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Utilization of agricultural waste can be done by converting it with conventional fuels to energy. For this purpose, it is necessary to understand the properties of waste and its mixture with the fossil fuels important for its storage and conversion. The objective of the work was to examine the influence of moisture content and the composition of agricultural waste with hard coal mixtures on the mechanical and rheological properties of the waste. The materials tested were powdered biomass: dried distillers grains with solubles (DDGS), meat and bone meal (MBM), and hard coal (HC). Mechanical properties were measured to investigate flowability with the Jenike shear tester. A technique with an annular powder rheometer was applied for rheological measurements. It was shown that an increased moisture content worsened the flowability of the mixtures, while an increased biomass content reduced the influence of moisture and stabilized the mechanical properties of the mixtures in quasi-static conditions. In dynamic conditions, moisture decreased the mechanical strength of the mixtures and increased their flowability.

The paper describes an application of a robust controller design method for calculating the parameters of a controller for a multivariable hard-coal preparation process. The parameters are optimized via a sequential design method in the frequency domain, being based on a combination of the Horowitz/Sidi design (1972), Mayne's (1973) sequential design and Steinhauser/Kreisselrooier's (1979) vector performance criterion method. The design was carried out using a relatively sophisticated CAD-program. The paper shows how the parameters are calculated with this CAD-method and discusses the simulated control results. The simulation is compared with the measured results at the plant after implementation of the designed controller on a process computer AEG 80/30 with a real time software control package ARSI * .

Актуальность исследования обуславливается поиском новых твердых топлив для расширения топливно-энергетического комплекса и совершенствования ресурсосберегающей и экологически безопасной энергетики. Цель: комплексное исследование процесса горения картона и каменного угля, включающее определение основных характеристик горения твердотопливных смесей, определение основных кинетических параметров и установление роли компонентов при горении смеси. Объект: твердотопливная смесь на основе каа-хемского каменного угля и картона. Методы. Теплотехнические характеристики топлив определены согласно: влага аналитическая ГОСТ Р 33503-2015; зольность ГОСТ Р 55661-2013; выход летучих компонентов ГОСТ Р 55660-2013; теплота сгорания ГОСТ Р 147-2013; содержание углерода, водорода, азота ГОСТ Р 32979-2014; кислород ГОСТ Р 27313-2015; сера ГОСТ 8606-2015. Исследование процесса горения топлив осуществлено с помощью дифференциального-термического анализатора SDT Q600 (TA Instruments-Waters LLC, США). Температуры, при которых происходит воспламенение коксового остатка топлива и завершается процесс горения, были определены по методу пересечения кривых. Для определения кинетических характеристик индивидуальных топлив и топливных смесей применялся метод на основе модели Коутса-Редферна. Результаты. Теплота сгорания каа-хемского угля в два раза выше, чем у картона, при этом содержание летучих у картона в 1,8 раза выше, чем у угля, что делает картон перспективным добавочным топливом. Увеличение массовой доли картона в смеси не влияет на температуру воспламенения смеси и находится около 300 °С. Добавление 25 % картона к углю положительно влияет на горение углеродного остатка угля, увеличивая максимальную скорость реакции на 30 % по сравнению с расчетными данными. Энергия активации при этом снижается на 39 %, индекс горения снижается в 2,5 раза. Результаты данного исследования могут быть применены при проектировании нового теплоэнергетического оборудования либо быть учтены при переводе котлов, сжигающих каменный уголь, на сжигание твердотопливных смесей. The relevance of the study is determined by the search for new solid fuels to expand the fuel and energy complex and improve resourcesaving and environmentally friendly energy. The main aim: a comprehensive study of cardboard and coal combustion, including the determination of the main characteristics of the combustion of solid fuel mixtures, the determination of the main kinetic parameters and the establishment of the role of the components in the mixture combustion. Object: solid fuel mixture based on Kaa-Khem coal and cardboard. Methods. Thermal characteristics of fuels are determined according to: analytical moisture - SS R 33503-2015; ash content - SS R 55661-2013; yield of volatile components - SS R 55660-2013; calorific value - SS R 147-2013; content of carbon, hydrogen, nitrogen - SS R 32979-2014; oxygen - SS R 27313-2015; sulfur - SS 8606-2015. The fuel combustion was studied using an SDT Q600 differential thermal analyzer (TA Instruments-Waters LLC, USA). Ignition and burnout temperatures were determined using the curve crossing method. To determine the kinetic characteristics of individual fuels and fuel mixtures, a method based on the Coates-Redfern model was used. Results. The heat of combustion of Kaa-Khem coal is twice that of cardboard, while the volatile content of cardboard is 1,8 times higher than that of coal, which makes cardboard a promising additional fuel. An increase in the mass fraction of cardboard in the mixture does not affect the ignition temperature of the mixture and is about 300 °С. The addition of 25 % cardboard to coal has a positive effect on coal carbon residue combustion, increasing the maximum reaction rate by 30 % compared to the calculated data. The activation energy in this case is reduced by 3,9 %, the combustion index is reduced by 2,5 times. The results of this study can be applied in the design of new heat and power equipment, or be taken into account when converting coal-burning boilers to burning solid fuel mixtures.

