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By D. J. Wesolowski, D. A. Palmer, P. Bénézeth, S. Hilic

The equilibrium solubilities of gibbsite, Al(OH)3, and boehmite, A1OOH, have been extensively studied in our laboratory from 30 to 90°C, and 100 to 300°C, respectively, to ionic strengths of 5 mol.kg-1 (NaC1) over a wide range of pH. The resulting solubility constants have been treated with consistent empirical models that incorporate appropriate experimental data taken from the literature. These studies were initiated in part to understand and quantify scale formation in geothermal fields as a result of fluid re-injection from electric power generating plants. Most of the experimental results were obtained through application of a unique potentiometric method that allows for rapid, precise measurement of the in situ pH and allows the approach to equilibrium to be monitored from under- and super-saturation. The experimental program was extended to deal with more basic solutions (e.g., five molal NaOH), in which the dissolution of boehmite was measured for application to the refining of bauxite by the Bayer process. More recent results in strong caustic solutions at temperatures below 90°C were obtained to investigate the dissolution of aluminum-containing sludge from holding tanks at the Savannah River waste reprocessing site. In this case the solubility enhancing effects (kinetic and equilibrium) of triethanolamine were also established and quantified. Finally, potentiometric solubility experiments were conducted (50°C in 0.l mol-kg-1, NaCl) on aluminum alloy sheets to identify mainly the nature of the aluminum oxide/hydroxide surface layer formed under these conditions.

Jan 1, 2004

By J. Bouchard, A. Desbiens, M. Maldonado, R. del Villar

ABSTRACT: Despite many years of practical applications in mineral processing plants, the potential of column flotation has still not been fully exploited. The challenge in measuring some key variables is certainly an important contributing factor to this situation. Reliable online measurement of varibles, such as the froth depth, bias, gas hold-up, frother concentration, bubble surface area flux, and bubble size distribution, provides opportunities for the application of various advanced control strategies and real-time optimization based on an economic criterion. For several years, Université Laval’sLaboratoire d’observation et d’optimisation des procédés researchers have been working on these opportunities. This paper describes the most recent advances and current research trends.

Jan 1, 2011

This paper describes the back analysis of the Pavoncelli tunnel, an hydraulic tunnel which was excavated between 1904 and 1915 in South of Italy and experienced severe damages during the 1980 Irpino-Lucano earthquake. A numerical simulation which is intended to study the behaviour of the tunnel during this seismic event is presented, also accounting for the swelling phenomenon that took place during and after construction.

May 1, 2009

By Euler De Souza

Backfilling in Canadian mines has been practised for close to 100 years and evidence anticipates the application of mine fill technology at an increasing rate during the foreseeable future. The evolution of backfill technology is closely related to the advancement of modern mining methods and the development of new backfill technology continues to evolve. The authors, after conducting extensive surveys of backfill practices in underground mines across Canada, have concluded that, because backfill operations employ large quantities of cement and experience large costs associated both with backfilling practice and cement use, opportunities exist for reducing backfill energy costs and enhancing the application of alternative cementing agents in backfill. Consequently, the authors have developed an alternate, equally effective and lower cost binder agent replacement for cement, and incorporated waste glass into the development of a lower cost backfill (glassfill). This paper presents the results of two design stages associated with the development of glassfill: strength development and flow performance. The advancement of this technology has reached a stage that should promote industrial implementation within the Canadian mining industry. A number of Canadian mining operations exhibit potential for plant optimization through possible binder source replacement, and might thus realize associated reductions in backfill and energy costs.

Apr 1, 2005

By Waldemar W. Koczkodaj, William O. MacKasey

Abstract - A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simplified case of volcanic-associated massive sulfide type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of nonmeasurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to refine at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By Waldemar W. Koczkodaj, William O. MacKasey

A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simpli?ed case of volcanic-associated massive sul?de type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of non-measurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to re?ne at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By S. Kelebek, E. Yalcin

