Table of contents

MINERAL ENGINEERING CONFERENCE MEC 2018

September 26^th-29^th, 2018

Zawiercie, Poland

Preface

The Mineral Engineering Conference MEC 2018 was held in Zawiercie, Poland and gathered over 100 participants. It followed the tradition of earlier conferences where mineral engineering science and industry can meet and exchange ideas. MEC has become one of the most highly acclaimed meetings in the field of mineral engineering in Europe. The MEC2018 for the third time is consisting of 14th International Conference on Non-Ferrous Ore Processing (ICNOP), 55th Symposium of Physicochemical Problems of Mineral Processing and 23rd International Conference of Mineral Processing.

The Conference welcome ceremony hosted vice-rector of The Silesian University of Technology prof. Bogusław Łazarz, Vice President of the Management Board of KGHM Polska Miedz S.A. Radosław Stach and senator of the Republic of Poland - Adam Gawęda. Plenary session was devoted to 20^th anniversary of copper ore enrichment plants of KGHM Polska Miedz SA and consisted of 4 speeches given by notable guests such as Prof. Tsuyoshi Hirajima, Prof. Andrzej Wieniewski, Dr Andrzej Grotowski and Miroslaw Kidoń from the Sierra Gorda SCM.

Seven sessions of the conference were devoted to Physicochemical Problems of Mineral Processing, Mineral Processing and Hydrometallurgy. One technical session was devoted to companies presenting their solutions and products for the mineral industry.

The conference series contains only selected articles but it gives an overview of current situation of mineral engineering and related fields.

Editors

Dr. Marcin Lutyński, DSc, Eng.

Dr. Tomasz Suponik, DSc, Eng.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The article presents the results of phase composition analyses of Zn-Pb slags based on selected structural tests. Based on these tests it has been found that the application of several complementary research techniques may provide reliable information regarding the presence of individual phases. In view of obtaining qualitative characteristics of the components of slags, the phase identification tests by means of X-ray diffraction were found to be precise. Based on them, also the percentage of the individual crystalline phases and the percentage of the amorphous substance have been determined. Studies using electron scanning microscopy and X-ray spectral microanalysis allowed for the determination of the chemical composition of the individual components. In that case, the X-ray spectral microanalysis was found to be more precise and it allowed for the identification of substitutions of elements occurring in small amounts in the crystalline phases, i.e. the rare earth elements.

Copper and its alloys are used for diverse applications that are required for us to attain a specific standard of life. Continuous copper production and use are needed for the development of the society. Future copper demand will be covered mainly by the discovery of new deposits and mining. However, technological improvements and efficient designs intended to limit copper consumption will be equally important, similarly to recycling, as part of the activities associated with circular economy. Current data indicate that the global extraction of copper reached 20.2 million tons in 2016, while the output from metallurgical plants attained the level of 19.0 million tons in the same year. However, the refined copper production output increased to 23.3 million tons in 2016, including 3.9 million tons obtained from recycling. One can ask the question: Can we run short of copper, considering the present 6% increase and projected further increase of copper extraction and use? This paper is trying to find an answer to this question, based on such factors as copper resources and their long-term availability, global distribution of identified and projected copper resources, global extraction rates, and the trends in copper extraction capabilities.

Dry separation method was used at the beginning of 20^th century to separate coal separation process. First industrial applications of dry separation took place in the middle of 1930s. At that time air separator Frazer-Yankey, based on aero suspension was used in in Pittsburgh and Lundale, West Wirginia coal preparation plants. Later, some more constructions like RAW air jig, air table "V" type Birtley, air jig type Kirkup, air table "V" type Peale-Davis or air jig type Bruay-Soulary were constructed. Fast development of wet technologies of processes, especially jigging and heavy dense medium separation caused the discontinuation of the further development of dry separation methods and replacement of dry preparation plants with plants based on wet methods of enrichment. At the end of 20^th century and beginning of 21^st century dry separation method started once again to be widely used in the world. New types of equipment like FGX vibrating air table, TFX air jig or KAT process technology were introduced to wide applications in Asian countries. The paper describes few constructions of old air separators and new ones, used nowadays. It contains comparison of the separation results obtained by means of various equipment and shows possibility to separate coal in laboratory scale air jig.

