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By R. Sage, N. Rillette, M. D. Everell, G. Herget

"CANMET has been operating as a Government Technology Centre for two years. Many of CANMET's programs involve long-term research and require special expertise, often available at Canadian universities. CANMET's involvement with universities ranges from research grants and contracts to exchanges of scientists and joint use of research facililies. Examples of CANMET - university cooperation in mining are presented. IntroductionIn the last two years or so CANMET has undergone a significant metamorphosis, resulting in greater emphasis on applied research to enhance Canada's industrial capability. CANMET's new mandate is reflected in the types of projects undertaken and their categorization, (Fig . I). Emphasis is being placed on two project categories: strategic R&D, to enable CANMET to serve the changing technological needs of the industry; and incrernental R&D, to serve the more immediate industry needs through modifications to existing technologies and knowledge. The balance of CANMET's e ffor t is devoted to providing Mandated and Specialized Services, and to Exploratory Research.CANMET interaction with universities can involve one of several available vehicles : contracts, research grants, exchanges of scientists , student employment and nomination of professors on CANMET's advisory council. Instances of key university technical support to CANMET mining projects are highlighted."

Jan 1, 1990

By H. Ikeman

"The highly specialized communication systems used in the mining industry place exacting demands on equipment and transmission media. Safely and reliability of services are perhaps the two most important factors. Fibre optics is ideally suited 10 meet these stringent requirements. Aside from being an intrinsically safe, non-sparking and EMI/RFI immune medium , fibre optics offers greater reliability , higher quality of services and superior flexibility over conventional copper or radio-based communication systems.This paper wilt show how fibre optics can be applied in mining industry applications. Emerging trends and concepts will be presented to show how fibre-optic-based integrated service communication networks and local distribution systems can be implemented.IntroductionCommunication requirements in today's mine s are varied and extensive. The communication system must be rugged , safe and reliable, yet provide an ever increasing amount of high quality services. Presently, these systems are implemented using conventional copper cable. As mining method s and technology advance and the demand for better and more communication services increases, traditional systems quickly reach their limitations. It is under these circumstances that we turn to fibre optic communication systems.Fibre optics is a mature technology which is finding its way into more and more applications worldwide. A fibre optic communication system can provide a level of performance unattainable by conventional cable systems yet ca n be cost competitive. As is well known, fibre optics provides a noise-free, noise-immune, high -capacity communications channel. Glass fibre, being dielectric and non-sparking, is an intrinsically safe communications medium. Clearly, it is ideally suited to the harsh environment present in a mine.From a communication systems point-of-view, the topology of a deep mine is unique. The objective of the systems engineer is to implement a total communications capability throughout this wide spread area. Ideally all classes of services should be accessible throughout the network-an integrated network concept. Recent advances in communications technology combined with fibre optics make this realizable."

Jan 1, 1984

By Darrell McClarty, Roger Payne, Matt Haggis, Michael Courtin, Deborah Berthelot

"Over forty years of uranium mining in the Elliot Lake region of Ontario (I 956-1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity, Rio Algom Limited and Denison Mines Limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and thereby significantly inhibit acid generation have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program. All five of Rio Algom Limited' s effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on ""Fix Dmacs"" technology. Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.IntroductionCost-effective management of multiple tailings management areas distributed throughout a 35 km watershed requires the application of leading-edge environmental technologies. Long-term monitoring, care and maintenance costs must first be minimized through the application of decommissioning technologies that inhibit acid generation and minimize the release of contaminants from the sites. On-going operating costs must then be controlled through the application of environmental management strategies that optimize the allocation of resources while ensuring compliance with regulatory and Company environmental requirements.Using sites in the Serpent River Watershed as an example, this paper demonstrates the effectiveness of water covers as a decommissioning strategy to inhibit acid generation. In addition, the Telemetered Environmental Operating Control System and Regional Environmental Information Management System are reviewed as examples of the application of environmental technologies to the management of environmental programs."

