficulty of achieving a uniform reaction throughout the block. Using newly developed conditions, large porous slag blocks (1.0 x 1.0 x 0.5 m) were produced by car¬bonation of steelmaking slag with the optimum amount of water and supplying CO2 deep into slag powder compacted in molds. The development of these blocks has great poten-tial to solve the problem of slag utilization, for example, by recycling slag in large car¬bonated blocks for artificial fish reefs and seaweed cultivation beds. This paper de¬scribes the carbonation reaction, the new process for producing large slag blocks, and the utilization of blocks in past and recent years.

Jan 1, 2004

By F. Golestani-Fard, A. A. Nourbakhsh

In this paper microstructural development of nitride-Bonded SIC refractories is reported in presence of Al203, Mg() and Urea additives .The samples were prepared by mixing, shaping and firing at 1400-1500°c in a controlled atmosphere furnace. Phase analysis, microscopic observation and mechanical evaluation were taken for microstructural investigations. The strength of samples doped with Al203 was first increased and then decreased at higher amount of Al2O3 additions. The addition of MgO decreased the strength while the urea showed an improving effect on strength. These phenomena could be attributed to microstructural evolution and mainly to liquid phase formation and grain morphology. It was found that the additives such as Al203, MO and urea could modify the microstructure in terms of phase formation and texture modification, which in terms influences the mechanical behavior.

Jan 1, 2004

By H. Asgari, A. G. Odeshi, J. A. Szpunar

In the present study, the dynamic response of AZ and AE cast magnesium alloys to shock loading, are compared for strain rates ranging between 900 and 1200 s-1. Texture measurements showed that after shock loading, the (00.2) basal texture component of both alloys was strengthened. However, the strengthening magnitude was higher for AE samples. Also, it was observed that the twinning fraction decreased in both alloys with increase in the amount of alloying elements. In addition, cracks are formed at the interface between matrix and second phase particles in the AZ alloys. However, crack nucleation and fracture in AE alloys occurred at the sites where twins accumulated. Furthermore, analysis of the dynamic mechanical behaviors showed that the ductility of AE grade is higher than that of AZ alloy for all strain rates used in this research. This difference was explained by differences in deformation mechanisms of these alloys.

Jan 1, 2014

By P. C. Sui

Numerical investigation and parametric simulations of the coupled electrical conduction and mass diffusion in the GDL of a PEMFC are reported. The coupled transport is solved using a 2D, "under-the-rib" computational domain for the cathode GDL. The current density on the GDL/catalyst layer interface, which constitutes one of the boundary conditions for the GDL domain and reflects the activation overpotential in the catalyst layer and the ohmic loss in the membrane, is solved iteratively using a novel numerical algorithm. A parametric study is performed to investigate the effects on current density distribution of various operating conditions such as oxygen concentration and membrane resistance, and of design factors such as GDL geometry, anisotropic transport properties, and deformation under the land area. The results show that the current density distribution under the land area can be dominated by either electron transport or mass transport, depending on the operating regime.

Jan 1, 2005

By Raynald Vézina, Richard Leclerc, Jean Boissonnault, Louis P. Gignac, Gérald Veillette

Since mid-1989, Cambior has increased its producing gold mines from four to six, having acquired the Chima Mine and brought the Silidor Mine onstream. In June 1990, the company announced that the Mouska project would also be put into production. Gold production reached almost 190 000 ounces in 1989 and is expected to exceed 220 000 ounces this year. Cambior has also a non-gold operation with an interest of 50% in the Niobec Mine and has recently signed an option agreement in the development of the Lac Knife graphite deposit in northeastern Quebec. During the past year, the company has extended its exploration activities to the United States and Indonesia, and now has interests in nearly 80 properties. Last May, Cambior signed an option agreement with Golden Star for a gold deposit in Guyana, the OMAI Project, containing at least 2 000 000 ounces of gold in situ.

