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By R. E. Phillips, L. A. Cramer, R. T. Jones

Atomaer (Pty) Ltd is a technology-driven company with interests in Western Australian nickel. Atomaer (RSA) Pty Ltd is a process technology company operating in Southern Africa. It is a subsidiary of Atomaer Holdings Pty Limited (Atomaer), which has operating companies in Australia, Africa, South America, and Europe. In addition, Atomaer has substantial shareholdings in Braemore Resources Plc, a nickel company with interests in sulphide nickel projects in Western Australia and Southern Africa listed on the Alternative Investment Market of London Stock Exchange (AIM); Mintails Limited, a gold company with interests in gold operations in South Africa listed on the Australia Stock Exchange; and Brinkley Mining Plc, a uranium company with interests in Southern Africa listed on the AIM. Independence Platinum Limited (IPt) has been formed by Atomaer to undertake the commercial development and exploitation of Mintek's ConRoast technology with the strategic objective of providing independent smelting and refining facilities with lower capital and operating costs for the treatment and processing of platinum concentrates, including those with high chrome and/or nickel and/or low platinum group metal values, for the development of platinum projects by junior resource companies in South Africa. The platinum mines of South Africa have traditionally exploited the Merensky Reef of the Bushveld Complex for platinum production. However, the mining of this reef is reaching depths that require significant vertical shaft systems and costly refrigeration for access to the ore bodies at deeper levels. In the past decade, all of the platinum producers have begun to mine the UG2 reef because of its cheaper mining costs. UG2 ore usually has lower platinum group metal contents and higher chrome values. The new junior resource companies have gained access primarily to UG2 reefs. Consequently, platinum mining is becoming more UG2-based and the resulting concentrates contain high levels of chromitite. UG2 concentrates are difficult to smelt in the current six-in-line submerged arc furnaces, and this leads to increased capital and operating costs for those smelting operations. The platinum mines of South Africa produce the majority of the world's platinum metal used in automotive catalysts and jewellery. As the platinum market is forecast to grow at a healthy rate into the future, the SA producers Anglo Platinum, Impala, Lonmin, and Northam are planning to expand mining operations in the next decade. Furthermore, a number of smaller new producers who are accessing other mineral resources are entering the buoyant market and will produce platinum concentrates for purchase or toll treatment. Hence, a shortage in both smelting and refining capacities is anticipated. Further smelting and refining facilities independent of the major platinum producers will be required in South Africa by 2010. Mintek's ConRoast technology is best suited to fill the need to treat a high proportion of UG2 concentrates in a cost-effective and technically efficient manner. Atomaer base metals technology has been developed for rapid leaching of nickel and other base metals from alloy. Significant reductions in capital and operating costs are expected from the combination of the two advances in process technology compared with that installed at the existing smelters and refineries that were established over 20 years ago. Independence Platinum will be listed on AIM and the Johannesburg Stock Exchange (JSE) in 2007, and developed as an independent, vertically-integrated platinum company using its independent smelting and base metals refining facilities as a strategic platform to promote the development and mining of platinum projects by junior resource companies in South Africa through technical co-operation, strategic alliances, joint ventures, off-take, toll-refining, and marketing agreements.

Jan 1, 2006

By D. G. Krige

D. G. Krige: The stimulating contributions from Messrs Cooke, Curtis, Martus, Johnston, Van Wyk, Van Rensburg and Wroth are appreciated by the author and provide clear evidence of the importance not only of the principle of assistance to gold mines, but also of its scope and form. In general all the arguments, raised by Messrs Cooke, Martus and Johnston in favour of extending the scope of the new assistance scheme can be accepted as sound.

