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By W. A. Parks

Stone that may be applied to purposes of construction is available in nearly all the inhabited parts of Canada, the most important exception being the prairie region, but, even here, the deficiency is overcome in many parts by a wealth of glacial field-stones. In many parts of the country, also, the accessible stone is of a quality so poor that brick is more generally used. There is a great difference, however, between stone that 'may be used' and stone suitable for buildings of a monumental type or even for 'trimmings' on the better class of dwelling in the cities and towns. It is in the latter sense that the expression 'building stone' is commonly used. Thus restricted the term includes varieties of sandstone, limestone, and granite, using the latter word in the custom of the quarryman, not only for the true granite of the geologist but for many other igneous rocks as well. Building stone of high quality grades imperceptibly into stone suitable for monuments, particularly in the case of the granites. The present review will deal with building and monumental stone in this restricted sense and will omit marble, although that material has been used to some extent for building. For instance, the Great West block in Winnipeg is built of marble from British Columbia.

Jan 1, 1925

By Gordon T. McKenna

"Syncrude Canada Ltd. is developing new concepts in lease-closure landscape design for its Oil Sands Leases 17 and 22 in northeastern Alberta. Closure planning is becoming an integral part of the planning cycles and of the lease operation. By incorporating closure planning into the day-to-day operation, the company will achieve acceptable lease closure in an economical manner. Ultimately, Syncrude will achieve lower operating costs through innovation in mine planning and a reduction in residual liabilities.New concepts being evaluated for lease-closure landscape design include: designing for closure, use of landforms and natural analogs, self-armouring bouldery ground, robustness in design, landform grading, terrain analysis of reclaimed land, geotechnical hazard assessments, choices in closure design timeframes, passive maintenance, determining post-closure monitoring goals, engineering tailings, engineering other substrates, use of test plots and field demonstrations, geomorphologic monitoring of reclaimed lands, defining closure goals, and visiting other mines. These concepts are being formalized under the new discipline of Landscape Engineering."

Jan 1, 1996

By Ahmad Ghahreman, Denver Cowan, Yeonuk Choi

"Previous testwork by the authors has indicated that both granular coconut shell based activated carbon and a new microporous carbonaceous bead, Lewatit® AF 5, are highly effective in improving the oxidation kinetics and decreasing the elemental sulphur yield when assisting the atmospheric oxidation of pyrite. While the two carbon catalysts show similar results and improvements to the pyrite oxidation, there are differences between them. For example, the activated carbon assisted oxidation showed faster kinetics than the AF 5 assisted oxidation, while elemental sulphur seemed to remain adhered to the surface of the AF 5 after oxidation when much of the elemental sulphur formed during the activated carbon assisted tests was found in the oxidation residue. The objective of this paper is to investigate the differences between the two catalysts through the use of scanning electron microscopy, photography, Raman spectroscopy, surface chemistry analysis, and Brunauer-Emmett-Teller (BET) surface area analysis. With this investigation the authors should be able to achieve a better understanding of the surface chemistry of the two carbon catalysts (i.e. functional groups, charges, acidity etc.) and help explain the strengths and/or the weaknesses of the catalysts when applied to the atmospheric oxidation of pyrite.INTRODUCTION Previous research conducted by the authors, indicated that both a granular coconut shell based activated carbon (activated carbon) and a microporous carbonaceous bead, Lewatit® AF 5 (AF 5), acting as a catalyst enhanced atmospheric pyrite oxidation in ferric sulphate media by approximately 40% when compared to unassisted oxidation and that elemental sulphur yields were increased from 23% to approximately 69 and 63% when assisted by AF 5 and activated carbon respectively (Cowan, Jahromi, & Ghahreman, 2017). The study indicated that although total pyrite oxidation assisted by the two catalysts was similar, differences were noticed in the impact that the two catalysts had on the outcome of the oxidation. Kinetic curves in the Cowan et al. study indicated that atmospheric oxidation of pyrite seemed to reach completion after 48 hours of oxidation when assisted by activated carbon. A similar trend was noticed in the kinetic curves for oxidation when assisted by AF 5, however the oxidation curve did not reach completion until approximately 96 hours (Cowan et al., 2017). This observation indicated that the kinetics of pyrite oxidation are enhanced by both catalysts, oxidation kinetics are much faster when assisted by activated carbon rather than AF 5."

