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By D. E. M. Plaumann

"The wet grinding of asbestos has attracted the attention of engineers for many years as a means of improving fibre liberation from the ore. Today, added impetus for wet grinding has resulted from a need to minimize worker exposure to asbestos dust in conventional dry mills using air, as well as a need to provide a cleaner, technically superior fibre for use by product manufacturers. However , high viscosities of asbestos slurries create transport and grinding difficulties which have been a factor impeding use of a wet grinding process.Laboratory evaluation of reagents to reduce viscosities of asbestos slurries found that one reagent, XFS-4272.00, reduced the viscosity of a 35% (by weight) slurry by 75%. The impact of XFS-4272.00 on actual grinding parameters were evaluated using a pilot plant rod mill. Slurries containing 78% solids and XFS-4272.00 were successfully milled and asbestos fibres from that milling compared favourably in liberation and relative surface area to asbestos fibres obtained from milling a 4% slurry without additives.IntroductionAlthough the use of asbestos has been declining over the last few years, the large deposits of chrysotile in eastern Canada (Quebec in particular) remain very important. Asbestos production in Canada stands ninth in volume for mineral production with over 740 000 tonnes produced in 1985. Of this quantity, 722000 tonnes were exported with a value of $446 million . Canada is second in world production of asbestos behind the U.S.S.R ."

Jan 1, 1988

By Robert D. Brown

"Important tax changes, many of them of direct interest to the mining industry, were contained in the budgets brought down by federal and provincial finance ministers across Canada this spring. This month, Tax Notes presents a brief summary of important tax changes introduced at the federal and provincial levels in the last few months.IntroductionIn the March 1980 issue of the CIM Bulletin, Tax Notes surmised that the short-lived 1979 budget proposals of the former Conservative government offered a unique glimpse of budgetary changes that might be unfolded in 1980. Scene II of this ""now you see it-now you don't"" drama opened on April 21, 1980, when Finance Minister Allen MacEachen, in an ""economic statement""' reintroduced a selection of tax proposals taken from the ill-fated Conservative' budget of December 11, 1979, but refused to bring forward major new proposals in tax and finance.Mr. MacEachen proposed a 5% surtax on federal corporation income tax to apply in the 2 years from January 1, 1980 to December 31, 1981, as a slightly modified version of the same surtax proposed by former Finance Minister Crosbie in his December budget address. Mr. MacEachen also reintroduced a number of technical amendments which would affect the taxation of mining income in certain instances. In addition, a large number of other tax proposals suggested in the previous Conservative budget were also reintroduced, although there are some notable omissions."

Jan 1, 1980

By Alex Henderson

The underground hard rock mining industry has had little change since the mobile equipment era began in the 1970s. Equipment has become larger and faster but has not kept pace with the following challenges: ? Improvements in safe production, ? Increasing demand for metals, ? Environmental improvements, ? Decreasing grades, ? Increasing depth of mining, ? More metal from underground vs. surface mining, and ? Energy and green house gas awareness. We are on the cusp of a new mining era and must rethink how underground hard rock mining must change in order to meet these challenges. This paper will show historical changes and propose a set of guiding principles for the next era of mining. Mining has changed over the last century. Initially mining was primarily an endeavor carried on by private companies with minor environmental controls and few social expectations other than employment. In the mid to later part of the century the mining industry was facing new challenges: deeper mines, the London Metals Exchange markets for pricing, and environmental concerns related to acidic rock drainage coming to the forefront. In today?s context, mining has evolved in complexity with the social and environmental aspects equally or surpassing the technical complexities such as expanding from mining hard rock to laterites, and mining lower grades or at greater depths. Nowadays, communities must be considered as partners, both locally and globally and the increased international visibility pushes the mining sector to take a more balanced approach to the business of mining (Fig. 1).

