Search Documents

"In numerous meetings, conferences and discussions over the past year, the Conference Board of Canada has been impressed with the efforts of Canadian organizations to improve their competitive position. The attempt should be made to try to pull together and synthesize what has been heard. The topic of this paper, however, is even more daunting. The task is not only to analyze and discuss what is happening now, but also to look into the future—to the year 2000.The future seems to have an endless capacity for surprises, often unpleasant. This is one of the lessons learned in the twentieth century, particularly over the last 15 or so years.This paper covers three areas of managing in a changing com¬petitive environment: (1) the major global and domestic trends that will influence the ways in which Canadian organizations are managed (2) how Canadian companies are responding or will need to respond to these trends; and (3) the implications of the preced¬ing for human resource management and human resource professionals."

Jan 1, 1991

By J. K. Gowans

"INTRODUCTIONTo bring a mining property into production in the Canadian High Arctic a company must deal with the harsh environment, the short shipping season and the high cost of labour. In trying to minimize the effect of these factors, the concept of a barge-mounted process plant was investigated as an alternative to the conventionally built concentrator. Cominco's previous experience gained at the Black Angel Mine on Greenland's west coast suggested that this would be a practical alternative.The normal shipping season at Little Cornwallis Island is approximately six weeks long, from mid-August to the end of September. All equipment and materials must be delivered during this small ''shipping window."" The logistics problems are enormous; if the conventional approach had been used the major process equipment would have been delivered to Little Cornwallis Island at the same time as the completed barge actually was! Construction would also be starting at the start of the worst climatic conditions, the Arctic winter. Nine months production was gained by opting for the ""Barge"" approach.What the Arctic winters do to the shipping season, so do they affect the productivity and the cost of labour. Construction labour must come from southern Canada. Thus higher transportation costs and higher wage rates, with more overtime and incentives, increase the labour costs to approximately 50% over normal southern rates. Couple these rates with the lower productivity involved with men working in the extreme cold temperatures and the net effort is worth avoiding. A process plant being constructed in Southern Canada can take advantage of more accessible labour at lower costs, increased productivity and a faster construction schedule. The barge concept must still deliver the equipment and materials during the ""shipping window"" but it can in the completed form."

Jan 1, 1983

By T. J. Yeomans

"The Kidd Creek metallurgical site is situated twenty-six kilometres east of Timmins, Ontario. The site consists of a 4.5 niillion tonne per year concentrator, a 127,000 tonne per year electrolytic zinc plant and a 79,000 tonne per year copper smelter/refinery complex.The concentrator commenced operations in 1966 and was expanded to its present capacity in 1978. The zinc plant commenced operations in 1972, and the copper smelter/refinery in 1983.The concentrator tailings, and both liquid and solid waste products from the other plants are disposed of within a 1215 hectare tailings disposal area. Here, a method known as centraljzecl thickened discharge is used to form a stable cone-shaped hill. A low permanent perimeter dyke structure encloses the cone and directs cone run-off and thickener overflow to a treatment pond. After treatment with lime slurry, this neutralized effluent is recycled to the metsite and also discharged into the Porcupine River system.The tailings system has been in operation in its present form since 1972, upon completion of dykes and a 110 metre thickener unit. Underflow densities were continuously increased until thickener overloading became a serious problem. This necessitated the construction of a second 110 metre thickener, which was completed in 1983. Target densities have been achieved without difficulty since then.This paper discusses the operation of the tailings system, reviews past performance, and outlines future operations."

Jan 1, 1986

By T. G. Edgeworth

Some of the historical background of the industry is reviewed, with reference to the different types of reduction cells in use for aluminum smelting. Factors to be considered in cell des1gn involve capital, power, and operating costs. The trend is apparently toward larger cells. The industry is studying new construction materials for cell linings, as well as alternate electrolyte compositions and other design changes which will improve productivity and energy efficiency. The aluminum smelting activity in other countries is briefly reviewed. TODA Y'S industrial production of aluminum is still based on the simultaneous discoveries made in 1886 by Charles Martin Hall in Ohio, and Paul Heroult in France. Up to that date, only about 50 tons of aluminum had been produced in the world, and the price at that time was about $5 per pound. Sucl1 figures must be contrasted with the present world aluminum smelting capacity of over five mil-lion tons per year, and a price of about 25 cents per pound.

