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By W. R. Cowan

The Caledon Outwash is a large deposit of glaciofluvial gravel and sand located 55 km north west of down town Toronto. For the most part it was laid down in a meltwater channel fronting the Paris Moraine about 14,000 years ago. Applying the braided bar model of Eynon and Walker (1974) the principal facies present are imbricated coarse gravels (bar corefacies); crudely stratified, imbricated bar top sandy gravels; and trough crossbedded side channel sands and gravelly sands. Of lesser importance are crossbedded bar front gravels, shallow braided stream facies gravels, and stoss side facies sands and pebbly sands (rare). Lithologically these deposits are characterized by FIGURE I. Geological relationships of Caledon Outwash. Industrial Minerals in Canada up to 95% Ordovician limestone and siltstone in the gravel fraction. A siltstone content of up to 34% requires that beneficiation be carried out for the production of better quality aggregates. Resources remaining are estimated to exceed 500 million tonnes in 3000 ha of the most suitable part of the deposit. Present production is about 4.5 million tonnes per year, shared by several producers.

Jan 1, 1984

By M. Krasowska

Dynamics of collision and kinetics of the bubble attachment to hydrophobic solid plates (Teflon) of different surface roughness were investigated. The experiments were carried out in such a way that probability of the collision and probability that the detachment will not occur were equal always 100%. Thus, it was possible to determine effect of the surface roughness on the bubble attachment (three phase contact formation, TPC) only. A high-speed camera (1182 Hz) was used to record the velocity variations, bouncing and time of attachment of the bubble colliding with Teflon plates having different surface roughness (5 different plates). Roughness of the plate surfaces was modified in a mechanical way using different abrasive papers. It was found that the roughness had a crucial influence on the time-scale of the TPC formation and attachment of the bubble colliding with the Teflon plates. Despite high hydrophobicity of all plates (contact angles 1100 -115º) it was observed that at the smoothest surfaces (called "Teflon I" and "Teflon II" and having surface roughness below 1 um) there was no attachment during the bubble first collisions. Prior to the attachment four or more "approach?bouncing" cycles of the colliding bubble were observed there and simultaneously the bubble shape varied rapidly within time intervals below 0.85 ms. Time of contact of the colliding bubble with the Teflon plates was very short; 2-3 ms. These results indicate that during that short time of the collision the liquid layer separating the colliding bubble and the solid surface did not reach a critical thickness of its rupture.

Jan 1, 2006

By C. Arson

"Optimizing hydraulic fracture injection parameters in order to maximize hydrocarbon extraction and to avoid extensive borehole spalling is still an open issue. In this paper, the Differential Stress Induced Damage (DSID) model is employed to simulate the anisotropic damage distribution around pressurized boreholes drilled in fractured shale. The loading path is purely mechanical: excavation and fluid injection are simulated by stress relaxation followed by pressurization. We investigate the effect of pre-existing fracture orientation, in-situ stress and injection pressure on the propagation of anisotropic damage during pressurization. Finite Element results indicate that (1) damage initiates and develops when the ratio of two in-situ stress component deviates from 1, and the magnitude of damage is proportional to this stress deviation; (2) For a given in-situ stress field, damage initiates for a certain threshold of injection pressure, and the damage zone extends as the injection pressure increases; (3) A pre-existing fracture only affects the damage zone locally; the orientation of that fracture does not affect the damaged zone, which is controlled by in situ stress and injection pressure.INTRODUCTIONHydraulic fracturing is used to increase shale permeability and to enhance hydrocarbon extraction. In order to maximize the extraction ratio and to avoid wellbore spalling and clogging during fluid injection, the parameters related to injection for each particular site need to be optimized. Therefore, it is necessary to clearly understand how shale responses upon excavation and pressurization.It is well known that breakouts grow in the direction of minimum compression and that plastic deformation around wellbores tends to arrest breakouts (Zoback et al., 1985). Laboratory acoustic emission tests revealed that fractures propagate along the direction of maximum compression stress, and fractures (breakouts) are surrounded by the Excavation Damaged Zone (EDZ), in which rock properties are weakened by the presence of micro cracks (Eberhardt et al., 1999; Martino et al., 2004). The anisotropy from orientated foliations and cracks may influence the development and propagation of fractures and breakouts (Everitt et al., 2004). Sonic televiewer logs proved that during hydraulic fracturing, fluid injection further alters the stress distribution (Evans et al., 2005). Shale natural fabric strongly affects the evolution of the EDZ around boreholes."