"Chairman: Dr DeV. HarrisRapporteur: Mr A.H. MunroPapers:Corporate exploration strategies by MacKenzie, B.W.The Engel Simulator and the search for uranium by Griffiths, J.C. and Singer, D.A.The Chairman opened the session by tracing the changes which have taken place in the exploration field since the days of the lone prospector who relied upon his individual skills and to a large extent on luck. The deposits which now remain to be discovered are better covered and are of lower grade. A much greater team effort, involving geoscientists and engineers, is required. The gamble is thus much greater -not only are the probabilities of failure still significant but the consequences are more severe. A recent Canadian survey indicated that expenditures of between two and nine million dollars on regional exploration programs are required to locate one significant deposit.The Chairman went on to say that these facts have led companies to regard exploration as another form of investment and to treat it accordingly. This had placed exploration in the context of corporate strategics and structures, which was the subject of the first paper of the session.In introducing his paper, Dr B. W. MacKenzie said that the paper suggested a decision framework for exploration planning. Initially the environment is analyzed to define observable and relevant economic characteristics. The terms of reference for exploration planning and the appropriate allocation of capital and skills are then established in the light of corporate objectives and growth alternatives. With the aid of this information and in the light of profit and corporate risk criteria, exploration strategies can be selected.Dr MacKenzie went on to say that the usefulness of the concept and criteria outlined in his paper depended critically upon three characteristics of any particular economic environment, namely, the return resulting from an economic discovery, the unit discovery Cost and the probability of making an economic discovery. He then showed by means of a case history relative to the Canadian Shield and Cordilleran areas that these three characteristics could, in fact, be evaluated for regions with reasonable histories of mineral activity.The first contributor to the discussion of the paper, Mr Alfred Weiss, mentioned that his group had been involved in exploration modelling for some ten years and were thus particularly interested in the paper. He went on to say that they had experienced greatest difficulty with reconnaissance programs and that he sensed that these difficulties were also present with the methodology which had been outlined. Mr Weiss asked Dr MacKenzie how he would deal with such situations when no information was available but where there was the potential for both exploration and discovery. Dr Mackenzie agreed that the lack of information was a very severe limitation and said that at the present time his methodology probably did not provide a basis for breaking down the broad geological regions he considered into areas for further assessment."

Jan 1, 2014

By I. Zh. Bunin, M. V. Ryazantseva, V. A. Chanturiya

The paper proposes a new method for selective calciferous separation. The effect was achieved through the application of the combination of high-power electromagnetic pulses (HPEMP) and a specific reagent regime of the flotation. The combined application of HPEMP with the special reagent regime allowed for the improvement of the scheelite floatability: the recovery of CaWO4 rises from 41.2 % (untreated sample) to 58.5 (sample treated at 103 pulses). In contrast, the floatability of calcite decreases significantly: the recovery of calcite drops from 74.7% (untreated sample) to 41.1 % (sample treated at 103 pulses). The conditions were found for the selective separation of the minerals with very close flotation properties. Keywords: Calcite, scheelite, flotation, high-power electromagnetic pulses, DRIFT, XPS

Jan 1, 2020

By C. S. Kucukkargoz, A. Bhalla

"The solid-state reduction of ilmenite concentrate with graphite was studied under argon atmosphere at temperatures between 1050°C and 1350°C. The rate of reduction increased with increasing temperature and decreasing particle size, with the maximum extent of reduction found to be 80% at 1350oC with a particle size in the range of -106 +90 µm. The activation energy for the reduction reaction was calculated to be 257 kJ/mole. The trivalent iron oxide was reduced first to divalent iron oxide and then to metallic iron. An annular ring of a partially reduced oxide phase containing metallic nuclei was formed around the core of ilmenite, which grew in size as the original ilmenite core shrank with progressive reduction. The reduction of titanium dioxide also took place during this stage, which produced the Magneli oxides in the form of TinO2n-1. The metallic phase had very high Fe and low Ti contents throughout the reduction, whereas the partially reduced oxide phase adjacent to the metallic phase was high in Ti and depleted in Fe. The metallic phase globules formed during this stage were small and are considered suitable only for leaching and not for other concentration processes. The core of the particle generally retained the composition of the original ilmenite. The purpose of this work was to remove iron and increase the titanium oxide content of the ilmenite to produce a high-titanium containing charge for subsequent smelting.IntroductionThe titanium-bearing minerals ilmenite (FeTiO3) and rutile (TiO2) are the primary natural raw materials used in industry to produce titanium metal and titanium-based products. The common titanium-bearing minerals are ilmenite, rutile, anatase, brookite, leucoxene, arizonite, and perovskite. Although the formula of ilmenite is commonly expressed as FeTiO3, the mineral can accommodate Mn and Mg, which are chemically bound in the form of (Fe,Mn,Mg)TiO3. Ilmenite concentrate can also contain Fe2O3 and Al2O3 in addition to the physically separable oxides such as SiO2 and CaO. The crystal structure of ilmenite is an ordered derivative of the corundum structure with a trigonal-rhombohedral symmetry. Fe2+ and Ti4+ ions occupy the octahedral sites, leaving the tetrahedral sites unoccupied. In each FeTiO3 unit, there are three O2- ions creating three octahedral sites, two of which are occupied by Fe2+ and Ti4+ (Wilson et al., 2005)."

