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By Arthur Lieu

The mill effluent treatment circuit (Bulk Neutralization (BN)) in the Cameco Key Lake Operation was modified in 2008 to enhance the removal efficiency of selenium (Se) and molybdenum (Mo) from the mill process water. This modification was completed in part due to increased knowledge of the effects these elements have on biota. In addition, legacy effects from the historical operation of the Key Lake mill in regards to Se and Mo were shown to have an effect on the regional biota in the downstream receptors. This was a challenging initiative as there was no off the shelf technology available and the removal process had to be incorporated into an existing (brownfield) process. These modifications have resulted in significant reduction in the concentration of these elements in the Key Lake mill effluent. The removal efficiency for Se and Mo in the modified circuit has increased to 95% and 75%. As a result, concentrations of Se and Mo are now consistently less than 0.4 mg/l and 0.02 mg/l. In addition, the Se and Mo precipitates formed were extensively studied to ensure long-term geochemical stability in the Key Lake in-pit tailings facility. This presentation will provide additional detail on the hydrometallurgical removal mechanisms and process modifications required in the Key Lake BN circuit to remove these elements to trace levels.

Aug 1, 2010

By Josée Dartois

En 1988, à l?instar de plusieurs états du monde industrialisé, le Québec décidait d?accélérer la cadence de l?assainissement des rejets industriels et lançait un programme intégré de réduction de la pollution industrielle visant, à la fois, les rejets dans le milieu aquatique, les émissions atmosphériques et les matières résiduelles. Ce programme fut intitulé le Programme de réduction des rejets industriels.

Nov 1, 2002

By T. S. Wanne

Tunnel sealing experiment (TSX) was conducted between 1997 and 2004 in the Canadian URL located in Manitoba. In the experiment, a tunnel was excavated parallel to the maximum principal stress direction, filled with sand and sealed with bulkheads at both ends. It was then pressurized and heated by injecting hot water. The rock mass response was monitored with seismic methods. The main interest in the numerical simulation was the damage formed during the heating phase. The large-scale PFC2D models replicated a central plane- strain section of the TSX chamber. The models captured the first-order phenomena observed in-situ displaying the difference in the damage in the roof and floor regions, respectively. This difference was due to the filling material confinement of about 100 kPa on the tunnel floor, which occurred in the course of the heated experiment.

May 1, 2009

By S. Knapp

Inconel 600 pipes welded to Carbon-Steel are used in CANDU nuclear reactors. Fracture of these welded tubes would have important consequences in term of safety, and therefore their mechanical properties need to be better understood. In this study, the weld region was analyzed at various length-scales using optical microscopy, micro hardness testing, small and large scale tensile testing and digital image correlation (DIC). Large grains were observed in the weld region and smaller grains in the Inconel and carbon steel base metals. Micro-hardness profiles showed variations across the weld and through thickness and were justified in terms of residual stresses in the sample. Large tensile samples were extracted from the welded pipe and were used to identify the material in which fracture initiates. In addition, the local strains in each material were obtained using digital image correlation. Local stress-strain curves were built from the DIC data and compared to stress-strain curves obtained from miniature tensile samples extracted from the carbon steel, Inconel and weld regions. The results demonstrate the advantage of using DIC for extracting local material properties in dissimilar weld systems. Variations in the materials stress-strain curves thought thickness are also presented and emphasize the need for obtaining a complete map of the mechanical properties in the weld region for predictive models to be accurate. Preliminary fracture studies will also be presented.

Jan 1, 2011

By F. Filzwieser, K. Gamweger

The process of gas purging in molten aluminium has been an industrial practice in Europe for many years. The advantages are a reduction in the hydrogen content and impurities in the melt, as well as a homogenisation of the temperature and chemical analysis in the molten metal. Formerly used lances or impellers are being replaced by porous plugs which are installed at the bottom of the furnace. This special product of RHI Refractories has proven its efficiency in primary melting as well as in die cast, sheet and extrusion plants.