Jan 1, 2017

By Oliver C. Ralston

DURING the development of froth flotation for the treatment of sulphide ores, a certain amount of information was collected about a few of the nonmetallic minerals, and occasionally the gangue minerals in the sulphide ores showed an embarrassing tendency to float. However, for many years efforts were expended to develop reagents that would cause wetting and depression of these minerals. Among the nonmetallics, the minerals sulphur, graphite, and talc probably should be classified as 'natural floaters', and perhaps sericite. They respond to almost any type of flotation reagent, and their beneficiation by flotation had been attempted years ago. Flotation of sulphur is now common practice, and graphite was concentrated during the World War in many mills, most of which have now closed down. A talc mill has just been constructed, and another may soon be erected. Second to the 'natural floaters' come the 'easy floaters', cassiterite, fluorite, barite, mica, colloidal gangue, and paper pulp from white water of paper mills. That these materials responded to some of the early flotation reagents, as oleic acid, has long been known; occasional references to their behaviour are found in the very early flotation literature and in that of today. In general, however, nonmetallic minerals, valued at $2.00 to $15.00 per ton, have for a long time been regarded as cheap products and not worth much beneficiation. Consequently, only high-grade natural deposits suitable for direct mining and sale have been gouged out. Furthermore, the mining of these minerals has too frequently been in the hands of 'super-practical' men-men of no technical or other training, willing to work for a very low compensation. From the social standpoint, nonmetallics has been the field for small, untrained enterprisers with little money to spend on plant or equipment. But times have been changing. The impact of technically trained men on the old industry has revealed appalling losses and inefficien-cies and proved the value of processing materials discarded or avoided by the old regime.

Jan 1, 1937

By Olanrewaju A. Ojo, Xu Wang, Jian Xin Dong, Lina Zhang, Jerzy A. Szpunar

"The influence of crystallographic orientation on the pitting corrosion behavior of Ni-Fe-Cr alloy 028 was studied by a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), potentiodynamic polarization technique and atomic force microscopy (AFM). The results show that there is anisotropy of pitting corrosion that strongly depends on crystallographic orientation of surface planes. The distribution of pits frequency in standard stereographic triangle shows that the crystallographic planes close to {100} are more prone to pitting corrosion compared to planes of {110} and {111}. The calculation of surface energy (001) and (111) shows that the planes of high packing density of atoms have low surface energy with concomitant strong resistance to pitting corrosion. A correlation function between crystallographic orientation and pitting corrosion susceptibility suggests a method not only to predict the pitting resistance of a known textured materials, but also to improve corrosion resistance by controlling materials texture.INTRODUCTIONNickel-iron-chromium(Ni-Fe-Cr) alloys are widely used in various industries and engineering sectors due to their combination of good mechanical properties and high corrosion resistance(Hibner, 2001; Thomas, 2006; Ghosh, 2005).Ni-Fe-Cr alloy 028 (alloy 028)has such important characteristics worth mentioning. Alloy 028 contains high amounts of nickel, copper and molybdenum which improve its resistant to corrosion attack in reducing medium, and presence of high level of chromium makes it more resistant to oxidizing species. Moreover, alloy 028 is less expensive because of higher amount of iron compared to other similar alloys. Currently, alloy 028 is manufactured as evaporator tubes applied in the phosphoric acid production; production tubing and casing used in deep and sour gas wells; heat exchangers employed in nuclear power plants, and seawater-carrying piping and seawater-cooled heat exchangers (Bankiewicz, 2012; Kivisäkk, 2003; Gómez, 2003; Xian, 2012; Bellezze, 2004)"

