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By M. J. Steffens

ESPLIM is a novel separation technique that combines the advantages of solvent extraction and electrostatic dispersion but its application in the extraction of nickel by the direct solvent extraction route and the effect of high electrostatic field on the stability of organics have not been explored. These were investigated in this study and it was found that the technique allows 97% extraction of the nickel in a single stage compared with 3 stages by the conventional solvent extraction. Also, three months of exposure to 5.0 kV under simulated operational conditions had no adverse effect on the stability of organics.

Jan 1, 2005

"Cambior currently has nearly 80 exploration properties, acting as operator on about 60 of these. The company's exploration budget has increased to over $11,100,000 for 1990. On-going efforts recently yielded a new gold discovery on the Douay- Vezza property, a joint venture project with Inco and Vior. Cambior continues to seek out new opportunities, recently acquiring an option agreement on the Sleeping Giant project in Quebec and four new exploration agreements in the United States, through its Reno office. Other nearly-concluded joint venture agreements have also given the company entries into Indonesia and Guyana.SummaryWhen it acquired SOQUEM's assets on August I, 1986, Cambior also acquired interests in 45 exploration projects. The subsequent mergers with Aiguebelle Resources and Sullivan Mines in 1987 brought the total number of exploration projects to 83, most of which are concentrated in northwestern Quebec. Cambior's strategy emphasizes gold exploration, and exploration activities were, therefore, initially limited to the Val d'Or and Rouyn-Noranda mining camps, where Cambior has a large portfolio of properties. Approximately $25.8 million has been spent on surface exploration in this area since the formation of the company, resulting in the discovery of the Mouska deposit and four sub-economic zones on the Porcupine, Forbex, Bloc Sud and Flavrian project s. In 1988, Cambior became involved in projects in the United States to which the company expects to allocate about 38070 of its 1989 exploration budget."

Jan 1, 1990

By Murray W. Grabinsky

The in situ performance of Cemented Paste Backfill (CPB) systems can be monitored to improve understanding of the paste?s behaviour and therefore optimize the geomechanical design of the cemented paste backfill system (i.e., minimize binder content, minimize fill barricade complexity, maximize fill rate-of-rise during backfilling, and minimize cure time before resuming production blasting in proximity). However, undertaking such a monitoring program is inherently complex, because the rate-of-rise and accompanying self-weight induced stresses occur at a time rate that is similar to the rate of hydration and associated increase in the paste?s stiffness and strength. In addition, arching within the stope complicates the overall stress distribution. Therefore, to obtain a complete picture of the CPB?s response, it is necessary to measure several variables (3-D total pressures, water pressures and suctions, hydration rates, and blasting induced vibrations) at a given ?point?, and take all such measurements at many points throughout the fill mass as well as at barricade locations. The overall testing program can therefore be logistically difficult to implement and have an apparent high cost. However, if the program is successful, the benefits arising from improved mine design can significantly outweigh the seemingly high initial capital and labour costs of the monitoring program. A case study involving an instrumented paste fill in a tall and narrow Alimak stope is briefly outlined. Plans for a similar experiment in a large long-hole stope are then considered.

May 1, 2008

By J. W. Coetzee, H. E. Deist

Carbon-in-pulp (CIP) and Carbon-in-leach (CIL) processes are used extensively in the gold mining sector to recover aurocyanide from solution. This paper discusses the modelling of these operations, using various simplifying assumptions, in order to simulate the effect of changing operating conditions on the dynamics of the system. It is assumed that the adsorption and leaching rates are a function of concentration difference between the source phase and recipient phase. The simulation was set up using Matlab's Simulink interface. Plant variables are solved using a medium scale Newtonian search algorithm in Matlab, where the differences between the actual and predicted plant outputs are minimized on a continuous time-line.

Jan 1, 2005

By Waldbillig. D.

