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By X. M. Chen

The selection of leach reagent mainly according to the ratio of useful mineral to gangue in mineral raw material and the structure of mineral raw material. Besides that the price of reagent, the capability of reagent decomposing mineral and its causticity on equipment is also supposed to be in regard. On common conditions, the scandium content in mineral raw material is low, even Sc concentrate of specimen-Yunnan rare earth ore which contain Sc used in this experiment only is 148 g/t. Moreover, in enlarging scale experiments the content of scandium in leach liquid is only 3.6g/t, meanwhile various and complicated impurity existing in it. At present, both domestic and abroad has succeed in enriching scandium from vitriol solution, while enriching scandium from hydrochloric acid only has been studied in some minority units, which is not reported to be practical in industry. Therefore, this item offer a new research issue on Sc?s extract, which is as well as the task of this research. Spectrum analysis, chemic component analysis and scandium content have been made in main mineral measurement on rare earth with Sc in the paper. Based on characters of sample, select hydrochloric acid, vitriol and nitric acid as leach reagent and make different blueprints to accomplish the experimental research about selecting leach reagent. In the aspect of rare earth leach scandium leach density is researched, leach liquid to solid rate, leach temperature, leach time, leach granule rate and leach solution. This experiment claims that in the optimal experimental ambience, leach rate of vitriol is 58.18%, the leach rate of nitric acid is 50.73% and the leach rate of hydrochloric acid is 59.34%. Among them, hydrochloric acid has the best effect, therefore this experiment choose it as the leach reagent.

Jan 1, 2014

To extract the gold from refractory gold concentrate with high sulfur and arsenic, the gold concentrate was catalytically oxidized to expose the gold for cyanide leaching. The effects of reaction temperature, initial nitric acid concentration, reaction time and initial gold concentrate concentration on the conversion rate were studied. The results show that the appropriate conditions for the catalytical oxidation of this gold concentrate are: reaction temperature of 65 oC; initial nitric acid concentration of 25% (wt.); reaction time of 1.5 hours; initial gold concentrate concentration of 10% (wt.). Under such conditions, the conversion rate of gold concentrate is 92%. The solution can be used to prepare nano-iron oxide red pigment. Gases released in the process can be recycled and reused by oxidation absorption. A chemical background of catalytic oxidation is proposed.

Jan 1, 2014

By André Mans, Frans B. Waanders

"Ferrosilicon (Fe-Si) is an important commercial material and it forms the basis of the powder used in dense medium separation (DMS) of various minerals in a minerals beneficiation process. Current losses of Ferrosilicon (Fe-Si), which is used in the dense medium separation (DMS) of iron ore at Kumba Resources, Sishen, South Africa occur due to adhesion to the separation products and also by being present in the effluent stream, due to abrasion. The losses contribute greatly to the running cost of the plant and the purpose of this project was to determine the characteristics of the unused Fe-Si and then to characterise the changes that occur during storage and the use thereof.A Scanning Electron Microscope (SEM) and Mössbauer Spectroscopy (MS) were used to investigate the characteristics of the fresh and used Fe-Si. The SEM analyses of the Fe-Si yielded a composition of 15 wt.% Si and 85 wt.% Fe with minor impurities of Mn and Cr (<1 wt. %), resulting in an ordered phase with a calculated composition of Fe2Si. The average density of the Fe-Si was found to be 7.177 g.cm-3 whilst the size distribution was determined with the d50 of the particles being approximately 30 µm. A slurry, containing 10% solids was prepared, which had a density of about 1.1 g.cm-3 and this slurry was used to conduct the various experiments under laboratory conditions at the university. Samples were taken at regular intervals from a storage container containing a lime solution as well as from a closed circulation circuit system, kept at a constant temperature of about 60°C. Mössbauer Spectroscopy yielded, for the new fresh Fe-Si-samples, a two-sextet spectrum with hyperfine magnetic field strengths of 19.9T and 30.7T respectively, and the yellow-brown froth was found to be akaganeite or ß-FeOOH.It was found that the biggest loss of Fe-Si was due to the abrasion of the particles during the DMS process. A possible change in magnetic properties was also observed, leading to further losses that could occur during prolonged use of the medium. No clear changes to the Fe-Si occurred during correct storage methods, as was initially thought."