Jan 1, 2017

By Martin P. O'Connell

"IT IS INDEED A PRIVILEGE to address a group representing a sector of the Canadian economy so important as is the mining sector. Important, not only today, but certainly of great importance for the future development of Canada, for employment, for our trade balance and indeed, when one looks at what we are calling increasingly an industrial strategy, for the future. Surely mining will have a very significant role to play in fulfilling that. It's of special interest to me, as the Minister of Labour - and I ought to confess at the very beginning that I am just two months into this function - of special interest for me to know that you are giving such attention to labour-management relations. I think it is timely that, from my point of view at least, you do this, because for the first time in twenty four years major revisions of the Canada Labour Code as it relates to industrial relations and disputes settlements are currently in the House of Commons going through their second reading, after an easier introduction and some changes which I would be very pleased to describe later this morning. It is very timely too, I think, that we should be looking at this area because public interest is certainly at a high level. It is not only at a high level but it expresses a good deal of irritation with the current status and procedures and results in collective bargaining and there is some urgent search for more sophisticated or modified procedures for settling differences in labour-management relations. The public wants different kinds of results. I think that is apparent to all of us. They want results in terms of justice and equity on both sides. And it means that a Minister of Labour and certainly governments who often are representing, or are the third party in discussions, have a very important and complex role to play in attempting to create a balance as these two parties come to contracts and come to agreements."

Jan 1, 1972

By W. B. Burchall

Introduction In presenting this paper the author wishes to state that the opinions here given represent only his personal views. A general survey of the subject has been attempted, but such deductions as may have been drawn are not necessarily endorsed by the Company with which he is associated. The aeroplane as an instrument of transport is yet a novelty, for it is only twenty-five years since man first flew. This statement, by itself, may be very deceptive, for compared with the steam locomotive or even the auto-mobile, this infant in industry has made some remarkable showings. The 'actual performance' speed-curve of aircraft plotted over a ten-year period is rising faster than the 'expectancy' speed-curve of 1924 indicated, and it should be noted that, today, the possibilities of 600 miles per hour provoke less scepticism than did the prophecies of 400 miles per hour only a decade ago. Commencing with the remarkable achievement of raising one man into the air, aircraft with an all-up weight of 14 tons are now in daily use on the British airways, and recently a non-stop flight of 5,340 miles was accomplished in an aeroplane, without refuelling. More true than ever is the statement that the records of yesterday are commonplace tomorrow, for new ideas are today seized on and exploited to the utmost once the period of scepticism and doubt has been overcome. In fact, so many new ideas have been brought forward, during the past few years, and applied successfully in our economic life, that one may well ask if today we are not a little too impatient, too exacting in demands, forgetting that real worth-while progress -is attained by no short-cuts.

Jan 1, 1933

By A. Welty, T. Garn, K. Lyon, B. Jakovljevic, R. S. Herbst, M. Greenhalgh, Cytec Solvay Group

"Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant enhancements to the current separation processes can be realized. These enhancements could be defined as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these enhancements can significantly affect the costs associated with these challenging separation proccesses.A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation."

Jan 1, 2016

By Howard Keele

"The Whitewood Mine near Edmonton, Alberta, is owned by TransAlta Utilities Corporation and operated by Manalta Coal Ltd. Approximately 2 million tonnes of sub-bituminous coal is supplied annually to the Wabamun Generating Plant. A high water table, high groundwater pressure, and structural folds contribute to stability problems in the fine-grained overburden. Significant increases in coal recovery have been achieved in recent years through improvements in water management and mining methods. Agricultural capability of the post-mining landscape has also been improved following the completion of mining/ reclamation activities. Introduction The Whitewood Mine, located to the north of Lake Wabamun and seventy kilometres west of Edmonton, Alberta, is owned by TransAlta Utilities Corporation and operated by Manalta Coal Ltd. Figure 1 shows the location of the Whitewood Mine with respect to the city of Edmonton. The mine presently supplies two million tonnes annually of sub-bituminous ""C"" coal to the 582-megawatt Wabamun Generating Plant located adjacent to the mine. The area is characterized by a high water table-, rolling coal seams and an overburden that consists of muskeg, clay and various sedimentary layers of sand, gravel and fine-grained sandstone. These distinctive characteristics require careful attention in order to not only meet the coal delivery requirements of the Wabamun Generating Plant but also to do so economically. Historical Background A small-scale underground coal mine was opened in the Wabamun area in 1910 by the Conner Coal Mining Co. Ltd. Underground operations were continued by several operators until 1948 when the Alberta Coal Co. Ltd. opened a strip mine which was subsequently taken over by the Alberta Southern Coal Co. Ltd. in 1951. The small-scale strip opera"