Jan 1, 2017

By D. Gregurek

The complexity of metallurgical processes in the non-ferrous metals industry. especially changes in the process conditions in combination with a diversity of metal processing furnaces, requires a precise knowledge of the system for the selection of refractory products. However, particular importance is still focused on the specific refractory consumption being as low as possible. The addition of recycling material with a high amount of impurities and the increase of low-grade ore concentrates used in the base-metals industry also entails a significant change of slag chemistries, process temperatures, etc., which influence the performance of already approved linings. This acknowledgement of process changes with decreased brick lifetimes provided the motivation for RHI AG to develop high-performance refractory bricks especially for non-ferrous metals applications. The internal laboratory tests with fayalitic slag showed very promising results compared with our approved magnesia-chromite bricks for this application. In order to identify suitable refractory products and to improve the life of the refractory lining, innovative product development has to be undertaken. In addition, the practical corrosion testing methods and facilities available within the RHI Technology Center, such as the induction furnace and the rotary kiln test equipment, allows the best possible understanding of brick wear at a laboratory scale. Based on the results of the test work, the optimal refractory solution can be recommended for a field trial at the customer?s site.

Jan 1, 2012

By M. A. Belokrys, F. O. Milovich, D. D. Aksenova, V. A. Ignatkina, V. A. Bocharov, A. A. Kayumov

Copper remains one of the most sought-after metals in the industry. Tennantite (Cu12As4S13) and tetrahedrite (Cu12Sb4S13) that occur in pyrite copper, copper-zinc and polymetallic ores are an additional reserve for increasing technological parameters of flotation. Pyrite mass (85% and more) has similar flotation properties to other sulfide minerals, and imperfection of reagent regime is a common problem that occurs during quality copper concentrate processing. Due to tennantite's and chalcopyrite's differences in flotation properties with butyl xanthate at pH > 10, tennantite often reports to the flotation tails. Hight alkalinity of the medium increases the oxidation level of sulfide minerals, thus increasing the concentration of S2O3 2-, SO3 2- SO4 2-. At processing facilities in the Russian Federation, the concentration of thiosulfate ions in pulp is in the range of 0.5 to 1.5 g/l and higher, which leads to a decrease in flotation activity of the tennantite. The effect of butyl xanthate (as standard), thionocarbamate, dithiophosphate and M-TF (a mixture of dithiophosphate and thionocarbamate) on monomineral (tennantite and pyrite) flotation in the presence of sodium thiosulfate was studied. The variable parameters of the "thiosulfate-collector" flotation complex were thiosulfate concentration (100-900); pH (8-12,5). The scientific methods included contact angle for hydration assessment; TEM for surface studies; UV spectroscopy and iodometric titration for solubility control. Comprehensive studies have established a connection between the concentration of thiosulfate ions and tennantite flotation selectivity. Flotation activity of tennantite is higher at pH 8 with a thiosulfate concentration under 300 mg/l. Pyrite remains active with butyl xanthate under the same conditions. TEM images of the surface films of the collectors on pyrite were acquired at pH 8. The MTF provides the biggest difference in adsorption, wettability and flotation activity between tennantite and pyrite at pH 8 and thiosulfate concentration under 300 mg/l, in comparison with butyl xanthate. The results of the research will be applied to improve selective reagent regimes of tennantite minerals flotation. Keywords: Tennantite, pyrite, chalcopyrite, sphalerite, flotation, sulfhydryl collectors, thiosulfate, adsorption, mechanism, reagent regime

Jan 1, 2020

By W. P. C. Duyvesteyn, J. R. Cutland, J. R. L. Russell

In 1970 it was decided to build a large new plant at the Chingola Division of N.C.C.M., Ltd., to treat concentrator tailings and leach residues with a low copper content by a leach-solvent extraction-electrowinning process. In order to assist in the establishment of the design parameters for the new plant, and to study the interaction of this plant with the existing leach-electrowinning plant, mathematical models, formulated as linear programs, have been developed and used extensively. The paper outlines the metallurgy of the plants and describes briefly the way in which the models have been formulated and used. The formulation involved the use of separable programming to form the products of some variables.