A baseline of the poisoning effect of hydrogen sulfide (H2S) fuel impurities on solid oxide fuel cell (SOFC) anodes was developed using polarization testing. After the baseline behaviour was characterized, tests to study the effect of various H2S concentrations on the rate and amount of cell voltage degradation and recovery were performed. Attempts were made to improve the rate and amount of recovery by various methods. Testing was very reproducible, but significant electrochemical performance degradation was seen after all H2S poisoning tests even at an H2S concentration of 0.1 ppm. Degradation is initially quite rapid, but after a period of time the rate of degradation levels off. After poisoning was complete, the H2S flow was stopped and the cells were allowed to recover. Some recovery was seen after poisoning, but cell performance was never fully recovered.

Jan 1, 2005

By M. Normandin

The performance of various polymers and other macromolecules used to flocculate red mud particulate materials in the Bayer process can be evaluated on the basis of their efficiency to achieve adequate settling velocity and turbidity level, The Jar Test is widely used in the mineral industry to determine the efficiency of solid-liquid separation processes, particularly for gravity settler of the Bayer process. However, a high level of variability is found in the data obtained by this methodology, In this study, different parameters of the cylinder test procedure are evaluated to determine their role in the overall variability of the method, As demonstrated by laboratory testing, the overall variability can be considerably reduced by good laboratory practices.

Jan 1, 2005

By Chin J. Chang

Powder metallurgy (P/M) technique is known for its capability of producing near-net-shape parts. Its specific characteristics have resulted in low cost and eliminated of many secondary machining. However, more and more P/M parts do require additional operations to fulfil their complex geometric features and surface roughness. Many of the machining factors that influence the machinability of cast and wrought steel parts, such as cutting speed, feedrate, coolant, tool geometry and shape, are also considered in the machining of P/M components. The special feature in P/M structure is the porosity that can decrease the machinability and shorten the tool life. Different variables have been considered in the machinability of P/M materials. Densities and the free machining additive manganese sulphide (MnS), are the two main factors of material composition, which dominate the P/M machining performance. Machining process is the main method that generates the desired working surface of machining components. This paper will discuss the metallurgical structure of the powder metallurgy components, their physical properties and possible issues when encountering machining operation. Turning operation has been tested in this investigation to show the relationship between the cutting speed, federate, cutting forces and chip formation. This investigation also discusses how the free machining additive, manganese sulphide, affects the P/M structure and machinability in order to understand how the metallurgical structure can affect the machining operation and, how to obtain the optimised surface results.

May 1, 2001

By E. L. Horner

"Srnoky River Coal is capable ofprocessing 3 million tonnes per year ofrun-of-mine coal at the Smoky River Coal preparation facilities to produce 2.1 million tonnes of high quality, low volatile coking coal for export markets. Multi-seam surface and underground mining operations are scheduled to maintain raw coal feed to the plant. Two beneficiating circuits wash the coal. A heavy medium cyclone circuit cleans the plus 0.5 mm coal and a froth flotation circuit cleans the minus 0.5 mm coal. Clean coal is thermally dried, loaded into unit trains, treated for dust suppression, and transported to west coast port facilitiesf or export. Plant by-products are used as thermal fuel Jn an adjacent power station. Quality control procedures ensure efficient resource recovery for a yield of uniform specification product, at a 7% ash level. Introduction Smoky River Coal operates surface and underground mines in the Smoky River coalfield. Approximately 3 million tonnes per year (mt/ a) of run-of-mine (ROM) coal can be processed at the coal preparation plant to provide 2.1 mt/ a of clean, high quality, low volatile bituminous coking coal. Coal is processed by heavy media and froth flotation cleaning circuits and is thermally dried.Raw Coal Characteristics The characteristics of the ROM coal, both in terms of quality and size consistency, vary with intrinsic seam qualities and mining methods employed. The two seams mined (No. 4 and No. 10) show distinctly different washability characteristics. Seam No. 4 contains relatively few middlings and can be readily cleaned by dense-medium cyclones and froth flotation to give a clean coal at specification ash content. Seam No. JO is more difficult to wash, and the ash content of the clean coal is higher than No. 4 seam at the same operating conditions. However, when the upper I m is excluded from the plant feed, the remaining lower section has washability characteristics similar to No. 4 seam. Coal mined by underground means sometimes contains caprock and consequently tends to be dirtier than similar coal mined by surface means."