The aim of the research was to demonstrate differences in the content of trace elements (U, Th, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Cd, Mo, Hg, Pb, W, Ba) in coal mined in Poland and coal imported from Russia, which are widely available on the market. Ecophile, cube and nut were selected for the research. Among them 3 come from Russia and 3 from Poland. The samples were mineralized and the heavy metal content was determined with the use of mass spectrometry with excitation in induced plasma. The research allowed us to conclude that the same carbon grades showed completely different metal contents and depended on the place of origin. The greatest amount of trace elements was found to be found in ecophysics from Poland (durin). Relatively large contamination with trace elements was also found in Polish peach (window) and in Russian walnut. A relatively high content of uranium was found in three samples, including the ecophyses. When burning coal, even of high quality, we expose the environment to the burden of trace elements, including radioactive elements present in their composition. Heavy metals from coal combustion constantly accumulate in the environment and so far no standards have been established for their content in this fuel.

Coal mining has the most risk in all the mining sectors. Hence in this sector with most work accidents are encountered in an intensive. The demographic characteristics of workers affect the occurrence of occupational accidents. This study aims to develop an equation that predicts workday loss by analyzing the relationship between workers' demographic characteristics and having an accident with workday loss. In this study, work-related accidents between 2014-2019 in underground hard coal mines in Turkey were analyzed using the logistic regression analysis method. An equation is derived that estimates the workday loss with the characteristics of workers in hard coal mines. With the equation derived in this study, employers will determine the potential for work accidents according to the demographic characteristics of the workers and serious work accidents will be prevented. Therefore, proactive solutions can be produced by applying the methods used in this study to different industries.

Purpose.In this paper we present and validate an analytical model of water inflow and rising level in a flooded mine and examine the model robustness and sensitivity to variations of input data considering the examples of three closed hard-coal mines in Germany. Methods. We used the analytical solution to a boundary value problem of radial ground water flow to the shaft, treated as a big well, and water balance relations for the series of successive stationary positions of a depression cone to simulate a mine water rebound in the mine taking into account vertical distribution of hydraulic conductivity, residual volume of underground workings, and natural pores. Findings. The modeling demonstrated very good agreement with the measured data for all the studied mines. The maximum relative deviation for the mine water level during the measurement period did not exceed 2.1%; the deviation for the inflow rate to a mine before its flooding did not exceed 0.8%. Sensitivity analysis revealed the higher significance of the residual working volume and hydraulic conductivity for mine water rebound in the case of thick overburden and the growing significance of the infiltration rate and the flooded area size in the case of lower overburden thickness. Originality.The developed analytical model allows realistic prediction of transient mine water rebound and inflow into a mine with layered heterogeneity of rocks, irregular form of the drained area, and with the inflow/outflow to a neighboring mine and the volume of voids as a distributed parameter without gridding the flow domain performed in numerical models. Practical implications.The study demonstrated the advantages of analytical modeling as a tool for preliminary evaluation and prediction of flooding indicators and parameters of mined out disturbed rocks. In case of uncertain input data, modeling can be considered as an attractive alternative to usually applied numerical methods of modeling ground and mine water flow.

