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By E. You

Kennecott Utah Copper Refinery and Outokumpu Technology have developed a wireless Electrolytic Cell Monitor (CellSensor) system to monitor cell voltage and temperature. The system is based on a robust self-organizing and self-healing wireless network with a very reliable redundant structure. The microprocessor controlled CellSensor device operates off a small amount of energy harvested from the cell bus and requires no external power source. The radio works in the 2.4 GHz international ISM band using robust Spread Spectrum technology. The CellSensor does not require end user calibration of either the voltage or temperature sensors and accuracy is superior to previous systems. The on-board computation power allows digital filtering of the cell voltage signal which results in very high quality data. The system requires much less maintenance than conventional hardwired systems and is intrinsically safer since no high voltage isolation is required. The advanced diagnostic functions allow the device to determine if the bus tap contact is degrading. The CellSensor can also be used for monitoring electrowinning (EW) cells for a variety of metals. CellSensor have been tested for over two years at the Kennecott Utah Copper and Boliden Harjavalta Pori refineries. The CellSensor system is now commercially available through Outokumpu Technology.

Jan 1, 2007

By Andreea Catalina Gluhoi

The oxidation of propylene and methane has been investigated over two series of Au/MOx/Al2O3 and Au/MIOx/MIIOx/Al2O3 catalysts (M, MI, MII =Li, Rb, Mg, Mn, Ce, Zr). Whereas the effect of the presence of MOx or MOI x/MOII x on the oxidation of methane is relatively small, a large enhancement in activity is observed for propylene oxidation. Synergistic effects have been observed by combining ceria or a transition metal oxide (high oxygen storage capacity) with an (earth) alkali metal oxide.

Oct 1, 2003

By M. D. Viera

The purpose of the study is to show, through real cases of companies in Chile, the different problems concerning valuing or economically appraising a mining ore resource with the traditional techniques. The study demonstrates that, with the risk analysis and real options theory application, one could determine the most probable value for a mining resource or mining business, and the risks cover of uncertainty scenarios. The study discusses different methods and criteria employed in the ore resource evaluation or mining assets. It also shows a comparative analysis of the different methods in order to explain various distortions, errors, risks and imprecisions of each of them. the companies are becoming aware of the risks' importance and the impact they have on the commercial value and resource estimation models. Now, the real options are the techniques that somehow make it possible to value and control the risk cover of the business. The company valuation could help respond questions like: ? How much is my business worth? ? How much has the investment profitability of my business been? What could be done to improve this profitability and create value?

Jan 1, 2007

By Fengxiang He, T. Meadowcroft, Yanjun Zhang

Slag from the zinc fuming furnaces contains about 3 percent zinc and 0.1 percent lead. The paper outlines several experimental techniques for recovering these components from liquid fumer slag. The simplest method, remelting followed by a hold period, indicated that a substantial fraction of the metal values was recoverable as a result of fuming into the gas phase, presumable by reduction of the metal ions by divalent iron ions. Following on from this, slag samples were equilibrated with copper, chosen because the activity coefficients of zinc and lead in copper are very low. This improved metal recovery, with substantial amounts of lead and zinc reporting to the liquid copper as well as to the fume. Application of an electrical emf across the slag-metal interface, using a graphite anode and a liquid copper cathode, resulted in further gains in metal recovery.

Jan 1, 2004

By D. P. Wilkinson

There are significant global environmental and supply issues with existing energy paths today . Global emission and fuel regulations, global fuel and power structure, energy security, and cost are driving new technology and non-conventional approaches . Fuel cells will play a significant role in the strategy to effect positive global change, increase fuel efficiency and decrease dependency on traditional fossil fuels. Fuel cells do not require recharging, just refuelling and a wide range of fuels are possible with hydrogen being the most desirable. Technical progress as well as investments in fuel cells for transportation, stationary, portable, and micro fuel cell applications have been dramatic in recent years. The present view is very optimistic for fuel cell power generation and the status is presently at the field trial level, or early commercialization stage, moving into volume commercialization. A number of demonstration programs are in progress worldwide such as the California Fuel Cell Partnership which involves original equipment manufacturers (OEMs), fuel providers, transit authorities, state and government bodies. Fuel cells and a hydrogen infrastructure are key to a long-term solution to global energy issues. Fuel cells will need to be competitive on an economic basis with the established and highly developed internal combustion engine and other forms of power generation There has been significant technical progress in a number of fuel cell areas including power density, transient / dynamic response, multiple fuels, cost potential, reliability and durability. However, significant technology gaps still remain today. This presentation will focus on the status and progress of the fuel cell today, current fuel cell research and development, the challenges going forward, and the future view of the fuel cell and it's impact on global energy issues.

