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By M. F. Goudge

MAGNESIA refractories and magnesium metal are both essential war commodities. The need for magnesium, which had just made its debut as a commercial metal a few years before the outbreak of the present war, is widely known because this new and valuable light metal has already received much publicity. Less widely known but equally important in the war effort are magnesia refractories. They are indispensable to the efficient functioning of the great metallurgical plants producing steel, nickel, copper, and other metals, where, because of their resistance to extreme high temperature and chemical attack, they are used in lining the furnaces, which are operated at a white heat. The demand for refractories in the metallurgical industries rose rapidly upon the outbreak of war, and now, in consequence of the continued great expansion under way in the manufacture of steel, nickel, copper, and other metals, the need for magnesia is greater than ever. Since 1915, part of the Canadian requirements of basic refractories has been supplied from the deposits of magnesitic dolomite in Argenteuil county, Quebec. The products from these deposits are excellent for many uses, but the magnesitic dolomite has too high a content of silica and lime to be used in making a type of magnesia brick required in nickel converters, and in the roofs of reverberatory furnaces used in the copper and steel industries. There is now a large and growing demand in Canada for bricks and shapes for these uses. This demand has always been supplied from the United States. Makers of these products in the United States, in turn, formerly imported most of the necessary high-grade, dead-burned magnesia from Austria and Manchuria. Not only are these sources closed, but refractory chrome ore from the Philippines is no longer available and chrome refractories may have to be in large part replaced by magnesia.

Jan 1, 1942

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

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

Jan 1, 2017

By A. Ouellette, E. Nilsson

"Preventative maintenance is a burden for equipment users but a demand from the machine suppliers to ensure performance. Machine availability depends on preventative maintenance being followed.Mining equipment is becoming more and more sophisticated and productive, yet less and less time is available for preventative maintenance. Manufacturers invest in reducing costs, simplifying operating requirements, and lowering maintenance requirements, but it is the users who must invest more heavily in the advanced maintenance systems to keep the units operating.IntroductionPreventative maintenance has been, and still is a key factor in avoiding disturbances in production due to equipment downtime. Manufacturers ask for it in extensive maintenance schedules, check lists, programs, etc. often with a ""threat"" that, if not performed, the machine guarantee will not be valid. Modern mining and construction machinery has become sophisticated, like all other machinery, with elaborate hydraulic, electric and electronic systems and computerized controllers. Maintenance organizations within the mining industry have grown to heavy cost centres just to keep up the availability of the equipment.It is difficult for machine manufacturers to have maintenance programs that suit every user. International suppliers have to deal with different cultures, education levels, environments, organizations, etc. Maintenance programs recommended by manufacturers often do not meet some user's needs while they are ""overkilling"" to others. Preventative maintenance schemes recommendations of what to do, in what frequency, etc.) usually fit mechanical components in the equipment, e.g. wear measurements, crack indications, lubrication, oil changes, etc. But how does one perform preventative maintenance on huge hydraulic systems, electrical and electronic systems and computers? Failures in these systems usually occur without any warning and are more or less impossible to predict. Another difficulty in creating effective preventative maintenance programs for these kinds of systems is the relatively low volume of mining and construction equipment that is produced per year. For example, although Atlas Copco is one of the largest manufacturers in the world of underground blast hole drilling machines, the company still does not produce more than a few hundred drilling jumbos per year. These are made in more than 10 different models, with different systems and components, and very often are custom adapted to the end user's requirements."

Jan 1, 1992

By P. Choquet, F. Miller

"The development and testing of a simple low-cost gauge for measurement of tension in a cable bolt grouted in a borehole are presented. Its principle is based on a resistance wire which is wound on a 70 cm length into the spiral grooves of the wire strand cable bolt. Readings are then taken by a robust automatic data logger with a several day autonomy or by a portable readout. In order to have a complete profile of tension along the cable bolt, a number of tension gauges can be installed along its length.This paper provides a description of the development and laboratory calibration of the tension gauge and addresses the two modes of loading for a cable bolt in a rock mass, namely pure tension and shearing at a joint location.In the second part of the paper, four field tests in underground and open pit mines are reported. The first test was used to substantially modify both the gauge and the readout unit principles while the other tests which are still on-going show a very satisfactory behaviour of the modified version of the tension gauge. IntroductionCable-bolting is often used as ground support in Canadian mines for a variety of applications. In underground mines, cable bolts can be installed vertically at the back of cut and fill stopes or in an inclined fashion in the walls of large open stopes. Alternatively, cable bolts at Mines Gaspe (Noranda Inc.) are used in a fan-shaped pattern from a drill drift to stabilize the inclined roof in 25 m wide open stapes. This new application oriented our research efforts toward the design of a novel instrumentation to monitor the efficiency of most commonly used 5/8-inch cable bolts."