In this article an attempt to determine the influence of mining factors on the seismic activity during the longwall mining of the upper layer of coal seam no. 405/2 in one of the Polish hard coal mines in the Upper Silesian Coal Basin was conducted. Two longwall panels were mined in analogous geological conditions and based on the same mining system and technology. However, there was significant difference with regards to the mining factors, which was reflected in the observed seismic activity. Some tools used in mining seismology were applied to illustrate the aforementioned influence of mining factors, e.g. the frequency-energy distribution, the frequency-magnitude distribution, the 2D distribution of released seismic energy, the relationship between released seismic energy and the volume of mined coal, the Benioff strain release, and the Gutenberg-Richter (GR) b coefficient distribution (b is the proportion between high and low energy tremors). Concerning the Benioff strain release, a new solution, based on the slope of a fitted line in a moving time window, is proposed.

The paper present the results obtained during hard coal ash reclamation. This model was created by covering the ash surface with layers consisting of ash, organic by-products and mineral fertilizers. The aim of the studies, undertaken 15 years after the experiment set up, was the assessment of the efficacy of ash waste reclamation on the basis of the overall and solubility analyses of metal content, including heavy metals, soluble in 0.1 M HCl. In 2003, on the premises of Dolna Odra Power Station in Nowe Czarnowo (53,20°N; 14,48°E) near Gryfino (53,25°N; 14,48°E) in Poland, a hard coal ash reclamation experiment was conducted. A 40 cm thick surface layer (fertile), termed upperlay, composed of the mixture of various materials was applied to ash substrate. One part was fertilized with mineral fertilizers NPK-60-70-70, the other was left unfertilized. After 15 years, in the autumn of 2018, samples of upperlays (0-40 cm) and underlays (40-60 cm) were collected from plots overgrown with grass. 15 years after the experiment, none of the underlays or upperlays showed an excess of threshold values as specified in the current Regulation of the Minister of the Environment of 2016. The particularly favourable effect was identified with respect to the application of fermented municipal sewage sludge and GWDA compost which were factors resulting in a decrease of the upperlay content of cadmium, zinc, copper and lead in the form available for plants. The characteristics of upperlays with respect to metal content indicates conditions favourable to plant cultivation on the reclaimed area. The recorded results on the change of the overall and bioavailable content of metals in upperlays and underlays justify the continuation of the undertaken reclamation experiment.

The zeolitisation of fly ash originating from hard coal combustion in a Polish power plant was conducted using the alkaline hydrothermal method with and without the application of ultrasound. The o...

To study the particle size distribution and energy variation law of hard coal under a load, an impact compression test of hard coal specimens under different impact loading conditions was carried out using a Φ50 mm diameter Separate Hopkinson Press Bar (SHPB) test system. We implemented the theory of dynamic impact energy of rock to establish the calculation expression of hard coal impact crushing energy dissipation, and we established the Weibull distribution model of a crushing body to analyze the impact velocity in relation to the particle size distribution of hard coal crushing and crushing energy consumption. The results demonstrate that due to the different original states of the specimens, the damage to the specimens under static action is in the mode of conjugate plane shear damage, single bevel shear damage, and tensile damage. The damage process of the specimen under impact load loading is divided into three stages: elastic deformation, elastic–plastic deformation, and plastic softening, while the increase in the strain rate caused the peak stress of the specimen to increase. The Weibull distribution can characterize the impact crushing size distribution of hard coal specimens very well. The parameter of coal rock crushing degree is a power function that is influenced by the impact velocity; the greater the impact velocity, the higher the coal rock crushing degree, but the characteristic index of coal rock crushing fluctuates with the increase in impact velocity. As the impact velocity increases, the incident energy and reflected energy increase linearly, while the transmitted energy increases first and then decreases. The dissipation energy of coal rock crushing also increases linearly with the impact velocity. There is no obvious regular change between the energy dissipation rate of coal rock and impact velocity during impact damage, and the dissipated energy of macroscopic crushing only accounts for 10~20% of the incident energy; most of the energy is used for damping loss and damage loss.