Jan 1, 1998

By W. A. Crosby, W. K. Smith, K. L. McDonald

"IntroductionThis paper describes how the introduction of two blasting techniques and the resuItant development of new dragline digging methods have increased the productivity of single- and double-seam dragline operations at the Rietspruit opencast mine.LocationRietspruit , one of South Africa's largest opencast strip mines, is situated some 11 5 kilometres east of Johannesburg in the Witbank coal field.BusinessRietspruit is a joint venture between Transvaal Consolidate d Land and Exploration Company (T.C.L.) and Shell, South Africa. Rietspruit is administered and managed by Rand Mines, the Mining division of Barlow Rand, transportation and marketing being the responsibility of Shell. The total saleable coal product, approximately 5,5 million tons per annum, is exported via Richards Bay.Presplitting and Throw BlastingPresplitting was initially introduced in September 1980, as a means of dewatering t he overburden and mid burden to facilitate the use of dry-mix explosives a s opposed to slurry explosives.The utilization of the throw blasting technique arose as a direct result of observed ground movement after the successful introduction of presplitting. The first trials commenced in March 1981 on the double-seam operation. The methods, economics and resulting advantages are fully described elsewhere. A brief description follows.Method of PresplittingAfter determining the desired presplit line, 250-mm holes are drilled to top of coal at 4-m to 6-m intervals, dependent on the competency of the rock overlying the coal. A single 60-kg charge of slurry explosives is located at the bottom of each hole, no tamping is used and all the holes are detonated simultaneously. The results are a competent, straight, vertical highwall. This enables accurate control of the first row of blast holes closest to the highwall, which is a prime requisite for successful throw blasting."

Jan 1, 1983

By W. J. D. Stone

"INTRODUCTION Over the past decade, a number of publications have described the advances in High Intensity Wet Magnetic Separation. A number of significant, but small capacity installations were made and are successfully operating. These were followed some three years ago by larger installations treating ilmenite gravity concentrates; at least one machine treating 25 tons per hour of new feed was installed and is successfully operating.However, this still did not result in general acceptance that High Intensity Wet Magnetic Separation could be applied on a large scale. Neither did it dispel the feeling that High Intensity Wet Magnetic Separation was ""expensive"" and hence, confined to small scale – high value applications suchas the cleaning of tin concentrates. In addition, there is the usual reluctance of being the ""guinea pig"" which has resulted in waiting to see ""someone else"" make the first large installation decision. Such a decision and installation has now been made.Therefore, the purpose of this paper is to show that High Intensity Wet Magnetic Separation has been commercially accepted on a large scale and to show its general application to the base metal mineral industry.Examples are confined to a few specifics due to the large volume of preliminary test data that is available. The art has now reached the stage where much of the preliminary work should be taken through to serious evaluation."

Jan 1, 1971

By Andrew Thrift

Overview ? Problem ? Research question ? Literature review ? Methodology ? Results ? Discussion and recommendations ? New developments Problem ? Increasingly higher expectations ? Inadequate consultation leads to conflict rather than collaboration ? Consultation practice is often weak on decision-making ? Influence of consultation on planning is Unclear Research question ? Are Structured Decision Processes (based on decision analysis) an effective methodology for involving stakeholders in consultative decisionmaking in the mining industry?

May 1, 2006

By Charlie Graham

Our Approach ? Industry Trends ? New Forces at Work in Mining ? Deep Mining ? Energy projects ? Air power ? Hydraulics ? Electric alternatives ? Drilling ? Productivity ? Conclusions ? Transportation ? References

