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By G. Bartolacci, G. Couture, Levasseur. B., A. Lockhart, D. Nathan

"Pulp and froth zone characterization in a flotation circuit to improve transport of valuable minerals remains a challenge. Even though some significant breakthroughs have been made in the development of collectors in terms of selectivity, the control of gangue drainage is still the main bottleneck to achieve the production of a clean concentrate.Over the last decade, COREM’s team has been working on technologies to improve the selectivity of flotation circuits by tuning their hydrodynamic conditions using online instruments such as the bubble viewer, Jg sensor and gas hold-up. As part of its research program, COREM also developed the half-life column that establishes the relationship between the collection zone (bubble-particle attachment) and the cleaning zone (foam) of a flotation machine. In recent years, COREM has continued the development of the prototypes to make them more robust and improve the accuracy of their measurements.Recently, these hydrodynamic instruments were installed in an industrial process at Raglan Mine in order to diagnose and control the impact of hydrodynamic parameters versus the recovery and the quality of the Ni concentrate produced. Sampling campaigns of hydrodynamic parameters demonstrated that froth height could be optimized in order to increase recovery and quality of the concentrate at the same time. The specific effect of the froth height impacts both the pulp and the froth zones. Along with the impact on the drainage of the concentrate, it was observed that froth height also contributes to enhance the collection of particles in the pulp leading to an increase in metallic units.IntroductionOnce the particles of the minerals of interest are attached to the air bubbles injected in the pulp, the flotation process is driven by air dispersion parameters and froth properties. The pulp is usually responsible for the collision between air bubbles and hydrophobic particles of interest while the froth zone aims to upgrade the selectivity of the particles floated through drainage of the unwanted hydrophilic particles. Over the last four decades, flotation hydrodynamics has been extensively studied. Superficial gas velocity (Jg), gas hold-up (eg), Sauter mean bubble diameter measurements (d32) and bubble surface area flux (Sb) are among the most assessed parameters in flotation plants worldwide either to quantify the gas dispersion parameters or to optimize them (Fournier et al., 2015). McGill University has developed several sensors able to measure these parameters at industrial scale (Tavera et al., 1996; Finch et al., 1999; Chen et al. 2001)."

Jan 1, 2017

By K. Zenger, J. Kaartinen, J. Huuskonen, S. Torttila, S. Lähteenmäki, J. Pietilä

"Pyhäsalmi Mine in Finland has a long history of continuous process development. The concentrator processes Cu-Zn-sulphide ore with high recoveries. An on-line flotation simulator has been developed to maintain and further improve the flotation performance. Consisting of a flotation kinetic dynamic model, and interconnected with process control software, the simulator can be used for training new control room operators in various scenarios. For daily operation, the model parameters are continuously adapted to take into account the changing process conditions. On-line simulator tracking the process can provide the process operator new information in several ways: a) values of unmeasured process variables are obtained by displaying the corresponding simulator values, b) predictions of future process states and outputs are calculated and displayed, c) information of changing process parameters can be used as an indicator of e.g. change in the processed ore type. This paper describes the adaptive simulation system and its usage at the Pyhäsalmi concentrator.IntroductionPyhäsalmi massive sulphide orebody is located in central Finland. Operation of the mine started in 1962 and it is currently producing copper (Cu), zinc (Zn) and sulphur (S) concentrates. The concentrator control and optimization system has a long history of successful continuous development during the past decades (see e.g. Huuskonen & Moilanen, 2010). An on-stream analyzer has been a part of the automatic process control since 1968 (Lähteenmäki, Miettunen & Saloheimo, 1999). First control algorithms based on a flotation mathematical model were developed in 1971 (Koivistoinen & Miettunen, 1985). In 1990’s the development of a froth machine vision systems started (Kaartinen, 2009; Kaartinen, Roine & Hätönen, 2009). More recently Pyhäsalmi Mine Oy has been involved with several national development projects dealing with particle size distribution measurements (Kaartinen & Tolonen, 2008), spectral analysis of flotation slurries (Haavisto, Kaartinen & Hyötyniemi, 2008), and dynamic simulation of flotation processes. The latter topic is further elaborated in this paper."

