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By M. C. Bluteau, G. P. Demopoulos

Arsenic reports in the effluents of many non-ferrous metallurgical operations. The production of scorodite, a crystalline ferric arsenate, is considered as an attractive option for the fixation of arsenic from aqueous effluents. However, scorodite solubility and long-term stability in the pH region of interest for tailings disposal have not been thoroughly investigated. In this study the long-term stability of scorodite in the pH 5 to 9 region and the mechanism of scorodite dissolution were studied. Construction of eh-pH diagrams indicated that scorodite stability is highly dependant on the nature (stability) of co-existing iron-hydroxide/oxyhydroxide. It was also found that when scorodite dissolves, a ferrihydrite phase having very small particles size (nano-scale) forms and that the growth and crystallization of this material are delayed by the presence of arsenate even under accelerated (75°C) ageing conditions. Around neutral pH and ambiant temperature (22°C) scorodite seems to reach an equilibrium with ferrihydrite after 48 weeks yielding soluble arsenic concentrations < 5 ppm.

Jan 1, 2004

By Dina Aloi

The need to be seen as responsible neighbours and good corporate citizens is a critical success criteria for mining companies. To be seen as responsible requires both achieving responsible performance, and making that good performance visible to the community, legislators, investors, and other stakeholders. This has broadened the skills required for the successful operation of a mining company to include social sciences, public affairs, communications, and environmental sciences. Mining companies still look to technical specialists to achieve the core of that good performance - broadly characterized as a sustainable operation. However, the degree of understanding that those specialists have of the requirements for sustainability and overall Corporate Social Responsibility has a tremendous impact on the overall performance of the project and company. In her keynote address to the Sustainability for Profit session, Dina will outline some of the key areas in which technical employees and consultants can contribute to achieving successful sustainable mining operations.

Jan 1, 2010

By J. M. Toye

The Canadian nuclear fuel business relates primarily to supplying fuel for Candu reactors. The product development, manufacturing and marketing activities of our nuclear fuel industry will therefore be determined by the rate of growth of the Candu nuclear reactor business. The nature of this relationship between the Canadian nuclear fuel industry and the Canadian Heavy Water Reactor program will be considered, with particular reference to the factors influencing future economic growth.

Jan 1, 1969

Fiabilité Totale d?Usine (FTU) Plan de la présentation ?Théorie de l?entretien ?Analyse comparative juin 2005 ?Session de travail 2005-2006 ?Suiviet Résultats(IndicateursdePerformance)

Feb 1, 2008

By Y. Miyabayashi, K. Nishikawa, H. Nagai

JX Nippon Mining & Metals Group recovers valuable metals from end-of-life electronic products in an economical and environmentally-benign way, based on technologies that have been acquired in mining, smelting, and refining operations over time. End-of-life electronic products contain halogens and hydrocarbons. When such materials are treated in the copper smelting process, corrosion of equipment and discoloration of sulfuric acid occur. As a countermeasure to these problems, we have developed pretreatment processes that include an incinerator, exhaust gas washing towers, and a defluorination facility. By implementing these improvements, we have been able to treat a large volume of end-of-life electronic products efficiently in the copper smelting process.

Jan 1, 2014

By J. P. Mogan, E. D. Dainty

Polynuclear aromatic hydrocarbon (PAH) levels were measured in underground mines in the vicinity of diesel vehicles equipped with several types of emission control hardware. In general, the emission control devices appeared to reduce PAH levels, but the companion mutagen study suggested that the reduction might not always be beneficial. All underground PAH concentrations were below the threshold at which a significant impact on health might be expected, but recent animal exposure studies have indicated that PAHs may not be the primary hazard from chronic diesel fume exposure.

Jan 1, 1994

By W. T. Thompson, S. Durham, K. M. Jaansalu

The role of platinum on the relative stability of gamma - gamma prime equilibrium is only qualitatively known, and may bear upon the stability of a superalloy under a protective coating. The binary phase diagrams Ni-Pt and Al-Pt, and the Ni-rich corner of the Ni-Al-Pt ternary, are reviewed and simple self-consistent thermodynamic models are derived. These thermodynamic models are incorporated into a database used to predict the gamma-gamma prime equilibrium for single crystal superalloys. In small concentrations, platinum is predicted to increase the temperature stability, but not the proportion, of the gamma prime phase over the gamma phase in third generation alloys such as CMSX-10. Another effect of platinum addition is to significantly lower the solidus temperature. These findings are compared to experimental data in the literature.