Jan 1, 1985

By Gaston Gendreau

CETTE PRÉSENTATION traitera des différentes phases des opérations de la mine du Mont-Wright depuis ses débuts jusqu'à présent. A une brève description de la géologie du gisement, suivra un exposé des méthodes d'exploitation de la mine et du genre d'équipement utilize.

Jan 1, 1977

By L. I. Kiss, A. Larouche, V. Dassylva-Raymond

Control of the quenching capacity of the cooling water is of primary importance for maintaining the quality and recovery rate of ingots produced by direct chill casting. Industrially, this can be done using a cylindrical metallic probe undergoing rapid quenching by direct immersion in a reservoir filled with casting water. Such a test rig originally developed at Alcan Arvida Research and development Centre was modified and used to assess the role of key parameters affecting the boiling heat transfer. During the tests, the probe of the instrument undergoes the effects of different heat transfer mechanisms. An experimental study was performed in order to clarify the details of the probe-water heat transfer during rapid quenching. The heat flux along the surface was determined by mathematical modeling using the measured temperature signals, while the corresponding heat transfer regimes like stable and unstable film boiling, nucleate boiling and natural convection were identified by the analysis of high-speed video recordings. Aluminium

Jan 1, 2006

By J. D. McFarlane, V. Robinson

"The paper begins with a brief account of the naturarly occurring resources of gypsum and anhydrite and a discussion of their relative value and utility as sources of sulphur. The fundamental chemistry of recovering sul-phur values from calcium sulphate is discussed. (a) Thermal decomposition -discussed as impracticable; (b) Reduction to calcium sulphide; (i) Total Reduction-The chemistry is outlined and the Dorr-Oliver and Bureau of Mines processes mentioned. The Elcor process is mentioned and certain deductions made from available information.(ii) Partial Reduction-This is stated as the basis of the only proven process, namely ""The Cement -Sulphuric Acid Process."" The possibility of recovering lime is mentioned as an aside, but dismissed for lack of commercial application. The history of the cement -sulphuric acid process is covered briefly and a list of plants in commercial operation included. A brief elementary account of the basic chemistry of cement production is followed by a discussion on raw materials and fuels. A short account of the flow scheme of a typical plant, with notes on the operating peculiarities, precedes an account of product quality. The latest developments which enable by-product gypsum to be used as a raw material are discussed, with an indication of how the flow scheme is modified. A statement of feasible plant capacities is followed by requirements of raw materials, services, labour, etc., and finally some indication is given of capital costs."

Jan 1, 1969

By L. Becze, B. Pierre, S. Di Carlo, G. P. Demopoulos

From January to June 2007, the autoclave production at the Kidd Metallurgical Site was severely affected as a result of plugged discharge lines and extensive precipitation/crystallization of sulphates that caused massive scaling in different autoclave compartments. Work was performed at McGill University to understand the root causes. The crystallization of zinc and ferrous sulphate salts was investigated in terms of solubility measurements. Scale samples were characterized using chemical and mineralogical-spectroscopic analysis. In this paper, following a description of the Kidd zinc pressure leach operation, highlights from this investigation are presented and solutions used to overcome the problem are outlined.