Jan 1, 2015

By J. Yue

"Mount Milligan mine is located in northern British Columbia. The concentrator employs conventional SABC grinding circuit with bulk sulphide flotation processes. Commissioning started in September of 2013 and nameplate production of 60,000 TPD was reached in the fourth quarter of 2015. As is typical with many mill ramp ups, bottlenecks developed as throughput increased. Since then, plant modifications and new control philosophies in the comminution and flotation circuits have been implemented and evaluated. The mine-to-mill collaboration played a key role in reaching target throughput rates by improving blast fragmentation and implementing temporary pre-crushing. Results of the projects as well as ongoing challenges/bottlenecks and solutions will be discussed.IntroductionMount Milligan Mine is a copper-gold producer located approximately 253 km northwest of Prince George in British Columbia. Production commenced in September 2013 and reached nameplate capacity of 60,000 TPD in December 2015. Average head grades for the mine life average 0.18% Cu and 0.39 g/t Au.Circuit DesignOriginal process design began with run-of-mine ore from the pit crushed through a 60-110 gyratory crusher, conveyed to a live ore stockpile and fed to the mill via four variable apron feeders. The concentrator circuit employs SAG mill - Ball mill - Pebble Crusher (SABC) grinding configuration to grind the ore down to a target P80 of ~200µm. It is then fed to two parallel trains of flotation tanks, each consisting of five 200 m3 tank cells with the first two being roughers and last three being scavengers. Concentrate streams from roughers and scavengers are separately reground with a closed circuit Tower mill and two open circuit ISA mills operating in parallel, respectively.Three stages of cleaners upgrade roughers/scavenger products to 25% Cu followed by a cleaner scavenger stage. The final concentrate is then thickened and filtered to approximately 9% moisture and shipped off site (Figure 1)."

Jan 1, 2017

By M. R. Dion, K. Frenette, R. K. Jonas, S. Simard, F. Robichaud

"In 2011, a site study indicated that the application of Honeywell’s Multivariable Predictive Control Technology (MPC) to the Goldex processing facility would provide significant opportunities for improvement. Grinding MPC was implemented in the SAG Mill in June 2015. This pilot application, called Phase 1, featured one of the first Multivariable Predictive Controllers to be installed in a Canadian mineral processing plant. Since the implementation of MPC, gold recovery from the gravity circuit has increased. MPC contributed to a decrease in flotation feed particle size (120 to 112 µm) and an increase in the SAG feed tonnage (8.5% increase). MPC also increased and stabilized the % solids of the SAG feed, which can have an impact on cost reduction (mechanical maintenance). Additionally, MPC increased productivity, providing grinding operators with more time to perform other tasks. Further anticipated benefits include the standardization of the grinding circuit operation from one team to the next, thereby minimizing circuit disturbances resulting from different operating philosophies. This paper will discuss the advanced control project development and justification, the technology and rapid implementation process, the performance results and the benefits obtained.IntroductionGoldex is an underground mine located near Val-d’Or that is owned and operated by Agnico Eagle Mines Limited (AEM). Between 2008 and 2011, mining focused on the Goldex Extension Zone (GEZ). In 2011, the project was halted due to geotechnical problems; operations ceased until late 2013. Goldex operations resumed in September 2013 with the M and E zones, for which there were 0.7M gold ounces of proven and probable reserves, 2.1M ounces of measured and indicated resources and 1.2M ounces of inferred resources, totalizing 4M ounces. Life expectancy was extended until 2024."

