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By Alan B. Morrow, William A. Poe

"Minerals processing operations are constantly challenged with improving production rates, yields, energy efficiency and process stability. Advanced Process Control has proven to be an effective tool for improving operations by capturing the full process capabilities consistently. However, the velocity of applying the technology as well as the sustainment of these significant benefits has been hampered by the usability of the software and adaptability of the applications.Some of the new technology developments that improve the usability and adaptability of advanced process control include:• modern and intuitive user interfaces,• customizable models to support unique process behavior,• fast and flexible OPC connection tools,• automated model building,• integration with first principles dynamic models and• improved performance monitoring.This paper will briefly discuss the new technology developments that have improved the usability and adaptability of advanced process control and how this can affect minerals processing operations.In today’s environment, Minerals Processing plant managers continuously face new challenges and requirements including:• higher energy efficiency,• increased run lengths,• reduced product quality variability,• reduced emissions,• higher availability, and• lower operating costsOperating a unit to meet these challenges in real time is not easy for operators and conventional process control systems. However, innovatively using existing technologies in Minerals Processing plants can improve operations on a minute by minute basis and reap significant benefits.Advanced Process Control (APC) can extract the maximum performance benefits from existing equipment while respecting plant operating constraints. Expensive capital projects to upgrade equipment are not always necessary. Advanced Process Control can deliver significant economic benefits by maintaining the plant at its most profitable point as conditions change."

Jan 1, 2016

By Karl Houseley, Dr. Robert J. Chapman

"A gravity concentration process has been applied to ores from the Clogau Mine, north Wales, the Tyndrum deposit, central Scotland and an alluvial ore from Leadhills area of Scotland. In the case of the Welsh ore and the alluvial deposit the gold grains in the concentrate and tailings streams have been characterised in terms of their three dimensions.In the case of Welsh ore, the thickness of a gold grain has been shown to be the single most important factor in determining behaviour in a gravity concentration operation. Six indices were used to quantify the overall geometry of the gold grains and those which incorporate a thickness term have proven to be effective in predicting the destination of gold particles within the concentration circuit. It is proposed that the most simple of these, the Heywoods flakiness ratio, has potential for the control of milling operations as an alternative to the established practice of characterising the size of the mill discharge.The effect of grain geometry on the recovery of fine gold has been studied using Tyndrum ore. The recovery of gold by gravity concentration increased from 20% to 70% when the criteria used to design the milling operation was the prevention of over grinding of gold grains.The destination of alluvial grains in the concentration circuit did not show such dependence on shape, and this has been attributed to the effective classification of all the gold grains in the sample by fluvial action producing a population of similar geometric characteristics."

Jan 1, 1996

By Martin Wacker

Cameco Corporation, on behalf of a joint venture, is preparing surface and underground facilities at their northern Saskatchewan property in preparation for the future operation of a high-grade uranium mine. The Cigar Lake orebody is situated about 430 metres below surface at the unconformity between metamorphic basement rocks and flat lying sandstone. Major technical factors influencing the mining method selection include ground stability, control of ground water, radiation exposure and ore handling and storage. A decade-long test mine program resulted in the selection and validation of ?jet boring? a non-entry mining method. Cigar Lake?s jet boring mining method involves several major steps; artificial ground freezing of the orebody and surrounding rock, TBM (tunnel boring) type development of access crosscuts below the orebody, installation of cased pilot holes upwards through the ore, and ore extraction using a rotating high pressure water jet within the pilot holes. The resulting cavities are surveyed and backfilled with concrete. The ore slurry will be processed underground and pumped to surface. This paper discusses the jet boring mining method in general terms and includes highlights of the Cigar Lake test mine program completed in 2000.

