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By MAX VOS

Lithium is the lightest and electrochemically most reactive of all metals. Renewed interest in lithium coincides with research in lithium batteries and power generation by atomic fusion. Ontario lithium resources are contained in spodumene pegmatites that can form where medium- to high-grade metamorphic volcanic-sedimentary formations are intruded by pegmatite and porphyritic granitic rocks. Spodumene pegmatites occur in at least twelve locales throughout northern Ontario, all of which are in the Superior Province of the Precambrian Shield. Tantalum, cesium, rubidium, beryllium, niobium and tin also were noted with lithium in spodumene pegmatites. Considerable potential remains for discovery of additional lithium and rare-element pegmatites in northern Ontario.

Jan 1, 1984

By J. A. Vezina

The effects of particle size distribution on metal extraction have been determined from pressure leaching Renzy Mines Limited concentrate with oxygen. Using a pulp density of 30 per cent solids, an oxygen pressure of 80 psig, a temperature of 230°F, a grind of 2.5 hours and a retention of 8 hours resulted in the almost complete dissolution of the nickel and the cobalt and the decomposition of over 96 per cent of the chalcopyrite finer than 20 microns. Only 11 per cent of the chalcopyrite coarser than 20 microns was reduced to smaller than 20 microns.

Jan 1, 1973

By E. S. Allen, P. R. Kruesi, J. L. Lake

An electrochemical process is described for converting concentrates of base-metal sulphides to the corresponding pure metals and elemental sulphur. The application of the process to chalcopyrite is discussed. The process is also of potential interest in processing copper-nickel sulphides, and laboratory data concerning this potential are presented. The process creates neither air nor water pollution.

Jan 1, 1973

By D. Sammut, F. Houllis, J-L. Huens, J. Moyes

The Intec Gold Process has been developed as a halide-based alternative for the recovery of gold from refractory sulphide deposits. The halide medium allows sulphide oxidation and gold extraction to be performed concurrently at moderate temperature and atmospheric pressure sourcing oxygen from direct air injection. The dissolved gold is loaded onto activated carbon and stripped in a conventional Zadra circuit. High gold extractions have been achieved from a range of refractory gold concentrates at laboratory scale, which has led to a continuous locked-cycle pilot plant program. The pilot plant operated at >99% availability, with a maximum of 96.5% gold extraction from a concentrate containing 58.6 g/t gold. >99% of the dissolved gold was loaded onto carbon at up to 1% w/w, with no loss of carbon activity detected over five loading/washing/elution cycles. This paper describes the process and presents both laboratory and pilot plant results as well as economic data from two costing studies.

Jan 1, 2005

By P. Roman, L. Daneshmend

"During the last decade, mining companies have been overwhelmed by technological solutions to perceived problems. This is particularly true with information technology where rapid advances have resulted in a professional climate characterized by technomania — the perception that failure to adopt emerging technologies will result in a loss of competitive advantage. This paper describes the applicability of structured analysis and design techniques as an appropriate methodology for integrating emerging technologies in the mining industry. The potential of this approach to improve overall mine effectiveness through improved communication and co-ordination between operations and maintenance is discussed. IntroductionA strong working relationship between the operations and maintenance departments in both open pit and underground mines is fundamental to the overall success of the mining endeavour. Unfortunately, for many mines, this characterization is far from accurate. Short-range production targets dominate the day-to-day management of the mines. This can be seen in Bostwick and Buchanan’s (1993) report on American Barrick Resources efforts to achieve an aggressive 415 000 tpd mining program at their Goldstrike operation in Nevada. When production managers do not meet their quotas, the finger is often pointed at maintenance. As a result, a confrontational culture can develop between the two organizations, resulting in a lack of cooperation that exacerbates the problem. Historically, production planning has taken priority over maintenance planning. This is reasonable since production is the primary purpose of the mine with maintenance serving in a support role. This basic relationship remains intact today. However, the trends toward mechanization, increasing levels of automation, and larger equipment, have resulted in increased reliance on the equipment used in the mine. As a result, downtime costs now go well beyond the direct labour associated with the repair of the machine. Lost production costs due to downtime resulting from failed equipment are becoming an increasingly important factor in determining a mine’s overall economic performance."

