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By Tuan V. Nguyen, Louis Mittoni, Murray Rudman, CSIRO Minerals, Jean D. Swift, John B. Farrow, Phillip D. Fawell

"Research projects towards developing a sound understanding of the factors controlling the performance of gravity thickeners have been conducted by the AJ Parker Cooperative Research Centre for Hydrometallurgy since 1988 through AMIRA International. The current phase of this work, the three year P266D “Improving Thickener Technology” project, has 27 sponsors comprising mineral processing companies, reagent suppliers and thickener manufacturers.These projects have resulted in the development of a range of tools and techniques to address flocculation, thickening and associated dewatering issues. A number of Computational Fluid Dynamics (CFD) models have been developed to predict likely full-scale thickener performance under various process conditions, based upon a knowledge of thickener design, plant flows and assessment of the flocculation behaviour of the feed slurry. At the same time, various laboratory and plant studies have been used to quantify important thickener processes, and to provide validation of the CFD models. These numerical and experimental capabilities have been applied to various thickener issues across a broad range of mineral processing operations, leading to significant process improvements and substantial financial benefits.This paper presents an overview of the work conducted during these projects, focussing on the research tools, the nature of the information that has been gained and the implications for thickener performance."

Jan 1, 2003

By S. M. Javad Koleini

Processing of phosphate ore sample was investigated for increasing phosphate content and reduction of its gangue minerals such as carbonates and silicates. Experimental designs were per-formed using Taguchi method. Different flotation methods were investigated for Moundon phosphate ore sample and three methods were used as follow: direct cellophane flotation, reverse calcite flotation and reverse quartz flotation. Because of the sensitivity of cellophane flotation to slime content, prior desliming was carried out before the experiments. Direct flotation experiments carried out and a concentrate contained 23.80% P2O5, 6.88% SiO2 and 72.33% recovery were produced. The achieved P2O5 content in the produced concentrate from reverse flotation of calcite was 26.44% and the recovery was 82.56%. The concentrate products obtained at optimum conditions by direct flotation of phosphate and indirect flotation of calcite were subjected to indirect flotation of calcite and direct flotation of appetite and final concentrates with P2O5 grade of the order of 24.19% and 26.96% were obtained, respectively. It was concluded that one stage direct flotation is unavoidable to achieve a product with low SiO2 content.

Jan 1, 2014

By Jannie van Deventer

"Innovation in the minerals industry has been lagging behind comparable industries like oil and gas. An incremental innovation culture that tolerates long lead times between invention and adoption has been exacerbated by a research grant structure that inhibits radical idea generation. Entrepreneurs who can make the link between ore source, technology and finance will cause a shift in innovation culture and open up substantial opportunities in the minerals industry of the future. By extrapolating existing trends in technology within and outside mineral processing, a crystal ball vision of future innovation is shaped with the aim to lower energy and water demand, reduce CO2 emissions, decrease operating and capital costs, reduce environmental impact, and secure a social licence to operate. Advances in nanotechnology, advanced materials and biotechnology will impact mineral processing, but the initiative for technology transfer must come from mineral processors. Laminates of graphene oxide can offer efficient filtration and separation media, while microfluidic devices will be used for desalination, solvent extraction and analysis. Substantial progress is expected on benign lixiviants and separation agents, such as nanoscale supramolecular hosts that can serve as high-capacity, selective and recyclable ligands and sorbents, and solid aminobiphosphonate-based adsorbents. Radical ideas for the recovery of precious metals from non-assayable ores and the generation of energy above unity will be adopted in selected minerals projects. In-situ mining in which microbes generate lixiviants at mineral surfaces will simplify processing circuits. Specific ores will be subjected to microwave processing and electropulse liberation to enhance recovery. Ultrafine grinding using devices of low energy consumption will be done mainly dry, followed by dry separation. New flotation cells will remove efficiently either coarse particles or ultra-fine particles, with mineral surfaces being modified not just by new reagents but also by selective microbes. Innovation in mineral processing indeed has a bright future."