The paper presents a case of a sinkhole located in a hard coal mine within the Upper Silesian Coal Basin in Poland and attempts to explain the causes of its formation. The calculations and analysis of geological and mining conditions carried out within the area of the sinkhole allowed to formulate conclusions that can support the decision-making process related to construction investments and environmental protection in the area of the decommissioned mine.

The exploitation of the underground is currently undergoing a major transformation process. Besides mining, alternative ways of utilization are playing an increasingly important role. These alternative utilizations include the storage of gases, the disposal of radioactive wastes, and the implementation of geothermal storage facilities. In addition, more and more mining operations are being shut down, like the German hard coal mining industry in 2018. But the integrity of closed mines must be ensured in the post-mining phase. In order to capture such large and complex structures efficiently and reliably, new surveying techniques are required. A promising approach is the use of photogrammetric methods to generate three-dimensional models of the cavity. Photogrammetry is currently known mainly from aerial photography. It is conceivable to use such methods for underground applications. In recent years, significant progress has been made in the algorithm-based orientation of unstructured image sets. More powerful computer systems and the growing range of unmanned aerial vehicles could enable partially automated capture. However, a number of problems have to be solved for underground imaging techniques. Unfavorable exposure conditions complicate image alignment. Furthermore, the models must be integrated into existing surveying systems with a sufficiently high degree of accuracy. In order to consider the numerous technical aspects, the development of an integrated capture and evaluation approach is necessary. This could make an important contribution to the monitoring of critical cavities of different commodities. Such an approach would also fit into the current digitization trend in the mining industry and provide new opportunities for ground control in particular.

Due to the longer distance of moving the crew to the workplace in hard coal mines, the possibility of increasing the maximum permissible speed of suspended monorails was considered. To ensure an adequate level of safety, decelerations affecting the crew in the case of emergency braking in various travelling conditions were analysed. The computational model was verified based on the results of the bench tests on a dedicated test track. The article presents a comparison of results of numerical calculations with measurements at the test stand, and results of numerical simulations in relation to the criterial states that could not be checked at the test stand as well as the analysis of overloads that affect the crew during the emergency braking. These overloads have a significant impact on safety of the operator and passengers, and their determination and analysis may be the basis for assessing the degree of safety as well as for the development of guidelines for designing the additional equipment for the operator's cabs and passenger cars, i.e. components increasing their safety

The Young’s modulus and Poisson’s ratio, parameters reflecting the elastic response of a rock to stress, are the key parameters used in many engineering activities, such as hard coal mining and natural gas extraction. The objective of this paper was to present the results of complex laboratory measurements of the static and dynamic Young’s modulus and Poisson’s ratio for Upper Carboniferous hard coals from the Upper Silesian Coal Basin. The coals differed in geologic age (Mudstone Series—younger coals; Upper Silesian Sandstone Series—older coals) and petrographic structure (vitrain, clarain, and durain lithotype). Elastic parameters of the coals were determined following compression tests under a complex state of stress, as well as using the ultrasonic method in reservoir conditions. On this basis, linear functional dependences between parameters such as UCS, differential stress, confining pressure, strain rate, P- and S-wave velocities, and the static and dynamic Young’s modulus and Poisson’s ratio were determined. These dependences turned out to be linear, with strong and very strong correlation, as indicated by the high coefficients of determination, R2. These new results significantly broaden the knowledge of elastic properties of Carboniferous hard coals, especially in the field of geoengineering, underground coal gasification, and reservoir stimulation for coal bed methane extraction.

The basic process of minerals’ mechanical preparation, including coal, is a beneficiation process which has a decisive impact on quantitative-and-qualitative parameters of commercial products. At present the products of the MBE-CMT, Allmineral and Tenova companies have big market shares as regards foreign water pulsatory jigs, as well as ITG KOMAG on the local Polish market. New implementations of jigs, developed at the KOMAG Institute of Mining Technology, for beneficiation of coking coal and steam coal in collaboration with Carbo-Eco Ltd. and Fugor Ltd. companies, were realized in 2019. Technical and technological parameters of new devices are described in the article. Supply systems of feed are presented as well as the method of collecting tailings and middlings. New design solutions, applied in modernized preparation plants, aimed at an improvement of jigs production capacity and efficiency are presented. In the case of each jig, after its activation and conducted adjusting processes, exact tests of a beneficiation efficiency were performed and their results are presented in the tabular form. Basic beneficiation accuracy indicators and parameters of products’ separation as well as balances of products are given. The test results, obtained from newly activated jigs, are discussed.

