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By N. Dufresne

"The evolution of mining methods at Brunswick Mining and Smelting shows that, in the case of a large deposit, technology must adapt itself to changing conditions. As problems are encountered, management must modify their approach if they hope to meet production quotas. This search for new and better ways started with the opening of the No. 12 orebody and is still going on today.From large-scale open stoping, the Brunswick Mining and Smelting operation went to transversal cut-and-fill, then to longitudinal cut-and-fill, which is the main mining method now employed. However, to solve certain problems experimenting with Avoca methods was initiated. Rebar grouting and prepinning have also made significant contributions toward securing relatively poor ground in the hanging wall and holding badly fractured backs in wide stoping areas. Introduction In 1952, M.J. Boylen had incorporated Brunswick Mining and Smelting Corporation Limited to develop his recently found No.6 and No. 12 orebodies near Bathurst, New Brunswick. Between 1953 and 1957, St. Joseph Lead Company was brought in to try and initiate mining . During those years, St. Joseph Lead sunk two shafts at No. 12-No. 1 to 425 feet below surface and No.2 to 982 feet. They also developed the 200 and 350 levels to sample the ore at depth and operated a 100-tpd pilot plant at the No.6 mine. However, due to low recoveries and depressed metal prices. the project was shut down in 1957.A group including M.J. Boylen. K.C. Irving. Maritime Mining Corporation and Patino Corporation reacquired the property from St. Joseph Lead Company in 1961. New financing was arranged involving La Societe Generale des Minerais, S.A . of Belgium and Engineering Consultants Limited of Saint John. New Brunswick. During the years 1962 and 1963, construction of surface and underground facilities progressed rapidly."

Jan 1, 1981

By Y. Okita

The Goro Nickel Process, developed over a ten-year period, uses a number of novel processing steps and treats two ore types, limonite and saprolite, together. Nickel and cobalt are solubilized using a 270°C pressure acid leach in sulphuric acid, which rejects the bulk of the Fe into the leach residue as hematite particles. The leach liquor, after CCD, is aerated to oxidize any ferrous iron to the ferric form and is neutralized with limestone to precipitate iron as hydroxides together with gypsum from the neutralization of the free acid. Further neutralization with lime, together with steps to remove suspended solids, reduces the iron to trace concentrations. Nickel and cobalt are directly recovered from the low-iron leach solution by primary solvent extraction using Cyanex 301® (SXl) in a high-strength hydrochloric acid solution. Nickel is subsequently separated from cobalt in a secondary solvent extraction circuit using tri-isooctylamine. A granular nickel oxide is made by pyrohydrolysis, and this allows the recycling of hydrochloric acid to SXl. The process is currently being commercialized to produce approximately 60,000 t/y of nickel as nickel oxide granules and approximately 5,400 t/y of cobalt as cobalt carbonate. This paper describes the process development to control the Fe concentration in the SX1 feed solution.

Jan 1, 2006

By J. Hoover

"IntroductionThis chapter will discuss the operational and maintenance aspects of a heavy media cyclone circuits as applied to coal processing and using magnetite as the media. It deals with heavy media bath separators in terms of types of media, equipment, circuits, media recovery, maintenance, and product handling. It will detail heavy media cyclone operation and supplement the previously described topics.The heavy media cyclone was first developed in the Netherlands by the Dutch State Mines in 1945. A cyclone plant was not built in North America until 1961. Traditionally, heavy media cyclones have been used to treat size fractions between 1lz in. (12 .6 mm) and 35 mesh (0.5 mm). High maintenance related to heavy media bath separators has recently prompted some plants to crush all raw coal to minus 2 in. for treatment in heavy media cyclones.The heavy media bath separators utilize only the force of gravity to make the separation between heavy and light particles. This requires lengthy retention time which can lower capacity and also is inefficient for finer particles. A heavy media cyclone utilizes centrifugal forces which are 20 to 200 times greater than the force of gravity. This means the separation between coal and the impurities occurs very quickly, therefore a low retention time is required allowing cyclones to have high tonnage capacities. Also these greater forces allow better separation for the finer particle sizes.Heavy media cyclones are now widely used to produce both metallurgical and thermal coal. Work is in progress to reduce magnetite consumption, extend wear life, increase tonnage capacity, improve separation efficiency and automatically control these cyclone circuits."