Jan 1, 1962

By A. P. Schissler

Mining has several characteristics, uncommon in other business sectors, which pose additional challenges to the implementation or design of IT and management systems that use the information. Understanding these characteristics would improve the chances of successfully importing new information technology and management techniques to mineral producers. The most important characteristics that should be understood are workplace issues, the industry’s dual nature of being a continuous construction project using cyclical factory processes, labour challenges, workplace culture, information availability, integrative data elements, and the current technical education of mining engineers. These characteristics were taken into account in two applications of information technology and systems design at operating companies. The research and consulting projects focused on the development of an IT-enabled performance management system at several underground metal mines in Canada and an integrated data warehouse for surface mines spread throughout the United States and Latin America.

Jan 1, 2006

By J. A. Russell

"UNTIL the last few years, the collieries of the Dominion Coal Company, Limited, while highly mechanized as to the cutting and transportation of the coal, still relied on the hand-loading of coal from the seam onto face conveyors. In these circumstances it was possible to assure that no large proportion of extraneous materials would be loaded with the coal, and the product could be quite well cleaned for the market by screening and hand-picking.Within the past few years, however, the Company has introduced an intensive programme of mechanization which will result in the virtual elimination of hand-loading .of coal. It has been the experience of other producers that mechanical loading inevitably leads to a very large increase in the amount of impurities in the product. This is occasioned by the fact that, at least up to the present, all types of loading machines have relied on the coal being broken from the seam by under-cutting and shooting. In this operation, a certain amount of roof and pavement material inevitably becomes mixed with the coal and, since selective loading is impossible with a loading machine, all this foreign material is loaded out with the product."

Jan 1, 1952

By E. I. Vargha-Butler

The determination of surface tensions and contact angles of coal particles is of great interest for coal beneficiation processes such as froth flotation and oil agglomeration and for the inclusion of coal particles into oil droplets as a means of enriching the fuel. Methods for contact-angle measurements on small irregularly shaped solid particles have not been available in the past. Therefore, we recently developed a novel technique to determine contact angles and surf ace tensions of coal particles. Two types of bituminous and one type of subbituminous coal particles have been tested. The technique used is called the freezing-front technique and it considers the behaviour of the test particles (in the range of 20-250 pm) at the solidification front of carefully selected, well-defined solidifying melts (matrix materials) such as thymol, biphenyl, naphthalene, salol and 2-phenyl phenol.The results show that the technique works well, providing quantitative and detailed information on the wettability of coal particles. The sensitivity of the method is so high that a difference in contact angle of approximately 4 degrees between the smaller and the larger particles is clearly registered.

Dec 1, 1981

By Yongjun Peng, Yufan Mu, Rolf A. Lauten

"Chalcopyrite, a major source of copper, is commonly found associated with iron sulfides, particularly pyrite. The separation of chalcopyrite and pyrite by flotation is difficult due to the galvanic interactions between pyrite and chalcopyrite during grinding and flotation. Galvanic interactions may cause oxidation and dissolution of chalcopyrite, copper activation of pyrite and the formation of hydrophilic iron hydroxide coating. The overall effect may change the floatability of the components and lead to the misplacement of pyrite into chalcopyrite concentrate. The objective of this study was to investigate the effect of lignosulfonate-based biopolymers on the depression of pyrite in the flotation of chalcopyrite with xanthate as collector and the mechanism responsible for the selective depression of pyrite. The flotation results showed that biopolymers depressed the flotation of both copper-activated pyrite and chalcopyrite in single mineral flotation although to different extents. In the flotation of mixed mineral systems, biopolymers significantly depressed pyrite flotation but had a less influence on chalcopyrite flotation. The selective depression of pyrite by biopolymers was due to the preferential adsorption of biopolymers on copper-activated pyrite surface. Galvanic interactions between pyrite and chalcopyrite surfaces promoted copper activation on pyrite. Presence of cuprous ions on pyrite surface favored biopolymer adsorption by the formation of a complex between the cuprous ions and biopolymer molecules. The same galvanic interactions also facilitated chalcopyrite oxidation leading to the formation of hydrophobic polysulfide that enhanced the hydrophobicity on chalcopyrite surface. The biopolymer structure controlled the depression effect. The results showed that the biodegradable biopolymers are promising depressants for pyrite.INTRODUCTIONCopper sulfide minerals, such as chalcopyrite (CuFeS2), bornite (Cu5FeS4), chalcocite (Cu2S) and covellite (CuS), are the major mineral source for copper. They are often found finely interlocked with iron sulfides, especially pyrite (FeS2) (Owusu, Brito e Abreu, Skinner, Addai-Mensah, & Zanin, 2014). Pyrite, as the most abundant sulfide mineral, is perceived as gangue in most cases and should be removed from the associated sulfides to minimize its contamination of the copper concentrate (Owusu, Addai-Mensah, Fornasiero, & Zanin, 2013; Wang & Forssberg, 1991). The commonly used strategy to remove pyrite is flotation (Wang & Forssberg, 1991)."