Jan 1, 1988

By Claude Deveau

"With ever decreasing feed grades, finer mineralogy and increased demand for product, it became obvious that a major step in equipment performance was required to reduce operating costs and increase production. Offsite testwork indicated that a Centrifugal separator was capable of recovering fine tantalum and that the newly developed C Series Falcon concentrator would be capable of replacing many pieces of aging equipment and provide improved performance. Further investigation led to the rental and the purchase of a Falcon C20 concentrator followed by a C10 to maximize circuit performance.Falcon Concentrators Inc’ s practice of working with the customer mirrors Tantalum Mining Corporation of Canada’s (Tanco) philosophy of continuous product development. This synergy honed valve design for continuous operation in a highly abrasive ore environment.Tanco has recently purchased two more Falcon concentrators for the recovery of additional tantalum from its spodumene circuit. These new units have additional user friendly operating features partially based on developments made at Tanco.The Falcon C Series units have enabled Tanco to maximize recovery of tantalum that was otherwise lost while using the original conventional gravity circuit."

Jan 1, 2000

By A. Ouchi

This paper presents ground control best practices in weak rock environments including the "Unsupported" Weak Rock Updated Span Design Curve and awareness pertaining to the potentially detrimental effects of using resin grouted rebar in weak rock masses and the false sense of security that the use of resin grouted rebar may instill. Ground support is almost always used in weak rock environments, though the type of support used can vary widely. The development of the Weak Rock Updated Span Design Curve by the addition of 463 case histories of RMR76 values ranging from 25 to 60, has also been calibrated to four different support categories; Category A: Pattern Friction Sets, Category B: Pattern Friction Sets with Spot Bolting of Rebar, Category C: Pattern Friction Sets with Pattern Rebar Bolts and Category D: Cablebolting, Shotcrete, Spiling, Timber Sets or Underhand Cut and Fill. Design of underground man-entry type excavations in North America relies heavily upon empirical analysis. This design requires a higher Factor of Safety than other non-man entry type excavations. A comparison of the calculated ½ span failure Factor of Safety between all the categories is also presented.

May 1, 2009

By P. G. Smith, A. Axiuk

The objective of this paper is to present, from a practical perspective, a review of the most relevant maintenance procedures that are accepted or prescribed to be the most effective in optimising service life potential and to ensure continued safe use of steel wire ropes for shaft mining applications. The paper will address the most common operational issues encountered in the care and operation of shaft ropes for both conventional drum hoists and multi-rope friction winders. For each distinct maintenance procedure presented, a limited amount of theory is discussed to identify the underlying mechanisms at play that must be addressed and to emphasize the logical basis for the recommended course of action. It is recognised that each installation is unique and that the recommended maintenance procedures may not always be practical or cost effective from an operations standpoint under select circumstances, however the intent remains to promote industry best practices for the knowledge and benefit of the mine hoisting community, from experienced maintenance personnel to new entrants to the industry alike.

Jan 1, 2023

By Lloyd Rowson

??Several factors have led to a review and reoptimization of the Midwest uranium deposit by AREVA Resources Canada Inc., the project operator, on behalf of the owners ??The current proposal is to mine the deposit using open pit methods and then transport the ore by truck on a dedicated road linking the Midwest site with AREVA?s McClean Lake Operation (JEB mill) for processing ??A decision has been made to begin mining the deposit by 2010 (pending regulatory approvals)

May 1, 2008

ABSTRACT This paper details the work of RISKGATE, the largest Australian Coal Association Research Program (ACARP) occupational health and safety initiative to date. The program is an interactive online risk management system developed to maximize health and safety performance in the coal mining industry by implementing continuous improvement in managing major unwanted events. The comprehensive knowledge base covers tires, collisions, fires, isolation, strata control underground, ground control open cut, explosions, explosives, manual tasks, and slips/trips/falls. All major Australian coal mining companies contributed topic experts to this broad industry initiative: nine coal mining companies, more than 80 experts, and more than 400 days of individual time for knowledge-capture workshops.