Jan 1, 1989

By Graham Davey

"Low speed stirred milling has been employed for many years in the metalliferous and industrial minerals industries. High speed stirred milling is a relatively new method of grinding in the metalliferous process industries. However it has been it has been in wide spread use in the industrial mineral field for over 30 years for various minerals. Many existing metallurgical operations are looking to maximize economic return from existing deposits, requiring new thinking and technologies. By combining low speed and high-speed milling fine and ultrafine grinding efficiency and operating costs can be improved.The correct selection of different fine grinding technologies is covered, when each mill is applicable and when a combination of the VERTIMILL® Grinding Mill and SMD provides the best economic solution.INTRODUCTIONUltra-fine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits, around the world are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The traditional approach for gold containing refractory material has been to liberate the locked gold by chemically destroying the pyrite through oxidation. Roasting, pressure oxidation, and bacterial oxidation all employ various degrees of temperature, pressure and catalysis to react the pyrite with oxygen to produce iron oxide and sulfur by-products. However all of these methods are economically impacted due to specific operational added requirements and emissions controls. Pressure and bacterial oxidation have very high capital and operating costs."

Jan 1, 2006

By Patrick Polk

For many years, sulfuric acid producers all over the world have been forced to meet ever more strict environmental regulations to reduce SO2 emissions. The sulfuric acid industry has implemented new solutions in order to comply with the new lower SO2 emissions target. Haldor Topsoe (Topsoe) has responded to this challenge by continuously improving the range of VK sulfuric acid catalysts and providing tailor-made catalyst solutions to meet the demands of the sulfuric acid producers for lower SO2 emissions. Reducing emissions through catalysis: requires less capital than installing a scrubber, requires no additional process chemicals, generates no waste or by-product to dispose of. In 1996 Topsoe introduced VK69, a cesium-promoted vanadium catalyst, designed for operation in the pass(es) after the intermediate absorption tower in double absorption plants. The high activity of VK69 allows for a more than 50% reduction in SO2 emissions from existing double-absorption plants. Topsoe currently has more than 110 installations of VK69. To comply with the still more stringent regulations being placed on the sulfuric acid industry to lower SO2 emissions, Topsoe has developed a new sulfuric acid catalyst designated VK-701 LEAP5™. This catalyst was introduced to the market in 2010. VK-701 LEAP5™ is based on a novel technology which circumvents the internal transport deficiencies of existing commercial sulfuric acid catalysts and thereby offers exceptionally high activity in strong, SO3 rich gases. Sulfuric acid plants have used this catalyst to meet emissions requirements lower than previously believed possible with a catalyst only solution. This paper will present examples on how to reduce emissions by implementing a tailor-made catalyst solution using VK69 and VK-701 LEAP5™.

Jan 1, 2014

By Cindy Schiewek

Industrial injury occurrences are an ongoing concern for Mine Operators. Along with the personal suffering of injured workers comes an increase in compensation and productivity costs. Growing recognition of repetitive stress and bodily injuries, accompanied by recent studies, validates the assumption that a relationship exists between ergonomic injuries and machine design. Intuitively, there is a belief that an ergonomically designed machine will reduce repetitive stress injuries through design and education however; quantifying this belief has been a challenge for Mine Operators. Sandvik Tamrock has undertaken a project aimed at developing a business model to assist in quantifying the benefits of ergonomic intervention. This model focuses on distinguishing and quantifying this method of intervention to allow for a better evaluation of the machine. For simplicity, the project initially focused on the Face Drill Jumbos. The target of the project was three fold: !" Recognition of the cost drivers for compensation; ergonomic injuries !" Identification of the relationship between ergonomic machine design, and the decrease of the negative effects associated with the cost drivers !" Systematic prioritization for ?prevention by design? The project findings substantiate the expected reduction in injuries and compensation claims. Based on all ergonomic intervention studies conducted, each case showed a reduction in compensation cost; through prevention by design, one can reduce the amount of potential risk. The paper addresses the resources and methodology used, along with the findings and its relevance to the issues that face the Mining industry.

May 1, 2003

By G. B. Harris, C. W. White

Cyanide has been used for the recovery of gold since the mid 1800s, but several jurisdictions have already banned its use, and environmental pressures are increasing to finding an alternative. Gold also forms chloride complexes similar to those of cyanide, but the use of chloride has never achieved widespread acceptance. This paper describes a chloride-based flowsheet, wherein the key unit process is the recovery and recycle of chloride ion. It is shown that the chloride-based flowsheet is competitive economically with the conventional cyanide-based flowsheets, and that it has a number of other advantages, particularly environmentally.