May 1, 2011

By E. Essadiqi, P. Poruks, D. Boyd, D. Emadi, I. Yakubtsov, T. Turi

This paper reviews the results of an extensive study of microstructures and mechanical properties in bainitic linepipe steels. The research was carried out as a collaborative project between Queen's, Stelco and CANMET. Basic studies of phase transformations and mechanical properties in these steels established important relationships between processing schedule and microstructure evolution, and between final microstructure and mechanical properties. The best combination of strength and toughness properties is obtained with a microstructure comprising a matrix of intragranularly-nucleated bainite (`acicular ferrite - AF') and small (~ 0.5 µm) dispersed particles of martensite (`M/A'). We describe this as a dual-phase AF+M/A microstructure. An experimental study on 15-mm thick plate determined the window of steel composition and processing parameters which gives the dual phase AF+M/A microstructure. The minimum strength and toughness properties for Grade 621 (X90) linepipe steel can be achieved by either a lean steel composition (0.04C-1.77Mn-0.04Cr¬0.32Mo-0.31Ni-0.29Cu-0.08Nb) with extreme processing parameters, or by a higher alloy composition (0.04C-2.07Mn-0.50Cr-0.51Mo-0.04Nb) with a more industrially realistic processing schedule. It is proposed how this approach could be extended to obtain higher strength linepipe grades.

Jan 1, 2005

By T. J. Bruce, G. E. Agar, R. Stratton-Crawley

"A technique by which the design of a flotation circuit may be optimized is described and examples of the application of this methodology are given.Three interrelated criteria are defined and the application of these criteria to the selection of the optimum residence time for each stage of a flotation circuit is demonstrated. The criteria are:(1) Add no material to the concentrate that is lower in grade than the feed to that separation stage.(2) Maximize the difference in recovery between the desired mineral and the gangue.(3) Maximize the separation efficiency.Three independent systems were examined experimentally and it was shown that application of any of the criteria yielded similar results.It was demonstrated how the application of rate measurements (Criterion #2) could lead to the selection of a set of optimized times for several stages in a flotation circuit and that these could in turn be used to simulate the results of a locked cycle test. The predictions were checked against the experimental results from a locked cycle test and there was substantial agreement between the predicted and observed results."

Jan 1, 1980

By Robert A. Gault, T. Scott Ercit, Mehmet F. Taner

"Abstract -Vanadium mineralization occurs in oxide-rich horizons within the layered gabbro zones of the upper parts of the Bell River Complex, Matagami, Québec and the Lac Doré Complex, Chibougamau, Québec. The vanadium-rich horizons are well defined on the ground and in aeromagnetic surveys by their high magnetic susceptibility; consequently, magnetic susceptibility can be an indicator of vanadium mineralization. The main oxide minerals are ilmenite and titanian magnetite, containing 20% to 70% of volume and the ratio of titanian magnetite to ilmenite is relatively constant, ranging from about 1:1 to 2:1. Their sizes are less than 5 µm to greater than 1 mm to 2 mm, occurring as coarse- to medium-grained subhedral crystals intergrown with cumulate silicate minerals (plagioclase, pyroxene, etc.). Electron microprobe analyses indicate that the ilmenite grains are mineralogically and compositionally homogeneous and have low V contents (average 0.18% equivalent V2O5). In contrast, the titanian magnetite grains are inhomogeneous, consisting of trellisworks of ilmenite lamellae in Ti-poor, V-rich magnetite [less than 2 wt% TiO2, and 1.41% equiv. V2O5 (1.16% V2O3) for 20 analyses]. Thus, the magnetite is the principal ore mineral of vanadium; it hosts vanadium in the form of V3+, not V5+, as is commonly and erroneously reported. We have also devised a flowchart for the beneficiation of vanadium-titanium ores. Sommaire - La minéralisation de vanadium se trouve dans des horizons riches en minéraux oxydés de la partie supérieure des zones de gabbros lités des Complexes de la Rivière Bell, Matagami, Québec et du Lac Doré, Chibougamau, Québec. Des horizons riches en vanadium ont été bien définis sur le terrain et dans les levés aéromagnétiques par leur susceptibilité magnétique élevée; conséquemment, la susceptibilité magnétique est l’indicateur directe du contenu en vanadium. Les principaux minéraux oxydés sont l’ilménite et la magnétite titanifère, contenant 20% à 70% du volume et le rapport de magnétite titanifère à ilménite est relativement constant, allant d’environ 1:1 à 2:1. Leur dimension varie de 5 µm à plus grande que 1 mm à 2 mm, apparaissant sous forme de cristaux subidiomorphes, de grains grossiers à médiums, intercroissant avec la gangue silicatée (plagioclase, pyroxène, etc.) de la texture de cumulat. Les analyses à la microsonde électronique montrent que les grains d’ilménite sont minéralogiquement et chimiquement homogènes avec un faible contenu en V (moyenne 0.18% équiv. V2O5 ). Contrairement, les grains de magnétite titanifère sont hétérogènes, contenant des lamelles d’ilménite en "trellisworks"; ces grains sont pauvres en Ti et riches en V pour la portion magnétite de la magnétite titanifère [surtout contenant moins de 2 wt. % TiO2, et en moyenne 1.41% équiv. (1.16% V2O3) pour 20 analyses]. Ainsi, la magnétite est le principal minerai de vanadium; elle renferme du vanadium sous forme de V3+ et non de V5+, tel qu’il a été communément et à tort rapporté. Nous avons aussi défini un "flowchart" pour la bénéficiation des minerais de vanadium-titanium."