Oct 1, 2010

By René G. del Villar, Jules Thibault, René del Villar

"Some key control variables of industrial processes, associated with product quality, often cannot be measured directly or frequently enough to establish adequate control. In such cases, it is possible to use available measurements to provide a prediction for these process variables and use them in a control strategy, thereby giving rise to what is now commonly called a softsensor.In some industrial grinding circuits, the on-line particle size analyzer is shared between various sampling points. Therefore, for a given location, the actual measurement is only available every 10 to 20 minutes, a delay which is unacceptable for automatic control purposes. To alleviate this problem, a softsensor based on an artificial neural network has been investigated. First, the structure of the neural network and different schemes for the training process are analyzed. Then, the performance of the neural network softsensor is compared with other inferential methods such as ARMA models and Kalman filters.IntroductionGRAHM, French acronym of the Research Group on Computer Applications in the Mineral Industry at Laval University, began in 1990 a research project on Knowledge Based Automatic Control (KBAC). This project, sponsored by a consortium of eight mining companies and the federal and provincial governments, seeked to screen advanced (knowledge-based) methods for data processing (filtering, mass balancing, etc) and automatic control (model-based) for their use in the mineral processing operations and the transfer of the project results to the sponsor companies.In parallel to more academic research work, a number of case-studies have been undertaken with the cooperation of partner companies. Among such works, a very successful one has been the design and installation of a new control strategy for one of the Kidd Creek (Falconbridge Ltd.) grinding circuits. This project was related to the evaluation of a number of control strategies and the implementation of one of them, as selected by the plant management, in the concentrator.A total of sixteen control schemes were evaluated on one of the dynamic phenomenological simulators developed at GRAHM, a trademark of this research group [ l]. The calibration of the simulator models was done based on industrial data gathered by GRAHM and Kidd Creek personnel. Then, the simulator was used to test the performance of various PID-based control schemes, designed to achieve the control objectives set by the Kidd Creek personnel. The best scheme proposed called for controlling the cyclone overflow particle size by manipulating the water addition rate to the cyclone feed box and the circulating load by manipulating the circuit ore feed. The particle size analyzer (PSI-200) available for monitoring the product size, was unfortunately shared (multiplexed) among various streams of the plant, which meant a 14 min delay between two consecutive readings for any particular stream. This induced the plant personnel to choose an alternative control strategy, one which controlled the cyclone feed density instead of the cyclone overflow particle size."

Jan 1, 1996

By A. R. Laplante

"In this paper, the performance of the Knelson Concentrator and of the batch and continuous Falcon Concentrators are compared. The units are based on different operating principles, and as such they perform quite differently. The Knelson yields very high free gold recoveries over a wide size range of both the recovered and rejected species. It is ineffective in recovering very fine ( <15 µm) or flaky gold, as encountered in flotation feeds, concentrates or tails. It is the: preferred unit for gold recovery from grinding circuits. The batch Falcon is effective in the fine range, typically less than 37 µm for gold. Its recovery zone is quickly saturated when there is significant heavies in the feed. It works best as a pre-concentration unit. The continuous Falcon is a versatile unit which is capable of recovering fine heavies (density down to 5 g/cm3 ), especially from coarser gangue. INTRODUCTIONThe purpose of this presentation is to describe the mode of operation of two Canadian centrifugal concentrators, the Knelson and Falcon. It is hoped that it will prove informative to prospective users in the selection, testing and optimization for applications of either machine. The work is based on testwork both in Canadian mills and at McGill. I am indebted to many colleagues at these locations. Appropriate references will be made to articles further describing the work, either already in the open literature or in preparation.Although this work is meant to be more practical than scholarly, it is appropriate to begin by considering how the two units achieve selective recovery. This will become useful in establishing a suitable testing methodology, which will then be described, and interpreting typical results. In the last section I will attempt to define appropriate applications for the two units. This is a thankless task, as I am likely to miss some applications or to make projections based on partial results, as much of the work is still in progress. In deference to the reader and both manufacturers, areas where reasonable doubt still remains will be identified."