Jan 1, 2003

By John Ralston, Stephen Grano, Yongjun Peng, Daniel Fornasiero

"A specially designed mill which allowed the control of pH throughout grinding was used to study the effect of rgrinding conditions on galena flotation and galena separation from pyrite. The various reactions occurring on the mineral surface were investigated by a range of techniques, including OH- addition to maintain the grinding pH, EDTA extraction, XPS and ToF-SIMS measurements.Galena flotation and galena separation from pyrite were strongly dependent on the metal oxidation species produced on galena and pyrite surfaces under different grinding conditions. Iron oxidation species depressed both galena and pyrite flotation, whilst lead oxidation species activated pyrite but had little effect on galena. Optimum galena flotation and galena selectivity against pyrite were achieved by selecting grinding conditions that enabled lead and iron oxidation production to be controlled."

Jan 1, 2003

By Susanna G. de Jager, Francis W. Petersen

"To enable the prediction of reagents suitable for fine coal flotation, it is necessary to develop a methodology applicable to different South African coal types. Statistical confirmation of the applicability of this methodology is important to avoid recommendation of reagents on a trial and error basis.The study included 5 coal samples from different collieries and included Highveld seam 3 and 4 coal (as one sample), Waterberg coal (zone 10 -11), Highveld seam 5 upper coal and Witbank seam 2 and seam 4 coal. Seam 3 and 4 (mixture) coal, Waterberg and the seam 5 upper coal were all found to be vitrinite rich coals. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements. Flotation tests were used to validate expectations from the characterisation of the coal samples.RESULTSThe flotation data indicated that all of the coal samples were amendable to froth flotation. The best results were obtained with the Witbank seam 2 coal and the poorest flotation with Syferfontein seam 5 coal. The flotation tests showed that the best reagents to float all of the coal samples studied were iso-decanol and dodecene. These reagents produced flotation products that were near to the release curve, which are the optimum flotation results (obtained when using iso-paraffin as collector). Dodecene resulted in low ash products and iso-decanol in high yield products."

Jan 1, 2003

By M. Barsky, A. Govorov, E. Barsky

A study was conducted to determine the structure and lifting capacity of a two-phase stream in a vertical pipe at different distances from the point of introduction of the material into the instrument. Stream velocity was set at 2.8, 4.0, 4.8, 5.6 and 6.25 m/sec to ensure separation regimes. It was found that the llifting capacity of the two-phase stream exceeded that of pure air by a factor of three or more, and that in a turbulent regime the velocity curve displayed marked deformation, becoming more rounded and tending towards a parabola. The following formula was obtained for entrainment of a given size fraction under turbulent, laminar and transitional particle flow regimes:

Jan 1, 2003

By Francesco Vegliò, Luigi Toro, Francesca Beolchini, Francesca Pagnanelli, Stefano Ubaldini

"Biosorption is an innovative technology used to remove heavy metals from aqueous solutions from mining waters and other industrial wastes. A wider application of this alternative process is strictly dependent on the understanding of the chemico-physical aspects involved, in order to optimize the operating conditions. Mechanistic models are the most useful tools used for understanding purposes, even if the empirical models are still widely applied for their simplicity.In this paper especially propagated biomasses of Sphaerotilus natans, calcium alginate and some waste materials were tested as adsorbents for single and binary solutions containing heavy metals at different pH. The equilibrium experimental results were fitted according to empirical and physical models with growing complexity outlining the inadequacy of the predictive models; in fact, the non-ideal interactions among metals require the insertion of additional correction parameters."