Jan 1, 2017

By P. Scinto, A. Festa

"Orway Mineral Consultants Ltd (OMC) as a consultancy has specialized in comminution circuit design for over 30 years. The OMC Power Model is OMC’s in-house software for specific grinding energy power-based circuit calculations. The model uses ore hardness parameters from testwork, circuit configuration, equipment geometry and operating conditions as inputs. The model combines proprietary and published power models to predict the total specific energy and the specific energy for each of the components of the comminution circuit. This makes the software a valuable tool for the design and validation of JKSimMet modelling or actual plant performance. Proprietary calculations have been developed and reconciled with over 100 plant benchmark projects encompassing a variety of comminution circuit configurations.This paper describes the OMC approach for determining power requirements for the design of grinding circuits. The accuracy of the OMC Power Model software is confirmed through plant survey benchmark performance and comparisons are made with other power modelling techniques. Practical examples are presented, showing applications for single stage SAG (SS-SAG), SAB and SABC circuit configurations.IntroductionConventional low throughput grinding options, consisting of multi-stage crushing followed by rod and ball mills, have almost become obsolete in the move to higher milling rates required to process lower metal grades. Grinding circuits with fully autogenous (AG) or semi-autogenous (SAG) mills, often combined with ball mills are now the standard to meet the high capacity requirement for processing ores with lower metal grades. Simulation software and power-based equation methodologies have been established for designing AG/SAG based grinding circuits and predicting their energy requirements.Presently, power-based equations remain the principal method for designers to size mills and estimate the power requirement for comminution circuits. The technique is simple and it relies on the design to specify a feed and product size plus a hardness index to produce a specific energy value (kWh/t). The desired throughput of the mill is multiplied by the specific energy to give the mill power requirement, which is used in turn to size a mill for dimensions, internal geometry and loading conditions to match the power draw."

Jan 1, 2015

By Nicolae Dobritoiu

The literature in this field and the practical activity record that a method, respectively the technology used for an underground mining work have many components which, in order to be applied, demand that for each of the parameters that describe the environment of the mining work and that influence the chosing of that method and that technology of execution, must have values in an interval well determined. There are situations when one or many parameters of the set of parameters that describe the environment of the mining work, can modify its values, and, as a result, one or more components of the methods or technology cannot be applied anymore, making necessary a replacement of their values. The information offered by this graphical-analytical model allow the determination of optimum solutions for the process of digging of the underground mining work and thus it will result the incresing of the technical-economical efficiency of the digging process and, also the increasing of the quality of the underground mining work.

Oct 1, 2009

By I. C. L. Webster, G. E. Ray

"The magnetite-rich Heff Cu-Au skarn lies in the Quesnel Terrane of south-central British Columbia, approximately 26 km northeast of Kamloops. The skarn formed close to the northern margin of the Heffley Creek pluton, and is hosted by Carnian (Late Triassic) Nicola Group limestone. The Late Triassic pluton (208.1 ± 6.1 Ma, U-Pb zircon) is a composite body of alkaline affinity that includes dioritic, gabbroic, and magnetite-rich clinopyroxene ± olivine ultramafic phases.The skarn has been discontinuously traced along strike for more than 1 km, and individual skarn layers are up to 40 m thick. The most common non-opaque minerals are garnet, clinopyroxene, and carbonate, with lesser epidote, biotite, amphibole, and chlorite. Apatite locally forms more than 3 vol.% of the rock. Compositionally the garnet is a low Mn grandite averaging Pyr3-Grs41-Adr56 mol.%.Mineralization consists of lenses, up to 10 m thick, containing massive low Ti-V magnetite (avg. 0.03 wt.% TiO2 and 0.01 wt.% V2O3). Magnetite is associated with up to 20 vol.% pyrrhotite, lesser pyrite, and trace chalcopyrite and gold. There is a moderate enrichment in rare earth elements with assays up to 570 ppm La and 490 ppm Ce. The Heffley Creek pluton belongs to a suite of Late Triassic-Early Jurassic alkalic and Fe-rich intrusions that are widely developed throughout the Quesnel Terrane. Some host Cu-Au porphyry mineralization, but less commonly they are associated with magnetite-apatite veins such as at the Glen Iron mine and Magnet occurrence, or with magnetite-rich Cu-Au skarns such as the Heff occurrence.Although abundant low Ti magnetite is present in the Heff skarn, it does not appear to represent iron oxide copper- gold (IOCG) type mineralization. Microprobe analyses completed during this study show that low Ti magnetite is not a unique feature of IOCG deposits, but also characterizes some other types of hydrothermal mineralization. In British Columbia these include some alkalic porphyry-related magnetite-apatite veins in the Quesnel Terrane, as well as the well-known Wrangellia-hosted Fe skarn deposits. Thus, low Ti magnetite appears to be a common signature of many magmatic hydrothermal deposits in contrast to the high Ti primary magnetite found in most igneous rocks."