Apr 1, 2005

By K. A. Foxford, D. A. Polya, R. P. B. Hebblethwaite

"Abstract-A variety of techniques for interpreting systems of mineralized echelon veins is discussed using examples from Panasqueira and SW England. As aids for exploration and mine planning, and as a tool for ore reserve evaluation, particular emphasis is placed upon establishing vein morphology in the third dimension, and upon understanding vein dilation and propagation histories. Special attention is also placed upon investigating vein thickness and spacing relationships, and upon understanding vein segmentation. The relevant data for these techniques are all readily obtainable from stope and core sources.The vein systems described were produced in host-rock sequences that underwent incremental dilation in response to fluid overpressures, and individual veins display evidence for mineral infilling synchronous with their propagation. Echelon vein geometries resemble those reported from igneous dikes and sills: vein walls are stepped and veins are divided into segments arranged in echelons. Changes in vein geometry, from arrays to composite structures, reflect both the evolution of the vein system with time, and the changes occurring between the margins (arrays) and core (composite structures) of the system. These characteristic morphologies can be used to infer vein propagation and fluid injection trends, proximity of neighboring veins, and the shape of the system as a whole. The techniques are applicable to systems of echelon veins produced under tensile conditions in rocks where faults were absent at the time of vein formation, and where subsequent deformation has been minimal. Further work is required to assess the application to echelon vein systems formed within more complex tectonic regimes."

Jan 1, 1995

By K. E. Waters, N. Brodusch, R. Gauvin, C. Teng, H. Demers

Rare earth elements play an increasingly important role in renewable energy devices and high-end electronics. In this project, the composition and morphology of REEs-bearing minerals are characterized with a field-emission scanning electron microscope at high spatial resolution and high counts rate using an X-ray silicon drift detector system. High spatial resolution imaging and energy dispersive X-ray microanalysis were applied at low and high magnification to obtain the composition of each phase in the minerals. From the standardless quantitative analysis results, the amount of REEs in each phase was measured and the relationships between those phases were identified.

Jan 1, 2014

By M. Tsesarsky, M. Hazan, E. Gal

"Rock masses comprised of stiff inclusions in softer matrix are common in various geological environments. The heterogeneity and multi-scale nature of these materials make the evaluation of their mechanical properties a challenging task, which cannot be accomplished using conventional laboratory tests and composite mixture rules. We employ the homogenization method to estimate the mechanical properties of geological materials with inclusions. The homogenization method solves the equations of elasticity on the material (microscopic) scale for a unit cell subjected to unit strains under periodic boundary condition. The micro-scale elasticity equations are solved using the Finite Elements Method, and are in turn used to obtain the structure scale (macroscopic) material matrix.In this research, Finite Element models for unit cells with spherical and ellipsoidal inclusions were developed. Using the unit cells, a parametric study of the geometrical and statistical microscopic properties of the material composites was performed. The following parameters were studied: volumetric ratio, Young’s modulus ratio, size-distribution of inclusion and inclination angle of inclusions. The main purpose of the parametric study was to study the deviation from isotropy as a function of the aforementioned parameters.It was found that for volumetric ratio of 5%-40%, the deviation from isotropy increases, as the volumetric ratio of inclusions increases. For spherical inclusions, most of the cases studied exhibit quasiisotropic behaviour; whereas ellipsoidal inclusions exhibit considerable deviation from isotropy. The inclination of the ellipsoidal inclusions enlarges the deviation from isotropy (9% at random orientation and 26% at 0°)."