Jan 1, 2001

By B. Calver, D. J. M. Farnsworth

"As open-pit operations expanded at Pine Point, hydraulic aquifer evaluation was undertaken to establish the criteria necessary for the design of a feasible dewatering system.The extreme climate of this northern location dictated that the ore zone under extraction be rendered as dry as possible to minimize freezing effects. The design and implementation of such a system necessitated detailed hydraulic evaluation, and the problems that occurred are typical of those inherent in open-pit mining operations in northern areas.The paper describes the problem solution as approached from a mine engineering point of view, with particular reference to the practical aspects of operation and installation. The hydrological analysis used is simple and readily applicable to most open-pit dewatering problems."

Jan 1, 1969

By R. Vergunst, E. A. Devuyst, G. Robbins

"INTRODUCTIONThe Inca process for continuous cyanide removal from industrial wastewaters was patented in 1984 by G.J. Borbely, et.al. (1). The process requires SO2, air, lime and a copper catalyst. Both free and complexed cyanide are oxidized to cyanate in the pH range 8 to 10. Cyanide bound to iron is removed by precipitation as a ferrocyanide insoluble salt and other base metals are removed as hydroxides.The process was piloted in 1982 on barren bleed solution at Campbell Red Lake Mines Ltd., Ontario (2). Since 1982, the Inca SO2-air cyanide removal technology has been applied in twelve commercial installations. The process has significant advantages over other commercial processes in the completeness of cyanide removal and lower reagent requirements and costs.COMMERCIAL INSTALLATIONSBy the end of 1988 Inca will have applied its patented cyanide removal technology to twelve commercial operations. Three of these, namely Scottie Gold Mines, Dupont of Canada Expl. Baker mill and Carolin, all in British Columbia, Canada, have ceased cyanidation operations but SO2-air cyanide destruction results were good for all mills, particularly so for over two years for the Scottie mill.Removal of cyanide from CIL slurry tailings is applied at Equity Silver (9,500 tpd) and Inca's new 1,200 tpd mill at Inca/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3,600 tpd) and Canamax's Ketza River operation (360 tpd). Repulped tailings from Merril-Crowe flowsheets are treated at Total Erickson's Mount Skukum mill (300 tpd) and Skyline's Johnny Mountain mill (200 tpd) and barren bleed at Inco/Queenston's McBean mill (500 tpd). Lynngold's MacLellan mill (1,800 tpd) treats pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating in Kitchener, Ontario. Many of the above commercial operations were described in some detail in previous publications (3,4). Typical installations are described in this paper. A summary of operating results is given in Table 1."