Jan 1, 2007

By Patrick Frenette

The Goldex Mine is an underground gold mine using a unique mining method where a single very large stope is being created. In order to maintain stability of the walls and roof of the stope which is 450m, 250m high and up to 120m thick, ore is left in the stope as long as possible and acts as backfill would do. At many occasions during the mining sequence, the walls will be exposed on height ranging from 30 meters up to 250 meters. A monitoring system comprising in-stope laser surveys, a seismic system and an array of extensometers and sloughmeters all remotely connected to surface is used to observe the shape and evolution of the stope. This paper will focus on the results obtained following some of the large blasts and on the long term monitoring of the stope.

May 1, 2011

By Christoph Broeckmann, Andrew Gardula

"The adoption of high-pressure grinding throughout the cement industry has yielded enormous savings in energy and wear material costs. There are also a number of installations, which are applied in iron ore and kimberlite processing operations. High pressure grinding offers the same potential for energy and media savings, as well as opportunities for improved, downstream metallurgical performance, in hard rock mineral processing. This paper focuses on developments in machine design and wear surface engineering for high-pressure grinding of the hard rock ores in the mineral processing industry.INTRODUCTIONIn the early eighties 3.4 % of the world electric energy was consumed for crushing and grinding operations of minerals and 0.6 % in the ore dressing industry. During that time using a laboratory press Prof. Schönert found that interparticle comminution at high pressure requires remarkably less energy as conventional grinding technologies. In grinding of cement clinker he expected energy savings between 33 and 50 % compared to ball mills [1]. Piston presses are limited in throughput. Thus, the principle of interparticle comminution was adapted by the use of high pressure grinding rolls (HPGR) to a continuous plant process. Figure 1 shows the main components of a roller press: The roller nip of width s is formed between the floating roller (1) and the fixed roller (2). The diameter of the rolls will be denoted with D, the width with B. The total press force F can be adjusted using a hydraulic system with two or four pistons (3). In order to compare machines with different roll geometries the specific pressing force p is introduced:"

Jan 1, 2005

By Paul D. Merica

This year of 1926 marks the 40th. anniversary of nickel mining in Canada. Although the first nickel mine of the Sudbury basin was discovered in 1883, it was not until 1886 that the Canadian Copper Company was organized and actually began to mine copper-nickel ore from the Lady McDonald, Stobie and Evans mines. The intervening years have witnessed some exceedingly interesting nickel history, particularly interesting and gratifying as well to Canadians. Forty years ago, at the inception of Canadian nickel mining, the world's consumption of that metal was about 1000 tons per annum and this was supplied largely from New Caledonia ores refined in France. This nickel was used principally for the production of nickel-silver, coinage alloys, and for nickel-plating. No processes were then known for refining the Sudbury ores nor for the separation of copper from nickel. Consequently, the pioneers in Canadian nickel mining faced the double problem of finding a method of treating their ores, and of finding a market for the nickel when and if they could extract it.

Jan 1, 1926

By G. H. Charlewood, J. W. McBean

"One hundred years after being developed, the diamond drill is still an essential tool in mineral exploration. The basic principle is unchanged, but the technique has been revolutionized, particularly in the past fifteen years. The cost of core drilling has not kept pace with the rising cost of living. The price of machinery, supplies and labour in drilling has doubled and trebled since 1946. Some of the techniques which have made it possible to hold the price line are described."