Jan 1, 2016

By W R. Honeywell

Two series of laboratory flotation tests were carried out to study the treatment of Faraday ore by two-stage flotation. First the acid-consumers and then the uranium minerals were floated. On ore ground in the Faraday mill grinding circuit, and using Faraday mill water in the flotation step, a recovery in the flotation concentrate of from 91 to 93 percent of the uranium was obtained in 45 to 50 per cent of the weight at a grade of 0.24 per cent U30s. The saving of acid in leaching the uranium-bearing flotation concentrate, as compared to leaching the whole ore, ranged from 30 to 46 per cent. The average over-all extraction resulting from flotation and leaching of the flotation concentrate was 88.1 per cent. The best collector for the acid-consumers was sodium oleate. Acintol F A-1 emulsion was the best collector for the uranium minerals, and, in the uranium flotation step, an acid pH in the slurry was found to be necessary. The reagent costs were estimated to be 22 to 26 cents per ton of ore.

Jan 1, 1963

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014

By Franco Oboni

Numerous voices are raising around the world to show how misleading and fuzzy commonly used risk assessments methods are. These criticisms come at a time when public trust in ?proponents of new projects?, operators, private or governmental, seems to have hit a low and the legal system ?targets? public officers. It is common that technical experts and the public strongly disagree in their analysis of risks. Risk definition requires the evaluation of probability and consequences and those words are oftentimes enough to stir great worry to the public. Thus it is nowadays commonly understood that ?reality? is not scientific, but resides in public opinion, hence urging technical people to communicate better, more transparently. Blatant failures on both counts have lead to the emergence of ?new myths? used to justify complacency using ?complexity? and other buzz words as an alibi. This paper (together with its companion presented elsewhere) explores how poor ?common practices? in Risk Assessment contribute to biasing project team, design teams opinions, skew decision-making process and finally misrepresent reality to the public resulting precisely in the raise of public distrust, legal implication witnessed around the world. The discussion first reviews the pitfalls of common approaches (FMEA, Probability Impact Graphs) pinpointing them as possible causes of future legal liabilities. An alarming disconnect also comes from various codes, ISO 31000 itself has this flaw, invoking the term ?acceptable?/?tolerable? without defining it or giving any guidance for its determination. Wide-spectrum public consultation could be developed to define a ?modern? social acceptability criteria helping all the stakeholders making/understanding decisions. Another alarming disconnect comes from the poor definition of consequences of mishaps and their societal ripple effects. This aspect is indeed mostly ignored in codes, leaving ample room to biases and censoring applied to potential losses. In our society no one seems to have anymore the possibility of hiding behind a shroud of ?carefully maintained? misrepresentation. It is time to act and ?write the book? for proper risk assessments avoiding misrepresentations.

May 1, 2013

By Christoph Broeckmann, Andrew Gardula

"The adoption of high-pressure grinding throughout the cement industry has yielded enormous savings in energy and wear material costs. There are also a number of installations, which are applied in iron ore and kimberlite processing operations. High pressure grinding offers the same potential for energy and media savings, as well as opportunities for improved, downstream metallurgical performance, in hard rock mineral processing. This paper focuses on developments in machine design and wear surface engineering for high-pressure grinding of the hard rock ores in the mineral processing industry.INTRODUCTIONIn the early eighties 3.4 % of the world electric energy was consumed for crushing and grinding operations of minerals and 0.6 % in the ore dressing industry. During that time using a laboratory press Prof. Schönert found that interparticle comminution at high pressure requires remarkably less energy as conventional grinding technologies. In grinding of cement clinker he expected energy savings between 33 and 50 % compared to ball mills [1]. Piston presses are limited in throughput. Thus, the principle of interparticle comminution was adapted by the use of high pressure grinding rolls (HPGR) to a continuous plant process. Figure 1 shows the main components of a roller press: The roller nip of width s is formed between the floating roller (1) and the fixed roller (2). The diameter of the rolls will be denoted with D, the width with B. The total press force F can be adjusted using a hydraulic system with two or four pistons (3). In order to compare machines with different roll geometries the specific pressing force p is introduced:"

Jan 1, 2005

By V. F. Hollister

Four conditions are commonly accepted as being needed for the development of native sulphur deposits in sedimentary rocks : (1) ample sulphate-bearing evaporite, normally anhydritic; (2) proximity to petroleum deposits; (3) a hydrodynamic system of communication between these two; (4) a stratigraphic or structural trap to prevent escape of the sulphur and sulphur -bearing reaction products. When any of these requisites are absent, apparently no significant residual bio-epigenetic sulphur deposit will form. These requirements are, however, satisfied in some areas, which include both the Triassic and Devonian evaporites of northeastern British Columbia.

