Search Documents

By Serge Perreault

Le cuivre est un métal fascinant qui joue un rôle essentiel dans le développement des différentes civilisations depuis 7000 ans. Le cuivre est aussi un métal polyvalent et essentiel qui est très présent dans notre vie quotidienne. L’un des premiers métaux utilisés par les humains, il est un élément chimique qui se trouve à l’état natif, ce qui est rare pour les métaux. Il apparaît principalement dans des minéraux, notamment sous forme de sulfures, en raison de son caractère chalcophile (c’est-à-dire son attraction pour l’élément soufre). Le cuivre se trouve dans la croûte terrestre sous forme de minéraux de cuivre, tels que dans les sulfures dont la chalcopyrite, la bornite, la covellite et la chalcocite. Il est également présent sous sa forme native ou dans des minéraux oxydés comme la cuprite et dans des carbonates hydratés, comme la malachite et l’azurite. La formation de gisements de minerai de cuivre implique des processus géologiques complexes, notamment l’activité hydrothermale, les intrusions magmatiques et l’altération des roches. Les gisements de minerai de cuivre se trouvent dans divers types d’environnements géologiques, dont les gisements porphyriques, les gisements de cuivre encaissés dans des roches sédimentaires, les gisements de type skarn, les gisements de sulfures massifs volcanogènes, les gisements magmatiques de type nickel-cuivre, les gisements de cuivre oxydé, et d’autres [1].

May 2, 2024

By Maria D. Mastalerz, Wei Wang, Maria E. Holuszko, Amit Kumar

In this study, the micro-FTIR analysis was used to investigate in-situ surface properties of coal and its components (macerals) and these were directly correlated to the coal hydrophobicity as measured by the contact angle before and after reagent addition to understand the suitability of the reagent for flotation. The micro-FTIR technique can provide a semi-quantitative analysis of the chemical functional groups on coal surface, exactly where the contact angle is being measured. Selected functional groups and their ratios that provide information about aromaticity, the contribution of oxygenated groups, and aliphaticity are used to evaluate the reactivity between reagents and various coal components. The observations made in relation to the susceptibility of some reagents towards certain coal components should lead the way to a smarter way of using process design in terms of reagents selection for coal flotation.

Jan 1, 2017

By Elizabeth Edwards, Radhakrishnan Mahadevan, Vladimiros G. Papangelakis, Srinath Garg, Kurtis Judd

Mineralogical characterization of the tailings showed the deportment of Ni to be similar in the Vale and Glencore tailings, with 60% of the total Ni locked in pyrrhotite, and the balance 40% associated with pentlandite. The overall Ni dissolution was correlated with the individual dissolution extents of pyrrhotite and pentlandite as functions of four leaching regimes: ‘anoxic acid’ (with and without pH control), ‘oxic acid’ (oxygen sparging), ‘oxic acid’ (air sparging), and ‘oxic ferric’ (air sparging). The results showed that the maximum Ni dissolution was obtained during the pH controlled oxic acid leach with oxygen sparging at pH 1.5, while the anoxic acid leach at pH 1.5 resulted in minimum Ni dissolution (10–15%) from pyrrhotite. An overall Ni mass balance showed that pyrrhotite and pentlandite dissolve simultaneously in the presence of Fe(III) and oxygen, in contrast to the preferential dissolution of pyrrhotite in the absence of Fe(III). Sulphur mass balances revealed that the yield of elemental sulphur is maximized (65%) during the oxic Fe(III) leach at pH 0.6. Furthermore, the kinetics of Ni leaching and elemental sulphur formation from pyrrhotite tailings leached with ferric sulphate between 55–80°C was investigated at constant oxidation-reduction potential. Elemental sulphur yield increased with increasing temperature, but no observable trend could be linked to ferric or ferrous ion concentration.

Jan 1, 2017

By T. Haubold, K. Ortner, T. Jung, D. Roth-Fagaraseanu, C. Mattern

Application of integrally bladed disks (blisks) is of increasing interest in compressors of aero engines. Blisks are preferred due to their potential for size and weight reduction, for increased performance and for reduced manufacturing costs compared to conventionally bladed disks. Erosion of the blisk aerofoils in service reduces engine performance, and can result in short shop visit cycles. This significantly increases the life cycle cost of these components, particular when considering that eroded aerofoils can't be exchanged easily for blisks during refurbishment. Shop visit cycle times can be extended and maintenance costs can be reduced through the application of an effective protective coating. The ongoing development of an erosion resistant coating and deposition process suitable for coating complex blisk geometries is described here. The coating is a multilayered W /TiB2 system exhibiting superior erosion resistance compared to known single- and other multilayer concepts. A modified sputter process is used to enable coating even of blisk geometries with shadowed surface to competitive recurring cost.