Jan 1, 2003

By Frank Cappuccitti, Stephen Chryssoulis, Stamen Dimov

Surface organic microanalysis of platinum (Pt) and palladium (Pd) minerals by TOF MS1 is an attractive complement and potential alternative to conventional collector screening methods. Its attractiveness lies on its ability to focus on individual Pt and Pd mineral particulates, therefore providing a more targeted approach. The only requirement is knowledge of the occurrence (mineral composition, grain size and association) of Pt/Pd in the feed sample. This newly developed technique can detect, and identify collectors and quantitate loadings on individual Pt/Pd mineral particulates at plant concentration levels. Using this technology, collector loadings were measured on Pt and Pd metal plates and on PtS2 and PdS particulates which had been exposed together to aqueous solutions of different collectors. Thus, data were obtained on collector selectivity, the effect of sulphur; and of depressants, the latter in combination with TOF-LIMS2 results. Staged rougher tests on North American and UG-2 ores linked Pt/Pd flotation kinetics with collector loadings and ultimately grade/recovery.

Jan 1, 2003

By F. L. Mentg

The utilization of acid leaching tailings was studied. It is obvious that the Fe in acid leaching tailings can be leached into solutions as Fe2+. In this paper, the influence of conditions, including the concentration of ferrous sulfate, pH, temperature and velocity of air flow was investigated. The optimum conditions for preparing seed crystal are as follows: the concentration of ferrous sulfate is 20 g/L; pH is 9.5~10; reaction temperature is 10~20?; velocity of air flow is 0.4m3/h. The optimum conditions for preparing iron oxide red are as follows: the concentration of ferrous sulfate is 5 g/L; reaction temperature is 80~85?; velocity of air flow is 0.13m3/h. At last, the product of iron oxide red could be prepared by ammonia method.

Jan 1, 2014

By Wei Sun, Chengwei Li, Zhiyong Gao, Yuehua Hu

"Grinding for mineral liberation is a prerequisite for a successful flotation separation. Different grinding media produce mineral particles with different morphologies and surface properties. In this study, the surface physicochemical properties of fluorite particles produced by ball and rod mills were systematically investigated through single mineral flotation experiment, wettability measurement, X-ray diffraction (XRD) test and scanning electron microscopy (SEM) observations. The XRD observations reveal that the surface exposure degree for both mill particles follows the order {111} > {110} > {100}. The difference lies in that the rod mill ones have a higher exposure of more reactive {110} and {100} surfaces, leading to a stronger interaction with the collector. The difference also leads to their higher elongation and lower roundness values of rod mill particles which are beneficial for the particle-bubble attachment by shorting the induction time. The wettability and flotation results show that the rod mill ones have a lower critical surface tension and a greater hydrophobicity when treated with the collector solution and accordingly perform a higher flotation recovery. This work, for the first time, revealed the importance of the exposure of crystal surfaces in determine the shape factors and reactivity of the mineral particles and will help provide guidance for optimizing flotation separation and particle surface modification. INTRODUCTIONFluorite (CaF2) is the most important source mineral for producing F-based chemicals and materials which are widely used in industrial, environmental, and medical fields [1, 2]. In ore deposit, there are two kinds of occurrence forms of fluorite mineral. Firstly, the fluorite mainly coexisted with the gangue minerals like calcite (CaCO3) and quartz (SiO2). Because of their similar density and fine-grained dissemination in ore deposit, ball mill grinding before flotation separation has been widely applied to produce relatively fine particles [3]. Secondly, the fluorite is often associated with other valuable minerals with higher relative density such as scheelite (CaWO4) and cassiterite (SnO2). Due to their obvious density differences and coarsely grained distribution in ore deposit, rod mill grinding before gravity separation has been usually used to produce more uniform particles and avoid over-grinding [4-6]. After the gravity separation, a flotation separation is also employed to beneficiate the fluorite [7]."