Jan 1, 2014

By J. Y. Liu

The comminution in a high-pressure roller mill is modeled by an energy-based population balance approach considering three aspects of breakage taking place in the active zones of the mill: the interparticle breakage in the high-compression zone, the breakage at the edges of the rolls, and the pre-breakage in the acceleration zone. Together with an appropriate model of classification, this model can be used to simulate steady-state performance of closed-circuit grindings with high-pressure roller mill. After a brief description of the basic modeling approach, the algorithm of the steady-state calculation for a generalized grinding-classification circuit is presented, from which the circuit configurations commonly met in industrial practice can be derived. With an iron ore as feed material for example, simulation results are shown and discussed in respect of circulating load, specific energy consumption and product fineness for closed-circuit grindings under various operating conditions. The effects of stressing intensity, working gap, classifier parameters as well as circuit configuration on the overall circuit performance are investigated systematically by means of computer simulation.

Jan 1, 2014

By David Verrelli, Melissa Kistner, Leanne Smith, Chris Aldrich, Lidia Auret, Warren Bruckard

In this investigation, different mixtures of realgar and orpiment particles were floated in a laboratory batch flotation cell and multivariate image analysis was used to estimate the arsenic content in the froths. The analysis was based on the froth colour, as well as extraction of three groups of textural features, namely those based on grey level co-occurrence matrices (GLCMs), wavelets and local binary patterns (LBPs). Collectively, these features provided better information on the arsenic content of the froths than any one of the individual groups of features. Partial least squares models could explain approximately 78% of the variance in the arsenic by using all the features combined. The colour content, particularly the green component in the red-green-blue (RGB) features, provided almost as much information as each of the three sets of texture-base features individually.

Jan 1, 2014

By C. A. C. Sequeira, G. N. Anastassakis

Electrochemical processes occur on nano-, micro- and macro- scale in numerous applications such as fuel cells, batteries, hydrogen production, mineral extraction, water treatment, electrotherapy, sensors and many others. In most of these applications, gases evolve either at one or both electrodes due to electrolysis. These gases form bubbles play a crucial role in electrochemical systems. For example, in electrowinning (EW) that is used to extract and refine metals such as Cu, Zn, Ni, Mn, and Cd from their solutions, in most cases the solution is acidic and oxidation of water molecules at the anode is the common counter reaction, which results in the liberation of oxygen bubbles. This generally requires a high overpotential and accounts for a considerable percentage of the energy consumed in metal EW electrolytic cells, apart from producing acid mist that is very corrosive for other cell equipment and building structures. The behaviour of bubbles in electrochemical systems is still a complex challenging topic which requires a better understanding of gas bubbles hydrodynamics and their interactions with electrode surface and bulk liquid, as well as between the bubbles themselves. The objective of the current paper is to briefly review the fundamental hydrodynamics of both gas bubbles on the electrode surface and gas bubbles interaction with the liquid bulk solution. The current work also investigates the impact of gas bubbling and some operating parameters in copper EW, such as current density (100-500 A/m2), temperature (25-75ºC), acidity (50-300 g/L) and a typical chemical mist suppressant (<50 ppm). The results clearly show that both suppressant and temperature reduced the overall surface tension of the solution. Also, chloride concentration and applied current improved electrolyte flow and copper quality at higher current densities. The current paper contributes to the development of mineral processing (specifically to copper hydrometallurgy), as it deals with fundamental hydrodynamics and interactions of gas bubbles that formed during copper EW and play a crucial role in copper electrochemical systems.

Jan 1, 2018

By C. Carrasco

"Over the last 30 years the average grade of mined ore bodies has significantly decreased while the proportion of waste removal has in many cases more than doubled. This has been identified as prime reason of a major increase in energy consumption and decrease in productivity across mining operation. Metal coarse preconcentration of ROM feed grades by size rejects low grade gangue/waste material in the size range of 10-100 mm prior to grinding, typically before primary crushing. This relies on propensity of metal to preferentially deport in the fine size fractions after breakage. Metal preconcentration by size has the potential to increase energy efficiency and therefore improve mining productivity on unit of metal basis. Results of an extensive belt cut sampling campaign conducted at a major Australian Au-Cu mine operation show that for some samples between 90% of Au and 80% of Cu is in 40% of the mass at -50 mm fraction. This indicates that low grade coarse material can be removed from the circuit, doubling feed grade at half of the tonnage and therefore improve energy efficiency per unit metal produced. This response, however presents significant variability in the same order as other processing attributes such as impact hardness and flotation recovery. This has led to development of geometallurgical laboratory tests using blast hole chips and drill core facilitating mapping and population of coarse metal preconcentration signatures in long term resources and short term production models. Preferential Cu deportment by size at drilling scale can be recognised, however scales up factors are required to transform laboratory results to production responses. At 50 % of mass the drilling products underestimate the belt cut responses by 20-30 %. Bulk sampling campaign with blast hole and drill core samples spatially related was also conducted to investigate in more detail the difference between production scale and drilling scale preconcentration responses."