Jan 1, 2004

By Kristie D. Tarr

Ideally, in situ monitoring would supply the input data for numerical modeling of backfill material property requirements. However, clue to production requirements and costs of conducting field tests, input data are often based on small-scale laboratory tests. The size of test samples is known to play an important role in the laboratory assessment of the behaviour of geotechnical materials, including backfill. There are observed differences between the mechanical properties of laboratory-scale samples and those of in situ materials, and these are generally attributed to the differences in scale. Various scaling factors have been proposed for converting laboratory observations to anticipated in situ conditions for soil and rock materials. With regard to mine backfill, very limited studies exist which have involved the effects of sample size on material properties. The literature indicates that reported backfill strength data are based on a variety of test sample sizes and in some cases, specimen geometries. Carefully determined laboratory scale effects could play an important role in estimating the potential backfill behaviour in the field, especially when developing new backfill systems. Laboratory studies were conducted with sample diameters ranging from 50 to 300 mm. Scale factors relating specimen size to strength were developed wherever possible, and are presented in this paper

May 1, 2008

By P. Mottahed, J. Ran

Mining practice and research have shown that the jointed roof in stratified rock behaves like a voussoir beam structure with strength greater than that determined by the continuous beam theory. Previous studies have demonstrated the voussoir beam mechanism and developed methods to estimate the crushing and buckling strength of voussoir beams. However, research on voussoir beams with multiple mid joints has not been suffICient and problems such as the voussoir beam support and applications of the voussoir beam mechanism to the mining environment have not been addressed. In this paper, mechanism of voussoir beams containing multiple mid joints and truss support are studied and applications of the voussoir beam mechanism to underground mine openings are discussed based on the numerical and experimental results.

Jan 1, 1995

By T. T. Perles

This paper will review the state of the global vanadium industry and outline the implications for the market in the coming years. Global vanadium resources and reserves will be defined. Current production of vanadium will be quantified and examined in terms of production by country, sources of raw materials for production and cost implications of the production processes. Current consumption of vanadium by country and by application will be reviewed. Vanadium supply/demand balance in recent years and the resulting impact on global inventory levels will be discussed. Projections for changes in global production, consumption and resulting inventory changes for the vanadium market in the coming years will be made.

Jan 1, 2014

By J. E. Gebhardt

Advances in computational modeling provide unprecedented process simulation tools for the process engineer to examine and explore options for optimizing heap leach operations. A phenomenological model developed within a computational fluid dynamic software framework provides a general heap leach modeling tool that describes reactive dissolution and fluid flow through the stockpile. A one-dimensional form of the model is used to parameterize the kinetic leach reactions for a mixture of copper sulfide and oxide minerals against data from operational leach tests. A two dimensional version of the model provides a means to investigate the effects of irrigation rate, lift height, air injection, bacteria limitations, and other factors on recovery and pregnant leach solution concentrations. The model was calibrated for the Nifty Copper operation and ore type in order to simulate heap performance. Model simulations are reported for the chalcocitetype ore and compared to process data. The application showed that the multidimensional nature of heap leaching causes heterogeneous effects that are not always adequately described by one-dimensional models. Irrigation flow rate and aeration effects were simulated for a multi-lift heap section, and model results indicated that air injection at the base of the second lift would be required to achieve expected copper recovery under these lift height and flow conditions.

Jan 1, 2007

By D. S. Cronan, S. P. Varnavas

Abstract - Metalliferous precipitates from submarine hydrothermal discharges have been investigated at four inshore locations off Milos in the Hellenic Volcanic Arc. The fine fraction of the sediments shows considerable variability in the concentrations of elements frequently associated with hydrothermal activity. Manganese varies from 30 ppm to 2500 ppm, encompassing the entire range of values found off Santorini also in the Hellenic Arc. Iron occurs in lower concentrations than off Santorini and Yali, while other elements often associated with hydrothermal activity such as Pb, Zn, As, and Cu also show enrichments in sediments from the hydrothermal vent areas. Selective leaching studies have shown that most elements are variably distributed between the different phases of the sediments but with enriched Pb, Zn, and Mn mainly in easily soluble secondary phases. Hydrothermal inputs are strongest at Palaeochori Bay, less at Voudia Bay and lowest at the Airport Springs and Rivari. The weathering of sulfide and possibly other orebodies is also thought to contribute to some of the elements enriched, while background concentrations are largely supplied from detrital sources.