Jan 1, 1989

By Q. Shi, Q. Feng

"The influence mechanism of chlorite on the flotation of pyrrhotite was investigated through flotation tests, Zeta potential measurements, optical microscope photos, solution ion measurements and absorption measurements. It is observed that, the addition of chlorite influences the flotation of pyrrhotite seriously. The IEP (isoelectric point) of pyrrhotite and chlorite is 7.6 and 4.3 respectively, in the condition of slight alkalinity, both pyrrhotite and chlorite are negatively charged, and the hetero-aggregation will not occur. With the existence of oxygen in solution, the iron ions are dissolved from pyrrhotite surface because of the oxidation of pyrrhotite during pulp conditioning. The dissolved iron ions adsorb onto the surface of chlorite in the forms of iron hydroxyl and iron hydroxide, and the adsorption results in the opposite charge of chlorite surface. As a result, the hetero-aggregation between pyrrhotite and chlorite occurs. The adsorption of chlorite changes the surface property of pyrrhotite and restricts the adsorption of amyl xanthate onto pyrrhotite surface, and then decreases the flotability of pyrrhotite.INTRODUCTIONIn sulfide ores processing, magnesium silicate bearing gangue minerals often report to the concentrate causing downstream processing problems as well as increased smelting costs. Talc,chlorite and serpentine are gangue minerals commonly encountered in complex sulfide ores (Engel, Middlebrook, & Jameson, 1997; Pietrobon et al., 1997; Witney & Yan, 1997; Chen, Grano, Sobieraj, & Ralston, 1999a, 1999b; Bremmell, Fornasiero & Ralston, 2005; Senior & Thomas, 2005; Wang, Somasundaran, & Nagaraj, 2005; WieseHarris & Bradshaw, 2007). All of them are characterized with uniform crystal structures consisting of silicon-oxygen tetrahedron and magnesium-oxygen octahedron. The magnesium-oxygen octahedron layers are broken during the liberation of serpentine to expose the magnesium-oxygen bonds with strong ionicity and hydration, which results in natural hydrophilicity of serpentine. In water, the hydroxyl on serpentine surface ruptures and dissolves into the aqueous phase while the Mg2+ remains, resulting in surface positive charge (Tao, 2012). As serpentine has a positive potential at alkaline condition, it is therefore likely that it will attach through electrostatic attraction to the negatively charged mineral surface and reduce both the flotation rate and recovery of target minerals (Lu et al., 2011). For talc, characterized as good natural hydrophobicity, the liberation comes from the interlaminar fracture to remain molecular bonds on surface with weak hydration. Being naturally hydrophobic, talc easily reports to flotation concentrates, thus reducing concentrate grade (Shortridge, Harris, Bradshaw, & Koopal, 2000; Beattie, Huynh, Kaggwa, & Ralston, 2006). Meanwhile, both molecular bonds and magnesium-oxygen bonds are exposed on chlorite surface when liberation occurs, resulting in moderate natural hydrophobicity between serpentine and talc (Tao, 2012). And thus the mechanisms of influence of chlorite on sulfide ores are more difficult to study."

Jan 1, 2016

By D. Runnels, Daniel Roy, Ricardo Esteban, J. Torrealba-Vargas

"An intuitive way to reduce power consumption in grinding operations is to feed the grinding circuit with finer feed by enhancing blasting and fragmentation control. The optimization of blasting with the objective of minimizing power consumption in grinding is not new.The study was based on a Canadian mine that processes a very hard ore. BBA conducted blasting/fragmentation and grinding circuit surveys in 2014. The results of the exercise were used to develop a base case model to simulate the effect of blasting in the operation on the grinding circuit. Tools for fragmentation simulations, particle size measurement and crushing/grinding simulations were used with the objective of reducing the OPEX costs including power consumption.The paper describes the steps involved in the model optimization as well as an economical evaluation of the OPEX savings.INTRODUCTIONIn 2014 BBA was retained by one of its clients to conduct a crushing and grinding survey. The objective of the survey was to update the grinding circuit model with production data and also to develop a tool to investigate opportunities for process improvement.A second phase of the study involved the development of drilling and blasting and crushing models. The models were used to diagnose the operations and to investigate opportunities for process improvement.The objective of the present study is to describe the approach and to identify potential improvements to overall mine site operating costs by better integrating mining and milling operating costs with blasting and grinding models."