Jan 1, 2015

By Terry J. Briggs, Ian J. Kelso

"Abstract- The Century mine in northwest Queensland,Australia, is a major sediment-hosted zinclead- silver orebody, located within the western Mount Isa Basin. Stratiform, carbonaceous shalehosted mineralization is developed within Proterozoic shale and siltstone sequences of the Lawn Hill Formation. CRA Exploration Pty Ltd (CRAE) discovered the Century deposit in 1990 and open pit mine development commenced in 1998 under the ownership of Pasminco Century Mine Limited (PCML). The deposit contains an identified mineral resource of 105 Mt @ 12.1% Zn + 1.7% Pb + 46 g/t Ag (Broadbent and Waltho, 1998) which is currently being mined at a rate of 5 Mt/y.In December 1998, an exothermic reaction was observed between explosives spilt onto shale drill cuttings from a blasthole. This reaction is referred to as ‘reactive ground’ and has the potential to cause premature detonation of explosives in a charged blasthole with catastrophic consequences. The incident led to a subsequent geological and geochemical assessment of the different rock types at the Century deposit and their potential reactivity with ammonium nitrate-based (AN) explosive products. This assessment was conducted in an attempt to characterize zones safe for blasting with uninhibited AN-based explosive products. A direct result of this study is a set of procedures outlining the use of different AN-based explosives in areas defined as potentially reactive or non-reactive for the different lithologies present. Black shales contained in both the waste and mineralized sequences contain the sulfide mineral pyrite (FeS2), which is thermodynamically unstable with AN contained in commonly used explosives. The potential reactivity of partially weathered pyrite can ultimately result in the decomposition of an AN-based explosive. It was determined that only pyritic black shales showed any potential to react with AN, irrespective of their position in the stratigraphic sequence. Other lithologies present at Century, including Proterozoic sandstone and Cambrian limestone, are classified as non-reactive with AN. This is a geological risk management situation present at the Century mine."

Jan 1, 2001

By G. W. Poling

"Construction, equipping and planned operation of a new laboratory for engineering-teaching and research in coal and mineral processing is described. This facility will provide approximately 1860 m2 (20,000 ft. 2 ) of laboratory space with nearly half devoted to a new venture in coal preparation. Two high-bay, overhead crane-accessed areas will accommodate major unit operations for each of the ""coal"" and ""mineral"" laboratories. COAL PREPARATION FACILITIES:The coal facility provides three main functional areas:(1) Sample preparation (drying, blending, crushing, screening) and sink-float washability testing.(2) Unit operations U1igh-bay, serviced by crane).(3) Analytical laboratories.(l) Sample Preparation and Sink-Float TestingBreaking or comminution of coal will be accomplished using a rolls crusher, a hammer mill, a jaw crusher, or a pulverizer. Capacity to prepare coal at rates of up to approximately 4 tph will be provided by some of these units. Large diameter (~0.5m) baths of heavy organic liquids will be available for sink-float washability tests on coal samples of several kg. Particle sizes of up to 25 mm can be tested in these baths. Smaller scale washability tests on finer samples will be accelerated by centrifuges."

Jan 1, 1980

By K. Wongpreedee

Recovery and recrystallization of Au wire can degrade strength and alter conductivity properties during exposure to elevated temperature. Au Deformation Processed Metal Metal Composites (Au DMMC's) are being developed for electronic applications requiring high conductivity and high strength. This paper discusses the relationships between microstructure, strength, and resistivity of Au DMMC's. It also presents the results of a recent study on the elevated temperature stability of Au DMMC's of several compositions. Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt DMMC samples were prepared by a powder metallurgy technique. All specimens were processed into wire by extrusion, swaging, and drawing. The smallest final diameter of these wires was 120 ?m. Thermal stability was analyzed by electrical resistivity measurements to determine the relation between transformation rates and time at elevated temperature. The extensive deformation used to produce these composites reshaped the initially equi-axed powder into filaments that are 30 to 100 nm in diameter and 16 to 180 mm in length. The small filament diameter confers high strength on the composite. The high conductivity can be explained by electrons flowing parallel to the filamentary microstructure aligned with the wire axis. Using the Avrami and Arrhenius equation relationships, it is possible to predict the times and temperatures needed to achieve various degrees of homogenization. The Au DMMC's were found to have good thermal stability compared to conventional coldworked Au interconnection wires. Although these composites will revert to solid solutions if exposed to high temperatures for prolonged time periods, their relative stability is sufficient to allow them to maintain their twophase microstructure during the anticipated lifetime temperature profiles of many products.