Jan 1, 2014

By Lev Filippov, Vyacheslav Severov, Inna Filippova

"Reverse cationic flotation is a very efficient method of beneficiation of oxidized iron ores when you need to separate hematite and quartz. This method can be also applied to reduce silica content in the magnetite concentrates obtained by wet low-intensity magnetic separation. However, cationic flotation in this case is less effective due to the presence of Fe-Mg-Al-bearing silicates as amphiboles in magnetite ores. These silicates are concentrated in magnetic products and determine the difficulties of their separation from iron oxides when amines and starches are used as collectors and depressants, respectively. The recalculation of the results of the electron microprobe analysis of three calcic Fe-Mg-Al-bearing amphiboles used to characterize cation distributions in structural units and to obtain structural formulas in accord with stoichiometric limits was conducted. The Mössbauer spectroscopy was used to examine the validity of the empirical estimation of cation distributions in amphiboles. The studied samples are metamorphic pargasite and ferrotschermakite and volcanic magnesiohornblende. The crystallographic analyses of the amphibole samples exhibited their heterogeneous surfaces explaining worse floatability of amphiboles with dodecylamine at pH 10. The electrokinetic measurements showed that the position of the isoelectric point of amphiboles is related to a substitution of Al3+ for Si4+ in tetrahedral sites and to an amount of Mg2+ cations in octahedral sites. Thus, the dodecylamine adsorption onto amphiboles through electrostatic interactions is mainly affected by a distribution of these cations in tetrahedral and octahedral sites of amphiboles. In addition, the effect of starch on the depression of Fe-Mg-Al-bearing amphiboles during flotation can be attributed to the presence of metal ions on the amphibole surface, which are capable of forming strong chemical complexes with starch molecules."

Jan 1, 2014

By U. M. J. Boin, W. L. Dalmijn, T. P. R. de Jong

"This paper explores the complex interrelationship between the resource cycle, recycling and metal production as a function of economics, environmental legislation, and product design. It is argued that central to optimising this resource cycle lies the control in particular of physical separation plants by the application of advanced sensor technology and sorting equipment, as well as suitable control and sampling algorithms supported by optimising mass balance models.Metals are produced through a long chain of processes. For primary resources, metals production goes through mining, mineral processing, ore smelting, conversion and refining steps or via low temperature hydrometallurgical processes, or a combination of both pyro- and hydrometallurgical operations. For the recycling of resources, metals are separated and recovered from metal scrap, which plays an increasingly important role in the world. Metals after being produced, either from primary or recycling resources, have to be further refined or manufactured into various types of alloys and finally shaped into different products for the end-users. Since the end-user discards products the contained materials find their way back into the resource cycle as scrap. Therefore, controlling the metallurgical reactors also controls, in a much broader sense, the material quality in the complete metals cycle, from the production phase, to the end-use phase, up to the recycling phase (Reuter et al., 2003). The recycling phase includes separation of materials into saleable intermediate products, which are reintroduced into the production phase as a recycling resource. Therefore, the metallurgical processes in each unit operation in the metals production and processing chain have to be controlled, so as to achieve optimal performance of high product quality, low energy and materials consumption, and low environmental impact."