Jan 1, 2014

By J. Hansen

"ABSTRACTThe paper addresses the application of automated monitoring, control, and navigation to improve dragline performance. SummaryImproving dragline performance in the Canadian coal mines is critical to the continued success of the industry. Draglines represent a large capital investment and coal prices are low by historic standards. This paper argues that the introduction of monitoring, control, and navigation on draglines offers an opportunity to significantly reduce a dragline’s operating cost per cubic metre moved. To place the importance of this in perspective, a North Dakota mine calculates that every 1% increase in dragline productivity means a savings to the mine of US$340,000 per year. MonitorsAutomated dragline monitoring is a well established technology with commercial products available since the early 1980s. The three main reasons for placing monitors on draglines are (Walker, 1993):1. productivity increases: reduce variations between different operators’ performance across different shifts;2. quality increases: increase the percentage of ore and waste loads that go to the correct destination; and3. special projects (engineering projects): justify installing static field exciters and regulator upgrades; implement power management; aid operator training; study high performance buckets, rigging changes, and various excavation sequences.Mines as diverse as Kennecott’s Cordero- Rojo Complex in the United States and Natal Coal Corp.’s Optimum Mine in South Africa report dragline productivity increases of 10% to 20% in the region attributed to the implementation of dragline monitoring."

Jan 1, 2000

By J. S. Phipps, D. R. Skuse

"Aqueous slurries of fine particle size calcium carbonate are used in a diverse range of end-use products. In many cases, the end use performance is governed by the fineness of the particle size distribution. In turn, the maximum fineness of the particle size distribution is primarily determined by the efficiency of the dispersants used during the production process. Here we report the sodium polyacrylate mediated dispersion of calcite and kaolin. Firstly, we report a colloid chemical description of the dispersant behaviour and attribute the stabilisation to both steric and electrostatic mechanisms. Secondly, we describe how the understanding developed in the first part of the study can be utilised to produce more effective dispersant systems which allow the preparation of, added value, higher solids and finer particle size calcium carbonate slurry products.INTRODUCTIONConcentrated aqueous dispersions of fine, particulate kaolin and calcium carbonate are used extensively in the coating of paper. Currently more than 10 million tonnes of such dispersions are used annually in North America and Europe alone, and worldwide consumption is growing at around 3% per year.Generally, paper is coated to enhance its visual appearance. Firstly, coatings improve the optical properties of the blank sheet, i.e. its brightness (or whiteness), opacity and gloss. Secondly, they improve the physical properties of the sheet that will influence the quality of the final printed image, such as surface smoothness, porosity, and ink absorption. In order to achieve these aims economically, paper coatings must be applied at high speeds and with minimal drying costs.Kaolin and calcium carbonate pigments are the major components of most paper coating formulations. Particle size distributions are chosen to maximise the optical benefits that they confer, and to allow the production of formulations that can be easily pumped, handled and coated. Coating pigments are generally produced and transported as slurries, and so it is important to obtain dispersions with the highest possible solids content, both to minimise drying costs and the quantity of water transported. This paper examines the dispersant technology that is currently used in the industry and the mechanisms by which it functions, and illustrates ways in which this technology has developed and could be further improved in the future."

Jan 1, 2003

By Sanat Talmaki

Construction and mining worksites pose unique challenges to workers and equipment operators due to their dynamic and unstructured nature. Narrow haul roads, crowded work spaces and presence of workers and equipment in close proximity, combined with large blind spots and overall poor visibility afforded to operators lead to collisions and run-over-type accidents between equipment, workers, and other entities that may be present on the jobsite. Operations that involve machine-infrastructure interaction, particularly in the case of concealed infrastructure such as excavation and drilling lead to unintended strikes between the equipment?s end-effect or and the infrastructure. Such accident-prone scenarios can be avoided by providing operators with real-time feedback and warnings using 3D visualization and proximity monitoring of the entities present in the equipment?s vicinity. Thus the jobsite in the real world is abstracted and represented in a 3D virtual world. However, this requires the ability to create a seamless link between real-world sensors present on the equipment and/or the jobsite and the virtual environment. This paper describes a non-restrictive acquisition allocation framework that allows position and orientation sensor streams from construction and mining job sites to be used for updating 3D virtual scenes in real-time for providing vital collision avoidance warnings to equipment operators.