The aim of the article is to present the results of laboratory analyses determining the content of rare earth elements (REE) in hard coal type 31.1. Coal was extracted directly from the mining excavation located in the Upper Silesian Coal Basin. Mass spectrometry tests with ionization in inductively coupled plasma (ICP-MS), were aimed at the quantitative analysis of the share of REE in coal, taking into account the economic aspects of recovery of these elements. Fine ground hard coal samples and ashes obtained after coal burning were assessed for the rare earth elements concentration. Results of the rare earth elements concentration (lanthanum and cerium) in hard coal are similar in the values obtained in previous tests. The current analyses present higher concentration of europium or neodymium. The article also contains the concept of possible future research work, consisting in the recovery of rare earth elements using, among others, a classifying hydrocyclone.

The Knurów hard coal deposit is characterized by rich fold and fault tectonics and diverse morphology of the overburden. The deposit contains a fold zone called Knurów anticline and four complex of faults with the total amplitudes reaching up to several dozen meters. While making a 3D model of the deposit, a range of complications related to the correct interpretation of the running and development of the aforementioned tectonic structures were encountered. Additional data were begun to be introduced during the detailed analysis of the 3D model being made in stages, thereby forcing the software to perform the modeling according to preset assumptions. This process covered such areas of the deposit that were poorly explored or documented to an extent requiring an intervention from a geologist.

A series of activated carbons prepared using hard coals from two different mines, Kozlu and Karadon in Zonguldak, with heat treatment and chemical activation (KOH, NaOH, ZnCl,2 and H3PO4) were eval...

Abstract Hard coal is an important source of energy worldwide. Owing to the imperfections of excavation technology, most run-of-mine coals must be processed before they can be utilised as fuel. In this study, tests on the dry separation process were performed with numerous different raw hard coal and coal waste material samples, using a newly designed and constructed negative-pressure pneumatic separator (NPPS). The experiments revealed the effects of the feed-material properties and material processing conditions. These experiments were preceded by additional tests for evaluating the influence of each device operating parameter on the process, to determine the optimal method of supplying the feed material. The calorific value of the processed materials was improved by 5%–40%, while a minimal output yield of products (60%–70%) was maintained. The trials indicated that in coal material processing, the developed NPPS can be used for not only raw coal enrichment but also coal recovery from materials stored at coal-waste dumps. The main advantages of the device are its mobility, low material processing cost, and lack of water consumption during operation. Graphic abstract

The production of electricity and heat in Poland is the reason why the commercial power industry is the largest emitter of CO2. At the same time, significant amounts of solid by-products of combustion, which can be used to bind CO2 by mineral carbonation, are generated during the production processes. The article presents the results of research on mineral sequestration of CO2 (suspension-CO2) using fluidized bed combustion (FBC) fly ashes from hard coal combustion. The analyzed fluidized bed combustion (FBC) fly ashes were characterized by a significant free CaO content (1.7–6.8%) and a high CO2 binding potential ranging from 9.7 to 15.7%. In the case of fluidized bed combustion (FBC) fly ashes suspensions, the basic product of the carbonation process is calcium carbonate, which is clearly indicated by the results of the phase composition determination of solidified suspensions of fluidized bed combustion (FBC) fly ashes. The degree of carbonation, i.e. the degree of CO2 binding, calculated on the basis of the calcium carbonate content, in the analyzed suspensions was up to 1.1%. Mineral carbonation also reduces the leachability of pollutants such as: Zn, Cu, Pb, Ni, As, Hg, Cd, Cr, Cl, and SO42-. The pH is also reduced from about 12 to about 9. Aqueous suspensions of fluidized bed combustion (FBC) fly ashes with introduced CO2 can potentially be used in underground mining. These activities are in line with the concepts of Carbon Capture and Utilization and the idea of circular economy.