Jan 1, 2018

By Hermann Wotruba, Lars Weitkämper

"Dry coal dressing was popular during the 1950’s and 60’s in many parts of the world. The devices mainly used were air jigs and air tables.The increase in ash and moisture content of run-of-mine coals due to the wide advanced mechanisation of mining methods during and after this period led to that pneumatic devices being unable to treat run-of mine coals with the desired efficiency. Since the 1960’s almost all new coal preparation plants have been based on wet processes that are highly efficient in terms of coal recovery and their ability to handle damp and sticky run-of-mine coals. (Frankland, 1995)However, water is becoming increasingly costly and the disposal of fine products, containing most of the water, is an environmental concern. There would be significant cost savings and a lower total energy consumption if coal could be cleaned dry. Efficient dry coal treatment would be an interesting solution in desert, arid or cold areas.In Germany one dry coal dressing plant is in operation. This is the last operating dry coal dressing plant existing in Europe. The actual technical standard of dry coal dressing has been analysed during test-work and sampling in this plant (Saar Region in Germany). The process and the advantages and disadvantages are presented. The plants problems are low efficiency in the fine fraction –6 mm and the coarse fraction +30 mm and a low overall throughput as well as the lack of an automatic process control system. The separation results in the medium size fractions between +6 and -30 mm are excellent"

Jan 1, 2003

By A. T. Sutaone

"In the Dongri Buzurg Manganese Mine of M/s Manganese Ore (India) Ltd., high grade lumpy manganese ore required for iron and steel industries is produced through multi-stage crushing and screening. This has resulted in accumulation of 50,000 tonnes of low grade fines over the years. This production of such fines is still going on. The fines create environmental problems, like air and water pollution and siltation in adjoining fields. Besides containing lot of manganese values, they occupy large space which is very scare in mining area.The Indian Bureau of Mines under one of its statutory functions has suggested the company to explore the possibility of recovery of additional values under conservation and environmental aspects. Hence the company has sponsored a bulk sample for beneficiation studies in the Modern Mineral Processing Laboratory and Pilot Plant of Indian Bureau of Mines at Nagpur, India. The main manganese minerals present in these mine rejects have been identified as pyrolusite and psilomelane. The purpose of this study was to explore the possibility of evolving a suitable beneficiation flowsheet to obtain manganese concentrates assaying over 72% MnO2 to be used as raw material for the manufacture of dry cell batteries.The sample/material was subjected to characterisation studies in terms of chemical analysis, granulometry and mineralogical compositions. Based on these characterisation studies, the beneficiation process developed comprised of desliming, jigging and low intensity magnetic separation mainly to reject quartz, silicates and jacobsite. The manganese concentrate thus produced assayed 70.2% MnO2 with MnO2 recovery of 78% and weight per cent yield of 63.5. This natural concentrate could be mixed with the electrolytic manganese dioxide produced by the company and this blend can thus be used as a raw material for the manufacture of dry cell batteries by the end users. The paper deals with the details of test work carried out in evolving the process flowsheet."

Jan 1, 2003

By C. S. Gundewar

About 90% of the barytes produced the world over is used for oil and gas drilling as weighting agent in drilling mud to control pressure, prevent blow out and provide lubrication. This is because of its unique properties like high specific gravity, water insolubility and intentness. India is one of the leading producers and exporters of barites. The Mangampeth Baryte deposit in Cuddapah district of Andhra Pradesh, India being the largest single deposit in the world having a reserves of about 80 million tonnes. Approximately 50% of the total reserves of grey barites of Mangampet deposit assays less than 92% BaSO4, the minimum stipulated grade for oil and gas drilling industries. To reach and recover the high grade barite, the overlying low grade has necessarily to be mined out and removed. At present this is being stacked separately at the mine site involving lot of labour and transport cost. Considerable barites is contained in the dumps adversely affecting the conservation and creating lot of environmental hazards. IBM being the premier organization in India in the field of conservation of minerals and environmental protection in mining has recognized the importance of adverse effect of these huge dumps at site. The Ore Dressing Division of IBM, Nagpur has characterized these dumps and developed the flotation process on a sample assaying 66% BaSO4 and 23.3% SiO2. The flotation concentrate obtained assayed 93.7% BaSO4, 2.38% SiO2 with BaSO4 recovery of 80% and meets the requirement of the oil industry. The flotation concentrate being non-wetable, can not be used as such as weighting agent, and hence the collector coating on the concentrate was removed either by acid treatment or heating to make it water wetable. The concentrate was 92% -325 mesh and having a specific gravity 4.3. The barites concentrates so produced meets the size, grade and specific gravity specifications required for use in oil drilling industry. Apart from the financial benefits the process augurs well for the commercial exploitation of these huge dumps in terms of (1) additional recovery of these valuable minerals and conservation, (2) reduction in dumps value, (3) improvement in environment and offering an excellent potential for export.