Jan 1, 1993

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003

By D. Shishin

Continuous integrated experimental and thermodynamic modelling work is conducted in Pyrometallurgy Innovation Center (PYROSEARCH). The target is to develop a tool, which is capable to predict the compositions of phases, phase equilibria and enthalpy balance for pyrometallugical processes with higher accuracy. All these can be achieved by thermodynamic calculations based on Gibbs energy minimization algorithm. Recent developments made it possible to predict important factors, such as the chemical solubility of Cu in slag as a function of matte grade, temperature, P(SO2), Fe/SiO2 ratio in slag, wt% Al2O3, CaO and MgO in slag. In industrial practice, it is not only chemical solubility, but the overall amount of slag, which affects the recovery of copper and other valuable metals. It will also impact the energy balance. The presence of solids in the slag matrix influences the physical entrainment of matte in slag. Oxygen enrichment which is sometimes used to control the temperature of the furnace, may also affect the volatilization of minor elements into the gas phase. Same is true if additional fuel is used to compensate for heat balance. In other words, all key process parameters mentioned above are interrelated. Present study demonstrates the ways thermodynamic modelling can be used to link those process parameters on the example of copper smelting. INTRODUCTION Research methodology involving integrated thermodynamic modelling and experimental approach has been recently reported by the authors (Shishin, Hayes, & Jak, 2018 Shishin, Hidayat, Jak, Decterov, & Belov, 2016). Present paper reviews the updates and discusses challenges in the development of a large self- consistent thermodynamic database. The database covers the Al-Ca-Cu-Fe-Mg-O-Pb-S-Si-Zn-(Ag, As, Au, Bi, Ni, Sb, Sn) chemical system. The database works in the environment of FactSage software Bale et al., 2016 and related family of products: ChemApp (Petersen & Hack, 2007), ChemSheet and SimuSage. A list of phases, and thermodynamic models is shown in Table 1. For the copper industry, most important phases are Gas, Slag, Spinel and Liquid matte/metal/speiss. Black-colored elements represent the base system, elements in green can be considered as slag modifiers (slagging elements), and elements in red are minor. Ni is highlighted because it was included recently, in 2019, and currently under development. In addition to copper, the database covers the conditions typical for lead and zinc pyrometallurgical extraction. It is developed in consistency with the experimental results for high concentrations of Pb and Zn. Examples of applications in the present study include the thermodynamic analysis of fluxing for an agitated copper reactor to show the effect of Fe/SiO2, and calculations of copper slag cleaning using reductant.

Jan 1, 2019

By Robin Perry, Claude Bazin

"Discrete transfer functions which use the grinding circuit feed tonnage to predict mass flowrates at reagent addition points in a flotation circuit were calibrated using a dynamic grinding/flotation circuit simulator. Predicted mass flow values are multiplied by reagent addition ratios to obtain actual reagent flow. The transfer functions are currently integrated into the distributed control system of Les Mines Selbaie.IntroductionThe development of adequate tools for the control of flotation processes is a continuous challenge. Since the early 1970s there have been numerous publications dealing with practical aspect of control of flotation processes. Most plants use a combination of feedback and feedforward controls to reduce the effect of the following flotation process disturbances (McKee, 1991):• changes in throughput;• changes in feed grade;• changes in particle floatability (size, liberation, surface oxidation ... ); and • deliberate changes of setpoint;Feedforward control manipulates variables such as reagent and/or air flow rate to attenuate the effect of disturbances such as changes of feed rate and mineral content. The feed forward strategy is driven by measurements of these disturbances. Feedback control is used to maintain process variables to targeted set-points of concentrate or tails grades. The feedback control action is driven by deviation from the set-point, caused by a deliberate change of set-point or disturbances.This paper proposes a method to improve feed forward control schemes by the addition of a simple model for solids transportation. The feedforward strategy considered in this paper is the ratio type, in which the manipulated variable is changed according to a predefmed ratio between this variable and the measured disturbance. A typical example is the ratio of the reagent addition to mass flow of ore.The paper reviews the state of the art in feed forward control strategy applied to flotation processes and describes the method used for predicting mass flow rates. The last section shows an application of the method in the Les Mines Selbaie flotation circuit."