Jan 1, 2011

By H. R. Manouchehri

"It is well understood that, apart from particle hydrophobicity, the flotation process is strongly influenced by the cell hydrodynamics. Once the chemical conditions were optimized and fixed, the flotation rate is essentially determined by impeller speed and the air flow rate.The collection efficiency in flotation is a product of collision, attachment and stability/detachment efficiencies. The collision efficiency for a given particle diameter is increased by decreasing the bubble size and bubble velocity as well as increasing the power input to the cell. The attachment efficiency, however, is defined by bubble size and its velocity. The detachment/stability depends on the relative magnitudes of the attachment force between the bubble and particles and the detachment force acting on the bubble-particle aggregates. For the particles having specific contact angle, the stability decreases as the energy input increases. Therefore, there must be an optimum energy dissipation to maximize recover of defined size fraction.A comprehensive laboratory study was devoted to determine the effect of power input in recovery of finely grind Cu-Ni bearing ore. Several flotation tests were conducted to define the hydrodynamic parameters for a laboratory scale Runge cell under different impeller speeds. An increase in flotation recovery of finely ground ore was observed when the impeller speed was increased from 450 to 1,200 rpm. The experimental results have shown increasing in water recovery and improving in flotation kinetics of fines by increasing the power input to the flotation cell. Implementation of the Wark flotation model to the experimental data revealed a good correlation between the experimental data and the model. For the particles having enough hydrophobicity the flotation rate increases by increasing the impeller speed due to a higher value for collision efficiency within the cell."

Jan 1, 2016

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 J. A. Meech, R. J. Tucker

"Since the establishment of froth flotation as an effective method of mineral beneficiation there has been both academic and industrial interest in the levels of the various reagents required to perform the desired separations. Academic interest was spurred by a desire to understand the mechanisms involved - industrial interest by a need to improve the efficiency of the process. These efficiency improvements can take two forms: cost reductions due to reduced reagent consumption and/or improved separation efficiencies. The latter are indicated by either improved grade-recovery relationships for removal of a valuable mineral from gangue, or improved separation of two similar valuable minerals.The processing of lower grade ore bodies at higher tonnage rates has necessitated increased interest in both reagent consumption and metal recovery. Furthermore, the development of accurate and functional on-stream analysis equipment in the 1960's and 1970's has allowed for a better understanding of the dynamic processes involved in a flotation circuit and has required a more concrete statement of the relationships and reactions between the minerals and chemicals in the flotation pulp. Development of these relationships is necessary in order to make use of on-stream analysis to control the process at, or near its more efficient level."

Jan 1, 1984

By J. C. Marchand, M. A. Berube

"L'objectif principal recherché lors du broyage d 'un minerai est de libérer adéquatement ses valeurs utiles en vue de leur concentration ultérieure. La pratique courante consiste à tenter d'obtenir un produit de broyage d'une granulométrie constante. Malheureusement, les propriétés texturales des minéraux utiles varient naturellement dans un gisement et une telle stratégie n'entraine pas toujours pour ces minéraux un degré de libération constant. Pour un rendement optimal du procédé de concentration, cette variable très importante doit donc être périodiquement vérifiée.Jusqu'à maintenant, la plupart des études de libération des minerais se font en examinant des sections polies de particules du minerai broyé. Le GRAAIM a récemment assemblé un système modulaire d'analyse d'images qui servira en grande partie à des mesures automatiques du degré de libération des minéraux. Le système s'avère relativement peu coûteux comparativement à la plupart des analyseurs de texture conventionnels si l'on considère que plusieurs de ses composantes, par exemple le miniordinateur, sont utilisées à une foule d'autres applications, et il permet de plus une grande souplesse d'utilisation puisque l'on a qu'à construire des algorithmes de mesure et de calcul en fonction de l'objectif recherché. Des programmes particuliers permettant des études automatiques de libération sur des sections polies de particules ont ainsi été élaborés. Ils permettent également des mesures de teneurs et de distributions granulométriques apparentes des particules. Des résultats obtenus dans le cas de minerais de fer sont brièvement présentés afin d'illustrer la technique."