Jan 1, 2014

By Anders Erlandsson

"The crude ores from the LKAB mines are sorted and refined into a number of products. As there are a number of different plants the flow of material is often complex.in connection with studies of a proposed extensive investment program it was necessary to get a good measure of the changes which would be caused in the total profit by the different possible investments. A linear programming model was set up to accomplish this, and to cover the consequential effects on the production system. The objective function of the model maximized the total profit, taking into account restrictions in materials balances, blending conditions, production capacities and market. The changes in total profit resulting from the different investment alternatives, together with investment and fixed costs, were used in a series of investment analyses. The application has proved to be very successful and the results come very near to what was expected."

Jan 1, 2014

By G. Akdogan, C. Bergmann, C. J. Coetzee, Q. G. Reynolds, S. J. Baumgartner

Submerged arc furnaces (SAF) are used extensively in the production of ferrochrome, where charge material – consisting of mixtures of carbonaceous reductants, fluxes such as silica, and ore in the form of pellets – is fed through chutes into the vessel. The feed typically forms a thick bed or ‘burden’ of solid particulates above a bath of molten material below. This burden layer surrounds three electrodes, which are typically arranged in a triangular configuration in circular SAFs. A major challenge in the industry is the availability of sought-after reductants, volatile market conditions, and increasing electricity tariffs in South Africa. A good understanding of the physical properties of the raw materials in the charge is therefore of great value in order to best deal with the reductants available at any given time, and thereby maximising furnace throughput. This paper presents a study of the effects of different particle properties on particle flow behaviour relevant to SAF operations. Discrete element model (DEM) simulations were used to estimate the sensitivity of the particulate flow of beds of charge material to properties such as the coefficients of friction, particle shape and size, and others. The present study lays the groundwork for the development of full DEM models of the SAF that will greatly improve understanding of the flow of complex mixtures of solid particles in the submerged arc furnace, and how the relative physical properties of each component in the charge can influence electrical behaviour of the burden.

Sep 1, 2021

By J. H. E. Perry, V. H. Wiik

"The ore deposits of the Zambian Copperbelt occur in sedimentary strata that have been subjected to relatively mild, flexure-type folding. Unrolling serves to reconstruct the original depositional geometry of the folded sedimentary strata and is in common usage on the Copperbelt both for geological analysis of drill hole data and in routine ore reserve estimation.A computerized method of unrolling was introduced at Roan Consolidated Mines in 1969 based on a standard contouring program. A contour map of the geological structure is drawn from a regular grid of elevations, interpolated from the original, irregularly-spaced intersections. Unrolling is performed across this grid, perpendicular to one or two axes specified by the geologist. Each intersection is unrolled independently, and the new co-ordinates are subsequently processed to produce unrolled maps.The technique has been used successfully at RCM over the last two years in both the estimation of ore reserves and exploration planning."

Jan 1, 2014

By H. Zhong, S. Wang, Q. Lin

To improve the flotation performance of chalcopyrite collector, 2-(tert-butoxy)ethyl xanthate (TBEX) and its derivative O-(2-(tert-butoxy)ethyl)-N-ethyl-thionocarbamate (TBEETC) were designed and prepared by the introduction of a 2-(tert-butoxy) ethyl group into xanthate and thionocarbamate. TBEX and TBEETC were both prepared via the one-pot method with superior efficiency, which has significant commercial implications. The micro-flotation tests demonstrated that compared with sodium isobutyl xanthate (SIBX) and O-isopropyl-N-ethyl-thionocarbamate (Z-200), TBEX and TBEETC both possessed better collecting ability and selectivity for chalcopyrite. DFT calculations and XPS were utilised to investigate the flotation mechanism involving TBEX or TBEETC and chalcopyrite. The results demonstrate that although 2-(tert-butoxy) ethyl group does not interact with minerals directly, its introduction reduces the energy of HOMO, so that they can better accept electrons instead of donating electrons which leads to better interaction with copper atoms rather than iron atoms. Keywords: Chalcopyrite, flotation, thionocarbamate, xanthate, synthesis