Jan 1, 2016

By B. Chambers, M. Yunovich

"Corrosion monitoring is commonly used in a variety of industries as a means of effective corrosion control programs to extend the life of the asset and ensure safe operation of the facilities. The majority of the monitoring tools have limitations and tradeoffs – e.g., sacrificing the longevity of the probe for higher measurement resolution. Linear polarization resistance (LPR) probes have the advantage of providing the operator with accurate, real-time corrosion rate data; however, the probes can only be deployed in conditions where the measured environment possesses certain minimal conductivity. In many instances, utilization of LPR probes in conditions with intermittent wetting (for example, conditions where the temperature fluctuates above and below the dew point) presents a challenge. To address this limitation, a special-design cooled corrosion probe has been developed, commercialized and integrated into the distributed control system in the plants. In addition to high-accuracy measurement of corrosion rates, the probe allows for monitoring of pitting corrosion. The most innovative feature of the probe is the cooling circuit, which brings the temperature of the sensors below the dew point, forcing precipitation of moisture and thus permitting corrosion measurements. Additionally, the probe was found to be well-suited for monitoring corrosion in crude distillation unit (CDU) overhead space, where condensation of hydrochloric acid may take place at relatively high temperatures, which would require relatively moderate amount of cooling to be imparted to the probe sensors. This paper presents laboratory-based data from a test simulating CDU refinery environment. A case study is presented to demonstrate how the cooling probe can be effectively used in the plants for corrosion monitoring.INTRODUCTIONConventional corrosion-monitoring techniques such as weight-loss coupons to assess corrosion damage are commonly used in plants1. However, the use of coupons is not only labor-intensive, but also does not deliver real-time corrosion data, thus effectively serving as a “backwards-looking” monitoring tool. Linear polarization resistance (LPR) probes have the advantage of providing the operator with accurate, real-time corrosion rate data; however, the probes can only be deployed in conditions where the measured environment possesses certain minimal conductivity."

Jan 1, 2012

By E. Thune, F. Stålesen, E. O. Stensholt, O. M. Dotterud, E. E. Henriksen, P. O. Ramsdal

"The development and commercial operation of the Falconbridge chlorine leach process have been described in papers in 1985 and 1987. Since this time, various process improvements have been implemented and the capacity of the Kristiansand refinery has been increased to 85 000 t/y Ni, 40 0000 t/y Cu and 4500 t/y Co. The focus has been on continuous improvements in productivity, the use of energy and other costs. Several environmental issues have also been eliminated or reduced since 1987. IntroductionThe first nickel refining operation in Kristiansand, Norway, started in 1910 based upon raw materials from Norwegian mines. In 1929, Falconbridge Nickel mines purchased the refinery to acquire information and the patent rights to the Hybinette refining process that was practised at the small Kristiansand refinery. Falconbridge ownership has now, for more than 70 years, provided a strong base regarding raw material supply, financial resources and technical support for further expansions and major technical improvements at the refinery.The main concepts of the new chlorine leach process were developed in the laboratories from 1966 to 1969 and the process was piloted from 1970 to 1972. The main stages in the commercial plant were started in the 1975 to 1981 period. After 1981, there have been a number of process modifications, plant expansions and improvements to operating practices. The developments up to 1988 have been described in previous publications (Stensholt et al., 1986, 1988).This paper presents an overview of the process and how it is practised at Falconbridge Nikkelverk AS (FNA) today and describes some of the main changes that have been implemented since 1988. During this time, the nickel capacity has been expanded from 54 000 t/y to 85 000 t/y and the cobalt capacity from 2000 t/y to 4500 t/y. The paper describes how these expansions were achieved together with continuous improvements in operating efficiency and also gives an overview of the main environmental concerns at the refinery."

Jan 1, 2001

By Nicole Peter

When introducing digital training technology a practical approach helps address cultural concerns.  Solutions to help create acceptance are discussed.  Resistance to change may be deeply rooted in traditional mine training personnel.  Traditional training staff members may consider themselves less digitally-savvy and resist technological methods available to them. A transitional approach intended to help mitigate or resolve resistance is presented as a continuous improvement pathway toward full adoption.  This presentation contends every mine should welcome the benefit of a digitally connected critical enabler.  The adoption of a digitally savvy learning centre is often viewed a disrupter to existing practice.  Given a commitment-driven learning centre model, technology offers the opportunity to transition from a compliance-based training model to one of competence.  Learning and Development practitioners should welcome the latest advances in neuroscience, Bloom’s taxonomy of learning model, and principles which guide mine safety training as outlined by the Lowell Institute for Mineral Resources at the University of Arizona. By employing digital applications to include animation, game-based simulations and immersive Virtual Reality (VR) these technologies create a viable digitally-savvy learning centre. We will outline the ingredients of a digitally enabled, or VR, Learning Centre to offer some observed benefits, successes, and potential short-comings. Much excitement in the industry surrounds implementation of simulation and/or VR headset training.  Given fair consideration of these as a ‘fit-for-purpose’ solution we examine the paradigm shift required to create real results for on-the-job learning.  Interim steps may be needed to meet the cultural transformation.   Simpler forms of VR, in the form of 3D models and VR environments as displayed on a large interactive touch screen, can serve to bridge this challenge and address a group learning environment. Features of the interactive 3D technology and ease of adoption are presented.  Usage of the touch screen is similar to that of a smart phone. It may be implemented as an obvious transitional tool.  To help describe merits of the interactive touch screen the presentation points out these sample underground and surface mine training applications. There are 3-D simulations such as ventilation, emergency response, support installation, and mine cycle and activity scheduling programs. These applications offer the ability to conduct entry examinations, complete digital pre-use checklists, and perform planned task observations in the virtual world of work. The tool may be used to teach the flow of hydraulics and do fault-finding on machinery such as loaders and dump trucks. Learners may navigate in a virtual mining environment to identify hazards, detect and assess abnormal ground conditions, address poor design features, and alleviate traffic constraints. It is possible to use connected physical controls to navigate machinery in the virtual environment. We conclude the presentation with a “compare and contrast” approach to cite potential cultural benefits by adopting a transitional method. 