Oct 1, 2003

By Behzad Vaziri Hassas, Firat Karakas, Esra Tanisali, Mehmet S. Çelik, Ahmad Hassanzadeh

Coagulation is basically an aggregation process where particles settle under the influence of interfacial forces with electrostatic forces playing a governing role. Although particle morphology consisting of shape and roughness dictates the physical encounter of two particles, their eventual coagulation is not only influenced by columbic forces but also other interfacial forces such as hydrophobic interaction, which affects the extent of aggregation of particles through increasing the distance of interaction. Roughness is well known to increase the effective contact angle on hydrophobic surfaces and also enhance interfacial forces. In this study, the effect of morphology of particles and particularly roughness on the settling velocity and in turn coagulation tendency was investigated. Batch settling tests (BSTs) of different particle morphologies were investigated as a function of pH. Two different morphologies of silica particles were utilized with the same particle size distribution (PSD) including smooth-spherical and rough-spherical (Etched). Rough particles were prepared by acid etching technique using hydrofluoric (HF) at different time intervals (15-300 sec). Etched samples were identified and quantified by optic profilometry. Settling test results showed that the settling velocity of particles in a suspension of 2% solids in the massive settling region is significantly affected by particle morphology of the suspension. Coagulation results further revealed that aggregation of rough particles is faster than smooth-spherical particles. Coagulation results are elucidated on the basis of particle morphology and its effect on distance of separation through hydrophobic forces.

Jan 1, 2016

By N. Ahern, M. Barbanell

Mercury is often present in gold ores and can be released during processing. In view of health and environmental concerns related to mercury, the mining industry takes leadership in the responsible management of mercury. This paper reviews various aspects of mercury management, including an overview of mercury deportment in typical gold processing flowsheets; trends in mercury legislation impacting the international flow and management of mercury in the gold mining industry; and treatment, storage and disposal options for mercury and mercury containing materials.

Jan 1, 2014

By Stephen Hardcastle

Personnel Heat Exposure Issues In Canada?s Deep Mechanized Mines ?Project developed in 2004 ?Base/precious metal industry identified heat stress/management as a major challenge affecting productivity and operating costs ?Project started in 2005 ?Current research nearing completion ?Guidelines, further data analysis and ?Communicating the Science? will continue into 2011

Oct 1, 2010

By C. R. Edwards, D. G. Feasby

"Over the last 50 years disposal of uranium mill tailings has evolved from dumping untreated tailings into the nearest depression to depositing chemically-stabilized tailings into highly engineered management facilities. This paper describes the evolution of disposal methods and the criteria which have determined the development path followed. Remediation techniques to bring older and now unacceptable tailings deposits into satisfactory compliance with today's· regulations are reviewed.With the closure of the uranium mines in Elliot Lake, Ontario, considerable effort is being made on decommissioning the tailings areas by developing long term maintenance of water covers. The innovative methods being used to develop these water covers are detailed. Methods now under development in Saskatchewan for subaqueous deposition of high density or paste tailings for permanent disposal in mined out open pits are described.SummaryThe technology for uranium mill tailings disposal in Canada has evolved considerably over the past 51 years. This evolution has been driven by an improving understanding of how best to safely and permanently store tailings, in conjunction with stricter environmental protection regulations. Old sites are being decommissioned in situ, but may require long term care and maintenance. The use of water covers is an important technique in eastern Canada to prevent intrusion, radon evolution and, for the Elliot Lake tailings, acid generation. The major drawback of water covers in any above ground disposal method is the requirement that a long term maintenance and monitoring plan be put into effect for each site.New higher grade mines in Saskatchewan will increasingly use disposal in mined-out pits using the pervious surround method and/or paste tailings technology as a method to permanently dispose of these wastes and to permit “walkaway” after a few years of monitoring."