β-diketones were used for Co(II) and Ni(II) separation from nitrate solutions by liquid-liquid extraction method. Pentane-2,4-dione (1), 3-methyl-pentane-2,4-dione (2) and 3-ethyl-pentane-2,4-dione (3), all in dichloromethane solution were extractants in this process. Potentiometric studies were used to determinate dissociation constants of investigated ligands. Stability constants of the created complexes were found by spectrophotometric methods and the increased in the order of 2 < 1 < 3. Extraction was carried out from three types of aqueous phase: one-component Co(II) or Ni(II), and two-component Co(II)-Ni(II). It was proved that pentane-2,4-dione (1) is the most effective extractant.

The recovery of Cu(II) ions from chloride solutions by the transport of a binary Cu(II)-Zn(II) and Cu(II)-Cd(II), and a ternary Cu(II)-Zn(II)-Cd(II) mixture ions through inclusion membranes doped with 1-decyl-2,4-dimethylimidazole (DDMI) was studied (cM(II) = 0.001 M; pH 5.5). The efficiency of metal ions separation by DDMI increased as: Cu(II) > Zn(II) > Cd(II). Selectivity coefficients Cu(II)/Zn(II) and Cu(II)/Cd(II) were equal 1.5 and 13.5, respectively for binary solutions and 1.6 and 27.7 for ternary solution. The step limiting the rate of transport of metal ions by PIM doped with DDMI may be membrane diffusion coefficients of cation complexes with DDMI. The recovery factor of Cu(II), Zn(II), and Cd(II) ions during transport across PIMs from an equimolar mixture of cations after 24 hrs was above 96%, 60% and 3.5% for Cu(II), Zn(II) and Cd(II), respectively. PIM containing DDMI are stable for 120 hrs.

Depressants are one of the most important reagents in flotation process. They are used to improve upgrading selectivity. Natural depressants, especially starch and its derivatives, are one of the most significant polysaccharides used in polymetallic sulphide ores flotation. In the paper influence of dextrin on flotation of copper, organic carbon and mineral components from rougher concentrate was investigated. It has been shown, that dextrin is a good depressant for organic carbon and clay minerals with micas as long as the appropriate collector for sulphides are added. Moreover, significantly better flotation of all copper sulphides and pyrite with marcasite was observed, in comparison with flotation test using collector and frother only. Using dextrin as a single reagent does not affect beneficiation of examined concentrate. However, dextrin had not depressed galena particles. It can suggest that various factors can influence on good flotation of galena, e.g. associations with other sulphides, mineral composition and structure of examined feed.

Influence of height of foam on salt flotation of copper-bearing shale, having different Cu and organic carbon contents, was investigated. It was found that the yield of flotation of copper-bearing shale in the presence of NaCl is directly dependent on the content of organic carbon and height of foam produced during flotation. It has been shown that the height of flotation froth h depends on type of shale, and its variation can be described by formula h/h_max = 1/(t+1)ⁿ, where t is the time of flotation and n is a constant.

Coal can occur in various natural forms and its quality depends on its various properties. Polish coal mines extract and process various coal types, according to the Polish nomenclature. The paper presents an attempt of determining whether is possible to statistically differ the typical coal types occurring in Polish hard coal mines by means of traditional statistical tests. To this purpose three coal types, namely 31, 34.2 and 35 were selected from three Polish mines located in Upper Silesia. After appropriate preparation of the raw coals selected coal properties were examined, including combustion heat, ash contents, sulfur contents, volatile parts contents and analytical moisture. Then, by means of several statistical tests it was verified whether it is possible to prove statistically that these coal types differ significantly not knowing the type of distribution they represent. To this purpose such tests as Kruskal-Wallis test, test of series, Wilcoxon test and median test were applied. The results were statistically evaluated and the conclusions were made. The presented methodology may serve to compare not only coal types but also other raw materials.