Jan 1, 1998

By John W. Korczak

The use of geological and grade block models has been standard practice in mine design for many years now, with a wide range of software available for creation and analysis. Although geotechnical parameters are of vital importance to mine planning there is very little in the way of commercially available systems for integrating geotechnical data into the mine planning and design process. Sirovision is a new technology developed by the CSIRO (Commonwealth Scientific and Industrial Research Organization) in Australia for automated, safe and accurate 3D mapping of geological and geotechnical features. Datamine has integrated this capability into its product range so that Sirovision has become an integral part of the day-to-day mapping, mine geology and geological / geotechnical modeling in both open pit and underground mine environments. This is the first integrated underground application of Sirovision from Datamine collaboration with Xstrata Nickel at the Nickel Rim South Project. This paper discusses the role of Sirovision in collecting the raw data required for geological and geotechnical analysis and the interpretation in a quick, safe, auditable and reproducible manner.

May 1, 2009

By Jiuhua Xu, Shuiku Jia, Weiren Sun

"The Jinqingding gold deposit, situated in the east Jiaodong Peninsula of Shandong province, is typical of the pyrite-quartz vein gold deposits in the Muping-Rushan gold belt of China. The gold deposit is controlled by a great NNE fracture zone and is composed of several lenticular orebodies within the fracture rone occurring in the Kunyushan granite massif. The Kunyushan granite massif was formed by the replacement of the Archean Jiaodong group.The main minerals associated with gold are pyrite, chalcopyrite, galena and sphalerite; the gangue minerals are dominated by quartz, sericite, microcline and calcite. The mineralizing event can be divided into four stages: (1) pyrite-quartz; (2) quartz-pyrite; (3) siderite-polymetallic sulfides; and (4) calcite-quartz. Gold occurs mainly as native gold and electrurn in stage I and stage II. There are some evident differences between pyrite from major stages of gold mineralization and that from minor stages; these include differences in crystal forms, size and composition of fluid inclusions.Wallrock alterations consist of sericitization, silicification, pyritization and potash-feldspar alteration. Five alteration zones can be distinguished from unaltered granite (zone 0) to vein lodes (zone IV). Au and Ag increase rapidly from zone 0 to rone IV, Cu increases continuously, while Pb and Zn increase slowly. R-type geological factor analysis indicates that the Au, Ag, Cu, Pb and Zn bear a close relationship to wallrock alteration."