Jan 1, 1999

By J. Aguilar-Santillan, H. Balmori-Ramirez, R. C. Bradt, I. Vernet-Patiño, F. Cunha

Kyanite is an alumino-silicate mineral that has been widely used for the production of refractory products for industrial applications. Kyanite provides a high alumina content, it readily produces mullite during firing, good hot strength of products and can be adapted to produce dimensional stability of products during firing. This research addresses the application of kyanite in mixes to produce (0 dense mullite aggregates with the addition of alumina, (ii) dense composite refractory aggregates of forsterite / spinel with additions of magnesia, and (iii) dense cordierite aggregates with the addition of talc. Effects of attrition milling and conventional ceramic processing are addressed as they affect the properties of these unique aggregates.

Jan 1, 2004

By J. Gao

We present results from our investigation of the concept and practice of using surface-charged latex nanoparticles as building blocks for conductive membranes. Nanoparticles were synthesized by free-radical co-polymerization of two hydrophobic monomers, butyl acrylate (BA) and methyl methacrylate (MMA), a crosslinker, N, N&apos;- methylenebisacrylamide (BIS), and a charged monomer, sulfonate styrene sodium salt (NaSS), in water. The resultant nanospheres were characterized with static and dynamic laser light scattering. Thin films were cast from concentrated particle dispersions, followed by incubation at ?110 °C. Conductivity, water uptake and final charge content were measured. The membranes have higher conductivities than both amorphous films cast from sulfonated BA-MMA-Styrene copolymer chains and BA-BIS-MMA-NaSS gel films. TEM images and neutron scattering spectra confirm the particulate structure of the membranes.

Jan 1, 2005

By Ron Doucet

Industry today is now more than ever dependent on its assets and on the standard of maintenance. Changes in technology, environmental regulations, a continually improving focus on safety and global competitiveness has made maintenance a key activity in sustaining safe, financially viable and environmentally integral operations. Maintenance used to be looked upon as a cost centre with a sole focus of fixing equipment to attain high availability. Maintenance today affects all aspects of the business: safety, environmental integrity, energy efficiency, productivity, costs, and product quality. These new demands on the function of maintenance requires us to think vastly differently about what maintenance is all about, even to the point of contradicting old beliefs. In the following paragraphs we will examine some of the changed thinking that has evolved over the last 50 years. These new concepts will lay the foundation for the implementation of 21st century best practice maintenance.

May 1, 2003

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

Cameco Corporation is in the process of revitalizing the Key Lake mill. As part of this process, the company is considering installing the Rabbit Lake style strong acid stripping in solvent extraction. This would lead to using hydrogen peroxide for uranium precipitation. The process currently employs ammonia stripping and ammonia precipitation. As part of the process evaluation, an indirect fired drier pilot plant test was conducted. This paper will discuss the results of that test work, including the relationships between the following: ? Drying temperature and product grade ? Drying temperature and product colour ? Drying temperature and product reactivity with water ? Drying temperature and energy input requirements ? Drying temperature and shipping costs

Aug 1, 2010

By Steven Dempsey

Overview What is Tubbing? A look at Cigar Lake Tubbing Design The Tubbing Installation Backwall Grouting

May 1, 2013

By Robert B. Parsons

"Canadian investment abroad has been the focus of considerable attention in recent years. Canadian mining companies have been heavy investors in Latin America and are taking a hard look at Central Asia and the Pacific Rim. This international flow of capital is not one-way however. Foreign mining companies continue to make substantial investments in Canada&apos;s mining industry. This month. Tax Notes addresses some of the main Canadian income tax implications of foreign investment in Canada.Foreign Investment in CanadaThere are two basic forms of foreign investment in a Canadian company: share capital and debt. The following comments deal with each of these investments separately. It is appreciated that the relevant tax legislation is, as always, quite complex, and that the notes that follow are intended only to serve as a guide. This article should not be relied on as a substitute for professional advice."

Jan 1, 1994

By R. A. Triglavcanin

Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ? all of these need to occur in the right order and in the right proportions within the thickener feedwell, the secret to thickener performance.

May 1, 2009