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By Xiaoping Xu

An albitization granite type tantalum-niobium ore from Jiangxi Province, China was taken as the research object in this paper. The main valuable minerals in this ore are tantalite-columbite and uranmicrolite, and the minerals that can be comprehensively recovered include cassiterite, sulfide minerals, topaz, zinnwaldite, and quartz-feldspar. Based on the research results of process mineralogy, the roughing process of gravity separation for coarse particles combined with flotation for fine particles is proposed. The combined cleaning process of flotation-gravity-magnetic-electric-hydrometallurgical separation is adopted for the rough concentrate of gravity separation while the combined cleaning process of gravity-flotation- hydrometallurgical separation is adopted for the rough concentrate of flotation. High intensity magnetic separation is used to separate and recover zinnwaldite and quartz-feldspar from gravity tailings. By mineral processing for the crude ore containing (TaNb)cassiterite concentrate is 0.0003% with a grade of Sn 63.22% and a recovery of Sn 47.42% while the yield of sulfide concentrate is 0.0783% with a grade of Pb 33.15% and Zn 27.09% which can be separated to get lead and zinc concentrate respectively. The yield of topaz concentrate is 0.1545% and the topaz mainly distributed in the size range of -0.4+0.074mm, which can be made into abrasive products of different particle sizes after classification. The yield of zinnwaldite concentrate is 16.91% with a grade of Liwhiteness of 75%, which is a glass-ceramic material of good quality. 2O5 0.0346%, Sn 0.04%, Pb 0.10% and Zn 0.33%, the tantalum-niobium concentrate with a yield of 0.00278%,a grade of (TaNb)2O5 53.61% and a recovery of (TaNb)2O5 44.49% is obtained. And the yield of 2O 1.34% and Rb2O 0.40%. The yield of quartz-feldspar concentrate is 30.42% with a grade of K2O+Na2O 8.98% and Fe2O3 0.11% and a natural All of tantalum, niobium, cassiterite, topaz, zinnwaldite, quartz, and feldspar are recovered effectively. Keywords: tantalum-niobium ore, gravity separation for coarse particles, flotation for fine particles, comprehensive recovery

Sep 1, 2012

By Xianjun Lu

This paper presents gold occurrence investigations on the altered rock gold deposit from Jiaodong area of China, and comparisons of gold occurrence in the ore samples from different mining levels. According to the results, the chemical and mineral compositions of raw materials from different mining levels are quite similar. However, the relative content and grain size of gold minerals are quite different between the two mining levels of -130m~-340m and -550m~-650m. In the ore of upper mining levels of -130m~-340m, electrum is the dominant gold mineral and accounts for about 80% of the total gold minerals, while native gold is minor and accounts for about 20%. As for the ore of deep mining levels of -550m~-650m, the major gold mineral shifts to native gold which accounts for 67%, while the ratio of electrum drops to about 33%. Coarser gold grain size was observed in the upper mining level ore with a mean size of 33.05µm while the gold grain size was much finer in the ore of deep mining levels with a mean size of 22.85µm. Furthermore, the gold mineral associations also show different patterns between the upper mining level samples and the deep mining level samples. Of the three observed gold association types such as inclusion gold, fissure gold and interparticle gold, more inclusion gold was found in the ore of deep mining levels. The inclusion gold accounts for 62% in the ore of deep mining levels, while that in the ore of upper mining levels accounts for about 56%. Further study revealed that the dominant gold associated minerals are pyrite and sulphides and only a small amount of gold is associated with quartz and silicates. It was shown that the altered rock gold ore from Jiaodong area can be regarded as a free milling gold ore, but the processing parameters should be optimized for the ores in different mining levels according to the different gold occurrence. In addition, it was predicted that enhanced gold liberation is necessary for the ore in deep mining levels.