Jan 1, 2005

By M. Rigaud, N. Zhou, K. Sankaranarayanane, X. Zhou

The effect of amount and type of dispersants on the rheological behaviour of bauxite-based low-cement castables has been studied in detail. The rheological properties: flow resistance and torque viscosity, as measured by a rheometer, are found to be strongly influenced by the amount and type of dispersants. In the present investigation, a mix containing sodium hexametaphosphate, at an optimal level, is observed to be theologically superior at the given experimental conditions.

Jan 1, 2004

By Patrick Andrieux

Cet article décrit une nouvelle méthodologie qui quantifie les chances de succès d’un sautage confiné à grande échelle de relaxation des contraintes dans un pilier de mine souterraine, pour un massif rocheux et un régime de contraintes donnés. La méthode est basée sur un nouveau paramètre nommé « Indice de relâchement », qui considère huit paramètres géomécaniques et de forage-sautage qui contrôlent ultimement le procédé. La rétro-analyse d’études de cas bien documentées a démontré que l’approche peut indiquer de manière fiable si une situation donnée de hautes contraintes de terrain est susceptible d’être améliorée par un tir de relâchement confiné à grande échelle et si le design proposé est adéquat pour atteindre ce but.

Jan 1, 2009

By Michel Aubertin

Using mine wastes as backfilling material for underground stopes has been a common practice for more than 60 years. Waste rock and tailings are used as filling materials because they are available at a reasonable cost to support the rock walls. Backfilling is also very advantageous because it reduces the amount of mine waste disposal on the surface. In underground mines, the backfill must first ensure stability of the opening, while increasing recovery of ore and minimising dilution. It is thus critical to accurately evaluate the pressures exerted on the walls and on the barricades placed near the base of the stope. In this presentation, existing solutions for evaluating the stresses on stope walls and barricades are briefly reviewed. The authors then present recently developed analytical solutions that take into account the stress transfer from the backfill to the walls in the stope and access drift. The stress state solution, which is based on arching theory, considers the influence of the stope geometry and barricade position within the drift. The method gives the pressure generated by partly or fully submerged backfill. The solutions apply shortly after backfill deposition, when the effect of pore water pressure cannot be neglected, and also for long term conditions under a fully drained state. Experimental testing and numerical modelling results are used to validate the proposed equations. Both numerical and analytical results show that the total pressure on barricades can be significantly increased by water pressure, while the effective stress is decreased (compared to dry or drained conditions). A discussion follows on the implications of the results for backfill applications.

Nov 1, 2008

By I. Mc Dougall, H. Joubert, G. de Villiers

The use of sidewall copper cooling systems to prolong furnace campaign life is becoming an accepted technology solution in the base metals industry. Tenova Pyromet has designed and installed a number of sidewall copper cooling systems in base metals furnaces, including the platinum industry. Apart from increasing the furnace campaign life through the formation of a stable freeze lining, a well-designed copper cooling system enables the plant operator to focus more on optimizing the process to achieve throughput and recovery targets, and to accommodate more varied and available concentrate feed blends. The paper discusses the design of sidewall copper cooling systems for copper smelting and converting furnaces to achieve the above objectives. More specifically, the design of copper cooling systems for top submerged lance furnaces are discussed. An overall increase in furnace heat losses has been raised as a concern for intensively cooled sidewalls. The paper explores the overall heat loss expectations for copper cooled furnaces versus traditional refractory lined furnaces. In addition, the potential use of alternative cooling media is discussed. INTRODUCTION Base metal smelting and converting furnace technologies have been evolving continuously over the past century to satisfy the need for higher throughput, improved efficiency, and longer campaign life. To accommodate these demands, in particular higher smelting intensity and throughput, furnace bath containment systems had to improve. The use of pure refractory lining systems has slowly made room for the use of more intensively cooled lining systems (Joubert, Nikolic, Bakker & Mc Dougall, 2016). These cooling systems evolved from external shell cooling, such as shower or film cooling, to copper plate coolers extending into the furnace refractory lining, and high intensity stave or panel coolers (Verscheure, Kyllo, Filzwieser, Blanpain & Wollants, 2006). Consequently, an increasing number of base metal smelting and converting furnaces are equipped with copper cooling systems, including flash furnaces (Bryk, Ryselin, Honkasalo, & Malmstrom, 1958; Yasuda, Motomura & Kawasaki, 2014; Marx, Shapiro & Henning, 2010), top submerged lance primary smelting and fuming furnaces (Bhappu, Larson & Tunis, 1994; Kim, Lee & Lee, 2000; MacRae & Steinborn, 2018), top submerged lance converting furnaces (Viviers & Hines, 2005; Nikolic, Hogg & Voigt, 2018), primary platinum smelting electric furnaces (Nelson, Stober, Ndlovu, De Villiers & Wanblad, 2005; Jones, 2005; Hundermark, De Villiers & Ndlovu, 2006; Mc Dougall, 2013), and electric slag cleaning furnaces (Joubert, Nourse, Masters & Hundermark, 2005).