Jan 1, 1994

By M. B. Kime

"A set of experimental batch leaching tests studied the effect of pH, time, temperature, and stirring speed on the relative Cu, Co, Ni, and Fe leaching yields of an oxidized copper-cobalt ore sample in an aqueous hydrochloric acid solution. The results were statistically analyzed and modelled using the structural equation modelling method. Models showed that Cu, Co, and Ni leaching yields were strong functions of the leaching time and leaching temperature, whereas the Fe leaching yield depended on the leaching temperature, stirring speed, and pH. Under optimum leaching conditions yields were 99.8% Cu, 82.4% Co, 91.3% Ni, and 30.6% Fe.RÉSUMÉ Une série d’essais expérimentaux de lixiviation en bâchée ont été menés pour étudier l’effet du pH, de la durée d’attaque, de la température et de la vitesse de brassage sur les rendements relatifs de lixiviation du cuivre (Cu), du cobalt (Co), du nickel (Ni) et du fer (Fe) d’un échantillon de minerai de cuivre-cobalt oxydé dans une solution aqueuse d’acide chlorhydrique. Les résultats ont été analysés et modélisés statistiquement à l’aide de la méthode de modélisation par équation structurelle (SEM, de l’anglais structural equation modelling). Les modèles ont montré que les rendements de lixiviation du Cu, du Co et du Ni dépendaient énormément de la durée d’attaque et de la température de la lixiviation ; le rendement de lixiviation du Fe, quant à lui, dépendait de la température de la lixiviation, de la vitesse de brassage et du pH. Dans des conditions optimales de lixiviation, les rendements étaient de 99,8 % pour le Cu, de 82,4 % pour le Co, de 91,3 % pour le Ni et de 30,6 % pour le Fe."

Jan 1, 2017

By André Bérubé

Since the disappearance of Les Forges du Saint-Maurice at the end of the last century, many historians have taken an interest in the lengthy past of this enterprise. They considered the political, socio-economic, administrative and anecdotal aspects of the industry, but barely dealt with the elements of technology. The purpose of this article is to try to fill this gap (1). Les Forges du Saint-Maurice was an integrated industrial concern, specializing in the production of semi-finished wrought iron and finished cast iron that operated almost without interruption between 1734 and 1883. Les Forges first came into being in 1729, when Montreal merchant Franc;ois Poulin de Francheville submitted to the King of France a request for the right to exploit the bog iron ore deposits on his seigneury of Saint-Maurice. This request, agreed to in 1730, was one of a long series of attempts, previously unsuccessful, to establish a local iron industry in the colony. Several such proposals were held up by a lack of capital from promoters or a too rigid application of the mercantilist policy by the metropolis. In 1730, however, the French minister Maurepas favoured a more liberal policy which would encourage private enterprise. The benefits of an iron industry to the naval construction industry was a factor that caught the attention of administrators. The choice of the site for Les Forges was based on the following factors: - the abundance of surface deposits of bog iron ore in the Saint-Maurice region; - the presence of a vast supply of hardwood and conifers needed in large quantities by this industry; - the proximity of sandstone and limestone deposits, md1spensable materials for the construction and operation of the blast furnace; - the presence of a water stream, with sufficient flow to provide the hydraulic power needed for the operation of the machinery.

Jan 1, 1999

By Robert Cameron, Colin Ashton, John MacNeil, Leo Piciacchia

"The in pit dam construction and utilities relocation, known as the East Mine Corridor Relocation (EMCR) project, was developed to extend the life of the east side of the Base Mine pit by two veal's. This will result in the recovery of an additional 80 million barrels of oil and delay expenditures associated with the opening of the North Mine by two years. To accomplish this, a large in pit earth structure was required to provide a new embankment foundation for relocating a public highway, four powerlines, a natural gas back-up pipeline, a substation, and a conveyor train. This structure would also he required as a temporary dam 10 contain mature fine tails on the west side until mining is completed in the east mine corridor area, that will then be filled with fluid.The in pit dam, known as The Highway Berm, is 2.5 km long, 63 m high and has 42 million m3 of engineered soil added to the already existing end-dumped soil volumes. To complete the design and construction of a structure of this magnitude, in the very short time frame of two-and-a-half years, presented many new challenges. The main challenges faced were: designing while construction was ongoing; designing without the use of clay cores or sand filters; using relatively non-select overburden material; proper dewatering and base preparation; changing from construction of 50 m high spoil piles to a high specification construction operation; compacting lifts with heavy haulers; constructing during the winter; and monitoring movement of the structure with satellites."