Sep 1, 2012

By A-M Ahonen

The paper discusses the experiences of a fast-track curriculum designed to provide the industry with engineers capable of working in minerals processing industry. The course has been done once before and the second course has been started. Students chosen have graduated from other fields of engineering. For the first course, twelve students were chosen from 152 applicants and for the second the twelve students were chosen from 96 applicants. The basic idea of the curriculum is to alternate between theoretical studies at the university and working experience periods at industrial sites. In addition, there are several one week assignment tasks at industrial sites. The theoretical periods are six to eight weeks long and there are three of them. During the first period, the teaching concentrates on unit processes and their chemical and physical background. The theme of the second period is mineral engineering systems; flowsheet development, process dynamics, control systems etc. The last theoretical period teaches environmental issues, leadership, project work and other similar topics. Each of the theoretical periods ends with an assignment week at industrial sites. The assignments are designed to wrap up the teachings of the period. For the industrial periods, the students are given learning goals, which have been discussed and designed with their industrial mentors. They are required to find relevant literature, make experimental designs, implement those designs, present the data, and make conclusions of their results. During these periods, a weekly meeting over the Internet is compulsory. Keywords: mineral processing, flowsheet development, process dynamics, control systems, constructivism, zone of maximal development, Vygotsky

Sep 1, 2012

By L. Pan

As an air bubble approaches a mineral surface, a thin liquid film (TLF) is formed in between. The excess pressure (p) in the film determines the kinetics of drainage, which is of critical importance in flotation. We have developed a new method of monitoring the kinetics for both stable and unstable wetting films and analyzed the results using the Reynolds lubrication theory. It has been found that initially a TLF is thinned by the Laplace pressure (pcur) due to changes in bubble curvature and subsequently by the disjoining pressure (?) created by the surface forces present in a wetting film. In the present work, we have derived an analytical expression for determining ? from the temporal and spatial profiles of TLFs on mineral surfaces. The results show that ? > 0 in a film formed on a hydrophilic surface and ? < 0 in a film formed on a surface hydrophobized by collector. Thus, the role of collector in flotation is to create a hydrophobic force and hence a negative disjoining present in wetting films. It is also found that smaller bubbles can create higher Laplace pressure, which helps the TLF drain faster.

Sep 1, 2012

By P. Prusti

An air dense medium fluidised bed separator (ADMFBS) is the efficient process for dry beneficiation of coal. Magnetite powder is used as medium to make required pseudo-fluid density in the fluidised bed. The dynamics behavior of coal particle with reference to its position changes from ideal solution to pseudo-fluid condition in different bed densities depending on its shape, size and density. In this study, three set of projected areas of coal particles were taken. Each set contains four different shapes i.e., cubical, rectangular prism, spherical and triangular prism with different density starting from 1.3 to 1.8 gm/cc. It is observed that coal particles having density less than the bed density, floats in different positions in the dense medium fluidised bed. Higher projected area particles float in deeper height in comparison with smaller projected area. The difference in position of coal particles in the bed increases (nearly 1 to 4 cm) as the coal density approaches towards bed density irrespective of the different shapes. Different shapes of coal particles behave in different ways based on the operating parameters like bed density, coal density and projected area of coal particle. Empirical model equations are proposed to predict the position of coal particle of each shape in the air dense medium fluidised bed system. Keywords: ADMFBS, particle dynamics, projected area, shape

Sep 1, 2012

By Katja Ohenoja

Polymer dispersants, also known as grinding aids, are widely used to reduce the viscosity of mineral particle suspensions and to improve energy efficiency during fine grinding. In this study, the effect of polymer dispersant with different molecular structure on the suspension properties in the wet stirred media milling of limestone was studied. The stability of suspension was studied by combining rheological and zeta potential measurements. The PDI value of polymers corresponds to the width of the molecular weight distribution so that low PDI corresponds to narrow MW distribution and high PDI to the wide one. In this study, two traditionally fractionated polymer dispersants with high PDI (over 2) and one novel polymer dispersant with low PDI (1.2) has been tested. It was noticed that dispersants worked as electrosteric stabilizators and prevented the agglomeration of ground limestone particles. The uses of dispersants could increase solids concentration used in the grinding experiments and at the same time lower the particle size and specific energy consumption. The obtained particle sizes were about 1 µm regardless of which dispersant was used or the amount of it. The novel dispersant with low PDI reduced viscosity most when compared with the traditionally fractionated polymer dispersants. Results indicated that even higher solids concentrations can be used at the same amount of dispersant when the novel low PDI polymer dispersant is used. Alternatively, lower dosage of novel low PDI dispersant can be used compared to traditionally fractionated dispersants.