Jan 1, 1996

By C. Poon

For slope stability, knowledge of major and minor discontinuity sets that form the rock mass fabric is paramount for pit slope designs. Due to the increased awareness of health and safety in mining projects, efforts have been made to limit structural mapping in order to minimize the risk to personnel associated with approaching potentially unstable areas. Recognizing the importance of such safety precautions, Golder Associates Ltd. is applying a combination of techniques including 3D photogrammetry, conventional mapping and drilling with core orientation to enhance structural data collection. Photogrammetry uses digital photographs to produce a virtual model of a rock mass surface. The application of these techniques will be exemplified through an expansion design of an existing open pit. A comparison of stereonets obtained using these techniques showed some agreements, but also highlighted limitations of each method. The application of photogrammetry was found to be very useful in complementing the other existing techniques.

May 1, 2009

By S. Kaushik

The control room in a mineral processing plant has become increasingly complicated with complex unit operations coupled with rapidly evolving systems of sensors and control. Even with significant automation, human intervention is required to counter various scenarios that play out every day. A typical control room operator must monitor over 300 individual points of data in order to ensure the safe and efficient operation of the plant. At the same time, the experience of the workforce is decreasing as operators retire and the new generation enters the concentrators. Global competition for skilled operators continues to be strong and the opportunity to apprentice has diminished. The challenge is to provide a skill foundation for the operators so that they can be effective in the concentrator in a timely and safe manner. Progressively, the industry is turning to dynamic simulation tied into the control system. The simulator environment operates behind the control system to emulate the plant operation, reacting as the plant would when a change is made. The operator drives the process, with realistic feedback, which enables learning in a safe environment. This paper will take the reader through a green-field case study and discuss the effectiveness of integrating an operator training simulator (OTS) on the operator’s learning curve.

Jan 1, 2014

By P. Woo, N. Brodusch, R. Gauvin, H. Demers

The scanning electron microscope (SEM) was primary developed for imaging applications. With the introduction of the Si(Li) energy dispersive spectrometer (EDS), simultaneous imaging and x-ray microanalysis became possible. However, long working distance and high current were needed because the position and small solid angle of the EDS detector. The high spatial resolution is generally obtained at short working distance with a SEM. Unfortunately x-ray microanalysis is never performed in the best imaging conditions. The annular silicon drift detector system is inserted below the objective lens which gives a higher solid angle (up to 1.3 sr). In consequence, a lower working distance and probe current can be used. An improved spatial resolution becomes possible during x-ray microanalysis. With this x-ray detector installed on a cold-field emission scanning electron microscope, quantitative x-ray microanalysis with high spatial resolution at low beam energy and low current becomes possible with the possibility of using the various different type of imaging at the same time. Also, since the count rate can be as high as 1,500 kcps, which lowers significantly the detection limit of elements as well as the minimum feature sizes of different phases that can be distinguished.

Jan 1, 2014

By Wouter Bleeker, Isabelle Cadieux

"Abstracts of theses related to mineral deposit studies and exploration, completed at geology or earth science departments of Canadian universities, have been compiled for the period 1991 to mid-I993. Part I, presented in the June, 1994 issue of the CIM Bulletin, gave a listing of thesis titles. Part II. which consists of edited abstracts of theses considered to be of direct application to mineral deposit studies and exploration. is presented under various themes as follows:A. Kimberlites, Other Alkaline Intrusions and Related Studies;B. Volcanogenic Massive Sulphide Deposits and Related Studies;C. Mineral Economics;D. Mesothermal Gold Deposits. Other Gold Deposits and Related Studies:E. Magmatic Nickel-Copper, Platinum Group Element and Chromite Deposits and Miscellaneous Platinum Group-related Studies;F. Granite and Pegmatite-related Deposits and Porphyry Deposits;G. Diverse Hydrothermal Deposit,>, Sediment-hosted CopperDeposits and Mississippi Valley Type Lead-Zinc Deposits; andH. Uranium-related studies, Evaporites and Exploration Geophysics.Abstracts related to themes A to F were presented in previous issues of the CIM Bulletin, abstracts related to themes G and H are presented in this issue.G. Diverse Hydrotbennal Deposits, Sedimenthosted Copper Deposits and Mississippi Valley Type Lead-Zinc Deposits"