Jan 1, 1967

By T. Bhambhani, D. R. Nagaraj

"Ultramafic Ni ores present significant challenges in processing in that both recoveries and grades are not satisfactory, due to the presence of Mg silicates in large amounts. Significant quantities of xanthates and CMCs are generally used for their recovery by flotation. Additionally, given that some of these ores are processed under acidic conditions, CS2 generation due to xanthate decomposition presents some safety hazards. Technology to replace xanthate has been developed for which the safety and health issues are absent. Collector S-10294 shows significant improvements in Ni and overall S recovery at a dosing rate of one half that of xanthate. New polymeric modifiers have also been developed that help reduce the Mg content of the concentrates at very low dosages. The reagents are custom designed for use in normal or hypersaline water, and acid or alkaline conditions.INTRODUCTION The use of xanthates in sulfide mineral flotation is reported to have started as early as 1925 (Nagaraj 2005). The reagent is now ubiquitous in the mining industry, accounting for 40-50% of total collector consumption. In recent years, the development of more selective reagents has rendered xanthates largely obsolete in Cu flotation. However, xanthates continue to be sold in large amounts in the Au, PGM and Ni flotation industry, where bulk sulfide flotation is required. The low cost and easy availability is the largest driver for the use of xanthates in the minerals industry. Of particular interest to this study is the use of xanthates in the flotation of Ni sulfide ores. About 60% of the world’s annual nickel output is obtained from sulfide Ni ores (Hoatson, 2006). A strategically important category of these ores is the ultramafic hosted sulfides, such as those of Western Australia and Canada. These ores are characterized by low Ni grades (<1%), with the Ni minerals being pentlandite, violarite, millerite and mackinawite, and gangue minerals comprising an array of altered Mg silicates, mostly serpentines. The challenges associated with treating these ores are well documented (Eltham et al. 1973; Claridge et al. 1975). One challenge is that Ni recoveries from these ores are lower. This has been attributed to the increased pulp viscosity, as discussed in detail by Vasudevan et al., 2010. Additionally, Mg silicates tend to report to the concentrate in large quantities, which is problematic for two reasons: a) concentrate dilution, and b) the high melting point of Mg silicates tends accelerate wear on the refractory lining of smelters. This has been attributed to network transport to the froth phase via bubble flux and entrainment (Patra et al, 2010)."

Jan 1, 2012

By Yaw Boadi, Andrew McCallum, Sandy Gray, Yavuz Atasoy, Peter Wemyss

"Various full-scale test programs and installations of the InLine Pressure Jig (IPJ) have provided evidence that pre-concentration of the difficult to leach sulphide mineral through gravity can provide significant increases in economic recoveries. The continuous gravity concentrates are intensively treated either by re-grinding or Intensive Cyanidation. Data from various mine sites worldwide is presented. Treatment of complex ore bodies with this low cost methodology may render previously uneconomic ore bodies financially viable and assist in the recovery profile of transitional ore.INTRODUCTIONThe use of gravity is made extremely attractive in complex ore situations due to the low cost of operation, typically a few cents per ton operating cost and lack of chemicals.Gold mines which suffer from poor recovery due to complex mineralogy such as Stibnite, Arsenic, Carbon, Telluride, Silver and other pacifying agents such as Iron, which can form coatings, can all benefit from the process proposed in this paper. The key issue is not overall recovery as much as one of economic recovery. The key to this is maximised recovery at the lowest possible capital and operating cost. Other options such as flotation are reviewed but are not seen in many instances to be the panacea due to issues discussed in the paper. The use of the InLine Pressure Jig in the re-circulating load of the milling circuit is a cost effective means of recovering a sulphide/gold concentrate containing the complex mineral assemblages which require re-grinding and intensive leaching for optimised gold recovery.The benefits of Jig Assisted Grinding (JAG) are many and the challenge over the past years has been developing, understanding, implementing and evaluating the benefits of various flowsheet models. This has involved the reconciliation of results in plant scale trials back to the original laboratory test program. The following paper outlines the insights gained in this area through extensive work carried out by many people across both laboratories and plant sites in Australia and overseas. The examples in this paper are some of the work carried out on a few selected sites but similar work has been carried out on other sites such as Penjom, Granny Smith and Agnew. This work has eventuated in several installations which we believe have great importance in the future of the gold processing industry. They will lead the way forward to the modern all-gravity plants of the future.Compared to flotation, for the recovery of sulphides, gravity is a simple option. The simplicity generally translates to low capital and operating cost."