Jan 1, 2006

By J. Wickens

"Campbell Mine is dedicated to quality management in the form of a Continuous Improvement (CI) Operating Philosophy. This paper discusses that philosophy, why and how it is being implemented in the milling facility, and some of the challenges experienced to date. Examples of mill CI team projects and results are described. This paper describes practical experiences for those who are considering or are in the process of adopting a CI operating Philosophy.INTRODUCTIONCampbell Mine is 100% owned and operated by Placer Dome Canada Ltd. The mine is located in Balmertown, Ontario approximately 300 km northeast of Winnipeg, Manitoba. Campbell Mine has produced over s,000,000 ounces of gold since commencing operation in 1949. The operation is profitable and continues to be a major contributor to the gold production of Placer Dome Inc.At Campbell Mine, the concept of Continuous Improvement (CI) is being implemented to make further improvements to safety, quality, productivity, and subsequently profits. CI is not a ""program"". It is a way of doing business that concentrates on improving the system rather than finding fault and being resigned to the status quo.CI focuses on involving all employees in the decision making process and tapping their expertise to improve every facet of the business. In the past, many solutions were simple ""band-aid"" fixes treating the symptom, only to see the problem resurface again. With CI, solutions endeavour to address the root cause of problems and eliminate them permanently. Another primary goal is to eliminate unilateral decisions that benefit a small group but have a negative effect on the whole system."

Jan 1, 1995

By J. E. Dodge

Tasu, currently an open-pit operation, services the primary crusher from two areas by ore-pass raises. The problems encountered and advantages gained are discussed. Mine equipment and operating practices are covered, together with blasting practices, line drilling and the pre-shearing necessary to stahilize the pit walls.

Jan 1, 1968

By Nathalie Gauthier

Bien que le système de ventilation du Puits Penna soit de taille imposante et que plus de $30M y seront engloutis pour son développement, aucun budget spécifique n?avait été préalablement consenti pour refroidir l?air acheminé aux places de travail dans la partie profonde de la mine. Le système de ventilation a été conçu en deux étapes distinctes : le réseau du haut de la mine lequel dessert jusqu?à 1550 m de profondeur et le réseau du bas de la mine (de 1550 m à 2200m) qui a été créé ultérieurement. Le réseau inférieur a été imaginé de façon à acheminer l?air frais directement au gisement et de permettre l?évacuation aux extrémités afin de rejeter l?air chaud immédiatement après l?avoir utilisé. Au total, lorsque le réseau de ventilation sera complété, plus de 670 m3/s d?air sera véhiculé dont jusqu?à 495 m3/s pour la partie inférieure de la mine considérant une capacité totale maximum de 710 m3/s en utilisant la mine adjacente.

May 1, 2003

By A. Carbonari

In order to gain competitiveness and compete at a global level, construction companies should improve their efficiency. The problem is even more relevant in the construction field, whose work processes find it hard to evolve towards new automated methods and techniques in the management field. For that reason, this paper suggests how construction companies could apply new technologies to implement automated management of environmental hazards. Based on a survey regarding the environmental risks presently experienced in construction sites, noise and dust were considered two of the main hazards. So in this paper a networked system for real time remote monitoring of the spatial distribution of dust in construction sites was developed. Such a system would relieve builders from the commitment of on-site surveys, allowing for a continuous monitoring of the site conditions and of the real exposure of each worker and pass-by to the pollutants generated by construction works. The main system requirements considered are: easy to deploy, reliable, as accurate as needed to be able to send real-time warnings and store a good estimation of the real exposure to which involved people have been subject to. So far the research produced a prototypical hardware for dust monitoring made up of wireless sensors which can be easily deployed on site. The sensors were calibrated by means of laboratory tests, where their measurements were compared with those collected by means of highly accurate instruments, which were taken as a reference. Thanks to these experiments, calibration curves for the sensors were worked out, showing also the measurement range of the sensors.

Aug 1, 2013

By Apoorva Bajaj

Iron ore mines of Steel Authority of India Limited (SAIL) have to comply with strict chemical composition norms laid down for iron ore lumps supplied to its steel plants. This requires a careful planning of the overall ore excavation operation. In general terms, the problem can be stated as: Given the chemical composition of ore for all excavation sites, excavation capacity of each shovel, distance of each excavation site from the crushing plant and the number of dumpers available for transport of the ore, find out the percentage of ore to be excavated from each excavation site such that the production rate is maximized and the chemical composition norm is satisfied to the best possible extent. This paper presents an approach to solve this problem using Branch and Bound method. The specification for r.o.m. quality has been modified by incorporating a new parameter, ?Al2O3 / SiO2? ratio, which has a significant effect on the performance of iron blast furnace.