Jan 1, 1990

By Yongqiang Liu

Background For refractory gold ores with high carbonate contents ! Acid pressure oxidation ! High acid consumption (if low sulfur content) ! Low oxidation efficiency due to CO2 in autoclave ! Problems with slimy precipitates (gypsum, etc.) ! Alkaline pressure oxidation ! Difficulty in fixing arsenic ! Low gold dissolution due to iron hydroxides/oxides coating ! High reagent costs Summary ! Carbonate and sulfide minerals had similar floatability across the pH range tested (5 - 12) using sodium oleate as a collector; ! Thioglycollic acid or citric acid depressed the flotation of pyrite but could not depress chalcopyrite when used alone; ! Combination of thioglycollic acid and citric acid had a much stronger depressive effect, and the mixture depressed chalcopyrite as well as pyrite between pH 8 and 11 without affecting the flotation of calcite and dolomite; ! Calcite could be separated from chalcopyrite and pyrite; dolomite could be separated from pyrite but not from chalcopyrite under the tested conditions.

Apr 1, 2005

By V. Pouyafar

In recent years semi-solid processing of steel alloys has gain more attention among researchers. Production of high quality complex steel parts with higher mechanical properties is the final goal for all these researches. A thorough understanding of the flow behavior of the metal under investigation is the key for a successful process design. The material used in this research is M2 tool steel. The experiments were performed using a Searl-type concentric cylindrical rheometer which is specially designed for high temperature rheological measurements up to 1500 ºC. The rheological techniques were consisted of continuous cooling experiments and isothermal holding and also shear rate step change experiments for different solid fractions. Based on the rheological data a single phase thixotropic model has been derived and adopted to the measured data. The state of the microstructure has been applied through a structural parameter. The model fits well with the experiments.

Oct 1, 2011

By T. Maruyama

Tamano Refinery started its operation in 1972 with the cathode production capacity of 84,000 tons per year. After several expansions, the production capacity increased to 228,000 tons per year in 2001. In this paper, we are introducing our next expansion projects starting October 2006. The project expands the production capacity of cathode from 228,000 tons to 260,000 tons per year. The main modification of this project is the conversion to the ISA process and the installation of additional seventy-two cells in the No.2 Tankhouse. The No.1 Tankhouse remains the same, using the conventional process. Half of our starting sheet cells are converted to commercial cells. The other expansions are to enlarge our purification plant. And the incidental facilities are enlarged, for example, circulation tanks, heat exchangers, filtration system, etc. Finally, this paper describes those improvements to our refinery performance and preparing for future expansions.

Jan 1, 2007

By Masaru Kato

The plated gold being used by the electronics industry can be broadly classified into two categories: soft gold and hard gold. Soft gold is used for circuit metallization and for bonding semiconductor chips, while hard gold is indispensable as the contact material on electrical connectors, electromechanical relays, and printed circuit boards. The traditional baths from which to plate soft gold as well as hard gold contain the cyanide complex, [Au(CN)2]-, as the source of gold, which liberates free cyanide ions during the plating. The free cyanide is not only highly toxic but also attacks photoresists used to delineate circuit patterns and bonding pads. For these reasons, non-cyanide baths are in use to plate soft gold, whereas hard gold can be plated only from cyanide baths at present. In this presentation, the current status of both electrolytic and electroless non-cyanide processes for plating soft gold will be reviewed.