Jan 1, 1983

By P. W. Godbehere, B. W. Brooks

"This paper deals with the milling of slags from the Noranda Continuous Process, in the Horne Concentrator at Noranda, Quebec. The milling of copper slags, although novel in Canada, has been practiced in Japan, Finland and elsewhere for several years.In March 1973, the prototype Noranda Continuous Process furnace or ""reactor'' came on-stream, In this pyrometallurgical process (see Fig. 1), copper concentrates mixed with flux are smelted in a single furnace to form copper or a high grade copper matte, and slag. The conventional smelting processes of roasting, reverberatory smelting and converting have been incorporated in a single 17 ft. diameter by 70 ft. long steel cylindrical vessel (l, 2). The copper or matte is tapped from the bottom of the reactor into ladles and transferred to an anode furnace or to a converter. The slag is tapped into 40 ton capacity ladles, cooled, crushed, and conveyed to the concentrator. At the present time, the reactor is operated to produce matte. The matte slag* containing 4 - 6 per cent copper is milled using conventional ore dressing grinding and flotation equipment. A flotation concentrate assaying 35 - 40 per cent copper is recycled to the reactor. Crushing, conveying, grinding, flotation and tailing disposal equipment previously used for over 40 years for ore treatment has been modified to suit the requirements of slag milling. Slag milling is essentially the scavenger circuit of a pyrometallurgical process."

Jan 1, 1977

By O. A. Carson

"IntroductionTHE ZINC-BASE die casting alloys in common usage contain approximately 4 per cent aluminum as the major alloy element. In addition, they contain about 0.05 per cent Mg .and may• have a small amount .of copper. These are usually the only •elements intentionally present.Small amounts of some impurities have been shown to have a deleterious effect on the properties of these alloys and therefore the impurities are kept low by starting with '99.99%' zinc.The reasons for holding the aluminum content at 4 per cent are not clear. Some statements appear in the literature that higher aluminum increases the brittleness, but probably the chief reason was the relative price of zinc and of aluminum when 4% alloys became firmly established. At that time, aluminum was three to four times the price •of zinc on a weight •basis. Recent prices, roughly equivalent per lb., make aluminum considerably cheaper than zinc on a volume basis and suggest that increased aluminum content would result in a decrease in the cost per piece due to the lower density of the alloy.Little information could be found in the literature and, therefore, it was decided to determine some physical properties of the higher aluminum zinc-base alloys made from high-purity zinc."

Jan 1, 1953

By T. Mulja, Michel Boily, Anthony E. Williams-Jones, Pierre Pilote

"The Preissac-Lacorne batholith is composed of suites of early metaluminous calc-alkalic gabbroic to granodioritic intrusives, three late peraluminous monzogranite plutons and numerous Li, Be and Ta-bearing granitic pegmatites. The Lacorne pluton is dominated by biotite and biotite + muscovite monzogranites containing abundant Be and Ta-bearing granitic pegmatites (40-80% volume). The pluton is surrounded by swarms of unzoned or poorly zoned spodumene-rich pegmatite dykes. The La Motte pluton is composed of biotite monzogranites, biotite+ muscovite monzogranites and rare muscovite + garnet monzogranites. Li, Be and Ta-bearing pegmatites are less abundant than in the Lacorne pluton and are commonly associated with molybdenite bearing quartz-muscovite-K-feldspar veins. In the Preissac pluton, muscovite + garnet monzogranites and muscovite + biotite + garnet monzogranites are the dominant rock types. The pluton rarely contains granitic pegmatites and these are generally barren. However, numerous molybdenite bearing quartz and quartz-feldspar-muscovite hydrothermal veins are observed.Li, Be andTa-bearing pegmatites display a crude spatial zonation around their parent monzogranites. Spodumene-rich pegmatites are generally unzoned or poorly zoned and are confined to the surrounding metasedimentary or metavolcanic rocks or crop out in the early gabbroic to granodioritic intrusives surrounding the monzogranites. Ta and Be-bearing pegmatites are usually concentrated towards the margins of their parent monzogranites. The highly fractionated nature ofmonzogranites (high Rb/Sr, low K?Rb, Ba?Sr, Zr/Nb ... ), their peraluminous composition (corundum normative and muscovite bearing) and the numerous occurrences of Ta and Be-bearing pegmatite dykes represent important criteria for the exploration of fertile granites."