Jan 1, 2004

By R. G. Hamm

A brief outline covering the shovels and draglines in use in the open-pit mines of Western Canada, including British Columbia, Alberta and the Yukon, is given, followed by the procedure for the selection of the correct wire rope for each application. Such fa ctors as wire rope constructions, lay directions and types of cores are mentioned. Once the correct wire rope has been selected, there are variousfactors that can affect the service fife ofthe rope and the reduction ofdown-time during rope change-overs. Factors such as hairpin winding, types of Becket loops, and shovel drum and bail adaptors are described.

Jan 1, 1979

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 Z. Xiao, A. R. Laplante

"The recovery of gold by gravity from grinding circuits differs from virtually all other gravity recovery approaches in that stage (or unit) recoveries are low, typically 1 to 5%, but overall recoveries are generally in the 25 to 60% range, because individual gold particles are presented many times to the primary recovery unit. Full-scale recovery is difficult to predict from benchscale tests. Further, maximizing metallurgical recovery is generally not the primary objective, because of the more efficient downstream recovery circuit (flotation or cyanidation). In this paper, a new concept, the gravity recovery effort, is presented to assist in the design and optimization of gold gravity circuits. It is defined as the product of the circulating load treated by the primary gravity unit, the recovery of this unit, and the gold room recovery. Predicted gold recovery is linked to the recovery effort, the size distribution of gravity recoverable gold (GRG), the dimensionless retention time in the mill and the partition curve of GRG. A case study of economic optimization of the gravity recovery effort is presented. INTRODUCTIONPredicting gold gravity recovery from grinding circuits has always been a hit-and-miss exercise. The problem can be traced to the highly variable gravity recoverable gold (GRG) content of ores, high GRG circulating load, fraction of the circulating load treated, and performance of primary gravity recovery and gold room. Typical values, highs and lows are shown in Table 1."

Jan 1, 2001

By Sylvain Létourneau

Help organizations maximize the benefits of the data that they collect ? perform scientific research in: machine learning, data mining, statistics, artificial intelligence, soft computing, information retrieval, information systems, and natural language processing ? preferred application areas: Equipment Health Management, Bioinformatics, Health, Web Mining ? today?s talk limited to Equipment Health Management While the aircraft is still in the air, IDS: ? clusters relevant WRN, FLR, and snag (pilot) messages ? identifies probable causes based on TSM and provide links to corresponding TSM pages ? assesses MEL conditions (GO, NOGO, GOIF, ?) ? displays relevant maintenance history, suggests fixes based on similar cases ? Commercialization with MxI Technologies Ltd and Air Canada in 2000

May 1, 2008

By Robert K. Jonas

"Minerals processors can improve production by using the best available control technology to control their operations. Many mines use expert systems that can provide improved results over manual or basic control, but better results can be achieved using multivariable predictive control. Over the past few years, the application of multivariable predictive control has gained acceptance in many mining processes and has recently proven to be suitable for some of the most challenging processes. This advanced control technology has been successfully applied to a wide variety of processes; alumina digestion, ball mills, CCD/thickeners, kilns/calciners/roasters, heat exchangers/evaporators, and more demanding processes like SAG mills and flash smelters.This paper discusses the needs of advance control technologies in the mining industry, including the impact of these technologies on best practices for implementation and long term sustainability. Results of the multivariable predictive control applications in mineral processing are discussed, and in particular the application to the SAG mill. In addition, an example of the benefits improvement that can be achieved with this technology is presented.INTRODUCTIONThere has been a long term perception in the mainstream mineral processing industry that best advanced control solution is an expert system. There a numerous instances of expert systems used for control of SAG mills, as well as kilns or roasters, thickeners and more recently flotation circuits. Many of theses expert systems have been installed by small, independent companies or by OEMs of processing equipment. Undoubtedly these expert systems have provided millions in benefits to the owners of mineral processing plants.It is this author’s proposition that it is a misconception to believe that expert systems are the best solution for mineral processors, and that in many cases the best solution is Multivariable Predictive Control (MPC). Better control and optimal operations can be achieved through the use of MPC. Another important consideration when considering advanced control technologies is the implementation and support effort. These types of applications have been known to deteriorate, even to disuse, when they are not kept up to date with changes to the process or equipment. The audience is invited to listen to discussion and draw their own opinion. The author has been involved in installing control systems for over 20 years, advanced solutions for over 15 years, and has had privilege to consult with many miners concerning the selection and application of advanced controls over the past 6 years."