Jan 1, 1995

By G. R. C. Pacheco, D. M. Fonseca, R. Neuböck, G. E. Gonçalves, W. Moulin-Silva

Degradation by sulfur gases is an important lining wear mechanism in the copper industry. SO2/SO3 gases infiltrate into the pores of the basic refractory bricks, combine with their raw materials through expansive reactions and significantly modify the bricks’ structure. This study presents a comparison of the corrosion resistance against sulfur attack of different magnesia-based refractories using a simple, low-cost and quantitative method. Recipes containing sintered MgO grains showed lower resistance to corrosion by sulfur oxides compared to basic grades containing fused grains. Chromium corundum grades were used as a reference and showed very good resistance to this corrosion mechanism under the test conditions. The novel test provided relevant results that agree with what is commonly observed during operation and in previous post-mortem studies. This tool could be very useful in selecting refractory grades for the copper industry and predicting their performance. INTRODUCTION Oxidation of matte sulfides during copper production leads to the formation of sulfur oxides, which infiltrate into the pores of the refractory lining and react with the basic oxides below 1000°C to form magnesium and calcium sulfates. This reaction is accompanied by an expressive volume increase, consequent densification of the refractory microstructure and weakening of the brick bond (Malfliet et al., 2013). Thus, corrosion by SO2/SO3 is an important wear mechanism in the non-ferrous industry and the resistance to this compound should be considered when defining refractories for this application. Previous studies on this matter include expensive and complex testing methods involving pressurized SO2 gas cylinders in order to investigate the corrosion resistance of MgO-containing materials by sulfur oxides (Gerle & Podwórny et al., 2016; Fotoyi & Eric, 2011; Fotoyi, 2009; Podwórny & Piotrowski et al., 2008). The current study was based on a test developed by Pacheco & Fonseca (2018) to assess alkali infiltration and aims to provide an evaluation method of the corrosion resistance of refractories by SO2/SO3 in a simple and quantitative manner. This novel test is useful to compare the corrosion resistance of different refractory recipes and properly select the grades that should be employed in the non-ferrous industry. A case study is provided to illustrate the damage caused by sulfur oxides in refractory linings.

Jan 1, 2019

By Lynne Bowen

"On the da y shift in Number One Mine at Nanaimo on Vancouver Island, on May 3, 1887, William Griffiths, a coal miner with many years experience, fired a shot to advance the face of the crosscut. A flame ran out for a distance of fifteen feet along the roof and then extended up the slope for ten to twelve feet, and although many would have called this a blowing out shot, Griffiths said it was just a feeder. ""A blower"", he said, ""would have caused an explosion."" 1There was no explosion. Griffiths reported gas and the area was cleared for three hours and then work resumed. When the shift changed at 3:00 p.m., the fireman reported all places clear of gas and the ventilation good.2The ventilation in Number One Mine was the best anyone had ever seen. The air in the mine was almost too cold. The current was so strong that it sometimes blew out the flame on the miners' fish oil lamps. It delivered five to six hundred cubic feet of air for every man and animal working in the mine. The law required only one hundred cubic feet 3The miners considered Number One to be relatively safe. The manager was proud of the mine and its up-to-date equipment"". Recently, there had been reports from France and America about the explosiveness of coal dust, but the manager did not think his mine was sufficiently dusty to be dangerous.5 The dust lay thick on the floor of the mine. Sometimes when a shot was fired the dust rose in great clouds. When a miner was shovelling it, the dust would billow up and be carried off by the current of air. The dust was also in the roof and in the stopings, put there intentionally to fill up the spaces and prevent the accumulation of methane gas."

Jan 1, 1992

By Garston Blackwell

Abstract - During geostatistical estimation of block grades, the kriging process produces a measure of error, the kriging variance or the kriging standard deviation. Estimation of the block error depends on the semi-variogram model for a deposit, which reflects fundamental characteristics of a deposit such as (1) nugget effect, (2) range of influence of grades, (3) different local spreads of data as a function of average grade (proportional effect), (4) nested structures, and (5) underlying anisotropies in the data; this model may be affected by sampling or assaying limitations, however. Because the kriging error incorporates so many features of both the deposit and data to be used for estimation, it may offer a substantial improvement on block classification over traditional procedures such as data density. Practice indicates that the relative kriging standard deviation (RKSD) is particularly useful for block classification in measured, indicated and inferred categories. Plots of RKSD in plan and section also can be used to demonstrate where extra drilling and sampling would be most advantageous for upgrading the class of some blocks. Moreover, the use of grade and RKSD filters can show where material near cut-off grade is poorly defined, indicating sampling target areas to improve block classification in the vicinity of the ore-waste boundary.