Jan 1, 1990

By K. A. Clark

SEPARATION of the oil from the bituminons sands of the Athabaska area of Alberta has been a subject of study by the Research Council of Alberta. The results of the study have been published in the Annual Reports of the Council. However, the last Annual Report in which there is mention of bituminons sand separation is that for 1934. The attention that is being directed toward the bituminons sands at the present time calls for an up-to-date summary of the work of the Research Council of Alberta on the hot-water separation process. STATEMENT OF FUNDAMENTALS OF HOT-WATER PROCESS Studies of the hot-water separation process have been largely empirical in nature. The objective sought has been a complete recovery of oil from the sand in the form of a separated oil which, itself, is free from mineral matter. Various procedures have been tried in the hope of attaining this objective and a very considerable mass of observations and background of experience have been acquired. lt is rime that a theory for hot-water separation should commence to emerge. As a start toward the formulation of such a theory, the statements which follow regarding the constitution of bituminons sand and its reactions with water and air are presented. It is not pretended that they are entirely correct, but it is believed that they lie not far from the truth. (1) Bituminons sand is an aggregate of sand, clay, oil, and water. The sand consists mainly of quartz particles of 100 ta 200 mesh size and smaller, but also of particles of other minerais including mica, rutile, ilmenite, tour-maline, zircon, spinel, garnet, pyrite, and lignite. Clay occurs interbedded with the bituminons sand, of which, also, it is a constituent. lronstone nodules of all sizes up to eight inches in diameter are likely to be present in the bituminons sand beds. The oil is viscous, naphthenic, and of a specific gravity slightly greater than that of water. The oil content ranges up to, and sometimes even exceeds, 17 per cent by weight. Rich bituminons sand from beds not invaded by water has a water content of 3 to 5 per cent by weight. The water is probably present as a film around the sand particles. The oil surrounds the moist sand grains as an envelope. (2) Water wets quartz and other siliceous minerals more readily than does mineral oil. Consequently, water tends to displace the oil film surrounding the quartz and other siliceous particles when the bituminons sand is mixed with water. Whether the oil is completely displaced depends on the properties of the water. That is to say, the materials dissolved or suspended in the water modify its wetting properties.

Jan 1, 1944

By B. Yu, S. Kelebek, C. Gibson, M. Aghamirian

There are a number of high grade niobium deposits worldwide which have been deemed untreatable by flotation due to the very fine grained nature of the in situ pyrochlore, the primary niobium bearing mineral. A known method of recovering extremely fine particles is through the use of chelating reagents such as hydroxamic acids which have a strong affinity for transition metals. However, one of the major issues in the flotation of niobium bearing minerals using hydroxamic acids is the corresponding recovery of other transition metal gangue minerals including magnetite, hematite, and pyrite. In order to better understand the differences in behavior of niobium and iron bearing minerals in flotation with benzohydroxamic acid (BHA) and sodium hexametaphosphate (SHMP) at a range of pulp temperatures, a Box-Behnken experimental design was employed. Regression models for the global recovery of iron indicated that iron mineral recovery was significantly influenced by both BHA and SHMP dosage. Upon examinination of flotation products by semi-quantitative XRD, it was observed that recovery of iron oxide and sulphide minerals (hematite, magnetite, goethite, and pyrite) was problematic at high benzohydroxamic acid dosage, while sodium hexametaphosphate was mainly helpful for carbonate mineral depression. Iron rich carbonates (likely an iron rich dolomite) largely reported to the tails with increased SHMP dosage.

Jan 1, 2015

"Shales play a major role in the stability of slopes, both natural and engineered. This paper attempts to provide a review of the state-of-the-art in shale slope stability. The complexities of shale terminology and classification are first reviewed followed by a brief discussion of the important physical and mechanical properties of relevance to shale slope stability. The varied mechanisms of shale slope stability are outlined and their importance highlighted by reference to international shale slope failures. Stability analysis and modelling of anisotropic rock slope masses are briefly discussed and the potential role of brittle rock fracture and damage highlighted. A short review of shale slopes in open pits is presented.INTRODUCTIONShales have been stated to form approximately 58% of sedimentary rock so it is not surprising that they are frequently encountered in both natural and engineered slopes. They represent challenging environments for slope stability due to the wide variation in their engineering properties, their changing behaviour with time due to geomorphic processes and the variation in the failure mechanisms as a function of both stratigraphy and tectonics. An extensive body of literature exists on the terminology and classification relevant to shales; it is not possible in the scope and length of the current paper to review these works in detail and the reader is referred to Farrokhrouz and Asef (2013), Bell (2000) and Goodman (1993) for detailed discussions. It is arguably the case that no universally accepted classification of shales exists today and depending on the field of application the terminology varies widely. Shales in slope stability, for the purpose of this keynote paper, are taken to include material varying in properties from weak rocks to soils and therein lies one of the most challenging aspects in shale slope characterisation for engineering purposes. They have been classified as “rock-like” or “soil-like’, (Underwood 1967) or compacted and cemented, Table 1, Yagiz (2001). Classifications have considered numerous factors including composition, cementation and a wide range of engineering properties.The propensity of shales to degrade with time due to geomorphic processes has resulted in an important aspect in their classification, that is, the attempts to incorporate slaking, durability and swelling and softening behavior through purpose developed testing methods (Gamble 1971, Morgenstern and Eigenbrod, 1974). Figures 1 and 2 show examples of terminology used to describe argillaceous materials and some proposed engineering classification schemes (Grainger 1984 and Bott 1986). Corominas (2014) provides a recent classification of argillaceous rocks and their durability relating five stages of slope deterioration to the texture of the rock on Ternary diagrams. No attempt will be made here to discuss the merits of the proposed terminology and classifications, suffice it to say, that the controversy and flux surrounding these issues is a strong indicator of the complexities in the behavior of these materials. In this paper the author will consider slope stability in the materials indicated in Table 1, Figures 1 and 2 without undue focus on terminology. At the lower strength limit of shales the engineer must design slopes using the principles of soil mechanics which may vary from the simple Mohr Coulomb plasticity constitutive criterion to modified critical state models, some even attempting to incorporate softening behaviour in the weaker clay shale materials. Given the transitional nature of shale materials several workers have treated overconsolidated clays and clay shales using concepts such as peak and residual shear strength, brittleness index and softening. Martin and Stacey (2013) provide a useful review of the importance of weak rocks in open pit mining, with mudrocks as a specific member, and note the importance of delayed failure, progressive failure and loosening in the stability of"