"Two composite samples of a gold-bearing ore from North Western Quebec (Barry Township) were tested to assess their grindability, recovery by flotation and Knelson concentrator as well as extraction using cyanidation.Work index values (BWi) for two composites were found to be 10.4 and 11.0 kWh/tonne, respectively. Flotation tests involved feed samples for which the particle size ranged from a P80 value of 205 ?m to 53 ?m, which resulted in gold recoveries of 91.8% to 95.8% (at gold grades of 130 to 140 g/tonne). Cyanidation tests indicated gold extraction levels ranging from 94.2 to 97.5%. Higher, recoveries were obtained at finer grind sizes and higher cyanide strengths. However, the grind size had a bigger impact on gold leaching. Gold grade and recoveries obtained with the Knelson concentrator device were lower than those obtained by flotation. Mass recoveries to concentrate products strongly depended on the fluidization pressure used. High gold recoveries can be obtained generally at low water pressures of 3 to 4 psi. Higher water pressures produced more selectivity at the expense of higher gold losses.It can be concluded that the gold ore samples tested have good characteristics due to moderate levels of energy requirement, high gold recoveries and extraction rates attainable.INTRODUCTIONBench scale testing of ore samples is an important step in the long series of metallurgical and economic studies involved in bringing new ore bodies into production (Coleman, 1980). Through a laboratory testing program, the behaviour of an ore in a particular process on a larger scale can be established. In an exploratory manner, this testing can be helpful for classification of ores in terms of “good ore” or “problematic ore” by providing preliminary information on recoverability of target minerals. Potential problems if any can be assessed by further investigation of products (e.g., middlings) obtained as a result of testing. A detailed bench scale experimental program in the metallurgical laboratory can also provide the background work for flowsheet development. Depending on the simplicity or complexity of the ore to be tested and type of details required from a testing program, the amount of samples required in the mineral processing laboratory can vary from several kg to more than one hundred kg depending on how detailed the metallurgical testing program is."

Jan 1, 2008

By T. Binnert Haites

INTRODUCTION NUMEROUS examples of troubled zones, interfering with the normal development of coal seams, have been cited in the literature. From a geological point of view they can be subdivided into structural and sedimentary troubles. Of the latter type, wash-outs are usually the most bothersome. Some years ago, A. A. Thiadens and the author arrived at the conclusion that they represent fossil river-beds. A method of predicting the course of these rivers was developed, which has been successfully applied in the Netherlands coal measures, and more recently by P. Stassen in some of the Belgian coalfields and by the author in the Sydney coalfield. The Sydney coalfield has long .drawn the attention of geologists, and three main periods of systematic geological research may be distinguished. The first period, 1872-1900, is covered by the studies of Ch. Robb and H. Fletcher (32, 10-13) (1). Their detailed sections of the cliffs have lost nothing in value, and are frequently consulted today.

Jan 1, 1951

By Kjell Winther

"Hydralift Scanmec introduced early in the eighties a new and different mill design for very large grinding mills. The design described has actually no size limitation upwards and is so far suggested with motor power up to 40 MW. The mill is furnished with gearless ring motor drive transmission. It is totally fabricated, without heavy castings. The first installation, an 8, 1 MW ball mill dia. 6,5 m x 9,65 m length, has been in continous operation in 13 years without problems. Total grinding costs has been reduced with 3 0% compared to traditional smaller mills. Reductions has been achieved in maintenance cost, power consumption, liner wear and grinding media consumption.So far 3 ball mills of the described design are delivered and in operation, one grinding Iron ore and two grinding Nickel ore.IntroductionThe design of mills for mineral ore dressing has basically been unchanged since grinding in mills started some I 00 years ago, in spite of the fact that mills have grown larger and larger. This has resulted in structural and mechanical problems, causing expensive failures and loss of production.Hydralift Scanmec engineers were designing mills for more than 20 years according to the old «rules». As they experienced interest for an increase in the mill size at the time when reports about failing mills were published, they started analyzing the different mill parts to find new solutions. One goal was to only use elements from proven technology in the new design. Two key items were ring motor (wrap around motor)(Isch et al. 1977, Meintrup and Klein 1982, Ranze 1983) and large diameter pad bearings (wrap around bearings)(Fuller 1984), both acknowledged from other industries."