Oct 1, 2009

By I. Stefanou, J. Sulem

"In the last thirty years, the study of earthquake mechanisms has emphasized the major role of rock friction. Earthquakes appear to be the result of a frictional instability and occur by sudden slippage along a pre-existing fault or a plate interface. Multiphysics couplings play a major role in earthquake nucleation and seismic slip. The effect of shear heating and thermal pressurization may be of prime importance in the control of the stability of shear deformation inside the slipping zone. Other mechanisms in relation with thermal decomposition of minerals affect the pore pressure and the temperature evolution of the system, and can play a significant role in the extreme strain localization observed in field. The actual width of the localized zone is a key parameter for understanding fault weakening mechanisms. On the basis of field observations, laboratory experiments and recent advanced modeling, these phenomena are analyzed and discussed in order to bring some new insights in the understanding of earthquakes nucleation.INTRODUCTIONIn the last thirty years, the study of earthquake mechanisms has emphasized the major role of rock friction. Earthquakes appear to be the result of a frictional instability and occur by sudden slippage along a pre-existing fault or a plate interface (Scholz, 1998; Sykes, 1978). The conceptual model of spring slider system is commonly used to represent the interaction between an elastic crustal block and a fault zone. Stick-slip instability is possible if the softening rate of the shear resistance of the fault zone is high enough as compared to the stiffness of the crustal block. Therefore, weakening mechanisms that can explain how the frictional resistance of a fault decreases with slip and/or slip rate is of prime importance to understand how an earthquake nucleates. In recent years, several drilling programs in active faults (e.g. the Nojima fault in Japan, Boullier, 2011; the Aigion Fault in Greece, Cornet et al. 2004, the Chelungpu fault in Taiwan, Ma et al. 2006, and the San Andreas fault in the U.S.A. Ellsworth et al. 2000) as well as high velocity friction experiments (e.g. Tanikawa et al 2012a; Tanikawa et al. 2012b) have highlighted the physico-chemical processes involved in the nucleation of seismic slip (see for the example the review paper of Niemeijer et al. 2012)."

Jan 1, 2015

The original JKMRC AG/SAG mill model was developed over 30 years ago and has been upgraded a number of times since then, with the current published version being the Variable Rates model that is now over 15 years old. Since this model was developed further enhancements have been derived, some of which are applied in-house and some which have yet to be incorporated. The published and the commercially available model in JKSimMet is currently undergoing a comprehensive overhaul with a vastly extended data base for model evolution and validation. Improvements developed within the AMIRA P9 project, in-house development and a number of collaborative projects, are being incorporated into the upgraded model structure. Enhanced capabilities will include: power-based breakage rates scaling; a far wider mill filling range (from 10% to 40%) that exhibits peak in throughput as mill filling increases; higher ball loads; improved pebble discharge function; improved slurry discharge function incorporating important mill design and operational influences; and the new size dependent breakage function. The model will also be able to accommodate some influence of liner design and multi-component ores (blends of hard and soft components). This upgrade is still a work in progress but substantial changes have been made to date. This paper presents some of the new improvements and their influence on the predictive capability of the model.

Jan 1, 2012

By John R. Sullivan, Real Daigneault, Mathieu Piché, Jayanta Guha, Gilles Bouchard

"RESUMELa stratigraphie du camp minier de Matagami se résume a la présence de deux groupes volcaniques: le Groupe du Lac Watson et le Groupe de Wabassee qui le surmonte. Les gisements de sulfures massifs volcanogènes sont situés au sommet du Groupe du Lac Watson. Ces roches sont déformées par l'anticlinal de Galinée dont l'axe, orienté E-W, plonge vers l'ouest. Le cœur de cette structure est occupé par le Complexe de la Rivière Bell.Les roches volcaniques du flanc sud de l'anticlinal sont peu déformées et pendent à 45° vers le sud. Les gites qui s'y trouvent présentent la morphologie typique des gisements de sulfures massifs volcanogènes. Ceux-ci se situent le long d'un horizon repère cherteux et sulfure, appelé ""Tuffite Clef', et leurs cheminées d'altération rejoignent, en profondeur, une zone d'altération stratiforme d'étendue régionale.Les roches du flanc nord ont été transposées tectoniquement en écailles chevauchantes, de dimension kilométrique, a l'intérieur d'un couloir de failles anastomosées d'orientation est-ouest. A l'intérieur: le ce couloir, les gites de sulfures sont déformes et sépares de leur héminée d'altération sous-jacente par des failles.Les gites de sulfures situes sur les deux flancs de l'anticlinal de 'Galinée se seraient mis en place dans un mime environnement volcanique. Leur position stratigraphique est identique puisqu' ils se 'rouvent au sommet de la rhyolite porphyrique du Groupe du Lac Watson. lis se seraient constitués au cours d'une pose volcanique recédant 1'éruption du basalte du Groupe de Wabassee. Le Complexe de la Rivière Bell est perçu comme la source de chaleur responsable de la circulation des fluides hydrothermaux qui sont à ""origine des gisements de sulfures massifs volcanogènes."