The paper presents the preliminary studies concern the results of Polish copper ore beneficiation in Jameson cell. To investigate the simultaneous influence of flotation machines type, grain size (0-25, 25-45, 45-75 μm), type (isobutyl and ethyl xanthate aqueous solution) and dosage (100, 150 g/Mg) of collector, flotation time on the efficiency of the process, the multi-level experiment has to be performed for carbonate lithological type of copper. Compering results of flotation test it can be concluded that the best results were obtained for 0-25 µm with the use of isobutyl xanthate aqueous solution in a dosage equal to 100 g/Mg. Tests of significance (MANOVA, ANOVA) showed a high influence of factors on the difference between an efficiency of separation in the most cases. This paper shows an attempt to create a model for the copper ore enrichment process at Jameson cell. The equations were described using a logarithmic substitution. The model evaluation was made based on mean squared error MSE and coefficient of determination R².

The aim of the article was to verify the possibility of using open source digital image analysis software to determine the particle shape. Devices using laser diffraction or dynamic image analysis could be used to determine size and shape of particles. However, the laboratory devices for digital image analysis are relatively expensive. For this reason, it was decided to use open source digital image analysis software Fiji Is just ImageJ and mobile phone with a 12 Mpx camera. Coarse aggregates of basalt and granite were used in the study. Flakiness index (FI) and shape index (SI) were determined using two methods: in accordance with the European Standard and with the use of digital image analysis (reference method). Based on the obtained results it was found that there is an appropriate relationship between the European Standard method and the reference method.

Separation curves such as kinetic (recovery R versus process time t), limits (kinetic constant k versus maximum recovery R_max), incentive (R vs incentive parameter i), and arrheniusan (ln k vs 1/energy - for a regent concentration (i = c) being kT·ln(c/c_o)), were characterized and discussed. Their usefulness for flotation was described and relations between the curves were presented. All the separation curves provide valuable parameters. The arrheniusan curves are exceptionally useful because they deliver activation energy, expressed in the terms of energy, a parameter indicating how well a separation system responds to a change of an incentive parameter. The incentive parameter can be temperature, reagent concentration, pH, particles size and many others.

This paper investigates application of Artificial Neural Network (ANN) for dolomite oil agglomeration modelling including parameters such as surfactants concentration, oil dosage, time, pH and mixing intensity. The main algorithm implemented for weights calculation was the Levenberg-Marquardt (LM) method. Common problem during process design of neural models is suitable selection of structure complexity. It is known that several connection can influence on final results after off-line training. For improvement of this stage of preparation of the net, pruning method was implemented. Analysed algorithm was based on the main theory of Optimal Brain Damage (OBD) technique. Results present high quality of process recovery prediction. Achieved outcome also shows that reduction of the applied of the neural network can lead to higher precision of calculation.

Morphological properties of mineral particles, in particular their size and shape, play a fundamental role in the course of mineral raw materials processing. They affect the efficiency of grain classification and downstream beneficiation operations. The article presents the results of the size and shape distribution for the particles after the comminution process. The measurements were made with using a vision system with dynamic image analysis. The aim of investigations was to evaluate the applicability of this technique for control of the particle size of raw material products crushed in various laboratory crushing devices.