Oct 1, 2003

By R. A. Frith

"Belts of Yellowknife Supergroup volcanic and sedimentary strata in the Slave Structural Province are separated by granitoid complexes. The strata and most intrusive rocks are 2.7 and 2.5 Ga old, but rocks around 3.1 Ga have been recognized in some of the complexes and are believed to represent a once-extensive sialic crust. Volcanics were erupted along rifts in this crust and the rifts became sites of crustal foundering and the development of troughs that filled with turbidites of volcanic and granitoid provenance. Present margins of the granitoid complexes may be close to the original margins of deposition of volcanics, with associated mineral deposits, and close to the thickest parts of basins of sedimentation.The Hackett River volcanic belt extends 100 kilometres between Mara River and Back River and is crudely S-shaped, with a northern sector surrounding a core of granitoid basement rocks, a northeasterly facin g central sector and a southerly facing southern sector. Up to 8 kilometres of andesitic volcanics with intercalated felsi c volcanic rocks are preserved within the central sector. The f elsic rocks include thick lenses of volcaniclastics with large, quartz-eye-bearing clasts, but the known metal deposits are not associated with these. Both of the deposit areas, the Hackett River area in the northern domal sector and the 'A itch ' Lake area 40 kilometres to the south in the central sector, are near the tops of relatively thin atypical volcanic sequences above suspected basement rocks. The Yava deposit near 'A itch , Lake overlies a unit of subaerially deposited, welded, andesit ic ash flows and the Hack ett River deposits overlie highly metamorphosed volcaniclastic rocks that include suspected ignimbrites.The deposits are notably argentijerous and lead-rich. They consist of stratigraphically zoned sheet-like bodies of iron sulphides, sphalerite, galena and chalcopyrite underlain by altered rocks containing chalcopyrite stringers. The Yava deposit was formed where hydrothermal fluids exuded through the fractured floor of a flooded caldera basin. The Hackett River deposits may have been formed in a similar setting and it is not inconceivable that all the known deposits in the belt were formed in a single large caldera basin, although there is no independent evidence for the required major fault separation between the Hackett River dome and the 'Aitch' Lake area."

Jan 1, 1980

By J. P. Sims

Abstract - Ultramafic to mafic igneous intrusions of the Las Aguilas district form part of a belt of generally mafic plutonic bodies within medium- and high-grade early Paleozoic metamorphic rocks in the southern Sierras Pampeanas region, Province of San Luis. The intrusions host the largest known nickel sulfide resource in Argentina and contain significant Cu, Co and PGE mineralization (2.2 Mt at 0.5% Ni, 0.5% Cu, 0.035% Co). Sulfides at Las Aguilas Este, one of two principal mineralized zones, are hosted by a body comprising subvertically dipping units of predominantly orthopyroxenite and melanorite cumulate, with lesser dunite, harzburgite, norite, leuconorite, and amphibolite. The units are zoned horizontally from ultramafic to mafic compositions, representing primary magmatic zonation away from an original base or side of the intrusion. Intercumulus nettextured and disseminated aggregates of pyrrhotite-chalcopyrite-pentlandite are concentrated in the peridotitic zones and extend into melanorite. Whole rock major and trace element compositions, and olivine chemistry, indicate that the parent magma was gabbroic/basaltic with 100 (Mg/Mg+Fe) near 59, and resembles tholeiitic magmas generated in subduction-related arc, or back-arc settings. Unusually aluminous Cr-bearing spinel is compositionally similar to those in some synorogenic mafic/ultramafic plutons in magmatic arc settings. Relatively Ni-depleted olivines and low Cu/Pd ratios are indicative of magmatic sulfide segregation early in the crystallization of the magma. Early orthopyroxene saturation and virtual lack of clinopyroxene, in conjunction with sulfur isotope values up to +6.6 ‰, spinel compositions, and presence of graphite, phlogopite and magmatic hornblende, all attest to probable crustal contamination of the parent magma. Assimilation of crustal sulfur may have been crucial in the early attainment of sulfide saturation and resultant formation of magmatic Ni-Cu sulfide mineralization. Fabrics, textures and mineralogy of the intrusions and country rocks and U-Pb zircon dating indicate syntectonic-synmetamorphic emplacement at 478±6 Ma during the Famatinian (Ordovician) orogeny. Minor to locally significant recrystallization and deformation of mafic-ultramafic rocks and redistribution of sulfides and PGE occurred during and following the Famatinian orogeny. The Las Aguilas intrusion is one of several tholeiitic mafic-ultramafic intrusive complexes within an Ordovician arc - back-arc system in the Sierras Pampeanas. Aeromagnetic datasets and regional mapping suggest there is further potential for intrusion-hosted Ni-Cu mineralization along this eroded magmatic arc.