Jan 1, 2008

By R. Simard

"Conventional exploration strategies identify many mineral deposits as potentially interesting, although only a few of them turn out to be of economic importance. In the context of exploration for sulphide nickel deposits in the Canadian Shield, a decisional model, based on a statistical study of parameters relative to nickel deposits as well as to barren sulphide occurences, has been developed.Because such geophysical variables as gravimetry, aeromagnetism and topography could be related to the relative importance of nickel-bearing deposits, a statistical analysis of 13 such variables was carried out for 98 targets which were considered promising after conventional exploration. Among these 98 targets are36 sulphide nickel deposits in the Canadian Shield and 62 drill-tested non-economic occurrences. The results of this study led to the development of a linear logistic model that permits evaluation, for each of the targets, of the probability of finding a nickel deposit of potential commercial interest. This decisional model can thus complement conventional exploration strategies.RésuméLes stratégies conventionnelles d'exploration définissent un très grand nombre de cibles comportant un inténet minier potentiel dont seules quelques-unes correspondent à des gisements économiquement importants. Dans Ie cadre de l'exploration des dépôts nickélifères du Bouclier Canadien, nous avons défini un modelé de décision fonde sur l'étude statistique de divers paramètres relatifs tant aux gisements d'importance qu'aux cibles dites stériles.Ayant fait l'hypothèse que certaines variables géophysiques (gravimétrie, aéromagnétisme et topographie) peuvent suffire à fournir des indications sur l'importance relative d'un gisement nickélifère, nous avons entrepris l'analyse statistique de 13 variables évaluées sur un échantillon de 98 cibles considérées comme potentiellement intéressantes par les stratégies conventionnelles d'exploration. Ces 98 cibles se composent de 36 dépôt nickélifères d ‘importance recontrés sur tout Ie Bouclier Canadien et de 62 cibles stériles reconnues par forage. Nous avons défini à l'aide de ces données un modèle logistique linéaire. Ce dernier nous permet d'évaluer pour chacune des cibles les chances de trouver un gisement. Ce modèle de décision peut done s'inscrire comme outil complémentaire aux stratégies conventionnelles d ‘exploration."

Jan 1, 1980

By J. Álvarez, J. Mesías, C. O. Gómez

"Operations routinely run flotation tests in laboratory mechanical cells to determine adjustments to plant operation based on feed flotation response or the effect of new reagents and dosages. The metallurgical results of these tests are certainly affected by changes in bubble size, which simultaneously impact the recoveries of the collection and froth zones. It is known that bubble size depends on the characteristics and operation of the machine in use, particularly on the gas flow rate delivered to the unit and the selected frother type and dosage. Although flotation rate constants have been related to bubble size, bubble surface area flux seems to be a more fitting variable to correlate flotation kinetics and cell performance, as it integrates bubble size and superficial gas velocity effects. However, although some evidence has been provided, a categorical relationship between cell recovery and bubble surface area flux has not been established. Our interest is to demonstrate this relationship to use it as a basis for developing soft sensors to track on-line collection zone recovery in cells. Flotation tests were designed to produce Cu concentrates for a range of bubble surface area flux values, obtained through changes in frother concentration at a constant gas flow rate, and by increasing gas flow rate at the same frother concentration. The tests were run on samples prepared from an ore batch supplied by a local operation, following strict grinding and flotation procedures, with a shallow froth to approximate cell recovery to that in the collection zone. Bubble sizes were determined using the sampling-for-imaging technique developed at McGill. The results unequivocally showed a consistent positive correlation between cell recovery and bubble surface area flux, and significant variations in performance when frother addition and gas flow rate were changed.INTRODUCTIONMineral flotation is a separation process to produce concentrates of valuable minerals by selective attachment of particles to the surface of bubbles. The process is carried out in machines where air is injected through a mineral pulp to form bubbles, and operated to create two zones: a bottom one (collection zone) where bubbles are continuously generated under conditions adequate to form bubble-particle aggregates by collision of the rising bubbles with suspended particles; and a top one (froth zone) where bubbles and bubble-particle aggregates continue to rise while concentrating and forming a froth layer for water and entrained particles to drain back to the collection zone, before overflowing as a concentrate stream. The phenomena occurring in these zones are complex and, in many cases, interactive, as they simultaneously affect stages of the particle separation sequence occurring in both zones. Although there have been significant advances in instrumentation to characterize particle and bubble populations, these have not resulted in knowledge to explain or models to describe phenomena from fundamental principles. Measurements continue to be limited to the development of empirical models for predicting the effect of operating variables on performance."