Antifiltration barriers are used to secure deep excavations and flood embankments as well as to prevent the penetration of harmful substances into the ground and groundwater, also as part of the environmental protection system of waste landfills and production plants. The barriers are usually formed from a liquid suspension with binding properties which, after being pumped to the destination, passes into a solid with a fixed strength. One of the main problems of degraded post-industrial areas, preventing their introduction into the secondary economic cycle, is pollution of soil and the impact of pollution on groundwater. The interaction process of contaminated sites is complicated and the transport of pollutants from the place of danger to usable aquifers underground levels passes through a series of varied course. The article presents the possibilities of applications ground binder to reduce the emission of pollutant ions from soils in order to develop new mixtures of binders. The carried out research has shown that in the case of highly contaminated soils (eg Glasgow), almost 100% of heavy metals can be accumulated using clay-cement composites, and also significantly reduce the penetration of aromatic and aliphatic hydrocarbons. Some of the aliphatic hydrocarbons that allowed to enter to the penetrating solutions during measurements also did not exceed the standards.

Results of investigations show that HPGR operating pressure is proportional to the metal recovery, however too extensive pressure values have relatively lower impact on the increase of metal recovery. Particle size distribution of HPGR feed has a lower impact on the recovery level than HPGR pressure which was also investigated in the paper. Flotation tests of each HPGR product were also performed in order to investigate potential impact of various conditions of HPGR process runs on the metal recovery.

Article concerns the issues of ore comminution in HPGR. A series of laboratory tests were carried out for three lithologic types of sulphide ore. Four values of operating pressing force were accepted. Bond's index value, determined with using a standard Bond method, was also determined for all HPGR products. There were also determined functional relationships between Bond index and operational pressure. Results of investigation showed, that application oh HPGR for that type of feed resulted in lowering the value of Bond index. The relationship between the pressing force and Bond index can be approximated with hyperbolic function.

Approximately 7 million tonnes of zinc is annually used for corrosion protection in processes of continuous galvanization and the hot dip processes. Two types of waste are obtained from the process: zinc ash and hard zinc and each of them constitute around 10% of the feed weight. Paper concerns the method of possible separation of metallic zinc from the non-metallic zinc compounds from the zinc ashes – the waste product of hot dip galvanization process. The investigative programme covered the comminution tests of the feed (zinc ash) in selected crushers: jaw crusher, roller crusher and impactor. Results of investigations show that application of individual crushing device results in various breakage of the feed sample. Impact force caused the highest increase in finest particles size fractions of the product, while metallic and non-metallic fractions were comminuted differently. The compression force, in turn, caused the selective comminution, i.e. the breakage of metallic zinc was observed in a higher degree.

The aim of this this paper was to investigate the effectiveness of flotation process depending on the changeable dose of reagents and variable speed of rotor in flotation device. HPGR crushing products were used as a feed in all flotation tests. Efficiency indices, along with Fuerstenau curves, were determined for each test. Both rotational speed and the dose of reagent have affected the flotation results in a lower degree that expected. However it could be possible to determine the optimal dose and rotational speed of rotor that increase the effectiveness of flotation process.

Energy production processes generate mineral waste – products of the combustion of solid fuels and waste from after-treatment systems. This is classified as group 10 waste – waste from thermal processes. For many years such waste has either been recovered or disposed of in landfills (D10 process), according to waste management hierarchy. The most important areas in which combustion waste is utilized are: the production of construction materials, macro-levelling, the rehabilitation of degraded land, and backfilling. Certain types of combustion waste are currently classified as a by-product. Energy mineral waste management is implemented in accordance with the provisions of the Waste Act of 14 December 2012. In spite of the examples of proper combustion waste management given in this paper, the amount of disposed waste had increased by 2016 while at the same time recovery on a national scale had declined. In 2016 both fly ash and compounds of fly ash and calcium-based reaction waste from flue-gas desulfurization in solid form were no longer disposal and the volume that was recovered had increased. The key problem are dust-slag compounds resulting from the wet treatment of furnace waste, almost 90% of which are landfilled.