Jan 1, 1995

By H. Asgari, A. G. Odeshi, J. A. Szpunar

In the current research, the role of grain size on the texture formation and mechanical behavior of rolled AZ31B Mg alloy is investigated under shock loading conditions. The grain size of the original asrolled sample was 8 µm and different grain sizes, e.g. 25 and 46 µm, were produced by heat treatments at temperatures in the range of 400-500 °C. In order to evaluate the effect of grain size on the anisotropy of mechanical behavior, the samples were cut along the rolling direction (RD), transverse direction (TD) and normal direction (ND) and tested at strain rates of 900 and 1200 s-1 using Split Hopkinson Pressure Bar. Texture measurements showed that initial texture of the samples cut from the as-rolled sheet is a weak rtype texture. However, a stronger texture was observed for samples with large grains. After shock loading, a (00.2) basal texture developed in all samples and the intensity of the basal poles was higher in samples with coarser grains. This observation is corroborated by high twinning activity and possible activation of pyramidal <c+a> slip in coarse grained samples. Besides, the strength of basal texture increased with increase in the strain rate. Furthermore, the samples with larger grain size showed lower strength and higher ductility, and this was observed for all investigated strain rates.

Jan 1, 2014

By B. McFadzean, J. Taguta

In order to recover minerals by flotation, the sub-processes of collector adsorption onto the valuable minerals followed by bubble-particle attachment should occur efficiently. This paper investigates both of these sub-processes for various thiol collectors and their mixtures onto base metal sulfide minerals. The aim of the work was to investigate whether there is a correlation between the strength of the collector interaction with the mineral and the subsequent bubble-particle attachment. The collector-mineral affinity was measured experimentally using an isothermal titration calorimeter in order to determine the molar enthalpy of adsorption for each collector-mineral system. The bubble-particle attachment was measured using a microflotation device which essentially determines the hydrophobicity of the mineral. Sodium ethyl xanthate (SEX) and sodium diethyl dithiocarbamate (DTC) and mixtures thereof were used as collectors with either single minerals or binary mixtures of pyrite and chalcopyrite, respectively. The adsorption enthalpies of the collectors were interpreted with reference to the chemical structure of the collector molecule and showed that the greater the positive inductive effect of the collector, which may be qualitatively related to their pKa, the greater their affinity for the mineral surface. In the microflotation studies, recoveries were strongly related to the alkyl chain length but there was no correlation between the enthalpies of adsorption and the flotation recoveries. When mixtures of collectors were used there was clear evidence of synergistic effects and in the case of DTC/xanthate mixtures it is possible that this synergism is related to a DTC promoted oxidation of xanthate to dixanthogen. When mixtures of pyrite and chalcopyrite were used the flotation recovery and enthalpy of adsorption of SEX onto the individual pyrite particles in the mixture increased substantially compared to the case of pyrite alone. Mechanisms are proposed to interpret these important observations.

Jan 1, 2016

By Pierre Montrueil, Marcel St-Amant

Within the next few years, underground mobile equipment will be partially automated. Mining methods will integrate more and more automation. Such an evolution will be possible only if adequate underground communication systems are developed. This is expected due to the available competence in Canadian telecommunication, to the economic pressure on the Canadian mining industries for international competitiveness and to the social changes where a better working environment (i.e. less accidents) becomes a major concern. CCARM propose the concept of a Production Area Network for Automated Mobile Units called PANAMU as an intermediate size communication system. It can be implemented using mature present-day technology and it can be integrated in some mine wide communication systems. It can evolve so as to incorporate new technologies because of its modular concepts. In this paper, the communication requirements are estimated, the amtmptions are defined, the concepts of the PANAMU are presented and an over- view of its implementation is described. CCARM presents this article to the mining industry as a document for discussion.

Jan 1, 1994