Jan 1, 2019

By K. Wongpreedee

Recovery and recrystallization of Au wire can degrade strength and alter conductivity properties during exposure to elevated temperature. Au Deformation Processed Metal Metal Composites (Au DMMC's) are being developed for electronic applications requiring high conductivity and high strength. This paper discusses the relationships between microstructure, strength, and resistivity of Au DMMC's. It also presents the results of a recent study on the elevated temperature stability of Au DMMC's of several compositions. Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt DMMC samples were prepared by a powder metallurgy technique. All specimens were processed into wire by extrusion, swaging, and drawing. The smallest final diameter of these wires was 120 ?m. Thermal stability was analyzed by electrical resistivity measurements to determine the relation between transformation rates and time at elevated temperature. The extensive deformation used to produce these composites reshaped the initially equi-axed powder into filaments that are 30 to 100 nm in diameter and 16 to 180 mm in length. The small filament diameter confers high strength on the composite. The high conductivity can be explained by electrons flowing parallel to the filamentary microstructure aligned with the wire axis. Using the Avrami and Arrhenius equation relationships, it is possible to predict the times and temperatures needed to achieve various degrees of homogenization. The Au DMMC's were found to have good thermal stability compared to conventional coldworked Au interconnection wires. Although these composites will revert to solid solutions if exposed to high temperatures for prolonged time periods, their relative stability is sufficient to allow them to maintain their twophase microstructure during the anticipated lifetime temperature profiles of many products.

Oct 1, 2003

By P. Mattar

The geotechnical importance of studying fluid flow through porous media and soils in particular, becomes evident when dealing with groundwater movement in surficial geomaterials that can be initiated by hydraulic gradients that develop during construction activity, groundwater extraction, impounding of reservoirs and groundwater recharge during adverse climatic events. In a geotechnical context, rocks are regarded as virtually impermeable materials, with comparatively greater resistance to flow of water through their pore structure. The importance of the permeability of rocks comes to the forefront when deep geologic formations are used in geoenvironmental activities for disposal of hazardous and toxic materials. The permeability of the rocks encountered is of critical importance to these geoenvironmental activities since the movement or transport of the hazardous materials during their eventual release will be largely governed by the permeability characteristics of the geologic formation. The estimation of the permeability characteristic of geologic formations is a non-trivial exercise since the measure of permeability can be influenced by the scale at which the measurement is made. Regional-scale and borehole-scale estimates of the permeability can be greatly influenced by the inhomogeneities, including fractures, fissures, solution channels and other anomalies that are present in naturally occurring geologic media. These anomalies are considered to be site specific and can only be determined in a reliable fashion by either conducting tests at the appropriate scale or in the regional-scale through inverse analysis of tracer movement patterns in rock masses. The estimation of the permeability of intact units of a geologic medium has important geoenvironmental applications in connection with storage of wastes since the units in which repositories will be located should be sparsely fractured and the sealing of the fractures and fissures are a prerequisite to developing an efficient solution for storage. The intact permeability of geomaterials is therefore regarded as an important property that influences efficiency and reliability of geoenvironmental solutions for deep geologic disposal. The permeability of geomaterials such as concrete and cementitious grouts are also important to many geoenvironmental and infrastructure applications where durability of structural materials in general and cements used for sealing deep boreholes and other access shafts employed in waste management endeavours is influenced by the permeability characteristics of these materials

May 1, 2009

By Albert W. Scragg

"THE ADMINISTRATION DEPARTMENT consists of six sections, all with their own supervisors, reporting to the superintendent of administration. Although each of these sections is uniquely separate, they all work together, in one department, to provide very necessary services.1. Accounting 2. Purchasing 3. Warehousing 4. Data Processing 5. Inventory Control6. Office ServicesThis department, which now numbers 108 people, had its birth in an office over a hardware store in downtown Timmins in 1964. Initially, only basic accounting and purchasing functions were performed and these, of course, were on a very small scale. The growth of the administration department is a function of the growth of the company."