Authors discuss the problem of how to monitor the coal/water pulsating bed in a jig with the use of a radiation density meter. Time of measurement applied in radiation monitors is usually constant in industrial radiometric monitors. The dynamic error in the process of measuring changes in density depends on the time of measurement; its optimal value can be found for a given shape of density changes. Authors propose an alternative method of signal filtration for variable time of measurement during a cycle of pulsations. Good results can be achieved for a linear relation between the time of measurement and time derivative of the density. The time derivative of the density can be determined for a long period of time on the basis of industrial tests which establish average changes in density in subsequent cycles of pulsations. In this case, the dynamic error of measurement MSE can be reduced by half compared to the optimal constant time of the measurement.

This paper presents the results of the evaluation of the coal flotation efficiency in the presence of an inorganic salt in the pulp. It was shown that change of salt contains (NaCl) in pulp affects to the stability and mineralization degree of floatation foam. These results have confirmed to the effectiveness of enrichment. The quantitative measure of foam quality was the water recovery in this flotation product.

In this study, culture supernatant of Bacillus subtilis KP7 growing on liquid LB medium consisted of 2 % of molasses was used for calcium carbonate synthesis. Synthesis of the calcium carbonate structures was performed in a reactor by mixing CaCl₂ and Na₂CO₃ solutions at 25°C. The calcium carbonate particles were characterized by optical microscopy, FTIR and XRD analysis. In addition, the size distribution and the value of zeta potential were determined. It was observed that properties of obtained calcium carbonate depend on the supernatant amount. The smallest crystals of pure calcite with disordered structure were obtained when the concentration of the cell-free supernatant was 5 % (v/v).

The paper presents selected results of the preliminary laboratory research on the application of histogram analysis to the problem of coal stream homogeneity evaluation. This is an important problem of industrial coal mine output stream quality testing. Image acquisition is fast and cheap, but needs complex analysis techniques. Histogram analysis can be considered to be one of them. There has been proposed a distance measure, and there have been presented analysis results which proved an ability to detect gangue, rock, schist, and even wooden block contamination of the homogenous coal stream. The method needs further improvement and comprehensive analysis of other available options of the RGB-to-grayscale conversion and of histogram comparison to make it more selective. These further research directions have also been described in the paper.

The article presents the method of utilization of rubber waste consisting in the production of coke from a mixture of hard coal and rubber waste from ground tires. In the coke obtained this way, the properties of the coal and rubber mixture were tested, the following indices were determined: reduction properties - CRI and coke strength after the reaction test - CRS.

Mining waste deposits (heaps) consist mainly of the waste rock, however, they may contain significant amount of coal, which was left after the coal beneficiation process. The laboratory tests, that verified possibilities of applying the technology used in the process of gravitational separation of raw minerals for recovery of grain class 6-0 mm are presented. The concept of recovering the combustible materials from mine waste by integration of the jig beneficiation technology with autogenous suspension bed technology is discussed.

The article presents a method for equipment designing and techniques to reduce methane ignition hazard, excessive dust in the place of operation and in conveyor transportation lines as well as methods to eliminate the risk of coal dust explosion. It describes technical solutions, the effects of these solutions and tests' results related to effectiveness of the described air-water solutions as well as water spraying devices. The spraying systems used in longwall shearers and roadheaders, on conveyor belt transfer points as well as the spraying curtains in the roadways are described. A new approach to the assessment of the safety level in the zones protecting against coal dust explosion hazard is also given. Intensity of dust accretion along the explosion protecting zones is analyzed. The spraying device is suggested, the operation of which depends on dust concentration in the ventilation air. The article presents the results of tests on the effectiveness in dust reduction and suppression of methane ignition. The tests were carried out in the laboratory, on testing facilities and in-situ.

The question of introducing new collectors into copper concentrator plants referring to KGHM experience has been presented in this paper. Description of present methodology of flotation reagents testing has been indicated followed by explanation of crucial problems and limitations with proper qualification of reagents. Some attempts to apply scale-up methodology have been reported in technical literature. In this article assumptions of new methodology based on advanced mineralogy tests have been suggested. This methodology should allow the more accurate forecast of flotation performance of industrial plant after the laboratory tests.

