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By William W. Shilts

"In carrying out a geotechnical survey of a proposed gas pipeline route from the Arctic Islands south to Longlac, Ontario, the Polar Gas Consortium contracted the drilling of several hundred 2- to 2D-m-deep boreholes in drift and bedrock. Samples from these holes were made available to the Geological Survey of Canada, where they were subjected to stratigraphic and trace-element geochemical analyses. The geochemical characteristics of the clay and sand-sized heavy mineral fractions of till samples from these boreholes have been summarized in a series of geochemical profiles.From the proposed pipeline terminus at Longlac northward to the vicinity of God's River in Manitoba, tills contain significant amounts of Paleozoic carbonate rocks and Proterozoic sedimentary rocks derived from the Hudson Bay basin and lowlands. Within this section, two sites were enriched in base metals, indicating the possibility of local mineralization of possible economic interest.From God's River northward to Seal River, Manitoba, no evidence of local mineralization was noted. The heavy mineral fractions of the tills are universally enriched in Mn-rich siderite thought to originate on or in the Paleozoic section of the Hudson Bay lowlands.From Seal River northward to Thelon River, near Baker Lake, tills contain only components originating west of the Hudson Bay sedimentary basin. Near the Keewatin-Manitoba border, all till is enriched in uranium, which probably originates in the ""young"" porphyritic granites underlying much of the region, and produces a distinctive airborne radiometric anomaly.At the Thelon River, multiple till sections are variously enriched in Cr, Ni, U, Cu and Mo in the vicinity of a distinctive aeromagnetic anomaly.From Thelon River northward, several coincident zones of chromium and uranium enrichment are found where the line of boreholes crosses east-west-striking belts of volcanic, ultramafic and sedimentary rocks of the Prince Albert Group.The results of this study indicate that till tends to have characteristic element associations or concentrations over each of several broad regions along the pipeline route. These are related both to large-scale bedrock associations and to largescale effects of glacial dispersal. In addition, the samples, collected more or less at random with respect to local bedrock geology, have intersected several small-scale geochemical anomalies that appear to be related to zones of mineralization of possible economic interest."

Jan 1, 1980

By T. Holmes, S. Davison

"The Special Standard Surge bin at Agrium’s Vanscoy Potash Operations (VPO) has been plagued with flow problems and wear, and corrosion issues for it’s entire working life. Investigation showed that the carbon steel construction, bin geometry, and resultant funnel-flow pattern were directly responsible for production losses and disproportionate maintenance and capital costs. Potash enters this bin at between 140°C and 165°C, but the stagnant potash outside the active flow channel was much cooler, allowing moisture to migrate toward the outer regions, which caused corrosion of the walls and reduced live capacity as the potash in this area hardened and built up on the walls over time.A 2013 inspection revealed holes and paper-thin areas in the lower cylinder wall sections and in the conical hopper. The only thing preventing major leaks and even a potentially catastrophic failure was the buildup of stagnant hardened product on the cone walls. It was concluded that the cone had reached the end of its life and required replacement. VPO’s original plan was to replace the cone in kind and repair the cylinder as necessary; however, a failure-mode and bin-performance investigation combined with a lifecycle- cost analysis indicated it would be better to redesign the hopper.For success in retrofit projects, it is essential at the design stage to consider the bulk solid flow properties and the operating environment involved. Because education in this area is not offered at a university level, engineers often do not fully appreciate the effects of the flow properties of bulk solids on bulk material handling equipment.Jenike & Johanson conducted flow properties tests on samples of potash and using the data, redesigned the bin and the feeder. After the modifications, VPO’s surge bin provides safer, more reliable operation with a much longer predicted working life. Using this retrofit as an example, we aim to provide a general understanding of bulk solids flow theory and highlight the importance of customizing the design to the appropriate flow properties in the cost effectiveness, reliability, and safety of a bulk material handling system."