Jan 1, 2004

By A. Mukherjee, C. Kelly, B. Markovich, G. E. Agar, G. E. Robertson, F. Khan, B. Shea

"Laboratory batch flotation tests were performed on a sample of bulk slow cooled converter matte (Cu:Ni = I) to optimize the time in each of the separation stages. Numerical simulations were carried out to estimate a continuous circuit material balance for the conditions selected. An experimental simulation of a continuous circuit (locked cycle test) readily came to steady state and there was reasonable agreement between the numerical and experimental results. The use of nitrogen as the flotation gas and the addition of collector to the grinding mill minimized the oxidation of chalcocite, which has previously resulted in increasing circulating loads, and led to a stable circuit with very low weights in the recycle streams.IntroductionINCO Limited developed a flotation process for separating the components of copper-nickel matte [Sproule, Harcourt and Rose 1945; Sproule, Harcourt and Renzoni 1960] in 1945 to replace the Orford process and continues to use the flotation process in almost the original mode to this day. Initially the matte processed was the result of smelting a nickel concentrate that analyzed about 12% nickel and 2% copper and all of the recycle material that was generated in the smelting process. The matte generated analyzed about 25% copper and 53% nickel, roughly 2: 1 nickel to copper. This matte was blown in Pierce-Smith converters to be sulfur deficient in order to produce a metallic phase that collected the precious metals contained in the smelter feed [Wilson and Stratton-Crawley 1991]. This process continued with little change until 1994 when the separation of chalcopyrite from pentlandite in the Copper Cliff mill was discontinued after 63 years of operation. As a consequence of the elimination of the primary separation of chalcopyrite from pentlandite in the milling process a bulk concentrate was produced for smelting. Bulk concentrate smelting came into practice in 1994 as part of the initiative to meet government legislation that restricted the emission of sulfur dioxide to the atmosphere. Previously, the copper concentrate was smelted in an INCO oxygen flash furnace which resulted in the capture of a high strength sulfur dioxide stream from which liquid sulfur dioxide was produced. Nickel concentrate was smelted in reverberatory furnaces that produced low strength sulfur dioxide gases which were difficult to treat. The action taken by INCO to meet the environmental constraints was to smelt a bulk concentrate in oxygen flash furnaces which would produce gases suitable for the production of liquid sulfur dioxide and another stream that was high enough in sulfur dioxide to be readily converted to sulfuric acid [Bell et al 1990]. The end result of this decision was that all the copper-nickel separation would be done in the matte separation plant."

Jan 1, 1996

By Walter Valery, Lauren Hafla, Megan Tibbals, Adrian Dance, Jeff Snyder

"Newmont Mining Corporation’s Carlin (“Carlin”) operation processes roaster feed through a double rotator, dry grinding mill following secondary crushing. Metso Process Technology & Innovation (“PTI”) was involved in a review of crushing and dry grinding circuit operations in August 2009. A number of opportunities for increased throughput were identified in the PTI study.Extended plant trials were conducted in July 2010 to provide justification for possible circuit modifications and if needed, additional equipment. The trials confirmed that a finer crusher product would reduce the build-up of material ahead of the coarse grinding chamber in the double-rotator. Also revealed were material transport and airflow restrictions in the dry grinding circuit that resulted in a high circulating load.The secondary crushing plant demonstrated it was capable of reducing the amount of +¾” material in the mill feed thus increasing dry grinding throughput. However, wet and sticky feed affected screening efficiency resulting in low utilisation of the existing crusher capacity. The open circuit configuration also made it difficult to control crushing circuit product size.For the dry grinding circuit, changes in grinding media size, transfer grate design and increased airflow were recommended to reduce circulating load issues and increase circuit capacity. This paper summarises the crushing and grinding circuit review, the extended site trials performed by PTI and the improvements in dry grinding operation that resulted from this study."

Jan 1, 2012

By W. M. Silva, Bittencourt. L. R. M.