Jan 1, 1999

By A. R. MacPherson

"This paper considers four aspects of autogenous grinding. Part 1 discusses statements on power efficiency of autogenous grinding compared to conventional crushing and grinding systems. It also demonstrates how high-power efficiency can be obtained from autogenous grinding systems. Part 2 considers a simple method of testing ores to determine the type of autogenous plant which can treat these ores on a commercial basis. A comparison of testing for simple small plants vs large plants or complex ores is included. Part 3 considers important aspects which have to be considered in proper design of an autogenous grinding system. Part 4 discusses problem ores and how they can be treated in an autogenous system. INTRODUCTIONAfter about 35 years of using autogenous grinding plants in the mining industry, it is perhaps time to review where we are with this, by now, relatively old development. Autogenous grinding in this paper means grinding run-of-mine ore by fully autogenous means or by using a ball charge to assist the grinding (semi-autogenous). Also, autogenous grinding can be eitherby dry or wet.The use of autogenous grinding in the fifties was making its slow start, and it was not until the sixties that more of the mining industry would consider its use . By the seventies, most builders of new plants would have considered autogenous grinding, whether they used it or not, in the final design.In the eighties, most large plants use autogenous mills and to reduce over-all operating costs, many older conventional plants are now looking and actually retrofitting these old plants with autogenous grinding mills.It is evident that many misconceptions concerning autogenous grinding are still current. Some come from improperly designed plants which result from poor test work. There are many considerations in the proper design of autogenous plants. Some ores have been found to give problems even in a well designed plant. These ore types are beginning to be classified and recognition in the test stage allows steps to be taken in the design so that these ores can be efficiently handled in autogenous grinding plants.Therefore, this paper will address the following aspects of autogenous grinding:1. Misconceptions regarding autogenous grinding.2. Testing of ores to ensure a well designed commercial plant.3. Important considerations in mill design.4. Difficult ores, their recognition and types of design to handle such ores."

Jan 1, 1989

By Zhang Wei

"Pulang Copper Mine is located in Shangri-La county, Diqing Prefecture, Yunnan Province, with currently defined copper reserve of 4.8 million tonnes of copper metal and an average grade of 0.34% Cu. The mineralized zone in a dome shape is 2,300 m long, 600–800 m wide, and 1,000 m high. At present, the project is at a construction phase, with a first-stage mining and processing capacity of 12.5 million tonnes of ore per year. Ore haulage is planned via a drift and ore pass development system. The cavability of mineralized rock is classified into three types (II, III, IV), with type III accounting for more than 98% of the total reserves. The cavability of the orebody is generally considered to be good and block caving mining method is planned. Semi-autogenous grinding and ball milling are adopted for the mineral processing. The tailing dam construction method is a center-line method.INTRODUCTIONAs the China's largest underground nonferrous mine, Pulang Copper Mine is located in the northeast of Shangri-La County, Diqing Prefecture, Yunnan Province, China. It is 62 km northeast of Shangri-La city. Shangri-La County is a Tibetan-dominated, multiple-ethnic region, with a population of approximately 163,000 in 2009. The county is rich in mineral and water resources, thriving with tourism. Its economy is also dominated by agriculture. To date, the defined copper reserves at the Pulang Copper Mine is 4.8 million tonnes of copper metal at an average grade of 0.34% Cu. In addition, it contains a gold reserve of 145 tonnes, a silver reserve of 2,754 tonnes, a molybdenum reserve of 0.19 million tonnes, and a sulphur reserve of 10.5 million tonnes. The first-stage mining and processing capacity is planned at 12.5 million tonnes of ore per year. When it ramps up to this production rate, the mine will produce copper concentrate containing 50,000 tonnes of copper and molybdenum concentrate containing 968 tonnes of molybdenum. A drift and ore pass system is planned for ore haulage and mining method is a block caving method. Semi-autogenous grinding and ball milling are considered for mineral processing. A center line dam is adopted for the tailing dam construction (Feng, 2010; Feng, Li, & Wang, 2011; China Enfi Engineering Corporation, 2014)."

Jan 1, 2016