Jan 1, 2003

By S. Saha

Minerals in coals cause operational problems in various coal utilization technology as well as act as diluents towards its heat value. Indian coals contain higher percentage of mineral matter compared to foreign coals due to its formation through drift origin. Efficient utilization of high ash coal in environment friendly manner is the driving force for the development of clean coal technology. Coal gasification offers practical means meeting stringent environment controlled parameters for producing power, chemicals, liquid fuels and clean energy on a single platform. It is well accepted that gasification technology has sufficient potential for sustainable development of clean coal technology. Gasification reactivity depends on the coal properties and operational parameters as well as minerals present in coal. Minerals not only create operational problems but on the other side also catalyze the gasification and combustion reaction. Therefore to understand the effect of minerals on the gasification reactivity, present paper proposes to study the variation of gasification reactivity with various gravity cuts such as, 1.4-1.5; 1.6-1.7; and 1.8-1.9 of a selected coal. Gasification reactivity has been studied by thermo gravimetric analyzer (TGA) using CO2 as gasifying agent. Surface properties such as, true density, apparent density, porosity, surface area of different gravity cut samples have also been measured to find out the effect of gravity separation on gasification reactivity. Keywords: gasification, reactivity, mineral matter, gravity separation

Sep 1, 2012

By Olgac Kangal, Ali Guney, Gulay Bulut, Guven Onal, Ayhan A. Sirkeci

This paper presents the results of pilot scale column flotation applications in the two different copper concentrators in Turkey. The Kure Copper Plant is located in the Black Sea Region of Turkey. In Kure, a very fine grinding requirement for an adequate level of liberation makes a successful flotation difficult and consequently the final concentrate can hardly assay above 16% Cu Column flotation tests were conducted at the plant site using two different column types The experiments proved that the grade of the concentrate could be increased from about 14% Cu to 25-26% Cu. Murgul Cakmakkaya Copper Concentrator is the largest copper concentrator in Turkey. Although concentrate production capacity is around 170,000 tons annually with 22-23% Cu content, this figure tends to be much lower than that. In Murgul a Turbo Column of Multotec Company of South Africa was employed. As a result of systematic column flotation tests, the grade of the concentrate was increased from 20.3% Cu to 28.7% Cu.

Jan 1, 2003

By Gautam Chandra Mondal

An attempt has been made to carry out qualitative assessment of mine water discharges from the different mines of West Bokaro Coalfields of Hazaribag district of Jharkhand, India. A total of 33 mine water samples were analyzed for pH, electrical conductivity (EC), major cations (Ca, Mg, Na, K), major anions (HCO3, SO4, Cl, NO3), and heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, Ni, Co, As). The hydrochemical data has been evaluated in terms of major ion chemistry, solute acquisition processes and suitability of mine water for domestic, industrial and irrigation uses. The pH of the analyzed mine waters varies from 5.27?8.43 indicating acidic to alkaline nature of the water. The electrical conductivity (EC) values varied from 276 µScm-1 to 1598 µScm-1 for measured samples and spatial differences between the EC values reflects the wide variation in lithology, surface activities and hydrological regime prevailing in the region. The anion chemistry of the analyzed water samples shows the dominance of SO4 and HCO3 with a minor contribution from Cl, NO3 and F. The observed high values of sulphate in the mine water of the area may be attributed to the oxidative weathering of pyrites. On average chloride is contributing 5% of the total anionic balance (TZ-). Fluoride and nitrate have low concentrations and on average contributing <2% the total anions. The cation chemistry indicates that 79% of the samples are Ca>Mg>Na>K, while the 6% belong to Ca>Na>Mg>K and 1% of Ca>Mg>K>Na. Weathering of rock forming minerals and cation exchange processes normally control the levels of these cations. Concentrations of some heavy metals (Fe, Mn, Ni, Cr) are found to be well above the prescribed permissible levels recommended for the drinking water. The water quality assessment for drinking purposes indicates that most of the mine water having high TDS, total hardness (TH) and sulphate concentrations. This suggests that mine water of the study area is not suitable for direct use in drinking and domestic purposes and needs a proper treatment before its utilization. The assessment of water for irrigation uses show that the water is good to permissible quality and can be used for irrigation uses. However, high values of salinity, %Na, SAR, RSC and Mg-hazard at certain sites restrict its suitability for agriculture uses. Keywords: mine water; ion chemistry; quality assessment; West Bokaro coalfields