Jan 1, 2015

By Lionel A. York

THE first application of the cementation process took place in the year 1864, according to H. Standish Ball, when a break in the brickwork lining at a depth of 270', in one of the Rhine Preussen pits near Homburg, was sealed by running in milk of cement from the surface by means of a small hand pump. At about the same time Monsieur Portier adopted the method in France for repairing breaks in shaft lining. Figure 1 is descriptive of the Portier system and is of interest when compared with modern practice. During the next thirty years numerous attempts were made to improve the process; the general method used in sinking being to put clown bore holes outside the perimeter of the shaft for the purposes of injection. The cementation process was first recognized as an important as-set to mining in 1896 when Monsieur A. Francois developed his method of boring and injecting inside the shaft below the permanent water level. The Francois cementation process rapidly attained fame on the Continent and many shafts were sunk by its use in France, Belgium and

Jan 1, 1961

By D. G. F. Hedley, F. Grant

"In 1958, the Ontario Department of Mines appointed a committee to study the accident situation and mining methods used in the uranium mines in the E1liot Lake district. This committee reviewed the existing knowledge on mine design, pillar support and roof spans and came to the conclusion that scientific knowledge had not yet reached the stage of producing rational design procedures which would reduce the dependence on trial-and-error methods. Since that time, the Mining Research Centre has made numerous stress measurements in two mines to define the pre-mining and pillar stresses. A comprehensive series of tests has been done in the laboratory to measure the compressive strength of the rock; a geological survey of the region has been made to evaluate tectonic stresses; and a survey was done on mining conditions with regard to stable and unstable pillar configurations. This information has been used to evaluate pillar design as effected by pillar width and height, depth below surface, extraction and pre-mining stress fields. The resultant design of pillar widths and corresponding extraction as the depth increased is in line with past and present experience in these mines. The information available on roof stability is still insufficient to design stable stope spans with the same degree of confidence; experience and trial-and-error methods are still required."

Jan 1, 1972

By M. B. Kime

"Discrete-element method (DEM) modelling is a powerful tool for studying particulate systems within the mineral processing industry. DEM simulations were conducted to investigate the power draw, load behaviour, and impact energy profile of an experimental ball mill under different milling conditions. The variables considered were mill rotational speed (percent critical speed), ball size, and lifter face angle. The simulation results indicated that the grinding efficiency would be enhanced by using 80% critical speed, 30 mm ball diameter, and 45° lifter face angle. These findings can be useful in guiding actual ball milling tests involving an ore sample.RÉSUMÉ La modélisation par méthode des éléments distincts (MED) est un outil puissant qui permet d’étudier les systèmes particulaires au sein de l’industrie de traitement des minerais. Des simulations par MED ont été menées de façon à étudier le profil de la consommation énergétique, du comportement de la charge et de l’énergie de rupture d’un broyeur à boulets expérimental dans diverses conditions de broyage. Parmi les variables prises en compte figuraient la vitesse de rotation du broyeur (vitesse critique en pourcentage), la taille des boulets et l’angle de coupe de la cornière élévatrice. D’après les résultats de la simulation, on pourrait améliorer l’efficacité de broyage en utilisant une vitesse critique de 80 %, un diamètre de boulet de 30 mm et un angle de coupe de 45 ° de la cornière élévatrice. Ces résultats peuvent se révéler utiles pour les essais concrets de broyage à boulets impliquant un échantillon de minerai.INTRODUCTIONComminution is a very energy intensive process. It consumes approximately 5% of the electricity produced worldwide and more than 50% of the total energy used in mineral processing plants (Pokrajcic, 2010). Among all the comminution stages, ball milling is one of the most energy intensive processes. In ball mills, rotational movement provides the rise of the load and the media that are projected and impact on the mill shell at lower angular displacement, resulting in particle breakage. Ball mills are able to reduce particle size over a relatively wide range of particle sizes. This explains their wide applicability in research laboratories and the mineral processing industry."