Jan 1, 1995

By C. A. Ingram

The Cigar Lake ore body is a high-grade uranium deposit situated within water-saturated sandstone. In order to extract the uranium ore remotely, ensuring minimal radiation dose to workers, and also to access the ore from stable ground, the Jet Boring System (JBS) was developed. This method of mining involves drilling a pilot hole up through a frozen ore body and utilizing a high-powered water jet to mine out cavities. During the mining process an ultrasonic sensor will be used to provide feedback to the operator, who is located beneath the ore body, as to the dimensions of the cavity. However, more precise data is required to determine final shape, volume, and location of the cavity for mine planning purposes. Selecting a device that will provide sufficient range data in the challenging environment will be vital to optimizing the mining process. Major issues include fog build up and flying debris during mining, and an environment that is wet, dark, and cold A test cavity has been designed and constructed at the Saskatchewan Research Council (SRC) so that a study comparing three different technologies, as prospective candidates for the survey system, can be conducted. The devices being evaluated include a Senix ultrasonic sensor, an MDL Cavity Auto-Scanning Laser System (C-ALS), and a MESA Time of Flight (ToF) camera. The ultrasonic sensor is known to provide range data in foggy conditions but has low accuracy. The C-ALS has been developed for surveying remote cavities but is expensive and does not provide reliable data in fog. The ToF camera provides a high volume of data in a short time period, with potential to provide accurate information in extreme conditions, but has not been tested in a mine cavity application. Iterative closest point (ICP) registration is applied in an attempt to create a 3D point cloud from the scan data and to also compute rotation and translation of the ToF camera. This paper presents an overview of the challenges involved in conducting a survey within a JBS mined cavity, the analysis used to determine the suitability of each device, and the data collected from the test cavity.

Aug 1, 2013

By J. Molgaard, J. Masounave, J. Prinsen, P. Beaulieu, G. Huard

"A study carried out on behalf of the National Research Council (NRC) indicates that economic losses due to wear in the Canadian mining industry are in excess of $700 million annually. Severe wear, mainly by abrasion, was identified as the most important wear mechanism in terms of possible savings. One way to reduce losses would be the proper use of databases. A joint project of The Canadian Institute of Mining and Metallurgy (CIM) and NRC (Tribology laboratories at IMRI) has been initiated to create a factual database containing all relevant experience in the area of wear in the Canadian mining industry. As a first step, a prototype covering slurry pumps is being built. This should help to answer many questions, such as the number of people involved, interest from industry, cost vs benefits, etc.IntroductionTribology is concerned with the understanding of the mechanisms of friction, wear, and lubrication.Tribology is concerned with the correct use of materials for interacting solid surfaces, with the interaction of those surfaces with lubricants, with the chemistry, physics and use of lubricants and their additives. It is concerned with the reduction of friction and wear (or, in the case of belts, brakes, clutch plates, and similar devices, in achieving optimum friction with minimum wear) and is concerned with the avoidance of associated failures in machinery.Lubrication is usually the solution to a problem of friction and wear. Yet far from all the problems of friction and wear are solved by lubrication. The wear of grinding rods or shovel track pads can hardly be solved by lubrication, to name just two examples with which mining engineers will be familiar. There are indeed many situations of wear and friction where the surfaces in contact are unlubricated.In part, tribology is a matter of design. A major aspect, however, has to do with the choice of materials, to satisfy external constraints upon the component design or choice. The operating conditions for much industrial equipment, particularly in mining are, often very severe. The development of wear resistant materials, including materials which are applied as coatings, is clearly an important technology from the point of view of tribology."

Jan 1, 1987

By E. C. W. Perryman

Materials research and development has played an important role in the commercial success of the CANDU- PHW nuclear reactor and in the production of heavy water. Both capital investment and energy conservation demand very high component reliability in such systems. The interactions among reliability, plant performance and economics will be discussed in relation to materials research and development. Likely materials requirements for the nuclear industry over the next twenty five years will also be discussed.

Jan 1, 1977

By Aparup Chattopadhyay, Barun K. Gorain

"Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.INTRODUCTIONA novel characterization tool has been developed for double refractory gold ores and complex copper-gold ores using state-of-the-art technology for quantitative gold and copper deportment study. The characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulphide phases and variable proportion of visible and invisible gold in different sulphides phases (pyrite, chalcopyrite, chalcocite and bornite) and iron oxide phases (magnetite, hematite and goethite). A study was initiated on various ore deposits and also on samples representing various processing streams of pilot plant batches such as flotation concentrates and tailings. This paper attempts to discuss the deportment characterization methodology through presenting results from investigations on four samples from a flotation circuit viz, Feed, Final concentrate, Cleaner Scavenger Tail and Rougher Tail samples. These four samples represent the key streams for a typical copper-gold flotation flow sheet. The key objective of this investigation was to identify and quantify visible and invisible gold along with understanding the morphology and liberation of gold associated with various sulphides, Fe- Oxides and non-sulphide gangue species. In addition, the aim of this study was also to relate this mineralogical and gold deportment information to metallurgical performance."