Jan 1, 2016

"The ore currently being milled at Delnite is a high pyrrhotite ore with the gold intimately associated with the pyrrhotite. To get maximum recovery of the gold with the lowest reagent cost, it is necessary to keep the pH as low as possible In the laboratory the best results were obtained with a pH of 10 but in the plant it was found that a pH of 11 was the minimum practical pH. With the n1anual control it was difficult to maintain this figure.The Mines Branch had a conductivity probe (see Fig. 1), developed by Dr. G .G. Eichholz that they wished to try out in plant operation.On June 17, 1963, the probe with all necessary control equipment was installed in the regrind circuit (see Fig. 2) at Delnite Mines. Crushed quick lime is fed at this point but it is also necessary to feed hydrated li1ne at two other points in the cyanide circuit in order to maintain the pH close to 11. 0 throughout the circuit. Only the feeding of the quick lime at the regrind mill was controlled in this test.One thing that concerned me with the operation of the probe was whether the reading on the probe chart would correspond to the pH. A look at the graph accompanying this paper will show that except for very minor variations the graphs of the chart reading and the pH reading are parallel. The upper graph shows that the pH reading and the lime titrations also correspond and that the cyanide titrations appear to have little effect on the pH reading.Table 1 gives the results obtained for the two months before and after the instal1ation of automatic control as well as the two months of control. Unfortunately there was a decided change in ore just after the automatic controls were removed. There was much less pyrrhotitc in the ore than usual thus changing the need for lime and cyanide."

Jan 1, 1964

By J. Manchisi

This study has investigated the use of blast furnace slag as functional adsorbent for metal ions in acid mine drainage treatment. This opportunity has not yet been developed into a practical process partly because of limited understanding of rates and mechanisms of adsorption process and inconsistency in interpretations of adsorption data. The overall objectives were to determine the efficiency and mechanisms of sorption process of metal ions in a multiadsorbate system. We employed standard materials characterisation techniques to analyse composition, structure and surface morphology of the slag. Batch adsorption experiments were then conducted to study the mechanisms, kinetics and efficiency of metal sorption as a function of pH, phase ratio, mixing time, mass and particle sizes of slag. Both XRF and adsorption data suggested the slag to possess acid neutralising capacity. This slag is non-crystalline based on XRD pattern, has adequate porosity and pore volume comparable to similar commercial adsorbents but it has inferior pore structure, pore size distribution and BET surface area to be effective under wide applications. Metal sorption increased with decrease in slag particle diameter, decrease in initial metal concentration and increase in the mass of slag. Although slags have demonstrated to efficiently treat low concentrations of single and multiadsorbate effluents using fine particle sizes, they have limited capacity to treat multiadsorbate systems for some metal ions. This is probably due to low affinity, competitive adsorption or limitation in material?s adsorptive properties. Sorption mechanisms probably involve precipitation and ion exchange on the basis of alkaline pH and exchangeable slag surface ions. Sorption preference is proposed as Fe2+>Cu2+>>Cd2+>Co2+>Mn2+. Despite these limitations, deeper understanding of sorption behaviour of metal ions by slags for application in dilute and large volumes of effluents is necessary where precipitation and other standard techniques are either inefficient or uneconomic. Thus, this study has established that sorption capacity of slag to remove metal ions from acidic effluents is selective, limited to certain metal ions and for other ions only at low concentrations. Further adsorption studies in multiple solutes under various experimental conditions or those that can propose an economic slag activation process are needed that improves or widens adsorption window.

Aug 1, 2013

By John Lund

INTRODUCTION GOLD-BEARING placers of Alaska and the Yukon Territories are buried under a layer of permanently frozen alluvial overburden, or 'muck', which varies in depth from twenty to one hundred feet. The placers, and the decomposed bedrock layers upon which they are deposited, are also permanently frozen. During the summer, surface muck which is exposed to the sun will thaw, but only to a depth of a few feet. To reach a valuable deposit, the frozen overburden must be either penetrated with shafts, or stripped from the deposit entirely. In either case, before the placer can be mined, it must be thawed. At modern dredging operations, the frozen muck is stripped from the placer by powerful jets of water from hydraulic giants. The placer, and several feet of decomposed bed-rock, are then thawed by forcing water through narrow pipes which have been driven into the deposit. Other methods of thawing frozen placers were used extensively during the early years of the Klondike 'gold rush', but experimentation later proved that creek water at its natural summer temperature was a more effective and economical thawing medium than any other which had been used. EVOLUTION OF COLD WATER THAWING Early prospectors of the far north reached placers by digging shafts through the frozen muck. They then thawed the placer sand and gravel by building wood fires at the bottom of the shafts.