Jan 1, 1985

By R. T. Erskine

"The No. 6 orebody is located 6 miles from the main op.eration of Brunswick Mining and Smelting Corporation Limited and includes open-pit and primary gyratory crushing facilities. Ore is transferred by truck to the secondary crushing facility at the main plant. About 3,500 tons of ore per day are crushed to minus % in. and ground to 68 per cent minus 400 mesh in rod and ball mills for flotation feed. Conditioning and aeration precede rougher flotation, and four stages of cleaning bring concentrates to a grade of 42 per cent Pb + Zn + Cu. Middling products are reground and refloated in a secondary flotation circuit, producing a cleaner feed and a final tails product. Primary bulk concentrate is treated with sulphur dioxide and steam-heated to l 70°F and the majority of the gangue is floated off, leaving a product that assays 57 per cent combined Pb + Zn + Cu and is suitable for marketing. This material is thickened, filtered, dried and loaded into railway cars for shipment to the smelter. Reagent use on flotation is conventional, with many compromises in dosage required to maintain the recovery of lead and zinc in the most advantageous proportions. Many refinements in the flowsheet have been made since start-up in 1966, and more may be made as laboratory and plant testwork indicate possible improvements."

Jan 1, 1971

By Q. Li

"The precursor of In2O3 was prepared by hydrolysis precipitation/hydrothermal method using In(NO3)3 solution as the feed material and ammonium hydroxide as the neutralizing agent. The crystallinity, morphology and particle size of the products were characterized by SEM, XRD, BET and LPSA. The results showed that the hydrolysis product consists of an aggregate of cubic In(OH)3 particles with a short rod morphology. In the hydrothermal process, the structure, morphology and size of the particles changes through the mechanisms of Ostwald ripening and phase transition, respectively. When the hydrothermal temperature was less than 280 ?, the Ostwald ripening process took place, which changed the morphology of the particles from short rods to cuboids through dissolution-recrystallization. When the hydrothermal temperature was higher than 280 ?, the processes of Ostwald ripening and phase transition took place successively. Firstly, the morphology of the particles changed from short rods to cuboids through Ostwald ripening, and then, the phase transition from cubic In(OH)3 to orthorhombic InOOH occurred and the morphology of the particles changed from cuboids to polyhedron. INTRODUCTIONDue to its excellent electrical conductivity and optical transparency, indium tin oxide (ITO) film has been wildly used in flat-panel display, solar cell, antistatic coating and EMI shielding (Medvedovski et al., 2008). Indium oxide powder is one of the fundamental materials for preparing ITO film. Along with the development of ITO targets of both high density and large size, high quality indium oxide powders, such as single phase, nano-size, spherical morphology and mono-disperse, have been in high demand (Nakashima and Kumahara, 2002; Betz et al., 2006; Kim et al., 2007). The main preparation methods for indium tin oxide or indium oxide powders include chemical precipitation (Nam et al., 2001; Xu and Yu, 2007), melt atomizing-combustion (Chen et al., 2000) and spray pyrolysis (Ogi et al., 2009). Among them, chemical precipitation has been preferred, since it is simple, easy to control and suitable for industrial scale-up. In chemical precipitation method, indium oxide powders were prepared through the following steps: firstly, indium hydrate precursor was precipitated from an indium salt solution by neutralization using an alkali, such as ammonia; and then, indium oxide (In2O3) powders can be obtained from the precursor through calcination (Li et al., 2006), or solvothermal method (Lee and Choi, 2005), or hydrothermal processing/roasting (Xu et al., 2005; Chen and Li, 2007), respectively. However, the indium oxide powders obtained by direct roasting are polycrystalline, dispersable with a wide size distribution (Liao, 2006). The disadvantages of the solvothermal method are high cost, complicated after-treatment processes, as well as bad performances of the powders (Udawatte and Yanagisawa, 2000). Therefore, among three methods of obtaining indium oxide from the hydrolysis precursor, the hydrothermal process/roasting method is the most feasible to synthesize high quality In2O3 powder with uniform crystallinity and size (Kim et al., 2002; Zhu et al., 2004; Xu et al., 2005; Xu et al., 2005; Chen and Li, 2007; Seetha et al., 2009). However, current research on hydrothermal process-roasting method has been limited to the synthesis of a certain ITO or In2O3 powders under specific conditions. A systematic study on the phase transition, as well as the change of the morphology and size of the particles in the hydrothermal process is still missing. In this paper, the effects of hydrothermal processing on the mineralogy, morphology and size of products were investigated. The results showed that the evolution of crystal structure, morphology and size in the hydrothermal process was affected through the mechanisms of Ostwald ripening and phase transition successively. These results are novel and have guidance for improving the hydrothermal process for In2O3"