May 4, 2025

By J. B. Brodie, C. Pelletier

"The vulnerability of Canadian and U.S. companies, their directors, officers and employees to onerous penalties associated with violations of environmental statutes and common law actions has provided the impetus for the increasing use of environmental audits. This trend is developing in direct proponion to the cost and difficulty of obtaining liability insurance. Companies operating in British Columbia should be cognizant of developing legislative and enforcement trends and their implications for individual and corporate responsibility. Canadian mining companies doing business in the U.S. should be particularly aware of the environmental exposure which may be assumed with property acquisition or by operations which produce or use any of an ever-increasing list of regulated substances.The environmental audit is now a key component of prudent business planning which will identify noncompliances and environmental liabilities, outline defensive strategies, and assist in a legal defence should charges be laid. This paper will discuss the purpose and mechanics of an environmental audit with emphasis on those features which will maximize protection against statutory and common law actions.IntroductionThe environmental audit is but one weapon in a comprehensive defensive strategy for corporate and individual survival in an increasingly litigious world. The principles of the environmental audit have been formulated as a logical response by management to an ever-growing list of environmental vulnerabilities, which often have the potential to result in plant shutdowns, prosecutions or fmancial liability of major proportions. Accordingly, the audit may play a critical role in maintaining profitability as well as assisting in the defence of a company and its employees against actions taken by regulatory agencies and citi7.cns under statute and common law. Should convictions result from these actions, the penalties are likely to be ameliorated by the demonstration of due diligence through management policy supporting the audit procedure.An awareness of environmental sensitivities, strict adherence to licensing requirements, and planning for environmental emergencies are now generally considered to be as important to profitable performance as operating costs, metal prices, and labour peace. Why is this so? The increased priority given to environmental matters is partly a result of changing attitudes amongst the mining profession, but perhaps more importantly, it is also a direct consequence of the proliferation of ever more stringent environmental legislation, the targeting of management for responsibility and the draconian penalties imposed for violations of such legislation. Contributing to this trend are recent court decisions involving disputes of an environmental nature in which the standard of care required for a successful defence now requires almost super-human diligence in environmental management. The principle of ""strict liability"" (in which negligence or permit violation does not have to be shown) is also being increasingly applied in the resolution of civil actions."