Jan 1, 1977

By Michel Doyon

Canadian Context: Exploration ??Space Exploration is within the unique mandate of the Canadian Space Agency ??Global partnerships ??Maintain close relationship with our partners ??New knowledge in S&T ??Retain and attract highly qualified personnel ??Participation in missions leads to design roles in industry and academia ??Collaboration between government laboratories, industry and academia

May 1, 2009

By Suping Yao, Chuanyu Jiang

In the last decade, the copper industry in China has witnessed a significant change. The capacity and production of refined copper has grown remarkably from 1.5 million tons in 2002 up to 5.88 million tons in 2012. And now, China has become the biggest copper producer in the world, counting about 30% of the global refined copper production. This paper summarized modern copper smelting and converting technologies employed in China copper industry, such as OT flash technology, TSL (ISA/Ausmelt), SKS bottom blowing, Jinfeng side blowing, etc…This paper also presents some key development and improvement of these technologies up to date from their practical application in China, what will contribute as great value to any new / or renovation copper smelting projects down the road. As an engineering company in China, NERIN has been involved in many of these projects in the past decade, played an important role in the engineering works and accumulated intensive experiences. NERIN is one of the best choices for the world clients in the copper industry, providing quick engineering service, delivering cost effective projects.

Jan 1, 2014

By Imre Gombköto, Barnabás Csoke

"Raw material management means not only mining and processing of primary raw materials like ores, but means also collecting and processing secondary sources of raw materials. Recycling is one of the most developing field of raw material management in Europe, and its solutions are derived from mineral processing roots and principals. Complexity and challenges of the field of recycling results innovative solutions of material processing- Since European Union identified 20 raw materials as critical (CRM) due to lack of primary sources within the border of the EU, recycling become more recognised as source of different raw materials. WEEE is the waste streams contains many of the critical elements and along them at least 15 different species of plastics of which recycling is delayed by a lack of effective separation technique. Most paper deals with separation methods based on different specific gravity, triboelectric charge or surface properties of plastic species. Plastics however have differences of thermal properties and thermoplastics, duroplasts and elastomers can be recognised. The experiments described in the paper aimed to determine thermo adhesive behaviour of plastic species often identified in WEEE streams for separation purposes. According to the results, some plastic types as PS, PP. PC or PVC and PET pairs are possible to easily separate from each other, however different additives are changing thermo adhesive properties of most of the plastics that makes industrial process difficult to develop. Along thermo adhesive behaviour, combination of physical interaction can be used to enhance separation selectivity.INTRODUCTIONPlastics has a relatively long term of history as a light, multi-functional material in construction, packaging, automotive industry and electric and electronic products. There are a numerous types of plastic species can be used for various applications therefore they amount are growing from year to year. This quantity however become part of the waste stream and while metal recycling has been done for decades due to its economic value - cheap plastic parts are less desirable as secondary products. In 2013 an annual 5% of plastic production growth has been estimated with a base data of 265 million tonnes at 2010 (Guiqing & Zhenming, 2013). Since landfill requirements are increasing while—especially in Europe where actual regulations are trying to deflect waste from landfills - landfill capacities are decreasing, costs are become more and more expensive, Applications like energy production based on plastics as a fuel or recycling are some of the options can be applied. Direct incineration of plastics are applied at many plants - in most cases where waste consist of dangerous substances are incinerated because plastics high calorific value helps correct average mixture composition enable operators reaching high enough temperature for combined power and heat generation while most of substances—like PAH, PCB or dioxins—are destroyed. Another path is using low temperature reductive cracking due to pyrolysis process, however the chance having higher concentrate of carcinogen substances in the products are higher since it applies around 400°C during the process."

Jan 1, 2016

By A. Warczok

Smelting slags contain payable metals in a dissolved form and as mechanically entrained matte or metallic inclusions in the size range from 2 to 1000 µm. Slag cleaning requires reduction of magnetite and metal oxides and sedimentation of inclusions. Slag cleaning in an electric furnace is carried out in batch or semi-continuous mode. The strong trend for continuous slag cleaning generates the basic question about the optimal geometry of the electric furnace. Results of combined CFD, potential distribution and heat transfer modeling allowed for the determination of the fluid flow pattern and the temperature distribution in a classical, circular electric furnace as well as in a rectangular furnace. For the rectangular furnace, various length/width ratios and position of electrodes have been simulated. Analysis of key phenomena pointed out the advantages of the rectangular electric furnace over the circular furnace, particularly for continuous slag cleaning. Phenomena that have been analyzed were mass transfer, the rate of slag reduction, coalescence and settling of inclusions, all on the basis of the calculated slag flow pattern and the temperature distribution.