Serpentine ore from the Eastern Desert of Egypt was leached with aqueous hydrochloric acid. Experimental statistical design program (ESD) was applied to study the influence of different variables on leaching efficiency (reaction temperature, leaching time and Hydrochloric acid (HCl) to Magnesium oxide (MgO) molar ratio (stoichiometry) where the liquid/solid ratio of 5:1 ml/g was maintained constant along the experiments. The mathematical model and the different contours (curves generated from ESD) were discussed. The results showed that, all the studied parameters are effective. The results have been collected at a 3-D cube showed that at high levels of parameters (4 hrs, 95 °C and 1.6 S), the Magnesium oxide recovery was about 96.5%, while M agnesium oxide recovery was 67.1% at the low levels (2 hrs, 65 °C and 1.4 Stoichiometry (S).

Ores difficult to enrich require the appropriate methodology of tests on enrichment for the preparation of ore for flotation tests and precise mineralogical analytics. A feature which should differentiate the separated ore samples for flotation tests is not only the size of grains, but also their density. These features reflect the characteristics of real industrial streams directed for flotation. The methodology for separating narrow grain classes by means of sieves applied to date did not guarantee meeting these separation conditions. The article presents a new methodology for examining the copper ore enrichment based on, instead of testing samples in grain classes, testing grain size-density fractions. To conduct these tests, the hydraulic classification in the field of centrifugal force which ensures the separation of grain size-density fractions varied in terms of granulation and density was used. Samples prepared in this way were subjected to flotation tests.

In the north of Chile, due to water shortages, the depletion of oxide ores and the abundance of chalcopyrite ore, mining industry is searching for sustainable hydrometallurgy processes that can use alternative water resources. The leaching process must enhance the dissolution of copper sulphide ore that are refractory to conventional leaching. This paper reports a study on the effect of addition of chloride ion using seawater and discard brine in the agglomeration stage of a secondary copper sulphide ore. The effect of curing time on the same ore also is reported. The leaching tests have been carried out in column irrigated with raffinate under ambient conditions. A size distribution with a P80 of 17 mm is used. A maximum of 72% of copper extraction is obtained using discard brine and 68% using seawater. The use of discard brine and seawater are favorable in all the tests performed. Through an Analysis of Variance (ANOVA), it is determined that the curing time has the highest contribution (92.37%) on the percentage of copper extraction.

The article presents the results of laboratory-scale research on the determination of the impact of ball mill parameters and the feed directed to grinding on its effectiveness and comparing it with the efficiency of grinding in a rod mill. The research was carried out for grinding copper ore processed in O/ZWR KGHM PM S.A. The aim of the research was to evaluate the efficiency of grinding in a drum mill dependably on the grinding media used (balls, rods) for various feed parameters - i.e. particle size distribution, mix of lithological type generating different susceptibility to grinding. Determination of the influence of the grinding media type on the efficiency of material grinding is of great practical importance in the designing of optimal grinding circuit. Furthermore, thanks to the acquired knowledge in this area it allows to improve the technological and economic indicators of the copper ore enrichment process.

The paper presents guidelines and recommendations for conducting the grinding process of mineral raw material (copper ore) enabling the achievement of optimal technological indicators. An important practical part of the recommendation is determination of the conditions for using a given type of grinding media, such as rods or balls.

Most of the technological operations related to the preparation of the output to be enriched and to the production of the final copper concentrate take place with the use of water environment. Water management, besides using innovative technical and technological solutions, is a significant factor in the whole copper ore enrichment process. Mine water resources and surface water of the tailing pond named "Żelazny Most" are the two sources of technological water. Its physico-chemical composition is not insignificant for both the flotation process and the machinery and equipment maintenance. The concept of electrochemical protection of the spiral classifier presented in this article is the supplement and alternative for anti-corrosion protection of the machinery and equipment used in KGHM Polska Miedź S.A. Ore Enrichment Plant. The adequate appreciation of the spiral classifier characterisation and the working conditions will allow for the optimal adjustment of cathodic protection installations with the anode polarization system. Research into the development of an effective protection method will combine two complementary types of anti-corrosion protection systems, that is the passive (a protective coating) and the active (a cathodic protection). The effect of the planned research will be the evaluation of the potential possibilities of the corrosive and erosive impact limitation of the spiral classifier working condition. And, moreover, it will lead to an extension of working hours and the reduction in the costs of the technological circuit.