Sep 1, 2012

By S. Swaroopa

Copper-chromium mixed oxides are widely used as catalyst for organic chemicals industry, NOx and CO oxidation, solid propellant etc. In the present investigation, one such spent Cu-Cr catalyst has been tested for recovering copper and chromium values through hydrometallurgical route. The spent catalyst used in this study contains about 42% Cu and 36% Cr. Phase analysis through XRD indicates that major phases are copper chromium oxide (CuCrO2) and copper chromate (CuCr2O4) while minor phase is copper oxide (Cu64O). SEM images show that high energy ball milling changes surface morphology significantly ? more regular shaped grains in unmilled samples changed to fine agglomerates. Surface area also changes significantly due to milling. Preliminary leaching experiments with NH3 and H2SO4 media using unmilled samples indicate that both the media are suitable for selective extraction of copper. About 55% copper recovery is achieved in 2 h using 1.2 M NH3 + 0.2M (NH4)2SO4 solution at 100°C. Increasing NH3 concentration or temperature does not improve the recovery significantly. Under the above conditions chromium, dissolution is insignificant (max. 2.24%). XRD analysis of the residue indicates that copper chromate fraction (CuCr2O4), which is a spinel structure, remains mostly intact. In sulphuric acid media at ambient temperature, 47% copper recovery is achieved with 7.5% (v/v) H2SO4 and maximum of 57% with the increase in acid concentration to 20%. However, 67% recovery is achieved by increasing the leaching temperature to 150°C. High energy ball milled samples show improved leaching efficiency. Under the leaching conditions of 7% H2SO4 (v/v), 2% pulp density, 80°C an unmilled sample yields 47% Cu recovery whereas 3h and 5h milled samples yield 65% and 90% Cu recovery respectively in 2h leaching time. Influence of temperature is also more pronounced in milled sample leaching in comparison to unmilled sample. Water leaching of alkali (NaOH) roasted milled sample carried out at 750°C for 2 h with 100% NaOH (w/w) resulted in 80% Cr recovery as compared to 37% Cr recovery using unmilled sample under the same conditions. Keywords: spent catalyst, copper, chromium, leaching, mechanical activation, roasting

Sep 1, 2012

By G. Semenchenko

Heterotrophic microorganisms Pseudomonas aureofaciens, microscopic fungi Fusarium sp. and their combinations with some chemical substances were used for gold leaching from refractory ore and flotation concentrateof Akbakaj deposit. All biological additives raised the speed of noble metals dissolution. The best results of gold extraction from ore were in the presence of bacteria or their associations with other solvents and from flotation concentrate in the presence of fungus - 30 % of additional amount of gold. The maximum extraction of gold speed value was during the first 8 hours of process. The electronic-microscopic researches of the ore samples showed almost complete decay of pyrite and arsenopyrite under bacteria influence whereas at chemical leaching most of these minerals stayed uncrushed. The presence of microscopic fungi in flotation concentrate during leaching provided full distraction of pyrite, but some crystals of antimony and arsenopyrite were undestroyed. During cyanide leaching of flotation concentrate there were accumulation of antimony and incomplete pyrite decomposition. Keywords: gold bioleaching, bacteria, fungi, complex solution

Sep 1, 2012

By G. K. Palshikar

Mining operations offer many opportunities for the use of IT and communication technologies to improve automation and thereby deliver higher levels of productivity, cost, quality and safety. In this paper, we discuss a particular application, namely, building a fully automated train control and operation system within a mining area. We first outline the basic architecture and functionality of such a system and then present a real-life case study where the railway system within a remote iron ore mine in Canada was converted to a fully automated train operation system. This hard real-time safety-critical system required the use of advanced technologies such as embedded systems (e.g., on-board train controller), radio communications, formal methods, optimal scheduling, and extensive simulations. We focus on the design aspects for maintaining the system in safe states.

Sep 1, 2012

By G. N. Jadhav

In India, bauxite deposits are concentrated in Central India, Western Ghats and Eastern Ghats. Bauxites from various regions in Gujarat were identified during the present investigations of geochemical mapping. Different types of Bauxites samples were collected from Kachchh, Jamnagar, Porbunder, Junagarh, Bhavnagar and Amreli areas of Gujarat state and were studied in detail for their geochemical signatures to plot the data on Geochemical map. Raw bauxites were characterized by using powder XRD, XRF, ICP and optical microscopy techniques (with the help of Model microscope having both transmitted and reflected light setups) and were later examined to grade their quality. Most of the bauxites from Kachchh region were of high-grade (gibbsitic) type; while those of Sourashtra region were of low-grade (lateritic / calcitic) types. Most of these bauxites were either of ferruginous/lateritic or of calcareous/calcitic types. Based on the mineralogical composition, such as gibbsite, hematite and/or goethite, Kaolinite and calcite minerals present in particular bauxites, the deposits were graded. Finally, the Geochemical mapping of Bauxites for Gujarat region was prepared and discussed.