Jan 1, 1998

By J. Palarski

Hard coal, mined in Silesia Region as well as in the eastern part of Poland, is a key national resource. In Polish underground coal industry, modern mining technologies have been successfully tested and used in the last 50 years. More than 98% of the coal produced underground is extracted by longwall mining method. Current underground coal mining expands into increasing depths. The use of conventional coal extraction methods ? room and pillar and longwall with caving - is becoming increasingly difficult. The coal mining is modifying existing methods and is testing innovative technologies. Backfill is an important component of modern underground mining operations. In Polish underground mines, backfill is recognized as an integral component for extraction of coal from greater depths in a densely populated environment. The modifying and innovative methods require the use of backfill or grouting of caving to provide structural support in underground excavations and to ensure that the mining operations are safe. Depending on the geological structure, mining conditions and environmental requirements there are several variations of longwall methods used in underground coal mining in Poland, in particular: longwall with caving, longwall with backfill, longwall with grouting of caving area. This paper will discuss the different components of an effective longwall production and filling process of caving area. The paper will give a overview of the current application of backfill technology, focusing on Polish coal mining operations. This paper will also briefly describe how backfill contributes to an innovative method ? underground coal gasification. The paper discusses specific requirements for fill materials and the technology of backfilling for underground coal gasification (UCG) operations and problems of implementation and correlation of backfill parameters with other processes that occur during thermal processing of coal.

Aug 1, 2013

By S. Koppalkar

ABSTRACT: The development and evolution of the gravity recoverable gold (GrG) test procedure at McGill university is reviewed in this paper. Since the late 1980s, the research group led by the late Professor André Robert Laplante at McGill university has undertaken fundamental studies and applied research of the Knelson concentrator to develop a sustainable method of estimating GrG. Historically, a concept of “free gold” was used, and it was de?ned as the gold that could be separated and recovered from gold ore by amalgamation. Due to health and safety hazards, the practical use of amalgamation has declined. around 1994, a methodology using a 3-in Knelson concentrator to measure gravity recoverable gold was established at McGill university. as a result of more than 10 years of improvement and optimization, this technique has become a standard method of evaluating GrG for gold ores, gold plant streams and platinum group metals. By 2006, about 200 GrG tests were carried out at McGill universityon ores from all over the world. recently, a modi?ed version of the GrG test (a simpli?ed test) was developed to provide a quick and rough estimate of the GrG in a sample; this simpli?ed test has theadvantage of reduced mass, processing time and cost. to recognize and honour the contributions madeby the late Professor Laplante towards the establishment of a standard test procedure for assessing gravity recovery potential, the authors propose that the GrG test be named after Laplante.

Jan 1, 2010

Electric Vehicle Controllers Ltd. ?EVC started in 1981 ?Underground electric locomotive drive systems ?Developed tandem load sharing system and radio ELOS controls ?Locomotive autonomy systems ?Entered space technology development in 1999 with NORCAT to develop Mars drill for CSA ?Commercial distributor for drilling systems, lunar physical simulants, electric mobility systems and lunar mining technologies