Jan 1, 2017

By S. K. Dimitrov

?Ellatzite Med? is one of the biggest mining companies in Bulgaria, processing about 12,000,000 t of ore per year. Waste materials left after extraction of copper concentrate are deposited in tailings dam ?Benkovski 2?. The hydraulic structure is built according to the downstream method, through hydrocyclonization where the downstream batter and the body of the wall are formed by the separated coarse sand particles of the separated tailings. In connection with the prolonged concession of Ellatzite Med and the enlarged capacity of Benkovski 2, the tailings dam has expanded on to the surrounding terrain. To guarantee a normal hydrocyclonization and build up of a tailings wall during waste deposition from the ore mill, the technological scheme of the hydraulic transport system of Benkovski 2 has been changed.

Aug 1, 2013

By J. G. Manchuk, M. Thurston

"The degree of uncertainty associated with a natural diamond resource is important to quantify from the time of discovery through the production lifetime. Data collection occurs during the discovery, exploration, delineation, and production or recovery phases. Quantifying the relationship between data and uncertainty is an important component of project valuation. The value of data is measured as their potential to reduce uncertainty if they are collected. A method is developed using Monte Carlo simulation for predicting resource uncertainty and valuing data during critical phases of development, particularly discovery and exploration. The technique is applied to diamond pipe deposits.RÉSUMÉ Il est important de quantifier le degré d’incertitude associé à une ressource diamantifère naturelle, depuis le moment de sa découverte et durant toute la durée de l’exploitation. La collecte de données se fait durant les phases de découverte, d’exploration, de délimitation, et de production ou de récupération. La quantification de la relation entre les données et l’incertitude est une composante importante de l’évaluation du projet. La valeur des données est mesurée en tant que leur potentiel à réduire l’incertitude si elles sont recueillies. Une méthode a été développée qui utilise la simulation de Monte Carlo pour prédire l’incertitude de la ressource et évaluer les données durant les phases critiques du développement, surtout celles de la découverte et de l’exploration. La technique est appliquée à des gisements de cheminées diamantifères."

Jan 1, 2015

By Elmer Palmer

As part of the Goldcorp Inc growth plan Minera Peñasquito SA de CV has developed its polymetallic deposit with a large ?state of the art? concentrator to process lead and zinc ores. The plant consists of two grinding lines including 38ft diameter SAG mills and 24ft diameter ball mills. During mid to late 2009 concentrator commissioning activities commenced. First concentrates were produced in October 2009 and now the plant is meeting its design basis of 65,000 mtpd per line. This paper describes the design and operational experience to date for its grinding circuit design, together with the recently commissioned HPGR crushing circuit.