Jan 1, 1994

By David W. Mogk, Tamara Darsow, Macgregor L. Fogelsong, Robert M. Hunter, Frank M. Stewart, Edwin H. Abbott, Courtney A. Young

Abstract: Development of cost-effective techniques for recovering precious metals from their ores has been the goal of metallurgists for hundreds of years. Today, metallurgists are increasingly called upon to design processes for ores that are refractory to conventional recovery techniques. These challenges and the addition of environmental costs (including site remediation) to the total cost of mining have stimulated a search for alternatives to conventional processes, such as cyanidation. This paper describes the progress made to date in development of an innovative alternative to cyanidation, termed bisulfide leaching, for extracting gold, silver and platinum-group elements from refractory ores and concentrates. While bisulfide leaching can be implemented abiotically, significant benefits accrue from its practice as a bioprocess that integrates the steps of precious-metals liberation and extraction. In many applications, bisulfide leaching appears to offer significant advantages over the traditional cyanidation process. Dissolved bisulfide and hydrogen sulfide are much less toxic than dissolved cyanide and hydrogen cyanide. Recommended workspace exposure limits and harmful concentrations for hydrogen sulfide gas are higher than those for hydrogen cyanide gas. While the facilities required to practice the bioprocess on an industrial scale would be similar to that of cyanidation plants, chemical reagent costs could be 80 percent less. The bioprocess may also offer advantages in the leaching of ores and concentrates that are not amenable to cyanidation. For example, bisulfide leaching of ores containing carbonaceous material may produce higher gold recoveries if the "preg-robbing" characteristic of the material can be controlled biologically or with dissolved sulfide binding. Moreover, in that precious metals are much more soluble than base metals in bisulfide solutions, bisulfide leaching offers distinct advantages over cyanidation for selective dissolution of precious metals from base-metal concentrates. Thus, the bioprocess uses the natural sulfur cycle to mitigate pollutant production and to enhance precious-metals recovery.

Jan 1, 1998

?Introduction to the Delphi Group ?Why is carbon important to your organization ?Key elements of a carbon management strategy ?Inventory ?Risk & opportunity scan ?Mitigation options and financial mechanisms ?Identify targets and develop policy ?Communication and improvement ?Manage for success

May 1, 2009

By T. S. Wanne

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

May 1, 2009

By M. Leijd, K. S. Forrester, M. Saxon, M. Oczlon

This paper provides an introduction to wet high intensity magnetic separation (WHIMS) and its successful application to the beneficiation of rare earth element (REE) enriched eudialyte. The analysis includes an in-depth reporting of the deportment of key elements as well as a statistical interpretation of the relative importance of operational parameters including magnetic field intensity, flow velocity, and matrix loading density. Conclusions are drawn on the relative success of the technology, potential areas for process improvement, and the research direction that continues to be investigated. Three original equipment manufacturer (OEM) technologies were subjected to a series of screening and characterization tests to identify the optimal operating parameter set to magnetically beneficiate eudialyte from Norra Kärr, Sweden. Upon the completion of the characterization test it was apparent that the Metso HGMS technology was superior with respect to REE recovery and gangue rejection for the Norra Kärr composite. The Metso HGMS was then subjected to a series of verification tests to confirm the repeatability and reproducibility of the system.

Jan 1, 2014

By G Anders

The effectiveness of two types of powder used in long-wall slashing was compared. The evaluation of the results can serve as a good example of how the application of statistical methods to underground test data can help to minimize the number of tests to be carried out. The conclusions are stated concisely, including a definite assessment of the reliability of the tests. Introduction AN assignment at the Algom Nordic mine called for a performance comparison between 70 per cent Cilgel B and 75 per cent Dygel in longwall stope slashing, particularly taking into account, in both cases, the build-up of bootlegs as dependent on hole deviation. Stopes were usually 8 to 10 ft. high and inclined at about 17 degrees. Starting from a raise, they were widened by consecutive longwall slashes to 60 ft., and, al-lowing for drift pillars, were approximately 300 ft. in length along the incline.