Jan 1, 1951

By M. J. Gagnon

The agglomeration of particulate materials is used in many mineral processes to enhance the settling of the fine particles, Depending upon many physical and chemical parameters, the aggregates demonstrate specific density-size distributions, In this study, a fractal model of the agglomeration process is introduced, Based on reliable experimental data and on physical calculation, the model presented helps to envisage the initial formation of the micro-flocs, and to interpret the subsequent interactions between the aggregates in terms of either coagulation or flocculation, Data from different sources, materials and different agglomeration processes are analysed and compared in the light of the proposed model.

Jan 1, 2005

By S. Timbillah, R. LaDouceur, C. A. Young

A low carbon-chain trithiocarbonate ((NaOOC)CH2SCSSNa), known as Orfom® D8, was tested as an organic depressant in the differential flotation separation of chalcopyrite and molybdenite in the presence of sodium isopropyl xanthate (SIPX) or potassium ethyl xanthate (KEX). Flotation studies show that Orfom® D8 depressed chalcopyrite while molybdenite remained floatable. A study of the mechanism of adsorption indicated that Orfom® D8 adsorbs on chalcopyrite through its trithiol (CS -) functional group via both chemisorption and Orfom® D8-metal complexation. The Orfom® D8 depressant is selective and does not form any Orfom® D8-molybdenite bonds. Thus, the combination of the depressant in the presence of either collectors depressed the chalcopyrite and floated the molybdenite. Fundamental parameters of the Orfom® D8 including pKa determination as well as possible decomposition products of the depressant are reported. This study includes an economic case illustrating why using Orfom® D8 can be beneficial. INTRODUCTION Depressants are incorporated in mineral flotation units in the minerals processing industry to make or keep certain minerals selectively hydrophilic. Most reagents used are inorganic and include, for instance, sodium hydrosulphide (NaHS) which is the major reagent used for depressing sulphide minerals, particularly those containing copper, iron and lead. However, the issues with its use include high toxicity, tendency to explode, strong odour, and high consumption due to required high dosages as well as its tendency to oxidise in air. The latter can be overcome by conducting flotation in inert atmosphere such as nitrogen and recycling of the flotation process water. The use of more novel depressants that are essentially organic including homopolar reagents with hydrophilic functional groups on both ends of its structure adsorb onto a target mineral surface with one polar end, the other polar end orients into the bulk solution making the surface hydrophilic and thus, ensuring that the desired mineral does not float. The stringent environmental and safety regulations being implemented in recent times mean that the search for more environmentally friendly chemical reagents is a must have. The use of organic depressants for flotation systems such as Cu-Mo sulfide bulk concentrates has become increasingly important because of the health, safety and environmental issues surrounding the use of inorganic depressants. Nagaraj et al. (1983) investigated the Cu-Mo sulphide flotation system using a structure-activity study of depressants. They found that a major advantage of organic depressants is the ability to tailor-make organic molecules to suit many requirements and thus, eliminate the guess work approach that was predominant in the industry.

Jan 1, 2019

By D. Chakravarty, B. Samanta, D. Ghosh

Autonomous robots are useful for 3D underground mine mapping to avoid human exposure to hazardous spaces. To prepare a precise mine map, a self-navigating robot must navigate an arduous path, avoiding obstacles and sensing the environment. A prototype laboratory-scale robot was built and evaluated through a mock-up in a test mine gallery. It was outfitted with a 2D laser scanner, a stereo camera for obstacle avoidance, and a high-precision, laser-based imaging and digitizing system for collecting 3D point cloud data. Various algorithms were used for scan matching to facilitate simultaneous localization of the robot for mapping.

Jan 1, 2014