Jan 1, 2014

By L. A. Vaisberg, E. V. Shishkin, S. V. Kazakov

"This research is targeted at finding solution to the problem of reduction of specific energy consumption during disintegration of solid materials with the help of machines, operating in a quasiresonant mode. The objective of the research is the development of an energy-saving method of disintegration of supestrong rock and by-products on the basis of vibrational units with two movable crushing elements, operating in a rigorous synchronous-antiphase mode without stringent kinematic links. In the course of investigations a mathematical analysis of the dynamics of vibrational units was performed to determine required mechanical parameters, allowing for adjustment of the machine actuating elements to high-frequency synchronous-antiphase oscillations in the quasiresonant frequency range. As a result of performed pilot tests, the reliability of desktop studies was confirmed and the dependency of process parameters on the machine regulated parameters in the quasiresonant frequency range was identified. The analysis of obtained data showed that during machine operation with cone-shaped crushing elements in the quasiresonant frequency range, the yield of the high-quality finished product (WFA grits of -3+1 mm grain size class) in one pass reaches 35%, whereas the form of the particles corresponds to the grain form with sharp edge. The quasiresonant operation mode of the vibrational unit with two freely suspended crushing elements (without stringent kinematic links) provided substantial reduction of energy intensity during crushing down to 0.16 kWh/t, which shows reduction of power consumption for crushing by more than 15% compared to conventional equipment.INTRODUCTION The most common and energy-consuming processes in the mining industry are the crushing and grinding of various solid materials. Such large energy costs are due to the fact that the capabilities of the existing crushing and grinding machines are based on traditional methods of destruction, and are limited by their kinematic features, which do not allow to reduce the energy intensity of processes, to lower the irreversible loss of useful components, to improve the quality of marketable products. In connection with the foregoing, the task of energy costs reducing for disintegration is one of the most important issues in the enrichment of both minerals and processing of man-made raw materials. The solution of this problem is possible only through the creation of a fundamentally new highly efficient technique and technology for processing raw materials [1, 2]. It seems that the greatest prospects in this respect are the vibration methods of disintegration, in particular, the vibratory cone crusher based on a two-mass system without rigid kinematic connections between the crushing bodies, with vertical vibrations of the working bodies. In this machine, the principle of rational material destruction is realized – crushing without re-grinding [3-5]."