Jan 1, 1964

By T. Negeri, M. Boisclair, A. Bouajila

CanmetMINING has been working on process development for separation and concentration of rare earth bearing minerals from various ores. Among others, the flowsheet development for the Montviel Rare Earths/Nb deposit, located at the north end of the Abitibi region in Quebec and owned by GeoMegA Resources Inc. (GeoMegA) is now at an advanced stage. The concentrate produced by a flotation-only process at the early stage of the project accounted for higher than 90% TREO and Nb recovery in 40% mass. This concentrate was submitted to SGS Lakefield for hydrometallurgical processing. Lixiviation of the concentrate using hydrochloric acid yielded approximately 99 % REE. An overall (from ore in ground to final precipitate) REE recovery of 80% was obtained through a series of selective precipitation steps. Recently significant additional developments have been made. CanmetMINING is steadily improving the quality of concentrate produced through a simplified, more efficient flowsheet which consists of flotation, magnetic separation, and a thermal treatment procedure. The paper discusses aspects of the process that allowed obtaining 82% recovery of TREO and Nb in 16% of mass, the best result to-date.

Jan 1, 2014

By Gordon Thompson

"Development of the unique Mine Games exhibition at Science World British Columbia is the largest ever collaboration of many interests to present the story of mining and the issues of mineral development delivered to the public by a science education centre.IntroductionMineral education programs have long been a major focus of the British Columbia mining community. Mine Games and its tremendous potential to enhance industries image and the public&apos;s awareness of mining is unequalled in the field of Issue Based Education Exhibits.The main goal of the exhibition is to look at the future of resource industries in a rapidly changing world of economic activities, new technologies, and growing public concern for the environment. Three challenges were the aim of the exhibition: to increase participation, to serve as a tool to increase interest in science and technology, and to draw an increasing number of school students to the interests of geology and the earth sciences. Mine Games is to serve as a meeting place for discussion of issues and where reliable information can be shared and new ideas explored.The exhibition is designed to develop new approaches to hands on learning that encourages visitors to explore and generate discussion and thinking with respect to resource development activities.The role of author, beginning in 1993, was, with senior industry leaders, to coordinate the raising of $1.3 million to complete the funding of the $1.6 million project total. The second and most interesting challenge was to work with the many minds that were collaborating to create the exhibition and to assure that the facts and science were correct. This involved the coordination of ""expert groups"" that verified the science and technology and the issues that the creative design team at Science World planned to use in development of each exhibit module."

Jan 1, 1995

By G. A. Gillett, C. F. Bonney

"The Davy McKee combined mixer-settler (CMS), is a liquid-liquid contactor, which has been commercially applied to the recovery of uranium from dilute sulphuric acid-bearing leach liquors. CMS differs from most other solvent extraction systems in that the mixing and separation of the phases is carried out in the same vessel.IntroductionTypical solvent extraction plants for the recovery of uranium operate at organic to aqueous feed flow ratios of 1 : 2 to 1 : 30. Because it is beneficial to mix the organic and aqueous phases at an organic/aqueous (O / A) ratio of between I : 2 and 2 : I there is incompatibility between the over-all and operating O /A ratios.Conventional mixer-settler designs require an external recycle of the minority flow which results in the possibility of over-mixing, increased settling requirements and entrainment losses. Other workers have approached this problem in terms o f enhanced sett ling and this has been partly successful.Davy McKee&apos;s approach involved a radical rethink of the principles of liquid-liquid contact and separation.Description of CMSThe CMS has the important advance that the required mixing O/A ratio can be achieved without external recycle and is not affected by the O /A ratio of the feeds. Three zones co-exist within the CMS unit-a central mixing zone and upper and lower separation zones. A pump impeller on a draught tube is installed within the mixing zone and baffles are installed above and below the mixing zone. Conventional mixer- settlers have several undesirable features which ca n largely be eliminated using the CMS system:"

Jan 1, 1983