Jan 1, 2016

By John C. Loretto

"The paper identifies two of the main problems encountered in recent hydrometallurgical plants for the recovery of gold and silver: firstly, the plant recovery is lower than anticipated from the testwork; secondly, the metallurgical accounting figures cannot be reconciled.The principal reasons for the plant recovery being lower than the testwork are discussed, together with solutions that can minimize these problems both during the design stage and during the plant operation after the problems have manifest themselves.The reasons for the difficulties in metallurgical accounting are analyzed by reviewing the various components of the plant figures. Recommended solutions are given for minimizing this problem and the realities of obtaining accurate figures are discussed.IntroductionThe start-up over the last few years of new hydrometallurgical plants for the recovery of gold and silver has brought to the surface again a number of problems. Most of the problems have existed for some time and they manifest themselves mainly in two ways. Firstly, the plant results do not agree with the metallurgical testwork figures; secondly, the metallurgical accounting figures do not balance.Metallurgical TestworkThe plant results not agreeing with testwork figures are mainly due to:a) testwork samples not representative of the eventual plant feed;b) misinterpretation or misunderstanding of testwork ;c) plant losses;d) plant design not allowing testwork results to be achieved;e) operating deficiencies."

Jan 1, 1982

By T. S. Golosinski

"This paper reviews the types of selective continuous miners (SCMs) available at present, and compares their main features. Furthermore, operating practices and mine planning aspects of the SCMs applications are reviewed and conditions for efficient application of this equipment are defined. Finally, the potential applications of the SCMs in surf ace mining of oil sands are discussed INTRODUCTIONIn the 1970s the United States Bureau of Mines (USBM) conducted a program of investigations, design and demonstration of various continuous surface mining concepts, This included continuous mining equipment which was an adaptation of several civil engineering and/or underground mining machinery concepts to surface mining. Upon termination of this program, the related development was continued by a number of equipment manufacturers, leading to development of several types of SCMs. This new type of surface mining equipment is able to mine selectively hard and thin multi-layered formations at high, sustained, and economically viable production rates.While used mostly in coal mining at present, the characteristic features of this equipment permit conclusion that it may prove to be an efficient tool for surface mining of oil sand, and/or related overburden stripping. Of particular interest here may be the ability to mine thin layers of hard material, without a need for its earlier fragmentation, and the ability of the SCMs to load a variety of haulage equipment, including belt conveyors."

Jan 1, 1989

By L. A. Mells

"A laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the applicability of a radium selective ion exchange complexer for removing radium from Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. under contract to the Department of Supply and Services using the Saskatchewan Research Council facilities located in Saskatoon, Saskatchewan.The results of this work showed the ion exchange complexer, Dowex XFS 43230.00, to be efficient in removing radium from contaminated water of uranium mining operations with the ultimate loading capacity of the resin on one type of water treated being determined as approximately 1,600 Bq/cm3 of new resin. Although this resin has potential application for treatment of effluent streams in uranium operations it has been identified that the resin efficiency and capacity is directly related to the chemistry of the water being treated and site-specific testwork is required in order to establish reliable design data for full-scale operations.IntroductionThe possible applicability of a radium-selective ion exchange complexer for removing radium from Canadian uranium mining effluents had been identified and discussed as a possible alternative to present radium removal methods during a review of disposal technology options for the National Uranium Tailings Program of the Department of Energy, Mines and Resources(1). Work by other workers(2.3) had shown the complexer to be very efficient in removing radium from contaminated water. Also, plant trials on contaminated minewater at the Mt. Taylor uranium mine in New Mexico is reported to have shown the resin complexer to be efficient under plant operating conditions.As a result, a laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the suitability of this resin for Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. (MCEL) under contract to the Department of Supply and Services using the Saskatchewan Research Council (SRC) facilities located in Saskatoon, Saskatchewan."