Jan 1, 1990

By E. C. Keeley

THE property of Buffalo Ankerite Gold Mines, Limited, is in Delora township, Porcupine area, Ontario. The southwestern part of the property is ground formerly owned by Marbuan Gold Mines, Limited, which was acquired by Buffalo Ankerite in January, 1936. Until 1938, the Ankerite (or North) mine and the Marbuan (or South) mine continued as separate operations, each developed through a surface shaft and winze to the 1050 level and each having its own mill. This meant high hoisting costs, which, in 1936 and 1937, amounted to 36 cents per ton. In 1938, the underground workings of the two mines were connected on the 1050 level, and ore from both mines was hoisted at the main, or No. 2, shaft of the North mine, location of which is shown in Figure l. This shaft was discontinued at a depth of 1150 feet because, owing to the soft nature of the talc (serpentine) rock in which it was sunk, it had to be concreted throughout, and also because of its great distance--1,100 feet and 1,400 feet, respectively-from the North and South orebodies.

Jan 1, 1945

The dissolution of chalcopyrite has received a significant amount of attention. The predominant paradigm of investigation is that its rate of dissolution is limited or passivated by a surface coating or film of material. The common candidates for such a passivating coating are numerous: polysulfide coating, metal deficient layers, copper sulfide coating, bornite layers, jarosite precipitates, and elemental sulfur films. While this line of explanation, that is, the explanation based on passivation, seems to have won some form of consensus with researchers, there is another explanation for the results that can account for all the results observed. Crundwell (1988) proposed that the solid state properties of chalcopyrite, in particular, the semiconducting properties, are responsible for the observed behaviour of chalcopyrite. The purpose of this paper is to outline the semiconductor mechanism of dissolution, and to show how this mechanism accounts for all the observed phenomena recently reported in the literature. The paper outlines the semiconductor mechanism of dissolution, shows how this mechanism accounts for the dissolution

Jan 1, 2014

By Jeffrey D. Oke

While significant progress in underground construction engineering has occurred in the past few decades, a number of fundamental deficiencies persist regarding the recognition, prediction, and mitigation of underground construction hazards associated with complex geological conditions in rock and soil works, such as tunnelling. Many of these shortcomings could be addressed by improving geomechanical models which, in turn, would provide more realistic frameworks for determining input parameters for design analysis. This would improve predictions of construction efficiency for tunnelling and the formulation of more accurate modelling techniques (2D, 3D and 4D) required to optimize the design of engineered rock structures. This research focuses primarily on the issues related to forepole temporary tunnel support within weak rock masses. This research attempts to determine how best to numerically model forepole support. The behaviour and mechanics of forepole support has not been quantified and/or optimized. As well, there is a lack of in-situ and/or laboratory forepole and weak rockmass interaction parameters available. In terms of numerical modelling, there is a lack of understanding of the use of proper interaction parameters associated with the forepole and the rockmass. The parametric study that has been conducted by the authors demonstrates the influence of each of the forepole-rockmass interaction parameters and their sensitivity. Introduction

Jun 1, 2012

By Mei-Yan Yang, Ltd. Yunnan Yuntong Zinc Co., Yong-Xiang Li, Xing-Zheng Dai, Hong-Liang Wang, Meng-Yang Huang, Peng Zeng, Guo-Feng Li