Three newly developed alumino-silicate refractory bricks for use in safety lining of aluminum electrolysis cells were compared to one commonly used bricks for the same application. It was shown that the increase in silica content and decrease in permeability led to a sensitive decrease in cryolite attack. Both parameters are of utmost importance in selecting bricks for these cells. The reasons for this observation were the formation of a more viscous liquid after the reaction between molten cryolite and the brick, and the reduction of the rate of penetration. Moreover, a novel mortar with high silica content was tested and has shown improved resistance to molten cryolite. The use of oxidizing atmosphere led to increased attack rate in the brick when compared to reducing condition. The opposite effect was observed in the mortars.

Jan 1, 2004

By A. Liard, H. Sommelet, G. Sauriol

"Description des études qui ant conduit à la conception spécifique du système de drainage de la mine à ciel ouvert. Les approches différentes sont examinées ainsi que la valeur du système recommande.IntroductionLa Division Mines Gaspé de Mines Noranda Ltée exploite un gisement de cuivre par mine souterraine et mine à ciel ouvert à Murdochville, Québec. L'exploitation par mine aciel ouvert a commencé en 1965 avec une operation à flanc de montagne. Elle se poursuit actuellement sous Ie niveau de la vallée dans une fosse dont Ie diamètre est de I'ordre de 800 m (2,600 pi), et la profondeur de 150 m (500 pi) sou s Ie fond de la vallee. Elle doit atteindre une profondeur de 360 m (l, 180 pi) sous Ie fond de la vallee , avec des murs hauts de 360 à 490 m et des pentes moyenne de 44°. Le rythrne d'extraction est actuellement de 85,000 tonnes par jour.Dans Ie cadre des etudes entreprises par les Services Techniques de la Division Mines Gaspé, la compagnie Géomines Ltée a été consultée pour étudier les conditions hydrogéologiques et hydrologiques locales et participer a la conception d'un système de drainage superficiel et souterr ain. Un tel systerne de drainage visait: a éviter les importantes venues d'eau qu i affectent I'exploitation en periode de crue; amaintenir les pressions hydrostatiques au sein des parois de la fosse dans les limites imposees par les etudes de stabilite des pentes réalisees par la Mine.Les principales étapes de cette etude ont porté sur: la collecte et la compilation des données sur la géologie, l'hydrologie et l'hydrogeologie du site; . la détermination des caractéristiques hydrauliques du milieu rocheux à partir d'études structurales et de test s de perméabilité;"

Jan 1, 1981

By R. W. Luhning, S. D. Gittins, J .. A. Haston

"The Underground Test Facility (UTF) project operated by the Alberta Oil Sands Technology and Research Authority (AOSTRA) north of Fort McMurray has achieved marked success in field testing mining access and horizontal well in situ recovery of bitumen from the Athabasca oil sands.Mine access has provided for effective placing and operation of horizontal wells in the oil sands from a tunnel system in the underlying limestone. Performance of the in situ recovery process, Steam Assisted Gravity Drainage, has substantially exceeded forecasts made at the start of the project. Over-all results of the program to date show great promise for horizontal well in situ technology as a competitive source of bitumen from Alberta's vast oil sands deposits. The potential economics of a commercial expansion at the site are reviewed in this paper.IntroductionIn situ recovery o f bitumen from the Athabasca oil sands has puzzled the oil industry for many year s, but a breakthrough appears close at hand. The Underground Test Facility (UTF) project initiated by the Alberta Oil Sands Technology and Research Authority (AOSTRA) has had notable success in the piloting of horizontal well processes, which offer prospects for commercial development even under the highly competitive situation facing the Canadian industry . This paper describes the project briefly and presents the potential economics of commercial development on the UTF lease."