Sep 1, 2012

By Diana Drinkwater

As ore grades decline, ore deposits get harder and mineralogical complexity increases, metallurgical skills are more important than ever to ensure that today?s mining operations are operating efficiently and profitably. Yet specialist undergraduate degree programs have all but disappeared and metallurgical skills training for graduate engineers in the workspace if often haphazard. In response to this situation, specialists at the JK Centre in Queensland, Australia, have put together a professional development program designed to fast-track skills development for early career metallurgical professionals. The program, called ?MetSkill ® ?, is offered as a group training package for young metallurgists in the workplace. It is centred on a meaningful technical investigation negotiated between the JK Centre delivery team and the client company. As well as learning about project management and data collection and analysis, the participants study specialist topics such as comminution, flotation and mineralogy under the tutelage of senior research and consulting professionals. The technical investigation provides an opportunity for immediate practice of these new skills and JK Centre specialists are on hand to provide feedback and support throughout the program. The participants are employed across different operations in Australia and the Asia-Pacific, and although they occasionally come together for group training activities they are often separated by considerable distance. Specialist educational professionals from The University of Queensland have provided an innovative web platform to support collaboration and communication between all participants. This paper will describe the MetSkill ® program in detail, as well as providing a report on its initial roll-out to 2 groups of Australian graduate metallurgists in 2012

Sep 1, 2012

There is a strong demand for nickel metal due to quick development of stainless steel and new electrical materials, most of which is extracted from sulfide resources, resulting in a serious depletion of sulfide resources. Therefore, more attentions have been paying to extracting nickel from nickel laterite, which accounts for some 50% of total nickel metal production. In this paper prereducing?magnetic separation?reduction smelting process is developed to manufacture ferronickel rom two types of nickel laterite DN and GN, assaying 1.42% 1.83% Ni and 49.09% 26.08%Fetotal, respectively. Mineralogy of two types of nickel laterite was determined and optimization of process parameters was conducted to manufacture ferronickel. Prereduction?magnetic concentration process is used to upgrade low grade nickel laterite firstly, two kinds of Ni-Fe concentrates being prepared of DN assaying 2.26% Ni and 69.45% Fetotal and GN containing 2.76% Ni and 38.00% Fetotal. Finally, two types of ferronickel were produced by reduction smelting of prereduced concentrates DN and GN, DN and GN ferronickel contains 2.97% Ni and 6.58%Ni, 89.25%Fetotal and 89.95%Fetotal, respectively. The total recoveries of Ni and Fe of the two ferronickel are beyond 90% and 80%, respectively. There is significant difference in grade of magnetic concentrates and ferronickel between DN and GN laterite due to their different mineralogy, the former belongs to limonitic laterite and the latter saponite one. There are some advantages for this process to manufacture ferronickel from nickel laterite, including effectively upgrading low grade nickel laterite by prereducing?magnetic separation technique, higher throughput and lower energy available for reduction smelting section due to some 40% gangue being rejected in pre-upgrading section, and much less metallurgical coke consumption by using non-coking coal as reductant for prereducing?magnetic separation?smelting process.

Jan 1, 2014

By A. P. Chaves, D. Jose Neto, M. G. Bergerman, E. S. Mano

"More complex ore comminution and concentration operations have found increasing application in the mining industry due to lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. They allow removing a significant mass of material with little or no content of the relevant mineral before the ore is fed into the processing plant, with the consequent reduction in the mass to be processed in downstream operations. Significant benefits arise out of the use of pre-concentration, such as higher contained metal output without the need to increase the grinding or flotation capacity, and longer mine life. The grade of marginal ores could be enhanced to a level that would make their exploration economically feasible, which would result in increasing exploitable reserves. Nevertheless, few studies to date have assessed the resulting impacts on ore grinding energy consumption and wear after the gangue is removed through pre-concentration operations. This study evaluated the energy consumption and wear of grinding circuits in Brazilian mining operations in which the feed has gone through a pre-concentration stage. Such assessment was based on different samples of sulfide and oxide ores. Laboratory tests were carried out to investigate the power consumption and wear of grinding circuits with and without a pre-concentration stage. Laboratory test results were used to simulate industrial grinding circuits based on both alternatives and illustrate the environmental and economic benefits of each one.INTRODUCTION Increasingly complex ore concentration operations in several stages have found broadening application in recent years in view of lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. Different ore processing technologies can be used for that purpose, such as magnetic separation, density segregation, and separation methods based on high-tech sensors (ore sorting). Currently, the most common methods are gravimetric processes, in view of their low cost, particularly jigging and dense medium separation methods, such as the drum and cone separators manufactured by Western Machinery Company, Teska, Drewboy, Norwalt, Dynawhirlpool and Tri-flo, and dense medium cyclones (CAMPOS; LUZ; BRAGA, 2010). The use of dry ore sorters has also grown significantly in recent years (Jose Neto et al. 2017). The selection of the separator type depends essentially on the ore particle size, required flows, and operating density ranges. All these methods may even be used after preferential blasting in mining (Grigg & Delemontex, 2015)."