Aug 1, 2013

By S. Nikolic, G. M. Stieper, D. P. Mallah, B. J. Hogg, P. B. Voigt

Copper feed materials processing is becoming more challenging, due to an incremental increase in the mineralogical and compositional complexity of these feeds. These complex and polymetallic feeds are now becoming more common and many sites have been forced to re-evaluate their operating strategies to process these materials at cost competitive rates, whilst meeting ever more stringent environmental regulations. Most operations must first evaluate the merits of pyrometallurgical and hydrometallurgical treatment routes. Although there are multiple copper smelting technologies available, only top-submerged lance (TSL) technology, supplied by Glencore Technology as ISASMELT™, has been applied in the real world to consistently and successfully smelt complex materials in integrated metallurgical facilities such as Glencore’s Kazzinc Ltd. operation in Kazakhstan, Umicore Precious Metals Refining in Belgium and Aurubis AG in Germany. Glencore Technology also offers hydrometallurgical processing, through the Albion Process™ technology, opening up viable flowsheet options previously not possible for these complex feeds. This paper describes a number of real world process flowsheets at global operations and Glencore’s own operations at Mount Isa and Kazzinc Ltd., which process complex feeds. These flowsheets integrate the ISASMELT™, Albion Process™, ISACONVERT™, ISAKIDD™ Tank house, and bottom blown oxygen cupel (BBOC™) technologies to provide an effective process solution for the treatment of complex polymetallic feeds to produce metallic copper and associated by-products. INTRODUCTION Traditional smelters and those built in recent times within the bulk smelting hubs of the world have been designed to treat standard/clean concentrates. In recent years the processing of complex polymetallic sulfide concentrates and the recycling of secondary copper and derivatives of waste electrical and electronic equipment, such as e-scrap, have become a focus for numerous companies (Alvear & Nikolic, 2013). Processing of these complex feeds, characterized by relatively high levels of minor elements (over 5% of elements such as arsenic, antimony, bismuth, lead and zinc) is more challenging. Facilities not designed for these types of materials may require significant modifications or a change in smelting technology to treat them. Often operations find themselves re-evaluating the merits of pyrometallurgical and hydrometallurgical treatment routes for their sites through a number of factors:

Jan 1, 2019

By B. R. MacKay

Introduction The Corbin coalfield is one of the smallest, and at the same time one of the principal, producing bituminous-coal areas in southeastern British Columbia, and is unique on account of the great original thickness of one of its coal seams and the remarkable concentration of coal in a small area that has occurred through intense folding and faulting of the measures. These are such that the deposit has been referred to at times as "the world's thickest coal seam" and as" a mountain of coal." The determination of the number, thickness, and character of the seams present, and the structure, extent, and geological relationship of the several deposits, are of vital interest both to the operating company in its endeavour to evolve the most efficient method of mining these exceptionally thick deposits and to the Government in estimating the coal resources of the different fields. With the object of ascertaining these data the writer was assigned in 1930 to geologically map and study the Corbin coal deposit. A topographic map covering Coal mountain and the immediate vicinity on a scale of 1 inch =800 feet, with a contour interval of 25 feet, made by the Topographic Division of the Geological Survey, served as the base for the geological mapping.

Jan 1, 1931

By R. L. Bishops

This paper discusses some of the materials, processes and systems used in motor insulation. Among the materials mentioned are epoxies, polyesters, mica paper composites and wire enamels. Two processes developed to take advantage of the special characteristics of two of these materials are described, and how these materials are used in several new insulation systems now on the market is discussed. Finally, future trends in motor insulation are outlined.

Jan 1, 1969

By A. J. Hynes, Lutes. G. G., Ravenelle. J. -F.