Jan 1, 2018

By Takashi Furuyama, Sukeyuki Mori, Abel Bissombolo

"In flotation practice, a good recovery of minerals largely depends on the degree to which the valuable minerals have been liberated from the associated gangue during the grinding process. Therefore, a regular measurement of the degree of liberation can provide data for the assessment of the quality of separation and predicts the effect of changes in the grinding-classifying circuit on flotation process. Generally, the standard procedure for measuring the degree of liberation requires the preparation of polished sections - a time consuming operation that also has the disadvantage of providing an overestimated number of free particles because of the stereological nature of produced samples.The present work is an alternative approach to avoid these miscalculations and establish a system of control for fluorite flotation plants. The system deals no only with the state of liberation but also the dynamic behavior of individuals particles and mineral components within the grinding-classifying and flotation circuits. It involves methods such as sieving, x-ray diffraction analysis, study of polished sections and microscopic counting of preliminarily sieved minerals particles from a fluorite processing plant, randomly dispersed on a glass slide, but not embedded in a resin mounting medium. If a complete information on the textural properties of minerals in the ore (including its mineral components distribution) can be obtained through x-ray diffraction analysis and study of polished sections, the microscopic counting is used to determinate with enough accuracy the mineral liberation, estimate the grade of fluorite ore and products, determinate the deportment and approximate recovery of individuals particles and mineral components within the investigated circuit. For a count of 100-1000 particles in each n-size range, the counting method was found to be a particularly reliable and less time consuming operation that could substitute the chemical analysis of fluorite ore for an estimate of the grade:"

Jan 1, 2003

By Carin Laubscher, Francis W. Petersen, Jaap P. Smit

"Waste streams, such as acid mine drainage, are often characterised by low pH values and high concentrations of heavy metals, dissolved solids, calcium and sulphates. Although lime remediation effectively removes most of the heavy metals as hydroxides, it is less effective at lowering levels of sulphates. Various methods of removing sulphates from effluents exist, such as precipitation with lime, precipitation with barium salts, co-precipitation with calcium carbonate, reverse osmosis, and ion exchange. Mintek developed a chemical precipitation (SAVMIN) process to treat acid mine drainage, which entails the addition of lime to precipitate the metal hydroxides, and the subsequent formation (precipitation) of calcium sulphoaluminate or ettringite. The key to the viability of the new technology lies in the correct use, regeneration and recycling of Al(OH)3 used to precipitate the ettringite. The water produced by this process is suitable for disposal to watercourses or for agricultural, domestic or industrial consumption. No brines are produced as the salts are converted to solid hydroxides, gypsum and calcium carbonate.The SAVMIN process has been tested successfully during several laboratory scale operations, and during two pilot plant operations at Stilfontein Goldmine for Anglogold and Navigation Plant, Witbank for Anglocoal. During the pilot plant campaign at Navigation Plant, metal and mineral precipitation was achieved with lime addition. The sulphate concentration in the water was reduced from 2136 mg/L to an average value of 102 mg/L and the calcium concentration was reduced from 727 mg/L to an average value of 70mg/L.The SAVMIN process generates a number of different waste streams including metal hydroxide sludge from neutralisation, gypsum sludge from the gypsum crystallisation steps, and calcite sludge from carbonation. The metal hydroxide sludge is composed of Mg, Ca, Mn and Fe hydroxide, and could be disposed of on a slimes dam. Gypsum sludge was greater than 99% CaSO4.2H2O. This gypsum could be used for dump or road capping, underground backfilling, production of wallboard and cement. The calcite sludge is pure CaCO3, which is recycled back to the neutralisation stage."

Jan 1, 2003

By Jochen Petersen, Steven Bradshaw, Guven Akdogan, Ngoie Mpinga, James Mwase, Jacques Eksteen, Cornelius Snyders

"The platinum group metals (PGMs) and associated minerals are particularly refractory to most traditional direct leach processes. However, the remoteness of many new ore deposits, socio-political risks, the scarcity of skilled labor and constraints on the availability of water and electrical power makes it increasingly more difficult to implement the conventional mill-float-smelt-refine process routes to extract and refine PGMs in remote areas. This paper discusses a process to extract PGM’s from low grade ore and concentrate using a sequential stage heap leach process entailing heap bioleaching and high temperature cyanide leaching, and evaluates the feasibility of implementing a carbon-in-pulp process to recover the PGMs from the pregnant leach solution. The heap bioleaching extracts the base metals in an acidic sulfate medium using a mixed culture of thermophiles. After heap bioleaching the heap is reclaimed, rinsed, agglomerated and restacked for high temperature cyanide leaching where the cyanide liquor is directly heated via solar energy in panels. Palladium, gold and platinum are recovered during the cyanide leaching stage. The pregnant leach solution was evaluated for potential carbon-in-pulp adsorption and subsequent elution similar to gold processing. The kinetics of adsorption and elution compared well with gold adsorption and elution."