Jan 1, 2012

By P. Langlois, G. Labonté, J. J. Barrett, J. Holmes

"The Voisey’s Bay mill processes a high-grade pentlandite and chalcopyrite ore in a largely pyrrhotite/troilite matrix. From 1994 to 1997, circuit development focused on making a 14% nickel concentrate. When flowsheet development resumed in 2001, the target grade was raised to 20% ni. initially triethylene tetramine and sulfite pyrrhotite depressants were used in a lime circuit, but by recycling process water and the contained thiosalts, the required nickel grade was made without depressants. construction of the mill was fast-tracked, with start-up in september 2005. ramp-up was faster than other recent nickel installations, with tonnage being limited by concentrate dewatering due to higher-thanexpected ore grades.RÉSUMÉ l’usine de traitement de Voisey’s Bay traite un minerai à teneur élevée en pentlandite et chalcopyrite dans une matrice formée surtout de pyrrhotite/troïlite. De 1994 à 1997, le développement du circuit ciblait la production d’un concentré à 14 % de nickel. lorsque le développement du schéma de traitement a été repris en 2001, la teneur cible a été élevée à 20 % de ni. initialement les déprimants triéthylènetétramine et sulfite de la pyrrhotite étaient utilisés dans un circuit à la chaux; cependant, en recyclant l’eau du procédé et les sulfosels qui y sont contenus, la teneur en nickel a été atteinte sans utilisation de déprimants. la construction de l’usine de traitement a été accélérée et elle a démarré en septembre 2005. la mise en opération a été plus rapide que pour d’autres installations récentes de nickel; le tonnage traité étant limité par le séchage du concentré en raison des teneurs de minerai plus élevées que prévu.INTRODUCTIONnickel was discovered on canada’s east coast in the vicinity of Voisey’s Bay, northern labrador, by chislett and Verbiski (Higgins, 2011) while working for Diamond Fields resources in 1993. The ovoid deposit was subsequently delineated in the winter of 1994–1995. By the end of 1995, the ovoid had been well explored, and at that time was thought to have a reserve of at least 30 million tonnes (Mt), with an average grade of 2.83% ni and 2.0% cu (naldrett, singh, Krstic, & li, 2000). Drilling to the east of the ovoid indicated the presence of significant mineralization. in June 1995, inco limited bought a 25% share in the Voisey’s Bay nickel company (VBnc), which was a subsidiary holding company set up by Diamond Fields. inco also bought 8% of Diamond Fields and negotiated the right to sell all the nickel produced from VBnc for 20 years as part of this agreement. in april 1996, inco bought Diamond Fields and acquired the remaining 75% of VBnc shares."

Jan 1, 2017

By J. M. Cooper

The HBMS reverb furnace in Flin Flon was originally designed in the late 1920s. Throughout the decades campaign life has been increased due to operational practices, technological changes and brick quality improvements. In recent decades the campaign life had been extended such that a complete rebuild was scheduled every 3 years. The latest furnace rebuild and start up has been after a campaign life of nearly 6 years. Brick construction methods and techniques along with furnace operational practices allow the present campaign to be double that of the historical campaign length.

Jan 1, 2007

By I. R. Jonasson, R. W. Boyle

"Current interest in the distribution of mercury in the natural environment comes from quite different, though not unrelated, sources. Mercury has long been an important metal in many industries and has, therefore, been much sought after by mining interests. The presence of mercury traces in the various media of the natural environment, namely soil, rock, air, water and vegetation, is exploited by geochemists not only to find mercury and polymetallic ore deposits, but also to find most other types of economic metal mineralization. More recently, however, mercury has caught the attention of health authorities and environmental scientists who are becoming increasingly concerned over the hazards of mercury wastes and the danger these present to the environment and to man. It is now apparent that the trace quantities of mercury, considered so important and helpful to exploration geologists, can be concentrated in the biosphere to such levels as to present considerable problems for ecologists. This article summarizes most of the available data on mercury contents in materials of geological interest and presents average normal values for rocks, ores, minerals, soils, sediments, waters and plants. The geoch.emical cycle for mercury in nature is presented and the mechanisms of mercury migration around the cycle are discussed."