"The Anomaly A area of the Clarence Stream gold deposits in southwestern New Brunswick contains mineralized structures that bear geometrical relationships to regional folding events. The four mineralized zones of Anomaly A (AD, MW, 93, and Murphy) are hosted by turbiditic graywacke, quartzose wacke, siltstone, and argillite sequences of the Kendall Mountain Formation. A regional scale structural analysis reflects at least four deformational events, three of which appear to control the folded geometry of Anomaly A (D2, D3, and D4). F2 and F3 folds are coaxial and are refolded into a dome and basin geometry by F4 folds. The mineralized zones are subparallel to axial surfaces of F2 folds. Structural analysis of a mineralized zone exposed at surface indicates that gold mineralization is hosted by a quartz-vein system that comprises veins generated during both D2 and D3. Threedimensional representations of Anomaly A created using drill-core data and ®GoCAD suggest that the quartz-vein system was emplaced in fault structures during D2 as well as within brecciated dilation zones during D3. Three of the four zones that make up Anomaly A have F2 hinge surfaces that can be linked through a geometry compatible with the style of F3 and F4 folds. The apparent continuity of these three zones indicates the potential for kilometer-scale mineralized structures at Anomaly A. Le secteur de l’Anomalie A du gisement aurifère Clarence Stream contient des zones minéralisées qui montrent des relations géométriques avec les épisodes de déformation régionale. Les quatre zones minéralisées de l’Anomalie A (AD, MW, 93, Murphy) sont comprises dans une séquence turbiditique composée de grauwacke, de wacke quartzitique, de siltstone, et d’argilite appartenant à la Formation de Kendall Mountain. Des quatre épisodes de déformation étudiés par l’entremise de cartographie structurale, trois semblent contrôler la géométrie de l’Anomalie A (D2, D3, et D4). Les plis P2 et P3 sont coaxiaux et sont replissés en dômes et bassins par les plis P4. Les zones minéralisées sont subparallèles aux plans axiaux des plis P2. Une analyse structurale effectuée sur une zone minéralisée exposée à la surface indique que la minéralisation aurifère est localisée dans un système de veines de quartz qui contient des veines générées durant D2 et D3. Des représentations en trois-dimensions créées avec le programme informatique ®GoCAD à partir de données de forages suggèrent que le système de veines est localisé dans des zones de failles D2 ainsi que dans des zones de dilatation associées avec D3. Trois des quatre zones qui forment l’Anomalie A possèdent des plans axiaux P2 qui peuvent être liés par l’entremise d’une géométrie qui respecte le style des plis P3 et P4. La continuité apparente de ces trois zones indique qu’une structure minéralisée pourrait s’étendre sur plusieurs kilomètres dans le secteur de l’Anomalie A."

Jan 1, 2008

By D. G. Hulbert, J. H. Schubert, R. G. D. Henning

"Froth depth, along with reagent addition and aeration rate, is one of the crucial factors that can be used to control a flotation circuit. Sub-optimal setpoints and disruptions in levels have a severe adverse influence on grades and recoveries. A novel control strategy has been developed which provides exceptionally tight regulation of pulp levels. The controller observes and acts on all the flotation levels simultaneously. This provides a clear improvement over the standard approach, which is to use a set of Pl controllers. The system has been run on several industrial plants and has resulted in reduced fluctuations in level; fast responses to setpoint changes, and fast settling times after start-ups or disturbances. Testwork has shown that the improvements in level stabilisation translate into improvements in recovery and grades.IntroductionProcess control and optimization have an important influence on the economic efficiency of flotation plants. Inefficient operation can allow the wrong balance between grades and recoveries, and can also lead to adverse shifts in the grade-recovery relationship. Of all metallurgical operations, flotation loses the largest proportion of valuable material. Better operation can reduce these losses.An essential requirement of a good controller is that it should be able to stabilize and regulate the plant. Stable operation allows the performance of the plant to be observed without being obscured by the effects of disturbances and fluctuations. The optimum conditions can then be detected more easily. Good regulation can maintain operation at the optimum with proper neutralization of disturbances. Only when good stabilization and regulation are achieved can an optimizing strategy be properly applied.Froth depth, aeration rate and reagent addition are the three means by which a flotation plant is generally controlled. These control actions are effective on different time scales. Reagent addition is slower in its effect as some conditioning time is required. Since reagents are only added at the head of the circuit and at a few selected points within the banks, time is required for the effect of reagent changes to move through the circuit. Because of this slower time constant, reagent addition is more suited to process optimization and to dealing with slower changes in the process. An example of these slower changes is variation in the feed."