Jan 1, 2012

By W. A. Gow, H. H. McGreedy

It is believed that many of the problems encountered in the operation of gold cyanidation plants are difficult to resolve due to the lack of sufficient and reliable in-formation regarding the variations and actual values of operating variables at any given time. The application of instruments to monitor the more important variables in the cyanidation process should result in more efficient plant operation and a better understanding of the process. The use of pH and conductivity sensing devices for alkalinity measurements, a monitor to determine the dissolved oxygen content of plant solutions, a continuous cyanide titrator and sonic control of grinding circuits are discussed. Although the discussion is oriented toward the cyanide process, much of the paper is applicable to other ore treatment operations.

Jan 1, 1966

By L. Tikasz

The primary purpose of ore hauling model studies is to capture the variability of the ore delivery ? stockpiling process in order to improve the estimation of equipment capacities and achievable throughputs. The operation of a mine-to-site ore delivery system is the subject of a number of challenges. Typically, ore is hauled by a given combination of trucks, conveyors and trains. In addition, ore loading, ore transferring to another means of delivery, stockpiling, reclaiming, and further deliveries involve many other types of equipment. The concurrent operation of all these units is scheduled; nevertheless, they are subject to planned maintenance and random breakdowns. To support our engineering design work on ore hauling operation, discrete event type models were built for each specific task. Then, due to recurring demands, an ore hauling library was gradually compiled. The now available model library allows fast and efficient simulation of various mine-to-site hauling arrangement, adaptable to various mining and mine construction operations (e.g. bauxite, iron ore, copper ore and coal).

Aug 1, 2013

By P. F. Berry

X-ray fluorescence analytical techniques are fairly well established in the mining and metallurgical industries. In recent years, instruments utilizing radioactive isotopes have been developed which, owing to their more compact size, greater reliability and independence of substantial power supplies, are often preferred to X-ray tube installations. Analyses can now readily be carried out in the field, on the factory floor and in otherwise difficult locations. This paper describes many examples of radioisotope X-ray fluorescence for the analysis of metallic minerals, finished metals and alloys and also for the continuous measurement of metallic coatings, such as tin and zinc, on steel. Radiation scatter techniques are also described for certain analyses and for thickness and density measurements.

Jan 1, 1967

ABSTRACT It is critical that historical processes and concomitant exposures to specific nickel substances be understood because some diseases linked to inhalation of certain nickel-containing substances have a long latency between first exposure and disease onset, and because nickel substances vary significantly in their toxicological properties. A discussion of the smelting history and related processes at Vale Canada’s (Inco’s) Copper Cliff, Ontario, smelter is integral to the understanding of these processes. The post-1950 processing history, equipment, propensity for aerosol formation, operational procedures, and ventilation controls used by Vale Canada in roasting, smelting, converting, and copper-nickel separation is discussed.