"The removal of iron asgoethite from the high iron bearing solutions generated in zinc hydrometallurgy using a strong airflow device was investigated. The influence of oxygen flow, copper ion concentration, temperature and reaction time on iron precipitation as goethite was studied. The optimum conditions were: oxygen flow 0.2-0.35m3/h, copper ion concentration 0.25-0.5g/L, temperature 80-90oC, zinc oxide powder neutralizing agent and a reaction time of5to 7hours. Under the optimal conditions, the Fe2+concentration was reduced to 0.025g/L after iron precipitation, and the goethite residue contained 38.7wt.%Fe. The SEM and XRD analyses showed that the iron was present as well formed FeOOH crystals in the iron residue, and the amount of iron sulphate was very low. Production practice shows that, when the average iron concentration in the feed solution was 11.61g/L and 4.08g/L after precipitation, the weight of iron removed was 1,439kg/day. When the average iron concentration in the feed solution was 14.51g/L and 2.73g/L after precipitation, the weight of iron removed was 2,454kg/day. This represents a ~70 percent increase in iron removal.INTRODUCTIONThe objective of iron removal is to produce a small volume of iron residue, and our industrial goethite process meets this requirement. The high Fe(II) solution in our reactor isoxidized/hydrolyzed to precipitate goethite and the precipitate is sent to a pyro metallurgical furnace for final residue treatment. Some literature discusses (DengYong-guiet al., 2008;Meiguang-guiet al., 2001;Zhongzhu-qianet al., 1980) research on iron hydrolysis; one of the reported rate limiting parameters was the low availability of the oxidant when using air and another was the inhomogeneous air distribution. There are two iron hydrolysis-goethite precipitation methods; the Electrolytic Zinc process (EZ) and the Vieille Montagne process (VM) (Lei Xiang, 2006; Xuguo-qiang, 2007;ZhaoYonget al.,2005). The EZ method hydrolyzes the Fe3+directly to FeOOH. The weakness of the EZ process is the low recovery rate of the associated minor metals. The VM method reduces the iron to the ferrous state and then oxidizes the Fe(II)to Fe(III),with simultaneous hydrolysis/precipitation of the Fe(III) as FeOOH. Before iron hydrolysis, the minor metals, such as indium, could be selectively precipitated, because Fe(II)requires a high pH for hydrolysis. So the VM method has a high recovery rate for the minor metals. There levant goethite precipitation reaction is:"

Jan 1, 2016

By A. J. Harrison

"The introduction of an amendment to the Mines Regulation Act in the Province of British Columbia, passed in July 1974, and similar amendments since enacted by other provinces introduced the Canadian underground mining industry to the use of fire-resistant hydraulic fluids.Few, if any, of the hydraulic circuits in use in underground mining at that time were specifically designed for use with fire-resistant fluids, compared with the increasing number of such circuits conceived and in production today. The technology required in designing equipment for use with fire-resistant fluids may be likened to that associated with conventional mineral oils, but, in many respects, a variety of additional and / or alternative considerations must be taken into account. The fast-increasing use and development of fire-resistant fluids throughout all facets of industry, world wide, during the past 20 years has led to a whole new technology in system construction and component design, whereby acceptable performance can be achieved . However , the transition from conventional mineral hydraulic oils has not been without its problems, particularly when retro-fit of existing units was involved."

Jan 1, 1981

By E. J. Wade

The general location, climatic conditions and access of the Tasu mine are covered briefly, with comments on the Jack of conventional transportation and communication facilities. The Haïda story of Tasu and early at-tempts at production are presented, together with a discussion of the government legislation which throttled exploration and production in the late fifties. General and specific details of local geology, mineralogy and current ore reserves are also covered.

Jan 1, 1968

By G. Zeng

Although the solubility of oxygen in zinc electrolyte is less than 9 mg/L, the effect on deposit stability and zinc-dust consumption can be significant. Sodium sulfite is used to deoxygenate the electrolyte. The effect of the sodium-sulfite concentration on cobalt removal is investigated. The results show the reduction of sulfite to elemental sulfur that adhered to the zinc dust surface forming a passivating layer, and small amounts of sodium sulfite have no effect on cobalt removal. The optimum amount of sodium sulfite is 100 mg/L. It is an important consideration in purification circuits to use sodium sulfite as an additive to cobalt cementation.

Jan 1, 2005

By M. Fairclough, B. Moldovan

Insights into uranium mining projects of the future can be gained by a careful statistical analysis of past and present deposits, as well as an examination of recent trends for uranium resource evaluation and primary uranium production. The International Atomic Energy Agency (IAEA) provides the necessary data and corresponding mechanisms as inputs for methodologies that enable strategic and scientific evaluations of long-term security of supply uranium required to sustain the demand for nuclear fuel. Sustainability of the uranium mining industry and subsequently new uranium mines of the future requires innovation and expertise to lower operating costs, maintain or improve uranium recovery while meeting the requirements of stakeholders in regard to protection of the environment and safety of the workers and general public.

Jan 1, 2020