Jan 1, 2008

By Erin Legault Seguin, Mike Rylatt, Curtis Mohns

"With energy costs increasing and ore grades diminishing, the role of pre-concentration in hard rock mining operations has been gaining greater interest. To maximize energy conservation, the pre-concentration process should be conducted at as coarse a crush size as possible while minimizing losses of pay metals. Dense medium separation (DMS) is a robust process that can be conducted at particle sizes as coarse as 300 mm and as fine as 500 µm with high separation efficiency, depending on liberation characteristics of the value minerals. The DMS process involves three steps: feed preparation, dense medium separation, and ferrous-based media recovery. This paper discusses each of these processing steps, but focus will be given to the dense medium separation stage. Various types of DMS equipment are reviewed. Pilot plant campaign case studies conducted at the SGS Lakefield site are presented, which have included a variety of mineral systems such as spodumene, sulphide-bearing gold ores, and complex sulphide ores. These case studies demonstrate that for amenable ores, mass rejection of 20-60% is possible while maintaining recoveries of greater than 90% in most cases.IntroductionPre-concentration is a process of rejecting mass of gangue while ensuring recovery of valuable minerals prior to more intensive, downstream processing. Pre-concentration has been practiced in industry for many years, and is gaining greater interest as the industry copes with processing lower grade, more difficult ores, typically requiring finer grind sizes and higher energy costs."

Jan 1, 2016

By Jacob Masliyah, Zhiang Zhou, Dharamdat Christendat, Tshitende Kasongo, Kevin Hyland, Zhenghe Xu, Ted Kizior, Douglas Cox

"A novel on-line visualization system, previously developed at Syncrude Canada Ltd., has been modified to characterize rising bubbles, particles and particle-bubble aggregates in a flotation process. With this system, the bubble size and rise velocity in a laboratory flotation cell can be determined. The technique allows the loading of solids on bubbles to be visualized, thereby providing an in-depth understanding of sub-processes of flotation. A step-by-step data processing procedure is presented. The applicability of the developed system to mineral flotation and bitumen extraction is discussed. Under batch flotation conditions in a laboratory Denver cell, three main bubble-particle attachment patterns are observed. They are: i) single particles attached to single bubbles, ii) particle aggregates loaded on single bubbles; and iii) a group of particles aggregated with a group of bubbles. The results demonstrate that the on-line visualization system is a powerful tool for understanding and diagnosing flotation processes.INTRODUCTIONAir (Gas) bubbles are an indispensable component in a flotation system. Both industrial practice and theoretical analysis indicate (Yoon, 1993; Diaz-penafiel and Dobby, 1994) that the size and population of bubbles are two important process parameters in modeling flotation. More recent investigations (Finch, et al., 1999; Gorain, et al., 1997) suggest that for a given flotation system, bubble surface area flux, defined as the air liquid interfacial area per unit time and unit cross-sectional area of flotation cell, showed a better correlation with the flotation rate constant. As a result, the bubble surface area flux is now being considered as a key parameter to account for the combined effect of bubble size and population in evaluating the performance of flotation machines and modeling flotation processes. However, the success of using bubble surface area flux in flotation process modeling largely depends on how accurate it can be determined or estimated (Finch, et al., 1999)."

Jan 1, 2000