Jan 1, 1985

By W. Petruk

A study was undertaken to determine whether interrelations between mineral grains affect ore breakage during grinding, and to establish a correlation between ore breakage and mineral liberation. A base metal ore from the Brunswick No. 12 deposit in New Brunswick was ground for different periods of time in a laboratory ball mill, and both the unbroken ore and the ground products were analysed by image analysis. The results show that the mode of breakage is strongly influenced by the behaviour of pyrite. Similar size distributions were obtained for material from the 15 minute grind in a laboratory ball mill, for the grinding circuit discharge from a commercial mill, and for pyrite grains in the unbroken ore. This similarity indicates that a 15 minute grind breaks poorly bonded pyrite grains along grain boundaries, and represents the limit of easy breakage for the ore. Such a grind liberates both large separate grains of ore minerals and poorly bonded mineral grains that occur in interstices among pyrite. On the other hand the 15 minute grind does not separate moderately bonded mineral grains nor release moderately bonded interstitial minerals from pyrite; a 45 minute grind in a laboratory ball mill is required. It is assumed that, for Brunswick No. 12 ore, a 45 minute grind in a laboratory ball mill is equivalent to regrinding in a commercial mill. Grinding beyond 45 minutes in a laboratory ball mill breaks the ore by fracturing pyrite across grain boundaries and by chipping grain edges. Such intense grinding does not markedly increase sphalerite liberation from Brunswick No. 12 ore, because most of the sphalerite that can be released was liberated at the 45 minute grind. In contrast the intense grinding increases galena liberation because a significant proportion of the galena occurs as minute inclusions in pyrite. These findings show that ore breakage and coincident liberation depend upon size distributions, intergrowths, and mode of occurrence of the minerals in an ore.

Jan 1, 1988

By R. A. Halet

"The Malartic Gold Fields mine is a good example of the association of ore deposits with a major fault zone. It also exemplifies the control exerted by the physical and chemical character of the host rocks on the localization of orebodies.The mine is in Fourniere and Dubuisson townships, Abitibi county. It is 6 miles east of the town of Malartic, 9n the main highway and railway from Noranda to Val d'Or.The discovery of the mine is due largely to the enterprise of the late J. P. Norrie, who organized the present Company in 1935. The ground is entirely covered by overburden, but Mr. Norrie believed that the extension of the Cadillac-Malartic 'break', the principal ore-bearing structure of the district, would be found on this group of claims. This belief was supported by the discovery of gold-bearing float in the area, and was confirmed by a dip-needle survey and a few pilot diamond drill holes that showed that the favourable Malartic greenstone band passes through the centre of the property.In this way the most favourable area for prospecting was narrowed to a zone 2 ½ miles long by ½ mile wide underlain' by greenstone. The remainder of the property is underlain by sedimentary rocks, which, from experience elsewhere in the camp, were not considered as promising. However, as the entire surface is covered by deep overburden, the location of orebodies even within this more or less restricted area could be accomplished only by a long campaign of diamond drilling. Systematic diamond drilling began in 1936.The contacts of the greenstone band were considered to be the most promising places to begin the work, and the early drilling was concentrated on the south contact, because the orebody of the East Malartic mine, 4 miles to the west, had been discovered on this structure and it was reasonable to hope for a repetition of these conditions. Although the south contact was very thoroughly explored, with a certain amount of encouragement, the work did not prove the existence of deposits of ore grade, and attention was shifted to the north contact zone of the greenstone band. In this locality much more promising results were obtained, and a number of good orebodies were outlined."