Jan 1, 1974

By J. M. Menacho

As usually occurs in technological development, heap leaching knowledge has been built upon two parallel lanes, theory developed on fundamentals but relatively far from industrial applications, and operational know-how generated from empirical trial and error. As a contribution to close the gap between the above-mentioned lanes, the De Re Metallica process consulting group has been developing and applying fundamentalsbased modeling tools for industrial process design and process optimization of existing plants over the last ten years. As result, a library of models is now available with application to the whole production chain from blasting to electro winning. This presentation is centered in heap leaching and several real case studies are developed, showing how paradigms are broken when fundamentals are applied. Cu2007 - Volume IV (Book 1) The John E. Dutrizac International Symposium on Copper Hydrometallurgy Edited by P.A. Riveros, D.G. Dixon, D.B. Dreisinger, M.J. Collins Toronto, Canada,

Jan 1, 2007

By Hani Henein

Most metals and alloys processed undergo a solidification processing step. Increasingly, there is a growing number of solidification processing routes that involve rapid solidification of the alloy. These include strip casting, high pressure die casting, 3D printing, and atomization for the production of powders or spray formed parts. By contrast, there are few experimental techniques developed to study the solidification path of alloys during rapid solidification. Amongst these laser melting and solidification, Electromagnetic Levitation (EML) and Impulse Atomization (IA) are the most prominent. Of relevance is the formulation of the solidification path of an alloy and the resultant identification and quantification of metastable phases and their relationship to processing conditions. This typically involves the understanding of the interplay between undercooling and cooling rate for the various phases that form. This presentation will outline some of the methodologies developed to quantify phase fractions and their solidification path as a function of processing conditions using EML and IA.

Jan 1, 2016

By B. T. Lu, J. L. Luo, T. Yu, C. W. Chen

In this paper, the synergism in erosion-corrosion process occurring in oil sand wastewater transportation caused by the interaction of mechanical and electrochemical factors was experimentally investigated. The erosion-corrosion tests were conducted with A1045 steel in synthetic slurries comprising tap water and silica sand. The material loss due to corrosion-enhanced erosion was assessed with the chemo-mechanical model developed by the authors recently. The results indicate that the material loss produced by corrosion-enhanced erosion at the open circuit potential can be formulated as a linear function of logarithm of corrosion current density. The wastage caused by the erosion-enhanced corrosion was analyzed based on the concept of non-equilibrium thermodynamics. The material loss induced by the erosion-enhanced corrosion is approximately a linear function of overall erosion rate measured in synthetic slurries, indicating that erosion-enhanced corrosion could be reduced by adopting surface strengthening techniques to improve the resistance to the plastic deformation in surface layer.

Jan 1, 2004

By T. Cutard, H. Marzagui, E. Ouedraogo, M. Roosefid, M. Prompt, C. Deteuf

The present work is achieved in the framework of a French national program on modeling and experimental characterization of the thermo-mechanical properties of refractory materials (PROMETHEREF). This research program is aimed to establish fair models and experimental database and to make it available to industrial partners for numerical simulation of industrial structures made of these materials. The present paper focuses on two silica-alumina refractory castables, an andalusite based one and a bauxite based one. We will present the first rheological characterization results achieved at room on normal and preheated samples of these two refractory castables. Refractory castables are characterized with the help of four points bending tests, compression tests and tensile tests.

Jan 1, 2004

Polymer electrolyte membrane (PEM) fuel cell has increasingly become the potential choice of zero-emission power source for portable, mobile and stationary co¬generation applications. However, technical barriers need to be overcome before its widespread commercialization; cost reduction and performance improvement including reliability are the two key areas, that can be realized through better cell/stack design and improved understanding of the transport processes occurring inside the individual cells and stacks. In this presentation, we will provide an overview of various cell/stack models that are available in the literature, their strength and weakness, and then present a comprehensive multi-species, multi-phase and multi-dimensional formulation of a single PEM fuel cell, with consistent and systematic formulation for all the regions involved, including the solid bipolar plates, gas flow channels, the electrode backing layers, the catalyst layers and the electrolyte membrane. Such a detailed approach allows us to extract sufficient information to the analysis of a stack of PEM fuel cells. Stack model will be presented that investigates the various stack designs and flow configurations, and the optimal stack design based on the present study will be described. Also some innovative cell/stack designs will be featured.