Jan 1, 2018

By C. G. Anderson

Industrially proven and applied nitrogen species catalyzed (i.e. NSC) acidic pressure leaching has been utilized to treat a number of ores, concentrates and recycled materials. This versatile technology offers many advantages including low temperatures, low pressures, low capital costs, low operating costs, faster throughput and less costly materials of construction than conventional pressure oxidation. This paper will elucidate the application of this technology for production of gold, silver, palladium, rhodium, zinc, germanium, gallium, cobalt, copper, molybdenum, rhenium and nickel. Recycled material applications will also be elucidated. In addition, details of an application for treatment of a refractory chalcopyrite copper and gold bearing ore will be presented and pertinent economics discussed.

Jan 1, 2014

By J. E. Gebhardt, D. McBride, T. N. Croft, M. Cross

"Heap leaching is well-established as a relatively low-cost and low-energy method of extracting metals from low grade ores. However, the design methodology, attention to the engineering details during heap construction and the long time scale in metal recovery makes the process susceptible to significant variation in the success of a heap leach operation. Often the laboratory predicted recovery rates are not achieved on site due to poor understanding of the complex physics of flow and coupled solid-liquid-thermal reactions within the multi-dimensional heterogeneous ore body. Given the large scale of commercial operations, small changes in metal recovery can substantially change the operating profitability. While there are a variety of approaches to heap leach modeling, computational fluid dynamics (CFD) modeling coupled with leach kinetic models offers a methodology to describe and understand the complexities of heap leaching. The CFD model uses leach kinetics specific for the mineralogy of the ore, including gangue chemistry, and provides an energy balance to calculate and predict temperature. Coupled with the CFD model’s inherent capability for modeling complex fluid flow, the physics and the chemistry of the heap can be simulated. This provides a tool for engineering design, as well as forecasting heap production under different scenarios. The calibrated model is used to simulate a three-dimensional test heap under fluctuating meteorological data, such as precipitation events, periodic solution application, and notably temperature. These simulations provide support for a methodology to design and engineer heap leaching of low grade copper sulfide ore. INTRODUCTION Worldwide copper ore reserves are faced with decreasing head grades with copper sulfides, particularly chalcopyrite being the predominant mineralogy (Nesse, 2000). Heap leaching offers an economical way to recover copper from low grade ore. The ore is stacked and a leach solution is applied and allowed to trickle though the porous bed of ore to extract target metals. The heap can be built with run of mine material or crushed ore and is constructed in order to achieve percolation of the leach solution to all regions. Bartlett (1998) provides an authoritative overview of the solution mining process where the leach solution interacts with the solid, the lixiviant dissolves the target minerals from the solid into the solution, and the dissolved species are transported out of the heap for subsequent recovery. Petersen (2016) provides a recent review of heap leach technology and emerging and potential future applications, and Ghorbani et al. (2016) summarizes the current state and challenges of the technology. Early applications of heap leaching offered a low cost technique to achieve high recoveries from oxide ores, typically greater than 70% depending upon the kinetics of reaction. As world copper resources transition to mainly copper sulfide mineralogy, such as chalcopyrite based ores, achieving high recovery from these copper sulfide deposits is proving more difficult due to the complexity of the leach kinetics, which leads to low leaching efficiency."