May 1, 2009

By Boyd Davis, Vladimiros Papangelakis, Douglass Duffy, Michael Carlos

"The processing of lateritic saprolite in hyper-concentrated magnesium chloride brines offers several potential advantages for the hydrometallurgical production of nickel. An aggressive HCl-MgCl2 leach at atmospheric pressure can significantly reduce magnesium dissolution, and offers the ability to recover HCl and MgO by a less energy intensive process than conventional techniques via the formation of magnesium hydroxychlorides. Inevitably, the high chloride concentration renders iron fully soluble during leaching and thus requires subsequent iron control and disposal steps. Experimental measurements coupled with OLITM modeling were conducted to investigate the behaviour of iron in concentrated magnesium chloride brines, in terms of chemistry (nature of iron species) and solubility limits. The solubility of ferric chloride in magnesium chloride solutions of concentrations and temperatures relevant to this process was controlled by a previously unreported solid phase: 2.5FeCl3·MgCl2·7.5H2O. Iron precipitation tests on synthetic leach solutions without seeding indicate a metastable akaganeite precipitate which transitions to hematite upon equilibration. Magnesium chloride solubility in ferric chloride solutions was also investigated to allow the simulation of a ternary phase diagram for the MgCl2-FeCl3-H2O system, in order to determine process conditions that avoid unwanted chloride precipitation.INTRODUCTION In the search for more economical processes to treat lateritic saprolite for nickel production, chloride hydrometallurgy has been increasingly investigated. While High Pressure Acid Leaching (HPAL) can frequently economically treat lateritic limonite, the presence of saprolite negatively affects process economics. The higher magnesium content of saprolite increases acid consumption, because magnesium sulphate, unlike iron and aluminum sulphates, does not hydrolyze in HPAL. This soluble magnesium decreases the sulphuric acid strength by an amount greater than the amount of acid stoichiometrically required to leach magnesium, which must also be disposed of or recovered (Jankovic, Papangelakis, & Lvov, 2009). Due to these issues, pyrometallurgy is most commonly employed to treat lateritic saprolite, via the Rotary Kiln-Electric Furnace (RKEF) process; this process uses a rotary kiln to dry and partially reduce nickel and iron oxides before sending the calcine to an electric furnace for smelting to produce a ferronickel product for the stainless steel market. Although the problems encountered during hydrometallurgical processing are avoided and nickel recoveries are high, high capital and energy costs prevent the application of this process to lower grade lateritic saprolite deposits (De Bakker, 2011)."

Jan 1, 2016

By R. Prioul, J. Kear, D. Chuprakov, A. P. Bunger

"Hydraulic fracture (HF) growth through naturally fractured rocks challenges the development of accurate predictive HF models. The authors present laboratory experiments differentiating behaviours associated with orthogonal and oblique intersections between HFs and natural fractures (NFs). HFs were created in sandstone and crystalline (gabbro) rock specimens, impinging orthogonally or obliquely on an unbonded machined frictional interface. Ultrasound monitoring was used to observe the rate of propagation through the interface. A contrast was observed between direct and offset crossing for orthogonal and oblique intersection, respectively. The stresses required to promote crossing depended on the intersection angle between HFs and NFs.RÉSUMÉ La propagation des fractures hydrauliques (FH) dans les roches naturellement fracturées pose un défi pour le développement de modèles prédictifs. Nous présentons des essais en laboratoire qui différencient les comportements associés aux intersections orthogonales et obliques entre les FH et les fractures naturelles. Des FH ont été créées dans des spécimens de grès et de roches cristallines (gabbro), heurtés de manière orthogonale ou oblique sur une interface machinée, non liée, de frottement. Un suivi par ultrasons a servi à observer le taux de propagation à travers l’interface. Un contraste a été observé entre un croisement direct et un croisement indirect des intersections respectivement orthogonales et obliques. Les contraintes requises pour promouvoir le croisement variaient selon l’angle d’intersection entre les FH et les fractures naturelles."

Jan 1, 2016

By J. Carr

This paper discusses: (1) the need for Western Canadian coal in eastern Ontario Hydro plants; (2) design parameters-unit trains, year- 'round receiving from trains, and shipping (Great Lakes season); (3) equipment chosen-dumper-indexer, outhaul conveyor, yard belt, stacker, reclaimer, surge-bin feeders, shiploader, docking system and dust control; (4) foundation and soil conditions-dumper house, yard belt, surge bin and dock-piling-runway; (5) winter conditions- thaw shed, feeder, lump breaker, beltings (oil), and dust control and disposal; and (6) operations to date.

Jan 1, 1979