Jan 1, 2020

By K. Shame, H. H. Thiele

South Africa holds approximately 70% of the world’s total chrome reserves. Chromium is an important raw material for the production of stainless steel and ferrochrome alloys. Over the years, China’s ferrochrome market has been dependent on chrome ore imports from South Africa. In 2018, China imported about 75% of its chrome ore from South Africa. With the low platinum price and the rising demand for stainless steel, a growing demand to evaluate new beneficiation technologies for fine chromite was identified. Gravity separation of fine chromite (<75 μm) is inefficient, due to the limitations of the technology to upgrade fine particle size distributions. Potential for the recovery of chromite, specifically fines (<75μm), lost to UG2 PGM flotation tails, but also from MG and LG6 spiral circuit tailings exist. Flotation of podiform chromite ores from India and Kazhkhstan is successful in generating saleable product grade, following acid or alkaline flotation routes. Application to South African stratiform chromite is being evaluated, with the emphasis on evaluating reagent type, optimising dosages and the effect of pH in optimising flotation performance. Flotation can unlock additional value from chromite tailings material. The effect of ore characteristics such as gangue mineralogy, particle size distribution and headgrade are reported. The performance in terms of product quality and yield are evaluated and compared. The impact of this paper will not only prolong life of mine and increase revenue but will also alleviate environmental burdens associated with tailings dams. Keywords: Chromite, flotation, fine material, performance optimisation

Jan 1, 2020

By K. Sasaki, Y. Oriia, Shigeto Kuroiwa, H. Miki, Yuji Aoki, T. Hirajima, G. P. W. Suyantara

The effect of a sulfite reagent on the floatability of chalcopyrite and enargite was investigated in this paper. The flotation tests using single and mixed minerals were performed under various concentrations of sulfite. The flotation tests using a single mineral showed that the sulfite reagent depressed the natural floatability of both minerals at pH 9. Surprisingly, enargite was floated after the addition of potassium amyl xanthate (PAX) following the sulfite treatment, and the floatability of chalcopyrite depressed under a similar condition. X-ray photoelectron spectroscopy analysis results showed that the sulfate species increased after the sulfite treatment on both minerals. However, the addition of PAX removed this sulfate species and rendered the enargite surface hydrophobic. This phenomenon was not observed on the chalcopyrite surface. FTIR analysis and PAX adsorption studies were performed to support this finding. The flotation of a mixed mineral was in agreement with the flotation of a single mineral, indicating a possibility for selective flotation of chalcopyrite and enargite using the proposed method. Keywords: Flotation, chalcopyrite, enargite, sulfite, potassium amyl xanthate

Jan 1, 2020

By S. T. L. Harrison, M. A. Fagan-Endres, M. D. Odidi

This paper investigated the ability of eight common hydrodynamic models – tanks in series (TIS); three compartmental model configurations (Comp-1, Comp-2 and Comp-3); advection dispersion (AD); piston exchange (PE); piston exchange-diffusion variant (PE-D) and piston dispersion exchange (PDE) – to simulate residence time distribution (RTD) data generated from tracer tests conducted on a packed bed composed of different size fractions of malachite ore. The chosen materials were packed into 0.1 m internal diameter columns to a depth of 0.155 m and drip irrigated at 5.11 L/ m2.h. The four size fractions tested were: 1 – 2 mm, 2 – 2.8 mm, 4.75 – 5.6 mm and 13.6 – 16 mm. Step-up tracer tests were conducted using potassium chloride. The results showed that an increase in the particle size of the malachite ore had little effect on overall bed porosity but resulted in significantly lower values of liquid holdup. Two of the monoporosity models tested, TIS and Comp-2, were the most affected by the changes in bed size fraction due to their inherent inability to cope with high degrees of non-ideal flow present in the larger particle systems. The dual porosity models performed relatively better with the dominant trend being a reduction in dynamic to total liquid holdup as particle size increased. Of all the models tested, the PDE and TIS models were the best and worst performers respectively, with R2 values averaging at 0.997 and 0.679 across all experiments respectively. Though the Comp-1, Comp-3 and PE-D models also performed well, the addition of the dispersion coefficient to take the axial spread of fluid molecules into account added a layer of complexity that allowed the PDE model to perform relatively better than the other dual porosity models. Keywords: Heap leaching, packing material, hydrodynamics, malachite, PSD, modelling

Jan 1, 2020

By W. J. Whiten

"Models of cone crushers and vibrating screens are described. These models have been constructed from actual plant data using a systematic model-building technique. Included in this technique is regression analysis using multi-dimensional spline functions.The models have been used to simulate complete crushing plants and hence to design and evaluate a control system for crushing plants."