Jan 1, 2018

By Grant C. Lukey, Jannie S. J. van Deventer

"The environmental effects of the mining and mineral industry include destruction of natural habitats, changes in river regimes and water tables, and other serious ecological impacts. In this century, it is likely that water will become a critical resource, and in most countries the mining industry competes for a share of this resource. The Kyoto Protocol may at first seem only relevant to the coal mining and power industry, however, it should not be forgotten that the mining and mineral industry is a significant consumer of power. Therefore the ratification of the Kyoto Protocol by most developed countries and the introduction of a carbon credit trading scheme will impact on the industry by potentially increased costs in utilities and waste discharges. It is clear therefore that the mining industry faces many challenges in the coming years. The mining industry?s commitment to sustainable development needs to continue to evolve, in order to meet these challenges effectively. With the advent of globalisation of the industry, it is now an opportune time for the industry to gain international agreement on how they want the industry to achieve sustainability in future years; such a progressive approach is necessary, otherwise government will force the industry to change, which may not necessarily be the best outcome for the industry.INTRODUCTIONThe Earth Summit in Rio de Janeiro in 1992 was an opportunity for world leaders to assemble and discuss strategies and initiatives that provide for further industrial growth without adverse effects on the environment. The World Summit on Sustainable Development held last year in Johannesburg, South Africa, was an opportunity to evaluate those initiatives implemented over the past 10 years, and to set a new and sustainable direction for the future. It is clear that industrial and technology development will continue at a rapid pace in order to serve the needs of a growing world population, but it is essential that the course of this development is well planned, well executed, and that it is sustainable. In reality, while government officials and politicians continue to debate policy and international protocols, the environment continues to suffer and the effects of climate change and global-warming become more real each day."

Jan 1, 2003

By T. Badrujaman

In September 2005, after 30 years experiencing in operating an ESF using a falling water film shell cooling system, Antam entered the new era in operating an ESF, after completely modernized its ESF No. 2 from a falling water film shell cooling system to a copper cooling system. Further, in the beginning of 2007, Ferronickel plant No. 3, where its ESF also uses copper coolers, was successfully commissioned. By operating an ESF using a copper cooling technology, Antam has to face some challenges to establish the operation stability. Besides that, the chances to maximize the furnace efficiency are greatly opened. The shielded-arc mode of electrode tip is selected to operate an ESF under relatively high furnace power to produce metal having tap temperature below 1500? and slag having tap temperature below 1600?. It leads to electric current unbalance. Further, operating an ESF using a copper cooler system under high voltage as consequence of the furnace power raise increases metal and slag tap temperature. This condition damages furnace integrity fast. Besides that, relatively high metal temperature increases its pressure during metal tapping. It leads to failure in closing the metal tap hole. The main different ways in operating an ESF using a falling water film shell cooling system and a copper cooling system lie in the electrode tip mode, the water specification used for cooler, metal tap block maintenance and allowed metal & slag level in furnace. Since a copper cooler system allows an ESF to be operated by consuming nickel ore having ratio Fe / Ni up to eight and producing slag having relatively high Fe content in slag, an undesirable silicon reversion phenomenon becomes an obstacle in reaching the operation stability. A copper cooler technology lets Antam to take a chance to increase its capacity. Modernizing the ESF No.2 had increased its furnace power from 17 MWh to 25 MWh. Meanwhile the ESF No. 3 can be operated up to 42 MWh. This technology allows an ESF to be operated under relatively high furnace power above 25 MWh safely as well as prolong the campaign life of ESF brick. Further, lowering ESF power consumption, extending the limitation of ratio S/M in nickel ore consumed and adjusting Ni grade in ferronickel product can be gained by applying this technology.

Jan 1, 2014

By G. Y. Liu

The structure-activity relationships for four thionocarbamate collectors are discussed in this pa-per. These collector classes are alkyl alkyl thionocarbamates, allyl alkyl thionocarbamates, acyl al-kyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates. The main emphasis will be to highlight the differences between collectors and their affinities for copper and iron sulfide minerals on the basis of data on electronic-structure properties obtained by vacuum and solution density functional calculations, flotation experiments and analysis measurements. The mechanism of interaction of these collectors with sulfide minerals is also discussed with perturbation theory. The theoretical study results indicate that acyl alkyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates have best performance in these agents as flotation collectors with improved collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals, which are consistent with the experimental data reported in the literature.

Jan 1, 2014