Jan 1, 1954

By John A. Meech

"Oleic acid flotation of Mount Wright thickener underflow tailing material has been shown to be capable of increasing plant recovery by 3%. High levels of oleic acid addition (1.5 kg/t) are required, which limit the economic practicality of the system at this time. Nevertheless, from a technical viewpoint, the process is stable with respect to extreme fluctuations in oleic acid requirements, pulp pH and pulp temperature. Methods to reduce the average consumption of oleic acid need to be found. One technique that merits further testwork uses the ""piggy-back"" principle to float hematite fines with coarsegrained hematite particles.IntroductionWith most large-scale iron mining operations treating specular hematite ores, flotation is not often conside red a necessary processing step. The bulk of the iron minerals can be concentrated by gravity techniques and the generation of fines can be minimized because of the course- grained nature of the mineralization. Nevertheless, production of some fine material is unavoidable, and recovery of iron from this fraction by spirals is poor (10-30%).When the proportion of the iron in these fines becomes excessive, alternative methods to conventional spirals are considered(11), Many of the techniques that have been developed suffer from either poor recovery (e.g. the Reichert cones at 36010 recovery)(11) or low throughput rates (e.g. wet highintensity magnetic separation)(12), Flotation is often passed over because of excessive reagent costs, pollution problems and/or balling difficulties from the reagents used.However, of all the processes available, flotation can yield high recoveries (60-90%) at reasonable throughput rates with excellent process control features (reagent addition and/or cell level). The key parameter is reagent cost.This paper describes testwork on the use of oleic acid to float hematite from the fine fractions of the Mount Wright concentrator tailing. The concentrate product from this plant is directly shipped, so no balling problems exist. As well, oleic acid may be considered a lesser pollution hazard than many of the cationic collectors used in other iron ore flotation systems. A reduction in fine hematite slimes discharged as tailing into lakes may also reduce environmental damage."

Jan 1, 1981

By C. Bourgoin

"The factors constraining productivity in the mining of narrow vein ore deposits are numerous and often interdependent. This paper concerns mining techniques capable of reducing some of these constraints in the case of vein deposits whose dip is less than 45 degrees. Modifications of conventional mining methods as well as suggested new developments are presented, as are matters pertaining to the mechanization of operations as a mean of increasing both productivity and work safety. IntroductionThe mining of vein deposits, whose width (thickness) is generally less than 2 metres and whose dip is often variable, calls for the use of varying stoping procedures as well as appropriate infrastructure and equipment. In the case of intermediate dips (15 degrees to 45 degrees), it is generally conceded that the degree of mechanization is limited and that ore removal via gravity is impossible. This paper proposes certain innovations in matters of equipment use and stoping methods, together with certain technical data pertaining to the application of these new procedures Stoping MethodsTo mine vein deposits, one must choose a method that can adapt to irregular ore limits and allow, as well, for good ore recovery with as little dilution as possible. In addition, it is important to minimize development work in waste rock. In principle, one selects a method that is both safe and profitable; this method will be defined mainly by the nature of the vein deposit and its dip, by the competency of the rock formations and by certain technical considerations. Moreover, the stoping procedure in a given deposit may well change with time as a function of new layouts or new equipment."

Jan 1, 1994

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

By C. W. Langenberg, D. E. Macdonald, R. S. Strobl

"The successful marketing of Alberta coals will increasingly depend, to a large degree, on an extensive coal quality information base. This information, at present, is generally based on a deliverable, cleaned coaland is confined to existing mine sites. Coal quality information is not as well understood for raw in situ coal outside of mine sites and even less is known about the geological factors that control it.If new uses and markets for Alberta coal are to be developed, such as gasification, coprocessing, and exploiting high rank coals for combustion, it will be imperative that the coal quality parameters important for these utilizations be known. These parameters need to be known for existing deliverable coals and, just as important, for as yet unexploited in situ coal. Factors such as the Cl, No, K, Co, P and trace element contents should be addressed to meet the requirements of these new utilizations.The geological characterization and explanation of what factors control these coal quality parameters is part of research being done at the Alberta Geological Survey. In-seam vertical profiling has been undertaken within the plains and foothills/mountains coals to determine exactly where coal quality variations occur and why. In the Ardley coal zone at the Highvale Mine it has been found, for example, that the ash content of the mined coal is made up of discrete partings and of microsized particles associated with inertinite macerals. The in-seam characterization of coal seams will lead to a better understanding of in situ coal quality variations, leading to new uses and markets for Alberta coal."