Jan 1, 1988

By A. Singh

"Flotation of fine (< 10 µm) minerals is a challenge exacerbated by the emerging practice of fine grinding flotation feed to better liberate targeted minerals; however, the ability of conventional flotation cells to float liberated fines remains questionable. The Gold Ore solution using Mach reactors was tested at Mintek, South Africa, and showed an ~180% increase in the Kelsall kfast factor, a projected recovery improvement of 4% for the Mach-reactor case, and final concentrate grade twice that of conventional flotation. Theory, pilot plant results, and key aspects of plant design, supplemented by operational plant observations after commissioning, are discussed.RÉSUMÉ Le procédé de flottation de minerais fins (< 10 µm) pose de grandes difficultés, lesquelles sont aggravées par la pratique émergente de l’alimentation du circuit de flottation avec des mailles de broyage très fines pour mieux libérer les minéraux ciblés ; la capacité des cellules de flottation classiques à flotter les fines de minerais libérées reste cependant discutable. La solution proposée par la société Gold Ore, qui utilise des réacteurs Mach, a été testée à Mintek, en Afrique du Sud ; elle affichait une augmentation d’environ 180 % du facteur kfast développé par M. Kelsall dans son modèle de flottation, une amélioration prévue de la récupération de 4 % dans le cas du réacteur Mach, et une teneur finale des concentrés deux fois plus importante que celle obtenue avec la flottation classique. Sont débattus dans cet article la théorie, les résultats générés par l’usine pilote ainsi que les principaux aspects de la conception de l’usine complétés par des observations relatives à l’usine en activité après sa mise en service."

Jan 1, 2018

By J. Dubinski

Passive tomographic imaging is a technique that can be used for assessing seismic hazard in mines with high seismic activity induced by mining. The basic idea behind such an interpretation is the assumption that there is a relationship between high values of seismic velocity and high values of stresses in the rock mass. This relationship was confirmed both in laboratory an in situ measurements and constitutes the basis for rock-burst and seismic hazard evaluation. In the paper seismic tomographic images of seismic P wave velocity and seismic P wave velocity gradient have been presented to determine rock-burst hazard and locate high seismic activity zones in the area of coal panel 306 in Zabrze Bielszowice mine. The zones of high values of P-wave seismic velocity gradient have been found to correlate with the distribution of high energetic seismic events. Passive tomographic images were obtained using modern bent ray tracing tomography algorithm with regularization. Recent study give rise to observation that not only high values of P-wave seismic velocity is important in seismic hazard assessment as many strong seismic events are located in the areas of high values of velocity gradient. This recent observation permits to increase quality of passive tomographic imaging for detection of seismogenic zones and is presented in the paper. The advantage of passive tomography comparing to active tomography is that sources of seismic waves are generated by rock mass itself and costly controlled explosions are not necessary. Another practical limitation of active tomography is the size of study area which usually do not exceed 200 m by 200 m. This restriction does not appear in passive tomography where area of study is usually 2000 m by 2000 m and the tomographic images delineate velocity structure in locations where mining induced seismicity take place. Passive tomography method utilized in analysis of rock mass state in underground mines encounter some difficulties concerned with the numerical stability of optimization algorithms. In the presented approach to passive tomography problem numerical stability is obtained by special regularization method and by application of very stable numerical seismic ray-tracing algorithm.

Aug 1, 2013

By M. M. Helm

Samples sourced from the Goldstrike property in Nevada USA, have been evaluated in terms of their preg-robbing capacity and the physical structure of the graphitic carbon component in the carbonaceous gold ore. The study highlights a wide range in preg-robbing capacity between samples collected from the Betze-Post open pit and Rodeo underground mine. The physical structure of the graphitic carbon was assessed using Raman spectroscopy, and is found to play an important role in influencing preg-robbing behaviour. Differences observed in the physical structure of graphitic carbon are thought to be the result of hydrothermal events that occurred at Goldstrike.

Jan 1, 2011

By John L. Mero

"The ocean has served humanity as a source of raw materials for thousands of years, but only on a minimal scale relative to its potential. Exploration programs have shown the ocean to contain a large number of mineral deposits of great extent and attractive grade. Recent research has indicated that a number of these deposits can be economically exploited with present-day technology and that the cost of winning many industrially important minerals from the oceanic deposits is potentially much less than that of winning similar minerals from land deposits. Although the finding of mineral deposits in the sea is a relatively simple matter at the present time, the exploitation of many of these deposits has lagged due to the lack of the availability of specific mining techniques for the individual deposits. Within the past two years, however, several developments have taken place in the design and testing of ocean mining systems in depths of water as great as 12,000 feet which indicate that the problem of mining in the ocean may soon be solved.Within the next decade, the ocean should prove to be a major source of many minerals for society and should come to dominate as a source of such metals as copper, nickel, cobalt, manganese, etc. Within a few years of the initiation of the mining of the deep-sea metalliferous nodules, land sources of such metals as nickel, cobalt, copper, manganese, etc. will be seriously affected and it is conceivable that the present structure of the world mining industry will undergo a substantial change in character."