Jan 1, 2013

By M. C. Villeneuve

A numerical modelling approach was developed to explicitly simulate geomechanical characteristics of intact rock: mineralogy, grain size and fabric. The approach involved creating a representative constitutive model for each of three common rock-forming minerals: mica, quartz and feldspar. The constitutive models developed are valid within the low confinement realm of excavation boundaries, where tensile fracture processes dominate. The mineral types were assigned to numerical elements, which were associated with each other through an algorithm created in a finite difference model, FLAC 2D (Itasca 2007a), to simulate real crystal geometries and orientations. The numerical models were used in a parametric investigation of the geomechanical characteristics and compared with published observations of the rock yielding process in laboratory testing. This approach has allowed the explicit grain-scale investigation of the impact of geomechanical characteristics on rock yielding at low confinement, leading to an improved mechanistic understanding of excavation-scale rock yielding processes at excavation boundaries.

May 1, 2009

By O. A. Bascur, J. Patrick. Kennedy

"The lack of integration of mining and metallurgical information at sufficient detail to act is a problem. Without such data, mine cut-off grade can not be optimized on a per grade basis. It is difficult to determine economics without integration of mine transactions, stockpile inventories, process flows and assays. Actions also require real time information from manufacturing assets, but corrected for gross errors from trucks, shovels, conveyors, faulty sensors, bad instrument calibration. Validation methods must include process models to identify corrupt actionable information. This paper presents new tools that use the model the process to sift through available data, identify and eliminate gross errors, and use statistical data reconciliation to create material balanced, internally consistent values. Uses of models allow data to be unified for useby both monitoring and decision making processes.A Real Time Performance Management (RtPM) uses unifying analysis methods to empower everyone in the organization with unparallel real-time intelligence, enabling them to continuously improve performance.BACKGROUNDExtraction of metals has become a global business; new economic and environmental forcing factors are present today which were unheard a couple of years ago that are causing companies to focus on plant operations. High ROI actions can be achieved internally which will increase mining and metallurgical processing unit efficiency and reducing operating costs if the proper information is provided those in the complex that can act. Large changes are possible with many of these small steps if the barriers for action are removed. The chief impediments are lack of infrastructure including the data, computing tools and essential data and bad information.Increased demands will be placed on the types, quantity and priority of information. Metallurgical complexes are attempting to become better neighbors, increase productivity, improve customer service, and satisfy the regulators and compliance groups -- all with fewer people and less costs."

Jan 1, 2004

By C. Stapel, AA Groningen, R. J. De Meijer

"In recent years the Environmental Research Group of the KVI has been developing a number of radiometric techniques that may be employed in mineral sand exploration. These techniques involve: radiometric fingerprinting for assessing sand provenances and mineralogical composition; thermoluminescence for dating and provenance determination of sediments; a towed seabed detector to map seafloors for radiogenic heavy minerals and assessing heavy mineral volumes; and simplified transport mechanism models to explain and predict heavy mineral concentrations.All techniques exploit the property that heavy minerals as a group contain concentrations of naturally occurring uranium and thorium that are a hundred to a thousand times higher than in light minerals. In this paper the physics of a number of methods will be described together with a number of results. Based on these results potential applications to mineral exploration and mining are discussed."

Jan 1, 1994

CORPORATE SOCIAL RESPONSIBILITY CSR is about how companies manage the business processes to produce an overall positive impact on society. - Indentured work, sexual slavery, fair trade, organic growing, business ethics, environmental issues, ?Right to know -Right to decide?, AIDS activism, civil society - Balancing stakeholder issues - Government responses Who are the bad guys? Where are the threats?