Jan 1, 1993

By A. B. Parsons, P. G. Howes

"This article discusses how recent changes in the federal and Quebec .income tax laws have contributed to an improved investment climate for mineral exploration in the Province of Quebec. Individual investors who are resident in Quebec and who are in the highest tax bracket (1984-60.4% marginal rate) may obtain tax benefits that result in only nine cents of each invested dollar being at risk.IntroductionIn a recent submission by the Mining Association of Canada to the Royal Commission on the Economic Union, it was stated that the mining industry ""is no longer discovering and opening new mines at rates sufficient to offset the depletion of existing orebodies and to maintain pre sent output"". With world metal prices still in a depressed state following the prolonged 1981-82 recession, moreover, the continuing success of Canadian mining in world markets will depend on this country's ability to compete in a new environment characterized by subsidized Third World production . For the most part, this new competitive environment will encourage the development of cost-efficient mines that are better equipped to withstand the troughs and valleys of international metals prices."

Jan 1, 1984

By Eugene F. Mehr, Dennis C. Martin

"Development of the final slope for the 340 m (1200 ft) high hanging wall at Cassiar Mine precipitated an area of deep seated instability involving an estimated 17.6 million tonnes. The deformation mechanisms involved squeezing of soft deformable serpentinite rocks in the toe which caused planar sliding and graben toppling of the stronger sedimentary rocks in the middle and upper sections of the slope. Although movement rates up to 150mm/day were recorded, by understanding the controls on failure, the mine was able to install a suitable monitoring system and complete the open pit with only minor loss of the mineable ore. Accelerated mining was required in the last full year of operation. This paper describes the deformation behaviour, failure mechanisms and back analysis results for the failure. The monitoring systems and operational aspects related to the failure are also presented.IntroductionCassiar Mine is located in steep mountainous terrain in northern British Columbia approximately 1200 km north of Vancouver (Fig. I). During the final mining phase of the open pit, instability developed in the approximately 340 m high hanging wall (east wall) slope. A unique graben toppling mechanism was identified based on detailed assessment of slope monitoring data and visual observations. Comprehensive slope monitoring enabled mining to continue even though movement rates as high as 150 mm/day were being recorded. Three-dimensional limit equilibrium back analyses and numerical modelling have been used to assess the various controls on the slope movements and to understand the failure mechanism."

Jan 1, 1993

By Jerry M. Whiting, Neil J. Duncan

"Does Canada need a mining industry? Isn't it a chronically depressed collection of businesses that pollute the air and water and tear up the countryside? Wouldn't it be better if Canada's investors devoted their attention to high-technology endeavours, tourism, and other relatively pleasant tasks?Probably the answer to whether Canada needs a mining industry in the 21st century is to look at the real mining industry that is in operation today. The facts indicate that mining is a very important contributor to Canada. It has certainly encountered some challenging times during periods of recession, and it face s severe and continuing problems of cost and competition in world markets. However, uneconomic mines have been closed, others suspended, and productivity has risen dramatically with employment at 77 000, down from 101 000 in 1981. The country's metal and non-metal mines, metallurgical plants and semi-fabricated metals industries employed an estimated 378000 workers in 1986, and paid wages than any other sector of the Canadian economy. This effort resulted in the production of 60 different metals, non-metals and structural minerals valued at $13.5 billion.The trade aspects of the mining industry are of paramount importance. If there is a reason for this situation to change during the next century. it eludes the authors. Canada has the well-developed expertise to discover, evaluate, develop, operate and profit from existing and new businesses based in an enormous area endowed with a nearly unbelievable variety of mineral resources. Many countries throughout the world must rely on producers like Canada, if they are to maintain and/or improve their standard of living."

Jan 1, 1988

By W. K. Chan, R. Lahaie

"The Suncor Oil Sands Mine located north of Fort McMurray, Alberta, produces about 80000 m' per day of tailings waste which must be disposed of economically in an environmentally acceptable manner. To date, this has been accomplished by impounding the high water content tailings wastes behind large dykes, many of which approach 100 m in height .The dykes are constructed using suitable overburden material stripped prior to the mining of the oil sands feed and/ or the coarse sandy fraction of the tailings waste itself. Although the above is common practice at many mining operations, the large volumes handled and the resultant costs require designs to be meticulously fine-tuned toward the optimum. As a result, considerable effort is expended on planning, designing and construction, and performance monitoring. The lack of precedent experience (Suncor pioneered oil sands mining), coupled with the realities of long, harsh winters and a variety of troublesome site conditions and construction materials, has led to some very unique dyke construction.This paper overviews current tailings disposal plans as welt as some of the key issues related to the design, construction and performance of these large dykes."