The paper presents study on the working chamber size influence on the technological and economic effectiveness of mineral material grinding in electromagnetic mill. Performance at desired throughput and technological effectiveness is the key issue for the processing apparatus application in the specific technological circuits. The problem of process effectiveness assessment for the specific mill's construction is important for the grinding circuit design and the process operating points' selection. It also allows for the proper control system design and the process optimization according to the specific criteria function. The research with electromagnetic mill was performed in order to assess the influence of the physical parameters of the mill's working chamber on the grinding process effectiveness. Quality factor was based on the chosen grain size fraction increase in the final product. Experiments were performed on electromagnetic mills with the working chamber diameter 200 mm and 320 mm respectively.

The paper presents a new design of a high-energy mill and describes a pilot installation equipped with a high-energy mill with an output of 3-7(8) Mg/h. The mill design was developed on the basis of a beater wheel mill used to pulverize coal. The potential of reaching good grinding results has been confirmed for the new mill. Achieved degrees of grinding for copper ore initially crushed in hammer and cone crushers range from over 80 to more than 150. The concept of a procedure based on a single-stage method of ore preparation for flotation process is discussed herein. The main elements of the technology are: preliminary flotation as an element of effective preparation of ore for the roughing flotation process, intensive roughing flotation, conventional cleaning circuit, separate processing of middlings with a grinding circuit involving the new type of mills and flotation with separation of tailings as the second component of the final waste.

Despite the recognized significance of ground product fineness on both line capacity and downstream process performance (typically flotation), less than 10% of mineral ore concentrators today use real-time particle size measurements in automatic control applications for the final product particle size. Although "near-line" particle size measurement instrumentation has been in place for several decades and is commonly installed in most modern concentrators, its availability and low measurement frequency have typically been inadequate for reliable use in automatic control. Their low availability is often associated with problems with slurry sample collection and handling systems required to present the samples to the size measurement instrument. Recently, an innovative technology for real-time, on-line particle size measurement has been developed by CiDRA Minerals Processing, under its commercial name Particle Size Tracking (PST), already proven in several commercial installations, demonstrating near 100% availability with minimal maintenance, thus overcoming the limitations of previous technologies. Investment decision makers require convincing, reliable estimates of the expected economic value that automatic grind control projects will deliver. This paper presents a methodology for estimating such value from the installation of the new PST particle size measurement technology, capable of tracking particle size on each individual hydrocyclone overflow stream, thus adding significant new options for improved process stability and performance. Based on actual plant operating records, accumulated over long periods of time, the evaluation approach herein described assesses and highlights the significant potential contribution to be expected from this unique PST technology.

Dense Medium (or Heavy Medium) Separation (DMS) is one of the most efficient and commonly used method of separation in different mining branches. Dense Medium for coal processing is based on the suspension of fine and dense material, usually magnetite or ferrosilicon, in water. Magnetite for that purpose is the most commonly used mineral in Polish mines, but has to be entirely imported from abroad. Ferrosilicon, recovered from Zinc-Lead waste could be an alternate to magnetite for use in DMS coal processing. In this study an attempt of recovering that material from "Miasteczko Śląskie" Zinc Plant wastes was made. By simple separation and comminution processes, large amount of magnetic fraction, which could be successfully used in dense medium as the substitution for the magnetite was obtained. Almost 70% of collected waste from lead refining process is proper for the use in the DMS process. Obtained fraction is relatively brittle and easy to grind, which should generate minor costs of production. Almost entire fraction is also highly reactive for magnetic field, which will be helpful in the recovery from dense medium solution, using existing magnetic separators in coal processing plants. Chemical analysis show that concentration of a few metals is significant, which may cause environmental obstacles. But that can also be solved, using simple method of recovery of metal ions from process water.