The primary objective of this paper is to present a model of a process management system developed to support the restructuring of Polish enterprises of the hard coal mining industry. The development of this model required research in three stages using several research methods. The stage I of the research was oriented towards the recognition of the existing state of knowledge in the scope of previously developed models of process management in enterprises. At this stage, a method of reviewing the literature, the analysis and synthesis of the results of considerations, was used. The stage II was oriented towards presenting of the current state of knowledge in the field of process management to the managerial staff of mines in order to identify their needs, capabilities and preferences. The research were attended by 24 managers from PGG SA and JSW SA. At this stage, the method of targeted free-form interview and discussions, was used. The stage III of the research was oriented towards the development of a process management system model in enterprises operating in the hard coal mining industry, based on the scientific achievements to date in the field of process management and consensus on the needs, preferences and capabilities of mine managerial staff with regard to its specific elements. At this stage, the method of analysis and synthesis was used. The results of the research presented in this publication are primarily addressed to the managerial staff of polish hard mines, as they provide a synthesized response to the problem of the lack of consistent process management guidelines that could set a standard within a mining enterprise. The model presented in the publication is of a general nature, although it may provide a basis for the application of process management for mines.

An analysis of the competitiveness of the Polish hard coal mining sector was performed. The most important conditions in which it operates were presented—the size of the resource base, the current organizational structure, and operating conditions. By presenting the most important sources of competitiveness, factors requiring special attention were identified. After presenting the SWOT analysis of the sector, the issues that were most important for the permanent preservation of the competitive position of the entire sector, as well as individual mining enterprises, were specified.

Mercury and its compounds are classified as very toxic and they pose a real threat to human health. Coal combustion processes constitute one of the main sources of mercury emission to the environment. The use of hard coal by the sector of non-industrial combustion installations (among others households) is a special issue. In contrast to large coal-fired power plants, such users are not equipped with systems for reducing emissions. For this group of users, it is necessary to use hard coal with the lowest possible mercury content. In the paper, a method for the production of hard coal with low mercury content based on combined processes of the dry deshaling and thermal pretreatment was proposed. The proposed method allowed for a reduction of mercury content in the analyzed coals in the range from 43 to even 92% (in relation to its lower heating value). The produced coals were characterized by relatively low mercury contents from 1.5 to 4.8 µg/MJ with the average of 2.4 µg/MJ. The application of this method...

The mechanism for Ukrainian coal mining industry's sustainable development management has been formed as a result of the study. Significant losses in the process of coal mining are proved to be one of the coal mining industry problems. It has been specified that the reserve for the industry's efficiency upgrading in the framework of more resource-saving behaviour is funding of mines reconstruction. Slowdown in the coal mining industry development has been determined to be the result of military operation in Donets'k and Luhans'k regions. The inefficiency of transport logistics for coal resources imported by Ukraine has been proved, since the rail freight transport is favored instead of cheaper maritime transport due to the underdeveloped quality of port infrastructure. Balancing mining, production of coal raw materials and their subsequent use in the production processes have been proved to be the ways to ensure rational use of coal resources of Ukraine. The processes for coking coal is metal production, and for anthracite – thermal energy production. Relationship between growth rates of coking coal mining and production, coke mining, exports and imports of coke and ironmaking during 2008– 2017s have been studied. It has been demonstrated that imports of coking coal essentially depends on the market pricing and has little to do with the needs of the metallurgical industry of Ukraine. It has been shown that the system for rational use of coking coal's capacity in Ukraine should include balancing flows of coal mining, coke and semi-coke mining according to the needs of national metallurgical industry, taking into account cyclical nature of its development. The necessity of coordinating the volumes of anthracite extraction, production and consumption and taking into account short cycles of heat power development have been defined.