Jan 1, 1988

By D. A. Trotter

"This paper traces the main advances in mine lighting from neolithic times to the 1960s. The earliest lights consisted of reeds or strips of wood soaked in grease. As man's knowledge increased, the oil lamp, the candle, kerosene, acetylene and finally electricity have allowed him to see where no natural light could penetrate. These advances in technology, however, did not come easily. Many false starts were made and great dedication was required by a few lighting pioneers to overcome the many technical difficulties that were encountered. The lighting of coal mines in particular caused unique problems, as there was the ever-present threat of methane explosions. Advances in mine lighting will continue, but these advances are only possible because men like Davy, Wolf, Marsuat and Edison paved the way.IntroductionMan's first efforts at mining consisted of merely picking rock off the surface of the earth. The sun was his only source of light. The early mines of the Neolithic age were simply vertical pits, 5 to 8 m deep. In order to follow an orebody, miners began to dig horizontally from the bottom of these pits, and as work progressed the need for additional light became apparent. With the discovery of the light-giving properties of fire, man was no longer dependent on natural light. Figure 1 gives an impression of the earliest artificial mine lighting used.Early Evidence of Mine LightingCarbonized residue from wood chips which had been inserted into rock cracks can be found in early Neolithic workings. The mines at Krzemionki Opatowski in Poland contain very narrow low tunnels that were lit in this fashion and were worked from 2300 to 1800 B. C. The wood had to burn downward to provide light and because wood burns poorly in this position, the chips were probably soaked in animal fat to make them burn more easily."

Jan 1, 1982

By Z. X. Cui, X. D. Ma, L. Contreras, X. Jiang

The bath smelting process is one of the key techniques applied in the current copper smelting production, which includes bottom-blown and side-blown furnaces differently from the direction of gas injection. Liquid matte and slag form the bath in the smelting furnace. To better understand the fluid dynamic of the bath and further optimise the operational efficiencies in the smelting furnace, physical simulation of the bath in the horizontal cylindrical reactor was investigated. The mixing behaviour and wave motion of the bath in the bottom-blown and side-blown furnaces have been studied systematically. The mixing time is reduced with increasing gas flowrate and height of the lower layer, while it increases significantly with increasing the height of the upper layer. The wave motion in the furnaces can be suppressed with the presence of the upper layer, but the bath with a lower density generates higher wave amplitude. Overall, in comparison to bottom-blown mixing, side-blown mixing shows better mixing efficiency and lower wave amplitude. In addition, the plume eye and splash phenomena occurred in the bottom-blown furnace have also been studied. INTRODUCTION The bath smelting process is one of the principal techniques used in the current copper making industry. The bath smelting techniques have some advantages of high smelting efficiencies, low capital costs, low energy consumptions and reduced dust generations. From the direction of gas injection, the bath smelting techniques can be classified into five general types: (1) top-submerged blown, e.g. Ausmelt and Isasmelt; (2) top-suspended blown, such as Mitsubishi smelting; (3) top direct-to-copper smelting, such as Outokumpu smelting; (4) submerged side-blown, such as Noranda and Teniente smelting; (5) bottom-blown, such as Dongying Fangyuan bottom-blown copper smelting furnace (Schlesinger et al., 2002; Zhao, Cui, & Wang, 2013; Perez-Tello et al., 2018). In many metallurgical processes involving bath smelting situations, the objectives of agitation are to accelerate the bath homogenization inside the bath which makes a significant contribution to process efficiency and product quality. Extensive mixing studies have been performed for ladle refining and tundish associated to steelmaking processes through water physical models. Mixing time is the parameter used to quantify the efficiency of mixing in the liquid bath and the first empirical equation predicting mixing time was proposed by Nakanishi, Fujii and Szekely (1975). Later on, more systematic studies have been carried out on ladle mixing and researchers realized that the geometry of the vessel could also have a significant impact on mixing (Khajaviand & Barati, 2010). However, the investigations using ladles which are vertical cylindrical vessels, cannot be directly used in the study of mixing behaviour in horizontal cylindrical reactors. Understanding the fluid dynamics inside horizontal cylindrical bath smelter is useful from the industrial perspective. Recently fluid dynamics of horizontal cylindrical smelter related to copper smelting have been studied by the authors’ group (Shui et al., 2015a, 2015b, 2018a; 2018b; Xu et al., 2018, 2019).