Jan 1, 1990

By Sarah Belair, Gauthier Deblonde, Valerie Weigel, Alexandre Chagnes, Gerard Cote

"Niobium and tantalum are strategic metals for electronic and alloys industries. They are produced by pyrometallurgy and hydrometallurgy but most of the niobium and tantalum production processes are not environmentally friendly. For instance, in the hydrometallurgical route, niobium and tantalum separation can only be achieved by liquid-liquid extraction in the presence of hydrofluoric acid by taking advantage of the difference in niobium(V) and tantalum(V) speciation in fluoride-based media. Therefore, the environmental footprint of hydrometallurgical processes for the production of niobium and tantalum could be clearly lowered by replacing HF or NH4F by greener media such as alkaline solutions in which high solubility of niobium(V) and tantalum(V) can be achieved.The development of such new efficient and environmentally friendly hydrometallurgical processes requires a fine description of the physicochemistry of niobium(V) and tantalum(V) in alkaline solutions. Unfortunately, literature data show a huge discrepancy on niobium(V) and tantalum(V) speciation in such media. This paper gives a brief overview of the niobium(V)-tantalum(V) production processes and paves the way to the development of alternative processes in alkaline media by presenting and discussing recent advances in the physicochemistry of niobium(V) and tantalum(V) in these media.INTRODUCTIONNiobium and tantalum are strategic metals since they are used for the production of alloys and super alloys, capacitors and magnets in strategic industries such as electronic, aeronautics and automobile. The main sources of niobium and tantalum are given in Table 1."

Jan 1, 2016

By Jr. Santos, T. V. Pignaton, R. B. Gomides, W. Phillips, M. P. D. Gomes

Kinross Paracatu started the operation of the new gold processing plant in the end of 2008, being composed by one SAG mill and two ball mills. During the first year of operation the plant had several problems related to stability and throughput capacity, mainly due to low grinding efficiency of the ball mills. In this period many actions were taken to maximize the throughput rate. Among the actions are reducing the size of balls in the mills, increasing the ball charge in the SAG mill, changing cyclone configuration and return of circulating load to SAG mill. With better stability of the circuit, the second stage of improvements has begun with the objective of increasing throughput rate and also reducing operation costs. Among the actions are the optimization of ball charge in the mills and a better operational control of cyclone parts. After two years of operation was obtained a significant increase in plant capacity, but still requires the addition of a third ball mill in order to maximize the use of SAG mill, which has spare capacity.

Jan 1, 2012

By Robert D. Brown

"Important tax changes, many of them of direct interest to the mining industry, were contained in the budgets brought down by federal and provincial finance ministers across Canada this spring. This month, Tax Notes presents a brief summary of important tax changes introduced at the federal and provincial levels in the last few months.IntroductionIn the March 1980 issue of the CIM Bulletin, Tax Notes surmised that the short-lived 1979 budget proposals of the former Conservative government offered a unique glimpse of budgetary changes that might be unfolded in 1980. Scene II of this ""now you see it-now you don't"" drama opened on April 21, 1980, when Finance Minister Allen MacEachen, in an ""economic statement""' reintroduced a selection of tax proposals taken from the ill-fated Conservative' budget of December 11, 1979, but refused to bring forward major new proposals in tax and finance.Mr. MacEachen proposed a 5% surtax on federal corporation income tax to apply in the 2 years from January 1, 1980 to December 31, 1981, as a slightly modified version of the same surtax proposed by former Finance Minister Crosbie in his December budget address. Mr. MacEachen also reintroduced a number of technical amendments which would affect the taxation of mining income in certain instances. In addition, a large number of other tax proposals suggested in the previous Conservative budget were also reintroduced, although there are some notable omissions."