Sep 1, 2012

By Robert Dunne

A review of the current ?state of the art? of refractory gold treatment will be provided. This will include a global perspective of the refractory processes that are being practiced, where they are and some discussion on why the processes were selected. Some discussion on the challenges that face the refractory gold industry will also be provided.

Sep 1, 2012

By Harshad Bhagwat

The objective of this work is to investigate the inadequacies of current CFD based methodologies of model development for predicting combustion behavior of pulverized coal in furnaces. In the present paper, a steady state CFD model was used for in-depth analysis of pulverized coal combustion. The model accounts for turbulence, coal combustion, convective and radiative heat transfer and motion of coal particles. It also uses coal combustion models to account for important processes such as devolatilization, combustion of char and the evolution of fuel nitrogen during coal combustion. The model predicts fluid flow, heat transfer, progress of combustion and pollutant formation (NOx, etc.). The model uses several parameters, which need to be tuned with experimental data, which is not only limited in quantity but also insufficient in detail. Various existing methodologies like part calibration method for tuning of the parameters are discussed. In the present work, the parameters associated with coal combustion models were tuned and validated with published data obtained from an experimental furnace using one such part calibration methodology. The results clearly show that the model predictions differed with the experimental data not only quantitatively but also qualitatively. These discrepancies were attributed to part calibration methodology. A detailed parametric study was carried out to demonstrate the importance of parameters from various classes, namely, combustion kinetics, heat transfer, process and geometry parameters, and CFD model parameters. This investigation clearly indicates that parameters from different classes have significant effect on combustion behavior. The discrepancies in current methodology are discussed and a need for comprehensive methodology is highlighted. Keywords: pulverized coal combustion, computational fluid dynamics (CFD), pollutant formation (NOx), mathematical modeling

Sep 1, 2012

By T. Surkova

For the moment reserves of high-grade ores are practically depleted requiring ever-increased involvement of low assay raw materials, such as black-shale ores, in industrial operations. Black-shale ores are constituted of minerals containing such valuable components as vanadium, uranium, molybdenum, manganese, and rare-earth elements (REE). We studied technogenic solutions of black-shale ores processing, after uranium, molybdenum, and vanadium were recovered. Mentioned solutions contain rare-earth elements in substantial quantities (S REE 70-100 mg/dm3) that is very important factor taking into consideration the world demand ever-increasing last years. Higher concentrations of iron and aluminum inhibiting REE sorption and extraction recovery are found in solutions. We propose a method of hydrolytic deposition to cleaning solutions from impurity elements (Fe, Al). Study of hydrolytic deposition kinetics allowed identifying optimal conditions to run this process. Rare-earth elements may be recovered from purified solutions through sorption process followed by their further deposition from eluates in form of concentrates. Keywords: black-shale ores, rare-earth elements, a method of hydrolytic deposition, impurity elements, sorption

Sep 1, 2012

By Zehong Wang

Selecting sodium polyacrylate (PAAS) as grinding aid, the effect of grinding aid on the grinding efficiency of bauxite taken from Shanxi province was studied and its mechanisms were analyzed by measuring the variation of adsorption characteristic, pulp viscosity, surface electric potential of the bauxite and the surface appearance of particles. The results showed that, compared with no grinding aids added the content of -0.074mm in the ground product was increased by 5.45 percentage points under the optimal grinding conditions adding PAAS as grinding aid when the amount of PAAS was 0.7%wt of bauxite. Because the physical adsorption and chemical adsorption were occurred on the bauxite surface, which could reduce the pulp viscosity, change the surface electric potential of the bauxite, enhance the surface appearance of particles and lower the surface hardness of the bauxite, the grinding efficiency of bauxite was increased by PAAS. Keywords: bauxite, grinding aids, grinding efficiency, mechanism