Jan 1, 1995

By Brad McBain

Agenda ? Accurassay Laboratories and Automation ? History and experience ? Features and benefits of automation in the lab ? Tata Steel Minerals Canada (TSMC) Iron Ore Laboratory ? State-of-the art systems and design ? The integration of fusion systems and XRF units ? Meeting deliverables: quality, reliability, safety

Aug 1, 2013

By Hans de Ruiter

"Delft University of Technology, RWTH Aachen, Helsinki University of Technology and Imperial College established the Federation of European Mineral Programs (FEMP) in 1999 as a legal body to coordinate joint M.Sc. education.By 2003 the number of participating universities in Europe has grown to 9 (in 7 countries) offering 3 different M.Sc. joint programs. Furthermore students from 8 universities in the USA, Canada, Australia and Chile participate through exchange agreements. About 25 companies are associated with FEMP. Further expansion with other clusters of universities is being investigated.So far some 160 students have taken the programs and are working in all parts of the world in a variety of jobs.The European Commission has recently announced the new “Erasmus World” program that will stimulate the offering of joint programs by European universities and offer third-country students and teachers a greater opportunity for mobility and an enhanced European added value. Host European postgraduate courses will be selected for a five-year period. They will receive funding from the Community and a “EU” seal. Around 250 “EU Masters Courses” will be established.The envisaged new Erasmus program and it’s network and operating practices are very similar to those being used by EMC, EMEC and EGEC. Erasmus World therefore offers a great opportunity for further developments with FEMP as the official body.INTRODUCTIONThe current situation in Europe is that globalisation of the supply of mineral resources has caused the larger mining and the manufacturing companies to expand and invest particularly outside Europe. However these industries still have a great significance for the European Union and its members, which means that mineral engineering know-how is still important in the E.U. It was therefore realised in the mid-nineties that is vital to maintain the very high level of knowledge and skill base in mining engineering and mineral technology that currently exists in the E.U., through good and well-balanced education programs."

Jan 1, 2004

By R. Dahlke, J. A. Finch

"A campaign was undertaken during the greater part of 2001 at Noranda’s Brunswick Mine Concentrator to investigate the role of gas (air) superficial rate distribution (Jg profile) to the cells in the final Zn cleaning stage (bank of seven cells). Three profiles were tested: Balanced (each cell with same Jg), Increasing (from cell 1 to 7), and Decreasing, along with an “as found” profile in a parallel control bank. The experimental design allowed for two confounding factors, changes in ore type and circulating load. The Increasing profile consistently gave the best metallurgy (down-the-bank grade / recovery). The reason for improved performance was traced to the response of the first few cells. The Increasing profile gave the highest selectivity of sphalerite against non-sulphide gangue (NSG) in these cells with relatively even recovery per cell down the bank (10-15% based on feed to each cell). The other profiles gave lower selectivity and higher zinc recovery in the first cells (up to 25% in cell 1), which combined to reduce overall bank performance. The increased selectivity with the Increasing profile is attributed to the low gas rate in the first cells reducing water recovery and hence limiting entrainment of NSG gangue. The Increasing profile was subsequently configured for all four stages in the zinc cleaner circuit.INTRODUCTIONThe performance of a flotation circuit is largely the result of the operator’s response to visual clues. This includes manipulation of the gas (air) input and how it is distributed to cells in a bank. A lack of sensors prescribes this approach. Over the past ten years the Mineral Processing Group at McGill University have developed a set of gas dispersion sensors including one to measure gas superficial rate (or simply “gas rate”), i.e., volumetric gas rate per unit cell crosssectional area, Jg (Gomez and Finch, 2002). The device collects bubbles in a tube immersed in the pulp and infers Jg from the pressure-time curve generated after a valve is closed and air starts to accumulate. The usual units are cm/s. It is robust, reliable and suited for plant use.A version of the Jg sensor was tested extensively during 2000 at Noranda’s Brunswick Mine Concentrator (Dahlke et al., 2001). The results were sufficiently encouraging that a sensor was fabricated to suit local requirements (Insta-Jg). The sensor detected malfunctioning field instruments and flotation mechanisms, and demonstrated that gas distribution to cells in a bank “as found” had no particular pattern, or profile. Preliminary testing suggested that a balanced profile (i.e., all cells with the same gas rate) gave superior metallurgy (grade / recovery down the bank) than the “as found” profile. This observation prompted a focused campaign to explore the impact of the gas rate (Jg) profile, introducing the notion of “gas distribution management”."

Jan 1, 2004