The work included a synthetic review of the occurrence of oxidized Cu minerals in the concentrators belonging to KGHM Polska Miedź S.A. and problems occurring in the flotation of oxidized Cu ores. The course of flotation of oxidized copper in concentrators A, B and C was examined on the basis of archival results and specialized sampling campaigns. It was found that the content of oxidized copper in the flotation tailings ranges from 0.015-0.05%, and in the concentrate from 0.23 to 0.72%. The share of oxidized copper is highest in the case of flotation tailings and ranges from 10.7 to 25.7%. Cu_ox's share is only a few percent in concentrates. Analyzing the average annual balance samples, the Cu_oxt contents were clearly higher for all concentrators than for the sampling campaign samples, which, as indicated, is caused by the long storage time of the analytical samples. Evaluations of revenues from Cu_ox recovery were made and a further directions of research on the recovery of oxidized copper from flotation tailings were proposed.

The article presents the results of research on the enrichment of fine-grained coal grades, also known as coal slurries. The research was carried out on a semi-technical scale, using the method of gravity flow enrichment on a spiral separator type Reichert LD-4. The research material used in the research were three types of coal slurries, diversified in qualitative terms that were taken from technological process of the preparation plants. The enrichment efficiency tests were carried out in relation to changes in the density of the feed directed to the separator. The best distribution results for all tested coal slurries were obtained for the feed density of β = 300 g/dm³, where weighted averages of ash content in the obtained concentrates reached values of several percent. A statistical analysis was also performed, to which the multiple regression model was used. Using the constructed models, it is possible to determine which technological parameters affect the process of enriching coal sludge.

The aim of this study was to verify the dynamic factor, that is the diffusion rate, which can directly affect the efficiency of CO₂ injection and as a consequence – storage. A manometric setup was used for experiments on two hard coals from Upper Silesian Coal Basin in Poland. A model combining two firs-order rate functions with different rate constants was used to plot normalized equilibration curves. Diffusion curves were plotted at three pressure ranges 5-6 MPa, 3.5-4 MPa and 1.5-2 MPa. Result show that fast adsorption rate is higher at 5.5-6 MPa than at lower pressure range with highest fast adsorption rate fraction both for CH₄ and CO₂. Lower (1.5-2 MPa) pressure range allows achieving sorption equilibrium in less time for both gases. Diffusion rates are lower for CO₂ than for methane the CH₄ desorption rate has a slight impact on the CO₂ adsorption and as a consequence CO₂ storage capacity.

Although the Salt Mine in Bochnia is designed for tourism, it still produces waste. In order to reduce the mass of waste and its harmful impact on the environment, the leaching method was proposed. The authors of the article have presented in their earlier works the method of leaching a salt debris as well as the large-scale laboratory installation used for leaching. The waste generated in the leaching installation are to be used e.g. for the production of building materials or, in the worst case, stored in landfill. The aim of the article was to assess the possibility of their storing at the landfill of inert waste or using them as a secondary raw material in the environmental aspects. The analysis of the mineral and chemical composition of salt debris and waste after leaching in the installation as well as the chemical composition of the leachate after the leaching tests of these waste were performed. Halite, anhydrite and gypsum are the dominant mineral in salt debris, whereas only anhydrite and gypsum in waste after leaching in a large-scale laboratory installation. The remaining, in smaller amounts, minerals are illite and quartz. Waste from the installation of salt debris leaching still releases small amounts of chlorides into the water. Therefore waste still poses a threat to the environment. In order to reduce the amount of chlorides released into the environment, the pump in the leaching plant should work longer than the assumed 5 minutes or the leaching temperature should be higher than 15°C.