Jan 1, 2014

By A. Schippers, S. Hedrich

Chalcopyrite represents the most important copper resource and is currently mainly exploited using pyrometallurgy. Bioleaching is an environmental-friendly and economic alternative to conventional mineral processing technologies. The technical feasibility of stirred tank reactor bioleaching of copper ore concentrates using acidophilic iron-/sulfur-oxidising bacteria is proven, however, often incomplete due to inefficient chalcopyrite dissolution. A decoupling of bacterial growth from bioleaching activity in one bioreactor by adjusting appropriate temperatures for both process steps allows for almost complete chalcopyrite dissolution. Separation of copper and recovery of other metals from the PLS was possible by implementation of different biological and chemical techniques. The Ferredox process has been proposed to treat limonitic laterite ores for cobalt and nickel recovery by means of anaerobic reductive dissolution with autotrophic, acidophilic bacteria. As a modification, aerobic reductive dissolution of laterites with acidophilic bacteria has shown economic and environmental advantages over anaerobic reductive dissolution. The reductive bioleaching technology has the potential to increase metal recovery in existing mines, and transform unexploited ores and limonite stockpiles into valuable resources. Keywords: Biomining, bioleaching, chalcopyrite, laterite, Ferredox process

Jan 1, 2020

An evaluation was made of the wear and performance characteristics of liter bars, and the cost-life effectiveness of backing materials for rotary-mil liners. In a large run-of-mine mil in which the liter bars were mounted on grid liners of austenitic manganese steel (AMS), the liners had an average life that was five to six times that of equivalent unprotected liners. For a single mil, this is equivalent to annual savings in the cost of materials of up to R320 000, and to a downtime of 100 hours. Of the five materials tested in a large pebble mil grinding quartzitic ore, AMS grids and &apos;white iron&apos; blocks performed best on a cost-life basis, with possibly improved performance from a real white cast iron. (The &apos;white iron&apos; was shown by microstructural analysis to contain flake raphite and pearlite, being in reality a grey cast iron.) The high-chromium white iron had by far the longest predicted life, with mild steel a surprising second. Rubber was shown to last well in this type of mil. The wear rates of liners change during their lifetimes. The protective effect of liter bars was clearly illustrated by the reduction of over 40 per cent in the wear rates of the liners when the lifter bars were renewed to a height of 80 mm from a fully worn height of 35 mm.

Jan 1, 1991

By R. Hoare

TSG Consulting works with many of the major global mining companies using simulation modelling as an integral component in their development team&apos;s processes to determine which combination of infrastructure options, operating performance and operating rules best achieve project goals. All systems can be divided into a series of subprocesses. Conventional management and design practices focus on the optimisation of these system components. However, the interaction between subprocesses means that improvements made to the individual components do not necessarily translate into total system performance improvement. TSG Consulting advocates a `total integrated system approach&apos; to understanding the behaviour and performance of complex interacting systems. In a constraint-based integrated set of processes, the instantaneous system capacity is limited by the subsystem component capacity that is the bottleneck at that point in time. Additionally, real world stochastic and dynamic influences tend to have knock-on effects across subsystem boundaries. This necessitates the requirement for simulation modelling to develop and validate solutions that are sufficiently robust to deliver sustainable outcomes. The key to maximising production is to understand the causes and effects the inherent variability has on component performance, subprocess performance and most importantly, the total integrated system performance. The correct use of simulation modelling techniques allows study teams to evaluate the relative merits of different capacity enhancement proposals. Put simply, when done well, simulation modelling provides a quantitative and rational process to enhance the knowledge and insight needed to make informed decisions.

Jan 1, 2007

By Pieter de Waal

The beneficiation equipment under the control of plant metallurgists exploits the differences in the physical properties between valuable and waste mineral components. In many cases, laboratory results are too late for process control and can only serve the purpose of "post" reports, the calculation of a mass balance and the issue of a quality certificate. As a result, experienced operators regularly adjust separation equipment based on the colour and texture of the various product streams in the beneficiation plant. Metallurgists quickly learn to recognise the different minerals in their ore body. The stereo microscope has been a valuable tool used by operators to quantify known mineral species. For many years it was the only practical method available for the purpose of process control and even for quality contro1. The modem spectroscope is far superior to the human eye and can rapidly detect a change in mineral composition. New generation optical scanners and digital signal processors can provide useful signals, related to mineral composition that can readily be applied for the purpose of process control. Successful case studies, covering dry in-line and slurry applications as well as in-plant fast spot analysers are presented.

Jan 1, 2014