May 1, 2010

By Brent C. Jellicoe, Phil Robertshaw, J. Murphy, Peter Williamson

Kimberlites and associated diamonds have been the focus of extensive exploration in central Saskatchewan since 1988. During 1989, Uranerz Exploration and Mining Limited identified 71 shallow magnetic anomalies in the Fort a la Corne area from detailed aeromagnetic surveys. By the end of 1991, 18 of these targets had been proven, by drilling, to be kimberlite bodies encased within Cretaceous sedimentary strata. From 1991 to 1997, the number of drill-confirmed kimberlite bodies increased to 69. Our current view, drawing on an integration of geophysical and geological information, is that the kimberlites are composed of individual bodies and multi-vent clusters of coalesced bodies, all apparently constructed of stacked, temporally distinct layers of pyroclastic crater-facies kimberlite. Diamond recoveries and geochemical results from associated heavy minerals at Fort a la Corne remain highly variable, although continued minibulk sampling is expected to improve the estimation of diamond grades for the most prospective bodies.

Jan 1, 2001

By Brian Hart, Roger St. C. Smart, James Francis, Mark Biesinger

"There are a number of challenges involved with the surface analyses of different mineral phases from process streams in a flotation facility. The first of course is to collect samples that are representative of the process and to ensure that they remain in a pristine condition prior to introduction into the instrument. In mineral processing, sample collection from the different streams is done on site and preservation involves simply removing oxygen from the sample by bubbling nitrogen or argon gas through the sample and snap freezing with dry ice.The second challenge in studying the surface chemistry of specific minerals is to find reliable methods of mineral phase recognition. In surface analysis of mineral particles confident mineral selection can be difficult with many multi-metal minerals (e.g. chalcopyrite, pyrite, sphalerite) and with precipitated, adsorbed, reacted and contaminant species in the outermost molecular layers.In this paper we show that principal components analysis (PCA) of ToF-SIMS data provides improvement in phase recognition, particle selection and associated variations in surface species. We will demonstrate, with specific examples, that this technique can be utilized to differentiate surface chemical factors promoting (hydrophobic species) or inhibiting (hydrophilic species) flotation.Species recognition based on the PCA method in a study of Cu transfer between chalcopyrite, pyrite and sphalerite mineral mixture clearly identified a statistical difference in copper intensities between the sphalerite and pyrite phases. A similar ToF-SIMS/PCA based study applied to concentrate and tails samples collected from the Inco Matte Concentrator demonstrated extensive CuOH and NiOH transfer between the chalcocite and heazlewoodite minerals. The statistical analysis has been able to confirm some mechanisms and deny others proposed to control recovery and selectivity giving more focus on the control factors.The ToF-SIMS PCA statistical analysis has elucidated differences in surface chemistries which illustrate the discriminating depressant action of adherent aluminosilicate (gangue) fine particles and adsorbed ions on the surface of sphalerite grains. In the flotation test concentrates, HIC conditioning resulted in the removal of these gangue fines thereby improving surface collector attachment efficiency, promoting a greater recovery of sphalerite."

Jan 1, 2007

By The Staff

BEFORE going into detail on the subject to be presented, a brief outline of the Company's earl y history would not be out of place. Prospecting and mining on a small scale was started in 1876 on the site of the present open pit at Thetford Mines. The property was purchased from the Crown in 1878 and Johnson's Company was incorporated in 1885. It is owned and operated today by descendants of the original shareholders. Many employees, through their fathers and grandfathers, have service records dating back three generations. The principal asbestos deposit at Thetford Mines is pear-shaped, with surface dimensions of about 2,200 feet in length by 1,300 feet in maximum . width. Its long axis strikes northeast and the dip is nearly vertical, but irregular in detail. It is known to extend to a depth 1,200 feet below the original surface, but its area at that depth has not been determined. Ownership of this deposit is divided among three active Companies: the Asbestos Corporation, Limited; Bell Asbestos Mines, Limited; and John-son's Company. Johnson's Company owns a section about 1,000 feet in length and 500 feet in width, bounded on the northeast by the King mine of the Asbestos Corporation and on the northwest by the Bell pit. On Johnson ground, there was originally a large outcrop o~ asbestos rock which dipped toward the south below overburden. This was mined until recently by open pit, the overburden being stripped off as far southward from the original outcrop as was economically possible. As the. pit was deepened, within side walls maintained at a maximum safe slope, its floor area, of course, became progressively smaller, and eventually the pit would have wedged out against the Bell property line. It became necessary, there-fore, to introduce some other method of mining before production became seriously curtailed by a shrinkage of the pit area.

Jan 1, 1941