Jan 1, 2013

By Enzo Angeles, Desmond Nanchengwa, Lee Julian, Julian Ruiseco

Since the early 1980s, surface hard-rock mining companies have searched for a blast movement model to enable grade control optimization efforts. Significant time and money were spent attempting to create blast simulations to aid post-blast grade control. Despite nearly 40 years of effort, practical blast movement models remained elusive until computing power reached levels that make real-time simulation possible. From the mid-1990s, mines have been creating in-situ grade control polygons and translating the polygon nodes horizontally to account for blast movement. In many cases, objects are placed in the blast volume and located post-blast to provide local vectors for these node translations. This method was always a compromise between practicality (2D) and reality (3D), but it was the only viable solution that matched the needs of operations. This study considers 21 blasts and evaluates the incremental value achieved by new processes unlocked through 3D modelling, while investigating challenges, limitations, and opportunities for each method.

Jan 1, 2023

By W. E. Oching, M. M. Ghomshei

"Collaboration among Ventilation Engineers, Mine Inspectors, worker representatives, health and safety officers and management is key to an effective operational mine ventilation management. Mine ventilation training, ventilation survey reports for mine stakeholders and interaction with mine frontline workers and management concerning safety, energy saving, assets management and maintenance are effective tools in implementing best industry practices and significant reduction of ventilation operating costs without compromising safety. These approaches may not be new to well established mining companies but the real dilemma is how to implement them effectively and this is what this paper will address.INTRODUCTIONManaging an effective mine ventilation system is becoming increasingly challenging, especially during tough economic times in the mining industry. Management strives for more production while frontline miners work hard to surpass the production targets, thus improving their incentives and above all aiming to enhance the prospects of their job security when the mining industry is facing challenging times. Taking shortcuts by not fully following the safety regulations or industry best practices are often notable, resulting in the rise of Workers Compensation Board claims and temporary shutdowns of active workings, compromising productivity and increasing the operating costs.In accordance with the Mines regulations in various jurisdictions in Canada and the US, it is evident that companies adhere to establishing basic ventilation management systems through the provision of the code of practice, procedures, work practices and standards/guidelines. This is aimed at ensuring the health and safety of underground workers (de Souza, 2017). However, the challenge to many operations is the improper implementation of the mine ventilation regulations including some managers showing reckless disregard for workers safety by focusing on production and not worrying to address ventilation problems (Steven & O'Keefe, 2010). Other challenges facing effective ventilation management include inadequate training of frontline workers on ventilation system and hazards associated with poor ventilation systems such as toxic gases, dust, heat, and underground explosions (Mufson et al., 2010; Suvar et al., 2017); friction between mine managers and the mine inspectors (Mufson et al., 2010), improper maintenance of ventilation system and inventory management, among others."

Jan 1, 2019

By Cy Jordan, Ben Burdett, Adrian Dance, Jack Rainey

"In 1997, EIMCO Minerals installed a knowledge-based control system on one of the five primary grinding lines at Highland Valley Copper. The objective of the system is to maximise throughput without affecting circuit product size or flotation recovery. The system was commissioned in October 1997 on a SAG mill/ball mill circuit following a plant audit and upgrade of the control instrumentation.The system monitors and controls the SAG mill power, bearing pressure and recycle load by manipulating the solids feedrate, water addition and mill speed. The two ball mill and cyclone circuits are controlled through water addition at various points in the circuit as well as the number of operating cyclones.An on-line particle size analyser is used to measure the cyclone overflow quality. Models of the SAG mill charge level and overflow product size are also incorporated. A method of predicting the SAG mill power response to feedrate changes is used to lessen the effect of dead time for improved mill power control. In the future, inferred measurements of SAG feed particle size and hardness will allow changes in ore behaviour to be predicted and compensated for by the system.This paper describes the development of the project -from installation and commissioning to modifications and refinement -along with prospects for the future.BackgroundIn early 1997, EIMCO Minerals was contracted by Highland Valley Copper to install a knowledge-based or expert system control strategy on one of the five grinding lines in the mill. This was to become the start of the Advanced Control Project at Highland Valley Copper (HVC). This paper will review the progress of the Project as well as discuss the prospects for the future.Following a preliminary engineering study (or plant audit) by EIMCO in 1996, it was decided to implement an advanced control system in order to improve plant operations and increase productivity. The study suggested that such a system had a pay-back period of a few months through increased throughput without loss in flotation recovery. Highland Valley already had successfully applied higher level control through their Elsag Bailey distributed control system (DCS) and this was the next stage in process optimisation."