Jan 1, 2014

By A. V. Nozhkina

"Transformation of diamond into graphite was investigated in the region of diamond metastability under the action of media chemically active relative to carbon in the temperature range from 770 K up to 2200 K and pressure range from 10-3 Pa up to 3 GPa/IV VIII group metals of periodic system and oxygen were used as media chemically active relative to diamond.Methods of electron diffraction, chemical analyses, emission spectroscopy and X-ray phase analyses were used for determination of the reaction products.It was found that in the region of diamond metastability the stage of catalytic phase transformation of diamond into graphite took place during the interaction between diamond and metal. Metal reduce activation energy for transition of diamond into graphite from 109,4 kcal/mole to 77,4 kcal/mole.Kinetic of phase transformation of diamond into graphite was investigated.Pressure does not considerably influence on the rate of phase transformation of diamond into graphite in the presence of transition metals."

Jan 1, 2003

By Paul W. Weiblen, Louis J. Cabri, Rolando Lastra

"Preliminary tests were done to determine whether comminution by electric-pulse disaggregation, or EPD (cf. Rudashevsky et al; 1995), was more effective than using conventional crushing for Merensky Reef ore. A hand sample of the Merensky Reef was sawn in two: then one sub-sample was comminuted to – 2 mm using E-PD at the University of Minnesota, and the other sub-sample was crushed to –2 mm using a conventional jaw crusher at CANMET.The products of the electric-pulse disaggregation and jaw crusher were fractionated by sieving and by a separation using a heavy liquid with a specific gravity of 3.3, because the proportion of platinum-group minerals (PGM) and sulphides to silicate minerals is very low. Thus, four mineral separates were produced: –2000 + 833 µm, -833 +208 µm, -208-µm float and -208-µm sink. All the mineral separates were studied by image analysis (Lastra et al; 1998). The main objective was to determine the liberation of gangue (silicate minerals), chromite, pyrrhotite, chalcopyrite, pentlandite and PGM. In the case of the PGM, a specific image analysis program was written to search and measure these minerals."

Jan 1, 2003

By Sami Makni, Ahmed Bouajila

"To remain competitive in an open market, mining companies are more and more requested to optimise their complex and highly multivariate processes. The increasing amount of process data, brought about by intensive use of instrumentation and the progress in computer data acquisition, enhances the need for more and more powerful and robust tools for the analysis and modelling of the process data. Now, with the emergence of multivariate data analysis (MDA) techniques, on-line clustering of mineral process behaviour is possible and could help in the extraction of valuable process operation indicators. MDA can be used in different mineral processes such as flotation, grinding, smelting etc. In this paper, the focus will be on grinding process as it is the one of the most costly node in the mineral processing scheme (i.e. power consuming) and it is a highly multivariable process. Particularly for primary grinding mills (SAG/AG), more instrumentation outputs and more powerful and significant process indicators are needed for efficient control and optimisation.MDA is a novel approach suitable for understanding mineral process behaviour compared to the traditionally approaches based on empirical and phenomenological modelling. Multivariate techniques can be used for several purposes. In this paper, the following objectives will be addressed:operation diagnosis: Shift differentiation and operation test differentiation can be showed by using MDA tools such as principle component analysis and factorial discriminant analysis.operation performance monitoring: operation regimes can be evaluated by clustering based on an economic criterion performance such as costs, tonnage, product quality, profit, etcIdentification of operation behaviour (monitoring) and selection of drift correction trajectories (control):MDA can be used to identify periods of unusual or abnormal process behaviour and to diagnose, if it is possible, causes for such behavior."

Jan 1, 2003