Jan 1, 2007

By J. Guha, el, G. Bouchard, W. Zuckerk, J. Carignan, G. Archambault

The Gwillim Mine, located 8 km northwest of Chibougamau, is underlain by two mafic volcanic cycles separated by a dominantly felsic cycle. These rocks are part of the Gilman Formation of the Roy Group. The mafic rocks are cut by weak shear zones containing the "North" and "Main" veins, both east-west striking gold-bearing structures dipping 75° to the north. The felsic cycle, which is also gold-bearing, contains textures suggesting a syngenetic origin. The Gwillim Mine presents an excellent opportunity for the study of what may be two coexisting gold deposits, a volcanogenic and a veine type.

Jan 1, 1984

By N. P. Hristov, L. V. Kuzev

"A simulation study of the fill factor of a drum mill was conducted using two types of grinding media: balls and tetraballpebs. Each medium was composed of equal number of grinding bodies having equal weight but different shape. The difference was in the density of the two grinding media.Standard spherical grinding bodies (balls), which were used in practice, and equivalent (by weight) grinding bodies in the shape of spheroidal tetrahedrons (tetraballpebs) were studied. The simulation was conducted in a module of a 1.2 m diameter drum mill, whose length exceeded twice the diameter of the corresponding grinding body. The grinding balls had a few percent (3 to 6) higher fill factor than the grinding tetraballpebs in the same shell.Vertical sections of the grinding medium were taken across the studied shell module along its axis. They showed the location of each grinding body in the fill volume. Defects in the packing of the grinding bodies and the contacts between them and with the inner surface of the shell were also show. Differences in the contact points of the balls and the tetraballpebs were noted. For the tetraballpebs, we observed contacts both between the spherical surfaces and with the edges and vertices of the grinding bodies.The topography of the grinding media is shown visually.INTRODUCTIONThe grinding balls have been studied extensively. It is the traditional grinding medium in ore processing industry. The parameter characterising the grinding medium is its density. It is the mass of the grinding medium per unit of volume. The parameter may have a range of values. It depends on:• The physical properties of the material they are made of;• The shape of the grinding body;• The dimensions of the body;• Size distribution of the grinding bodies in the grinding media.In comminution, the fill factor of the mill shell is the process parameter that is representative of the grinding medium. Some publications have indicated the disadvantages of ball grinding. For example, Wu, Xiang, Glen, and Duan (2008) note in the analysis of the mechanism of grinding that the balls are not the best grinding media and disadvantages include among others:• Easy over-grinding resulting from the point contact between the balls;• Attrition surface is the smallest in the grinding media;• Poor selective exposure of minerals resulting from the accidental and often significantly more powerful impact on the feed;• The grinding efficiency drops as the fineness of grind is increased;In the Handbook of mineral processing, Polkin (1950) noted that the shape of the grinding bodies determines the volume of the void spaces therein and therefore the shape affects the grinding efficiency per unit of volume of the grinding medium."

Jan 1, 2016

By Don Peel

Mineral aggregate, the most widely used mineral resource globally, has attracted little academic or public interest. Of all mining developments, the aggregate resource is seldom factored into resource management decisions. This lack of recognition to the strategic aggregate resource has significant economic, environmental, and social implications. Impact to the economics, the environment, and the community coincide with the key elements of the United Nations concept of ?sustainable development?. To build on the concept, the mining sector contracted the International Institute for Environment and Development to assess how mining activity contributes to sustainability. As a result, a useful assessment process was developed by the Mining, Minerals and Sustainable Development (MMSD) Task Group entitled ?Seven Questions to Sustainability: How to Assess the Contribution of Mining and Mineral Activities.? In Alberta, recent opposition to mineral resource development by community residents offers an opportunity to employ the MMSD?s assessment procedure. The public opposition to the mining activity was addressed through a stakeholder planning process initiated by the municipal council of Sturgeon County, Alberta. As a result the Calahoo/Villeneuve Area Structure Plan (CASP) was formulated and adopted. To measure the effectiveness of the CASP planning process in terms of sustainability, this paper applies the MMSD?s Seven Question assessment to the Calahoo/Villeneuve Area Structure Plan.

May 1, 2004