Jan 1, 1980

By F. G. Boehm, T. S. Golosinski, P. M. Tucker

"In an earlier paper(1) the visits to several European mines using the bucket-wheel excavator (BWE) technology were described. It was during this trip that information was gathered on some interesting developments related to this type of mining, taking place elsewhere. It was learned that an across-the-pit system (XPS) comprised of a BWE and stacker has been operating successfully in a Hungarian mine for some time. Also the use of stackers with 225 m long booms and draglines with 125 m booms and 125m3 buckets in Soviet mines was indicated. Such equipment could be of great value to some Canadian strip mines, in particular the equipment proven useful in severe climatic conditions of U.S.S.R., similar to those of the Canadian prairies.To follow up on this information a field trip to Hungary and the U.S.S.R. was organized by the Department of Mineral Engineering, University of Alberta, to study the applications and performance of the systems in question. Visited were the Thorez mine near Visonta, Hungary, U.S.S.R. Ministry of Coal Mining and Skotchinski Institute in Moscow, Karagandashakhstoi Institute (designers of Ekibastuz mines in the Kazakh Republic) and Kostenko mine in Karaganda, Vostsibgiproshakht Institute (designers of Irsha Borodinski, Kharanovski, Moguntski and Tugnuski mines in Siberia) and the eastern Siberian Unit of the U.S.S.R. Coal Mining Ministry in Irkutsk as well as Azeiski mine located some 250 km northwest of Irkutsk. The findings of this field trip are presented."

Jan 1, 1985

By P. R. A. Andrews, I. Jackman

"A mineral processing investigation to recover chromite was performed at Lakefield Research, under the guidance of CANMET personnel, on a 70 tonne ore sample from the Bird River deposit in Manitoba. In the laboratory phase a flowsheet was developed which involved grinding, gravity separation and flotation. The gravity concentrates were upgraded by magnetic separation and the flotation concentrates by gravity concentration. Pre-concentration by electronic ore sorting, magnetic separation and heavy media separation also was examined.The developed flowsheet was applied on a pilot-plant scale in the second phase of the testwork to the ore as received, and to ore pre-concentrated by electronic ore sorting and magnetic separation. Ore pre-concentrated by heavy-media separation was treated on a laboratory scale based on the pilot-plant flowsheet.Processing the are as received resulted in 77% recovery of chromite in a concentrate analyzing 30% Cr20 J; processing are pre-concentrated by electronic are sorting resulted in 64% recovery of chromite in a concentrate analyzing 30.5% Cr20J.IntroductionA five-year mineral development sub-agreement was signed between the federal government and the province of Manitoba in 1984. The purpose of the agreement was to establish a work program which would strengthen and diversify the mineral resource industry of Manitoba. Basically, the agreement covers three sectors: Sector A, geoscience; Sector B, mining and minerals technology research; and Sector C, development studies.Project selection involved input from industry, federal and provincial representatives. In the case of industrial mineral s, the selection was initiated at a meeting held at the offices of the Department of Mines and Energy, Winnipeg, Manitoba, in October 1985. One such project was the evaluation of the chromite ore deposits at Bird River, Manitoba."

Jan 1, 1988

By Bernard Tougas, Franco Chiesa, David Levasseur, Bernard Duchesne

"In the present paper, the optimization of a tilt poured permanent mold will be carried out using filling and solidification modeling. This exercise resulted in 3 modifications of the initial mold design which was based on the foundry experience. The optimization provided a 20% improvement in the yield while increasing the output from 10 to 15 castings per hour.In a subsequent study, the value of the critical fraction solid of AlSi7Mg (A356) alloy was verified by radiographic analysis of the castings produced in the first 5 cycles of a run, which are necessary to bring the mold to a dynamic thermal equilibrium."

Jan 1, 2014

By J. W. Keyes

"The original grinding circuit at East Malartic consisted of two 8 by 8 C.A.C. mills in closed circuit with two 72 inch Akins Classifiers and an 8 by 10 secondary mill in closed circuit with two 48 inch duplex classifiers. With this circuit, we experienced a drastic drop in tonnage from one month to another, due to variations in the hardness of the ore. The first step to overcome this difficulty was made by increasing the critical speeds of the mills from 78% to 82%. This resulted in an increase in the secondary mill throughput; but, when the change was made on the primary mills no increase was obtained.The drastic drops in tonnage were still experienced and through working with Allis Chalmers the 8 by 10 mill was converted to a rod mill and the two 8 by 8 n1ills to secondary mills. This change eliminated the two 72 inch Atkins classifiers and the scoops on all the mills, since the 48 inch Akins classifiers sands could then be fed by gravity to the secondary mills through feed pipes.The rod mill and secondary mill discharges were fed to a common pump box using 5 by 5 S.R.L.'s running at 1085 R.P.M. with a twenty-five foot head. When this was done the pumping costs jumped from $105. 00 for 6 months to $1050. 00 in one month, or from 0. 0004 to 2. 75 cents a ton milled. Several factors contributed to this jump in pumping costs as follows:"