Jan 1, 1972

By W. C. Zhu, C. H. Wei, L. L. Niu

With an increase of mining depth, a series of mining-induced hazards such as rockburst, coal and gas outburst, roof collapse, and water burst are getting more serious and more frequent. The intrinsic mechanism responsible for the occurrence of mining-induced hazards is the damage and unstable failure of rockmass or coal seam. The most distinct difference between deep and shallow levels is the so-called three ‘high’ (H3) conditions, i.e. high geo-stress, high fluid pressure and high geo-temperature. Therefore, the response of rock or coal to the deep mining operation is a phenomenon involving thermal (T), hydraulic (H), and mechanical (M) processes. Most importantly, mining excavation may vary the rock stress condition greatly, which may be a key factor to trigger the mining-induced hazards such as rockburst. In this regard, it is of great significance to clarify the damage and failure mechanism of rock and coal under coupled THM conditions, in order to clarify the rock failure mechanism responsible for the occurrence of mining-induced hazards. Thereafter, the mining-induced hazards cannot be predicted with confidence by considering each process independently. Of course, the requirement to include coupling of these processes depends on the specifics of the mining-induced hazards under consideration. For example, the water inrush is considered as a coupled hydro-mechanical (HM) process, in which the unstable failure of rockmass occurs under the combined contribution of geo-stress and water pressure. As for the coal mining at depth, in addition to high geo-stress and gas pressure in coal seam, the high geo-thermal condition that may greatly change the adsorption / desorption of gas and gas flow should be taken into account. Firstly, a general-purpose mathematical model for rock damage and failure process under coupled THM conditions is formulated based on damage mechanics principle, and it is solved by finite element method (FEM). In this model, the deformation and damage of rock, fluid flow and thermal transfer in rock would interact with each other, one process affects and initiation and progress of another. Then, the model is used to predict the mining-induced water outburst, where it is simulated as coupled hydro-mechanical (HM) problems. Based on the numerical simulation, the dimension of water-proof pillar is designed. Finally, the gas drainage from deep coal seam is numerically evaluated, where the coupled coal-gas interaction considering the effect of gas adsorption/desorption, gas flow in coal seam and geo-stress and geotemperature, is comprehensively taken into account. The proposed model could be used for clarifying the mechanism of mining-induced hazards in deep-level mining.

Jan 1, 2015

By Dean Millar

Clean, green, cheap compressed air can be produced efficiently and renewably by modernization of a 19th century technology ?The hydraulic air compressor has no moving parts ?After commissioning, the Ragged Chutes HAC operated for 70 years, only being stopped twice for repairs to the intake heads ?Operates using hydropower from Montreal river ?Produced air for ~29 silver mines in Cobalt, 20 km distant

May 1, 2013

By J. A. Harle

Introduction When considering power in Alberta, there automatically come to mind ideas of either hydro or thermal generation, leaving in one's thought an uncertainty as to which one would propose. There is frequently an obvious source of power in some locations on our fastflowing rivers, the major possibilities being described in the report on Surface Water Supply and Water Power of Alberta issued by the Alberta Government in 1948, but it must be realised when reading that report that the sites so described will require extensive geological and other surveys before they can be exploited, and account must be taken also of the transmission distances involved in each instance. From a conservation point of view, where water power can be economically developed and power transmitted to the load centres, this should be done, and our thermal resources should be husbanded for our coming generations, especially if our water resources are falling owing to glacial shrinkage.

Jan 1, 1951

By Alan Rice

Abstract-The mechanism by which stratiform ore deposits of PGE (platinum-group elements) are laid down in ultramafic igneous complexes is not completely clear. Early studies by the author and coworkers on numerical analyses of the convective cooling of low-Rayleigh-number magma chambers examined the effect of suspended crystal load on fluid density, and raised the possibility that the growth of the suspended crystal load during cooling could split a magma chamber into several convecting layers. The lower layers would have a higher content of refractory phases than the upper layers, which would consist of more evolved melt. This paper considers numerical modelling, as well as theoretical and experimental work in other fields dealing with suspended loads in fluids. The calculations, which are based on the physics of convecting magmas, yield quantitative relationships consistent with the observation that economically interesting stratiform PGE deposits are restricted to large magma bodies, and also yield estimation of the depth in a magma chamber at which certain grades of mineralization may occur.