Underground mining negatively impacts the rock mass and land surface, as well as the objects located on it. One of the forms of such impact are linear discontinuous deformations, which presently in Polish Upper Silesian Basin conditions are more and more often accompanied by underground mining. Discontinuous deformations of mining origin not always arise on the surface, resulting from the occurrence of unfavorable geological and mining factors, and create different forms, mainly ground steps, cracks, and fissures. Presented in this article results of the research concern the problem of the occurrence of linear discontinuous deformations in the area of the greatest Polish hard coal deposit, Upper Silesian Basin, where several unfavorable factors triggered the system of linear discontinuous deformations in the shape of ground steps. Ground steps caused several damages to building objects, small architecture elements, and roads in surrounding area. One of the most important objects exposed to damage threat here is an old historic church. Ground steps occurred as a joined effect of underground mining influences together with impact of fault zones located close to the church and probably activated by mining works. In the paper, mining and geological conditions have been discussed, that led to arising of discontinuous deformations on the surface. Apart from description of mentioned factors, detailed calculations were carried out aimed at recognition of probable distribution on the surface of subsidence, horizontal displacement, and horizontal strain around the church. Their contribution to ground steps creation process has been discussed as well.

Coal mining waste rock dumps contain a lot of rare and precious microelements and are a single complex mechanism of the chemical and biochemical transformations of substances, and the key role in such transformations belongs to sulfuric acid formed as a result of the vital functions of thionic bacteria Th. Ferrooxidans. The aim of the present work was to develop an environmentally friendly biotechnology for processing coal mining waste rock dumps of the Luhansk Region as man-made metal deposits. The spectral analysis of the waste rocks of the Luhansk Region revealed high concentrations of precious, rare-earth, and trace elements. A high prevalence of gallium and germanium clarkes was found, and their actual concentration in the waste was close to the minimum industrial concentration. The results of chemical analysis of the waste rock for Al2O3 showed that its concentration was close to that in poor bauxites, a traditional raw material for alumina. A method and technology of the biochemical leaching of aluminum, gallium, and germanium, which make use of the natural processes of sulfuric acid formation in waste rock were proposed, and their efficiency was experimentally confirmed. The proposed biochemical technology for the processing of coal mining waste rocks can serve as the basic method for diminishing their environmental impact and rational use of natural resources.

The present study examines the sorption of Cs (I) and Sr (II) on organic sorbents in the pH range from 2 to 10, as well as the mechanisms of their binding. In order to determine the influence of the physical properties and the quantity of functional groups of the organic sorbents on sorption, experiments were carried out on organic materials of varying degrees of metamorphism: high-moor peat, hard and brown coals and shungite. A detailed description of their mineral composition, cation exchange capacity, buffering capacity and elemental composition of sorbents is provided. XRD, XRF, SEM and BET adsorption methods were used for assaying. As a result of the conducted research, it can be concluded that Sr (II) showed a higher sorption per unit specific surface area than Cs (I) in the studied range of concentrations and pH values. Sr (II) sorption decreases in the following order: high-moor peat > brown coal > shungite > hard coal. The sorption of Cs (I) is highest on brown coal and lesser for high-moor peat, shungite and hard coal. It is suggested that Cs (I) and Sr (II) can be fixed on carboxyl functional groups and Cs (I), possibly, in insignificant amounts on phenolic hydroxyls of all four studied organic sorbents.

Of late, sustainable energy development has received considerable importance throughout the world due to the growing concerns regarding climate change and environment protection. This in turn, has led to the search for alternatives, which are ecofriendly and cost-effective. Turkey possesses vast resources of lignite and renewable energies, which if utilized properly can reduce the current energy deficit and imports from other countries. Though renewables have received more attention in the past few years; yet, the vast lignite reserves of Turkey cannot be averted while considering the major indigenous energy resources of the country. The present review briefly discusses the existing energy situation in Turkey with particular focus on the indispensable role of coal as a valuable energy resource in meeting the country’s growing energy demand. Biodesulphurization as a green treatment technique for sulphur removal from coal is discussed along with some of the recent advances made with respect to the Turkish lignite. A brief description relating to the impact of COVID-19 on the energy sector is also discussed. Furthermore, future outlooks towards sustainable development are presented.