Sep 1, 2012

By L. Tong

Stirred milling of laterites offers possibilities for improving liberation and selective size reduction of soft nickel-bearing minerals in laterites. Batch grinding tests were performed in a Netzsch LME4 stirred mill on a siliceous goethitic (SG) nickel laterite sample (-2000 µm particle size) to evaluate the effect of operating conditions such as stirrer speed, grinding time, pH, solid content, water salinity and charge volume. The target was to produce a -38 µm fraction in the milling product with high nickel recovery and grade. Addition of dispersant (sodium hexametaphosphate) was also optimized with respect to the rheology of the slurry. In terms of stress intensity, the optimum grinding conditions for selective size reduction were: 1000 rpm, 50 per cent charge volume. At higher stress intensity (2000 rpm), Ni recovery in the -38 µm product was higher, but Ni grade was low, due to the breakage of the harder siliceous particles. Decreasing the yield stress by modifying slurry pH or adding dispersant improved the rheological properties of the pulp, but had no great influence on Ni upgrade in the fine product. Modifying water salinity by adding 2 M NaCl had also little effect. The breakage of the +38 µm particles in the feed determined Ni upgrade greatly. Ni grade in the -38 µm product decreased with grinding time, suggesting that the Ni-bearing minerals break first, while the harder siliceous minerals have a lower breakage rate. The breakage rates with respect to sample mass for Ni, Mg and Si indicate that: Mg > Ni > Mass > Si. The optimum grinding time for the highest Ni upgrade was 0.25 min. The Ni grade increased from 0.88 per cent to 1.35 per cent (upgrade 54 per cent), with 24 per cent Ni recovery. Keywords: fine grinding, stirred media mill, nickel laterite, slurry rheology

Sep 1, 2012

Considerable attention has been, and is being, given to the physics of water-films associated with bubble interactions at surfaces. In contrast, little information on the chemistry of such films has been reported. This communication reports a method using sum frequency vibrational spectroscopy (SFVS) to describe hydrogen bonding of interfacial water molecules in water films created with bubbles at hydrophilic and hydrophobic surfaces. The SFVS spectra of water films at hydrophilic silica surfaces differ significantly from the spectra of water at a hydrophobic silica surface. The SFVS spectra indicate that a very ordered water structure exists in water films at the hydrophilic silica surface during contact with a bubble and that the extent of hydrogen bonding increases with an increase in contact pressure. Such structural considerations as well as repulsive electrostatic and Van der Waals forces account for film stability for a bubble at the hydrophilic silica surface. In contrast, the SFVS spectra of water at a hydrophobic silica surface show a lack of hydrogen bonding and are characterized by a distinct absorption at about 3700 cm-1 similar to the spectrum of the air/water interface. These results suggest the presence of a water void, or water exclusion zone, at the hydrophobic surface, as supported by X-ray reflectivity measurements reported in the literature, by atomic force microscopy, and by the results from molecular dynamics simulations. Of course the water film at the hydrophobic surface is unstable with film thinning and rupture upon bubble contact. Under these circumstances it is shown that an attractive Van der Waals force between the bubble and the hydrophobic surface can be expected when the water exclusion zone is taken into consideration. As the thickness of the water exclusion zone increases to a thickness corresponding to the size of nano bubbles, the calculated attractive Van der Waals force increases. This analysis may help to explain the so-called ?short range? and ?long range? hydrophobic forces. Keywords: SFVS spectra, hydrophilic silica surface, hydrophobic silica surface

Sep 1, 2012

Producing robust agglomerates with desirable structural properties is the key to success of the heap leaching of complex, low-grade nickel laterite ores. Mechanically strong but porous agglomerates with narrow size distribution (e.g., 5 ? 40 mm) are required to build permeable and perennially stable heaps of 4 ? 10 m height. The characterization of granules? microstructure is essential for greater understanding and correlation with the concomitant mechanical properties and robustness. In this study, we used non-destructive, computed X-Ray tomography analyses and scanning electron microscopy (SEM) in tandem with conventional compressive strength,and integrity/stability tests to draw links between nickel (Ni) laterite agglomerate strength/stability, internal microstructure (e.g.,porosity, inter-particle bridges) and binder type. It is shown that binder composition (e.g., tap water vs. 30% w/w H2SO4) and post-agglomeration drying both significantly impact on granules? physicochemical and microstructural properties. Acidic binder, in contrast with tap water, leads to significant incongruent leaching of different species from particles during ore-binder mixing and agglomeration. Upon wet agglomerate curing, solidified/recrystallized leached species form strong intra-granular solid bridges which, lead to greater compressive strength of dry agglomerates. Structural stability/integrity of cured agglomerates in acidic solution, however, decreases dramatically due to greater porosity and acid solubility of intra-granular solid bridges. These findings are useful in shedding more light on agglomerate structure characteristics and their optimization for enhanced column and heap leaching with concentrated sulphuric acid.