Jan 1, 1997

By Alan Rice

The mechanism by which stratiform ore deposits of PGE (platinum-group elements) are laid down in ultrama?c igneous complexes is not completely clear. Early studies by the author and coworkers on numerical analyses of the convective cooling of low-Rayleigh-number magma chambers examined the effect of suspended crystal load on ?uid density, and raised the possibility that the growth of the suspended crystal load during cooling could split a magma chamber into several convecting layers. The lower layers would have a higher content of refractory phases than the upper layers, which would consist of more evolved melt. This paper considers numerical modelling, as well as theoretical and experimental work in other ?elds dealing with suspended loads in ?uids. The calculations, which are based on the physics of convecting magmas, yield quantitative relationships consistent with the observation that economically interesting stratiform PGE deposits are restricted to large magma bodies, and also yield estimation of the depth in a magma chamber at which certain grades of mineralization may occur.

Jan 1, 1997

By G. Wren

As base metal sulphide resources become increasingly challenging to process, producers seek alternative options to treat concentrates. This study considers the mineral, elemental, and leaching character of a West Australian nickel sulphide deposit (Cosmos Nickel Project). After a brief review of the published work bench top leach tests were conducted to examine the factors which impact the kinetics of nickel sulphide leaching such as particle size, temperature, acid strength and type, concentration of copper sulphate and sodium chloride, and oxygen partial pressure. The effect of sodium chloride was considered due to the common occurrence of hyper saline water at West Australian nickel sulphide mine sites. Ultrafine grinding to an 80% passing size of 10 µm resulted in high nickel leaching efficiency. Moreover, higher concentrations of acid, copper(II) and sodium chloride also gave higher nickel and cobalt leaching efficiencies but arsenic precipitated as FeAsO4. Under the most suitable conditions the extractions of nickel, cobalt and arsenic at 90oC after 6 hours were >95%, 90% and <5%, respectively. The comparison with results from high pressure operations indicates the possibility of using a hydrometallurgical flowsheet based on fine grinding and atmospheric pressure leaching and warrants further investigations.

Jan 1, 2014

By Kenneth G. Thomas

Since approximately 2003 we have witnessed the unprecedented escalation in commodity prices. Coupled with economic chaos following the 2008 economic downturn this has caused difficulties in controlling schedule, capital costs and operating costs for mining projects. Once again escalation has returned to commodity prices fuelled by growth in the BRIC countries especially China and Brazil. This is further exasperated by the missing generation of skilled technical personnel not graduating from universities in the 1980s and 1990s owing to depressed commodity prices. This paper examines the six tenets for successful project implementation.

Jan 1, 2011

By Anton Gronningsater

MR. J. R. GORDON: The authors are to be congratulated for their excellent papers on Copper-Nickel Matte Converting. Mr. Drummond&apos;s paper contains the results of a thorough and exhaustive study of a series of converter charges. Mr. Gronningsater has presented convincing arguments in favour of his claim that the converter has been neglected as a smelting machine for ore. Some of us may not be inclined to agree with his conclusions. Converting, like most metallurgical operations, is a compromise between an ideal and a practical operation. If it were possible for one to neglect entirely the matter of converter linings, I believe we would all agree that the proper flux for matte in a converter would be pure quartz. Under such ideal conditions, one would, if proper temperature were maintained, make the smallest quantity of slag containing a minimum of magnetite. Converter slags are notorious for their high metal content and must always be subjected to a further cleaning treatment before being discarded. For that reason, the tonnage of converter slag produced should be minimized. If norite is used as a converter flux, then the tonnage of converter slag would be greatly increased if the silica content is maintained at 27 per cent or higher. I cannot agree with Mr. Gronningsater&apos;s suggestion that, in con¬sidering a converter flux, the sum of the silica, alumina, alkaline-earths, and alkalis should be considered as being of value. The alkalis and alkaline-earth contents of the flux will replace iron in the silicates formed and tend to increase the viscosity of the slags. However, if the converter is to be used as a smelting machine, it will be necessary to drop the silica content of the converter slag in order to avoid production of excessive slag tonnages.

Jan 1, 1942