Jan 1, 1964

By G. E. Agar, R. Stratton-Crawley

"The applicability of a hydrocyclone model to simulation of the cyclone banks in a multi-stage sandplant circuit producing mine back fill has been demonstrated. The model ha~; been used in conjunction with a modular computer program for circuit simulation in order to study the effect of changes in the operating conditions. It has been shown that weight recovery to sand fill increases as feed percent solids decreases, and, to a lesser extent as pressure drop across the banks increases. An increase in apex diameter also causes an increase in weight recovery. Increased weight recovery must, however, be balanced against sump an1l cyclone capacity and dilution of sand fill by fines. The predicted results from circuit simulation were in good agreement with plant data.The model has been found to be applicable to widely different ores."

Jan 1, 1979

By C. B. Mapes, E. C. Dowling Jr.

"To reduce concentrate dewatering and drying costs, the Concentrator Division at Phelps Dodge Morenci, Inc. investigated available filtration technologies. Numerous methods were explored, including: drum, disk, belt, pressure, hyperbaric, and ceramic media filtration. An economic evaluation of the individual filtration technologies indicated the advantages of ceramic media filtration for Morenci concentrates. This paper discusses the technological development culminating in the first full scale application of ceramic media disk filters in North America. Low moisture contents are obtained at high production rates and greatly reduced operating costs.INTRODUCTIONPhelps Dodge commissioned the Morenci Concentrator Filter Plant in 1942 with four 8'6"" Dorr-Oliver cloth disk filters. That year, the filter plant processed 265,537 tons of concentrate grading 20.5% Cu. The filter cake production averaged 9.3% moisture. In 1944, the Extension Filter Plant commenced operation with three additional 8'6"" Dorr-Oliver cloth disk filters. This coincided with the expansion of the concentrator. Production that year totaled 451,567 tons of concentrate grading 23.8% Cu. Moisture averaged 9.4%.Through the years additional filter units have been added in response to increased concentrate production. An Eimco drum filter was installed on the extension side and an additional Dorr-Oliver disk filter was installed on the original side in the 1950's. In 1961, two 8'6"" Peterson disk filters were installed, one on each side to replace two worn-out DorrOlivers. The installation of four 10xl2 foot Peterson drum filters was completed in 1974, coinciding with the Metcalf Concentrator startup. An Eimco belt filter was installed later.The greatest change to concentrate dewatering at Morenci occurred in 1963 with the addition of a 10x60 foot rotary gas fired dryer. The installation also included a number of conveyors to deliver filter cake from both plants to and from the dryers. Other ancillary systems included dust scrubbers and their slurry pumps. The commencement of drying was undertaken due to the rapid increase in cake moisture as a result of the LPF process and the recycling of acid plant scrubber dust slurry from the smelter. In 1972, a second dryer system was installed to increase capacity."

Jan 1, 1993

By Larry T. Yano, Gerald T. Handford

"Tailings Engineering has the responsibility for planning and coordinating tailings disposal and for ensuring the stability of the tailings dyke. The inclusion of both the planning and geotechnical functions in one team has resulted in greater efficiency in the design and planning process. Major challenges in tailings disposal facing Syncrude are in the areas of: (1) sludge disposal; (2) instrumentation and monitoring; and (3) liquefaction. Meeting these challenges will have a significant effect on the cost effectiveness and reliability of the mining operation.IntroductionThe size of the tailings disposal operation has led to the establishment of a large engineering team devoted solely to the disposal of tailings. This paper discusses: the tailings disposal operation, the role of tailings engineering, the organization, inter faces, and the present and future challenges with respect to tailings disposal."

Jan 1, 1990