Sep 1, 2012

By S. Serranti

A fast, reliable, and low cost characterization of ore minerals products, as they result from different processing actions, represents one of the most challenging targets in the mineral processing sector. Today different techniques are available according to different sampling strategies and analytical principles. In this paper, the possibilities offered by the adoption of hyperspectral imaging based sensing units working both at micro- and macro-scale are presented and discussed. According to the different phases and stages of ore minerals and products characterization, and starting from the analyses of the detected hyperspectral firms, it is thus possible to derive useful information about mineral flow stream properties and their physical-chemical attributes. This last aspect can be utilized to define innovative process mineralogy strategies and to implement on-line procedures at processing level. The present study discusses the effects related to the adoption of different hardware configurations, the utilization of different logics to perform the analysis and the selection of different algorithms according to the different characterization, inspection, and quality control actions to apply. Keywords: process mineralogy, hyperspectral imaging, NIR spectroscopy, surface mapping, textural analysis, quality control

Sep 1, 2012

Hydrofluoric acid (HF) is traditionally used in plant operation to separate feldspars from quartz. It acts during the conditioning step as a pH regulator and an activating agent providing an excellent selectivity. However, a corrosive chemical environment and the ecological impacts from the potential fluoride ion contamination are limiting factors to use this chemical agent at an industrial scale. Investigations of the amine-feldspar interactions in the absence and presence of non-linear long-chain alcohols were carried out on two ore samples. The presence of alcohol molecules led to form a closed packed layer only on the surface of feldspars. The highest order and packing at the feldspar surface were observed with a particular alkyl chain structure as Guerbert alcohols. A new flotation process was developed and tested at both lab and pilot scales on different feldspar ores. The Guerbert alcohols allow to perform a feldspar concentrate with very low content in quartz (2.3-3.5 %) and feldspars recovery from 78 to 81 % while the aliphatic isoalcohols show a more higher recovery level (88-89 %). New HF-free process is strongly dependent on the pH range (1.7-2.5) and sulphuric acid consumption during conditioning steps. Optimal amine/alcohol weight ratio is ranged between 0.8 and 1.0. The values below 0.8 decrease strongly the flotation selectivity and the quartz recovery within the feldspar concentrates is higher than that occurs with HF.

Sep 1, 2012

By L. Rintala

The design of a hydrometallurgical process starts with the analysis of the raw materials to be treated, for example mineralogy, chemistry, deposit size are analysed. Based on this information suitable unit processes for pre-treatment, leaching, solution purification and product recovery are selected. Typically, process design for the new ore deposit relies on laboratory tests such as pre-treatment and leaching experiments. The experimental work is the most time consuming and expensive part of the process design. Reducing the number of experiments would shorten the time of designing a new flowsheet or development of new process technology. A large amount of information is available about the hydrometallurgical experiments and the amount is increasing continuously. For example, word search using ?hydrometallurgy? from Scopus database results in over 4 000 publications with the word in title, abstract or keywords. This number consists of 2 500 articles, 900 conference papers, and 90 reviews since 1972. The number of hydrometallurgical publications per year has increased from 13 in 1972 to 150-200 in the last few years. The objective of this study was to analyze how detailed data of experiments about the gold extraction is published and how that data could be exploited more effectively when designing hydrometallurgical processing for new ore. The leading idea is that similar ores should have the similar response in leaching. If the published information was used more efficiently, the amount of experiments would be reduced. More than 200 cases of experimental data of gold leaching have been analyzed for this study. There are over 30 factors that could be used in comparison when selecting process alternatives, but challenging fact is that not all these factors are documented in all publications. Results show that the usefulness of the published data in the development of hydrometallurgical flow sheet for gold using decision-support tools is not that straightforward. The quality of the published information about gold extraction varied between the publications and the descriptions of the raw materials, experimental arrangements and results were often missing details. Methods to normalize the data for description of the cases and a system to describe different features unambiguously are needed. Keywords: refractory gold, host mineral, leaching, data analysis, case-based reasoning

Sep 1, 2012