Jan 1, 2015

By Horace Freeman

The sulphur consumed in Canadian pulp mills and acid plants is worth approximately three million dollars annually and amounts to one hundred and fifty thousand long tons, all of which is imported from the United States. Concurrently with a decline in the value of newsprint there has been a gradual increase in the price of this raw material. Most pulp mills in Canada are situated within reasonable distance of domestic pyrite deposits; nevertheless it has not yet been found possible to mine these deposits and utilize the contained sulphur in competition with the imported material. It is the purpose of this paper to elucidate the reasons therefor, and to describe? a commercial-scale experiment undertaken with the object of introducing a native raw material into the Canadian pulp industry on the purely economic basis. Reasons for the Preferred use of Sulphur The known sulphur deposits in the United States are very large, so that at least a twenty-year supply of this material is assured. It is recovered cheaply and in pure condition. Although large deposits of pyrite are known in Canada, nothing has yet been developed to compare in size, cost of mining, or purity with the United States material. It has been necessary to handle and transport more than two tons of pyrite to equal a ton of sulphur.

Jan 1, 1930

By M. J. Allan

"The paper describes the author's experiences in the startup of autogenous and semiautogenous grinding circuits gained over the last twenty years on both large and small grinding circuits. Typical phases in commissioning from construction to startup with ore are covered. The paper also describes experiences with material handling systems, slurry pumping, vibrating screens, trommel screens and pebbles crushing systems. INTRODUCTIONThe commissioning of any new mineral processing plant is an important and exciting milestone in any project. It is at this point in time that the efforts of developers, design engineers, equipment suppliers and operators culminate in a finished product. The successful completion of any project requires that the plant achieve design throughput as quickly as possible. The success of any startup can generally be anticipated by the amount of careful planning which takes place before equipment is operated. The first part of this paper describes the steps in going from construction through to introduction of ore. The organization and planning of startup activities is also covered.The second part of this paper describes some typical problem areas and past experiences in the startup of semi-autogenous grinding circuits. Semi-autogenous grinding circuits present some special challenges in the startup phase. The description of some of these problems and experiences will hopefully provide other operators with suggestions on how to avoid (or at least prepare for) these problems."

Jan 1, 1992

By D. M. Aloi

In today's evolving and globalized world, mining companies are being pressured to move beyond compliance towards long-term sustainability and sustainable development. Companies are expected to "engage" with communities and measure the success of these engagements without a clear understanding of "how" to do this. This move, away from "Corporate" Social Responsibility (CSR) and compliance, develops more of a focus on "Community" Social Responsibility and sustainability. This shift in focus leads to the development of world-class projects that provide sustainable development for people, reduces the incidence of costly delays, and promotes good global citizenship for corporations. The process of "engaging" communities in mining project design and development leads to a stronger license to operate and sustainable development. To create this mutually beneficial relationship between communities and companies, communities must be "engaged" in the mining process as early as possible, preferably during the exploration or the concept phases. How to create this "engagement" remains elusive. How to measure the progress of this engagement is also problematic. The quantitative and qualitative metrics needed to measure both positive and negative impacts of the mining and community relationship will be discussed.

Jan 1, 2007