Jan 1, 1998

By T. Gerritsen, T. Plikas, K. Ochoa, M. Loveless, R. MacRosty, J. Reichart, R. Pula

Sidewall accretion in a smelting furnace plays an important role in furnace integrity as it provides protection to the sidewall cooling elements and thereby extends the furnace campaign life. The extreme thermal and mechanical stresses in the furnace and changes in the slag chemistry can cause the sidewall accretion to melt or break away decreasing the lining protecting the cooling elements. Thin accretion is highly undesirable as it increases the risk of exposing the cooling elements to the molten bath and in the worst case may lead to a failure. Therefore, monitoring the sidewall accretion on an operating furnace is extremely important to manage furnace integrity and to support safe furnace operation. Operators often generate estimates for sidewall accretion and refractory thickness using either copper cooler temperatures or heat load into the cooling water circuits. Multivariate statistical models, on the other hand, have the capability to consider all the process measurements simultaneously to provide a more reliable estimate. This paper describes the application of multivariate statistical models for sidewall integrity monitoring on a Flash Converting Furnace (FCF) and also discusses the online implementation of these models as the Sidewall Accretion Monitoring System. INTRODUCTION Rio Tinto’s Kennecott Utah Copper (KUC) smelter located near Salt Lake city, Utah operates a Flash Smelting Furnace (FSF) and a Flash Converting Furnace (FCF) to produce high-grade matte and blister copper respectively. Since the commissioning of smelter in 1995, several improvements were made to these furnaces to increase their efficiency and operational safety. At present, Kennecott smelter is known to be among the lowest-emission and highest energy recovery copper smelters in the world. Since the smelter start-up, Kennecott has invested in several advanced furnace monitoring practices to evaluate the integrity of the furnaces and improve their campaign life. An example is their temperature monitoring system installed for the smelting and converting furnaces, which continuously monitors the furnace sidewall temperatures and notifies the operators during temperature excursions. During an investigation on the converting furnace, it was revealed that there were frequent temperature excursions in the settler sidewall area towards the reaction shaft end of the furnace that caused significant furnace downtime. The reason for the sidewall temperature excursions was not clearly known.

Jan 1, 2019

By J. Salazar

This paper presents a dynamic simulator of the semi-autogenous grinding operation deduced from first principles (non-stationary population balances) coupled to a Model-Based Real-Time Optimization (MBRTO) system to study optimizing strategies for an industrial semi-autogenous mill using genetic algorithms. For the design of the MBRTO both a validated first-principle steady-state model adapted on-line and a dynamic model were used to study the transient effect. The objective function considered is to maximize the ore throughput or the fine-product rate by changing the power-draw. For these purposes, these two performance indexes were introduced as fitness functions in the genetic algorithms. The three decision variables used were the ore feed rate, the water feed rate and the mill rotating velocity. The optimization problem was solved using a classical genetic algorithm with constant population. Constraints in the power draw and the filling level were handled by assigning a penalty function to the fitness function. Simulation results using industrial data for a large 1800 t/h copper-ore mill show the effectiveness of the system in finding the optimum controller set-points as a function of the process-operating constraints; mainly maximum ore feed rate, power draw and filling level. Starting from non- optimum conditions, the optimizer is able to improve the global performance index by 50% relative to a base case.

Jan 1, 2007