Jan 1, 2005

By C. Sideco

"Concentrate drying at the Sullivan Concentrator goes back to 1937 when the original coal-fired dryer was put into operation. This was a second hand 8' dia. x 56' long Struthers-Wells rotary dryer that came from the phosphate plant in Warfield, B.C.In 1962, replacement of the old dryer was seriously considered. The shell and the auxiliary drive mechanism were badly worn and needed replacing. In April 1963, the new 8' dia. x 65' long fuel oil-fired Struthers-Wells dryer went in operation at an installed cost of $174,000.In 1965, it was apparent that a major rebuilding of the dust collecting system would have to be done. A study was carried out and a Ducon Dynamic Gas Scrubber was installed. The system went in operation in November 1966 and has fully met expectations.In the same year, the zinc dryer was converted from fuel oil to natural gas. The conversion has resulted in savings in fuel cost of 12 to 15%.Frame No. 1Zinc Dryer PerformanceDryer Make - Struthers-WellsDryer Size 3/4 8' dia. x 65' long Drum Drive - 100 HPSpeed of Rotation - 5 RPMFeed Rate - 50-65 TPHFeed Moisture - 10-12%Discharge Moisture - 4-6%Dryer Inlet Temperature - 1600-1800°F Dryer Outlet Temperature - 200-250°F Stack Gas Volume - 25,000-40,000 CFNDust Collecting Efficiency - 99.75-99.98% Duet Loss in Stack - 50-300 lbs./day"

Jan 1, 1972

By Norma G. González

La littérature et notre expérience en Bolivie dans une communauté minière très divisée comme celle de Huanuni nous montrent le besoin d?envisager des négociations gagnant-gagnant entre communauté et entreprise minière, non pas comme un point de départ, mais comme un résultat à atteindre, qui nécessite la préparation de conditions préalables. Cela implique fondamentalement de mettre l?accent sur le processus qui permettrait par la suite aux parties de mieux traiter les questions de contenu. Suivant cette hypothèse générale, l?initiative conjointe entre le Ministère des ressources naturelles du Québec et le CECI ?Développement des mécanismes de négociation entre communauté et entreprise minière? peut dégager, après un an et demi d?expérience pilote dans le site minier de Huanuni, département d?Oruro, Bolivie, les leçons préliminaires suivantes. Ce processus requiert: ??Agir, en tant qu?organisme consultant tierce partie, selon des principes et une méthodologie qui relèvent de la Communication publique et de la Médiation ; ??Comprendre et agir à partir de la ?réalité sociale? des parties en présence: l?entreprise minière, l?État et les différents groupes de la communauté; ??Intervenir sur les ?réalités sociales? des parties, par des actions d?éducation et de diffusion dans le but de préparer les personnes, les institutions et les organisations de la société civile, à des changements durables du modèle de communications existante; Approfondir la compréhension de la ?réalité sociale? du conflit (la culture du conflit, les méthodes populaires de résolution des problèmes et de gestion des conflits) afin d?offrire aux bénéficiaires les technologies appropriées pour la transformation de cette culture de confrontation violente en gestion constructive des conflits. Par ricochet, nous espérons ainsi faciliter l?attraction des investissements dans le secteur minier.

May 1, 2001

By Bruno Bussière

Acid Mine Drainage (AMD) from mine wastes is one of the most environmental challenge currently facing the mining industry. AMD is the result of the natural oxidation of sulphides exposed to air and water. When mining wastes have the potential to produce AMD, these reactive wastes have to be managed to meet existing environmental regulations. The LTA site (property of Barrick Gold Corp.) contains sulphide tailings that have the potential to generate AMD. The closure option Barrick selected was to construct a multilayered cover with capillary barrier effects (CCBE). The main objective of this CCBE is to prevent the production of Acid Mine Drainage (AMD) from the tailings stack covering an area of approximately 60 ha. Since its construction in 1996, the cover has been monitored to evaluate its performance. Two of the measured parameters are volumetric water content and matrix suction. This paper presents some of the main results from the monitoring program that started seven years ago. The results show that the cover is largely able to maintain a high degree of saturation (greater than 85%) in the moisture-retaining layer. The actual performance of the CCBE on the flat surface of the 60 ha site is even better than expected at the design stage. The area that requires more specific attention with the LTA cover is the influence of slopes that can reduce the performance of the CCBE during dry periods. However, these effects seems to be local and do not significantly affect the overall performance of the CCBE to mitigate the production of AMD at the LTA site.

May 1, 2003