Jan 1, 1972

By C. Klinkenberg, G. Zhu, K. Hulka, S. V. Subramanian

A quantitative model based on strain accumulation in multi-pass rolling is developed to overcome a large critical strain for dynamic recrystallisation in a Nb microalloyed steel with high Mn content (HTP steel). The larger the critical strain for dynamic recrystallisation, the finer is the dynamically recrystallised grain size. The initial mill trial showed that it is feasible to achieve ultra-fine grain size by dynamic recrystallisation but the prevention of static recrystallisation in between passes is identified as an essential condition to suppress mixed grain size. The data-base on static softening kinetics at short interpass time was experimentally determined on WUMSI and incorporated in the model. The model is used to optimise the strip rolling schedule to prevent static recrystallisation in the interpass time. The rolling simulation of strip rolling schedule has validated the model prediction that it is possible to obtain a uniform ultra-fine ferrite grain size of about 1-2 micrometer diameter in final ferrite microstructure for industrial rolling parameters. A user friendly software package has been developed to apply the model for off-line control of mill processing parameters, i.e., time-temperature-deformation schedule of finish rolling in order to accumulate large strain to overcome a large critical strain for dynamic recrystallisation. The model is a powerful predictive tool for grain size control in multi-pass rolling.

Jan 1, 2004

By R. K. Jonas

"Pressure leaching and pressure oxidation in autoclaves are important alternatives in the extractive processing of gold, copper and nickel ores. The application of advanced control to pressure leach and pressure oxidation autoclaves could achieve significant benefits as has been shown in alumina pressure leaching. This paper compares and contrasts alumina digestion autoclaves to other mining autoclaves with respect to advanced controls. The application of advanced control in alumina with over 30 units controlled worldwide, and its benefits will be reviewed. The design and potential benefits from advanced control for pressure oxidation and leaching will be presented.INTRODUCTIONIt is this author's position and the purpose of this paper to propose that advanced control could be effectively applied to autoclaves in the nickel, gold, and copper mining processes. This is based on the proven effectiveness of advanced control on autoclaves used in the alumina industry for pressure leaching of bauxite ores. Incremental, but significant increases in production could be realized by applying advanced control to autoclaves, as evidenced by the alumina industry, and this not being implemented in other autoclaves in the mining industry.In addition, today the mining industry is being challenged to improve their production methods. In some markets like nickel, there is pressure to improve productivity and reduce the cash cost per ton. While in other markets like copper and gold, demand is vigorous with favourable pricing, and there are advantages to increase production and productivity given limited plant capacity. Advanced control has proven its capability to improve mineral processing operations through increases in throughput, recovery, as well as reducing variability. In today's mines, autoclaves are being used to a much larger scale and with much larger importance, thus it would be beneficial to improve operational performance through the use of advanced control.Accordingly, it is the author supposition that an opportunity exists in the mining industry to use a proven advanced control technology to improve the operations and financial performance of mines using autoclaves."

Jan 1, 2012

By J R. Barber, B. E. Rogers, R. Fukuzawa

Mercury is sometimes present in non-ferrous ores including gold, zinc, copper and lead. The selection and use of appropriate mercury abatement technology is critical for preventing its release to the environment during ore processing and to protect workers from mercury exposure. This paper presents a general decision-making process for mercury abatement technology selection for major emission sources in the gold industry. Mercury abatement can be accomplished through making process changes and/or by adding a process step to an existing system (i.e. "end-of-pipe control"). Advantages and limitations of the technologies along with waste / by-product management options are discussed through case studies of current operating mercury abatement systems.

Jan 1, 2015