Jan 1, 2019

By B. D. H. Knights, N. B. du Preez

The recovery of the economy of the Democratic Republic of Congo has allowed for the rapid increase in production of copper from this region, while the increased price of cobalt continues to support the recovery of that country’s economy. This has enabled the modernization of the process technology used, particularly the change from direct electrowinning of copper to solvent extraction-electrowinning. With this change has come a variety of technical challenges in optimizing the recovery of cobalt from these sources. In this paper, we discuss aspects of the flowsheets for the production of cobalt from the ores of the DRC and Zambia, highlighting the technological improvements that have been made. Following this description of the practice, we assess the challenges of further improving the recovery and purity of cobalt from these sources. INTRODUCTION The African Copperbelt (Figure 1) is by far the biggest producer and holds the greatest reserves of cobalt (Sheed, 2015). However, the ores of this great mining region are extracted primarily for their copper content, and cobalt is a by-product. The ratio of copper-to-cobalt is between 6 and 20 to 1, with the ores from the DRC richer in cobalt than those from Zambia. The overall supply of cobalt, shown in Figure 2, is increasing due to an increase in demand for its use as a battery material. Cobalt is used in superalloys, hard metals, pigments, catalysts magnets, tyre adhesives, lithium-ion rechargeable batteries, and wear-resistant coatings, amongst others. Although these generic categories persist, Figure 3 shows how the relative usage of cobalt is changing due to the uptake of electric vehicles in China and Europe. Cobalt is a key element in lithium-ion batteries, and because it is widely anticipated that electric vehicles will be legislatively encouraged, it is anticipated that the demand for cobalt will rise. This anticipated increase in demand resulted in an increase in the price for cobalt, to which suppliers responded over-eagerly, and the price has dropped dramatically in the first few months of 2019, as shown in Figure 4. However, there is a clear cycle of price peaks in cobalt’s history.

Jan 1, 2019

By François Charette

High stress conditions in weak rock masses lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock failure. Typical support systems combine various reinforcement and support mechanisms to provide the required convergence control and retainment, but results are often mitigated by failure of surface liners, shotcrete and tendons. The paper reviews differing requirements of support and reinforcement for different failure types. In addition, the mechanical performance of a new reinforcing tendon is presented and analysed in view of the field requirements. Field tests results are presented.

May 1, 2011

By Hugh K. Taylor

"With some justification, people have long complained about the indefinition of ore reserves. Perhaps they were led to expect too much; from former and easier definition practices in the once common underground mines with exposed and available assets, where the obsolete term 'ore in sight' was at least partly literal. But such mines have become rarer, and their underground development less affordable. For most projects, valuations and its definitions have thus been advanced from actual to prospective mines, leaving a very wide gulf between 'what is there' and 'what may happen to it'. This brings the double challenges of reduced geological and technical assurance and the protraction of economic uncertainties.This paper avoids the popular field of regional resources, being confined to what may possibly be mined within single or closely grouped deposits. For these, many estimates of tonnage and grade must be made, defined and declared long before assessment of feasibility; and the uncertainties of the latter make it an unsound base for defining the earlier quantities. Despite the best of intentions, implied or inferred promises may proveimpossible to honour.A simpler framework of definitions is suggested, to some extent reverting to an earlier dependence on supporting work rather than on opinions of economic assurance or future events that are more properly the functions of production and cash flow schedules."

Jan 1, 1994