This academic paper revolves around the results of research on the change in emission parameters of the used heating boiler following the introduction of the overheated water stream, which had an impact on different emission parameters. The research results provide an insight into the hard coal combustion process, which had a significant impact on the change in the chemical composition of exhaust gases: it contributed to the lower mass concentration of the emitted dust and black carbon (PM) as well as nitric oxides (NOx) while, at the same time, playing a significant role in increasing the mass concentration of the emitted carbon oxide (CO). Two types of devices were used for the purposes of conducting the research at hand: a boiler with an automatic fuel feeding system with one combustion chamber and a boiler with a combustion chamber and an afterburning chamber fitted over it. Apart from the measurements of mass concentration of the emitted harmful substances, the research also focused on measurements of temperature inside the combustion and afterburning chambers, as well as the temperature of exhaust gases and their oxygen content. As part of the research, water steam was introduced to the combustion and afterburning chambers at the flow rate of 0.71 kg/h and 3.60 kg/h for boilers operating at a minimum power of 30% and a nominal power of 100%. An original steam generator with an overheated water steam production range from 0.71 kg/h to 3.60 kg/h was used to create and feed the water steam. The efficiency of the combustion process was calculated using the obtained results for each operating configuration of a given boiler.

The main purpose of this study is to investigate the relationships between key sources of air pollutant emissions (sources of energy production, factories which are particularly harmful to the environment, the fleets of cars, environmental protection expenditure) and the main environmental air pollution (SO2, NOx, CO and PM) in Poland. Models based on MLP neural networks were used as predictive models. Global sensitivity analysis was used to demonstrate the significant impact of individual network input variables on the output variable. To verify the effectiveness of the models created, the actual data were compared with the data obtained through modelling. Projected courses of changes in the variables under study correspond with the real data, which confirms that the proposed models generalize acquired knowledge well. The high MLP network quality parameters of 0.99–0.85 indicate that the network generalizes the acquired knowledge accurately. The sensitivity analysis for NOx, CO and PM pollutants indicates the significance of all input variables. For SO2, it showed significance for four of the six variables analysed. The predictions made by the neural models are not very different from the experimental values.

About 700,000 years ago, Homo erectus understood how to light a fire himself. About 100,000 years ago he understood that he could also use this fire to cook the meat that had been eaten raw until then. At that time, Homo erectus burned wood, oil and grease. From 900 BC the people in China burned natural gas. And much later, from the XII century in Belgium the humans burned lignite and hard coal. And then, from 1859 in Pennsylvania/USA, crude oil.

The subject of the discussion is oriented toward limiting the energy consumption of the bucket conveyor used in jig concentrator plants by controlling its speed. A method of predictive control of the bucket conveyor speed is presented. It allows for reducing the energy consumption due to appropriate selection of bucket movement speed to ensure the nominal filling of buckets along the entire length of the conveyor. This approach enables limiting the idling speed of the conveyor, extend its life, and also reduce the electricity consumption of the entire system. Experimental studies, carried out at the “Sośnica” Coal Mine working facility, confirmed that the use of a predictive algorithm for controlling the bucket conveyor speed and adapting the bucket speed to the current load decreased in energy consumption n by 9.6%, with 80% of the filling conveyor.

The method of analyzing the results of dust concentration measurements in mine workings that was conducted within the ROCD (Reducing risks from Occupational exposure to Coal Dust) European project using the developed dust prediction algorithm is presented. The analysis was based on the measurements of average dust concentration with the use of the CIP-10R gravimetric dust meters, for the respirable PM4 dust concentration, and IPSQ analyzer for instantaneous concentration measurements (including PM2.5 dust) and with the use of Pł-2 optical dust meters for instantaneous concentration measurements of PM10 dust. Based on the analyses of the measurement results, the characteristics of the distribution of PM10, PM4, and PM2.5 dust particles were developed for the tested dust sources. Then, functional models based on power functions were developed. The determined models (functions) allow predicting the dust distribution in such conditions (and places) for which we do not have empirical data. The developed models were implemented in a specially developed online tool, which enables predicting the concentration of PM10, PM4, and PM2.5 dust (on the basis of dust concentration of one source) at any distance from the dust source.

The calculation method commonly used in the industry takes into consideration mainly fuel consumption (excluding electricity) and the amount of removed moisture which is reflected in the unit MJ·(Mg·%)−1. This is not a scientific approach because the result will change if the basic moisture is different (drying from 21% to 18% will consume less energy than drying from 18% to 15%). This paper aims to compare the energy consumption of two industrial continuous flow grain dryers powered by LPG and hard coal based on a comprehensive approach to energy efficiency calculation enriched with electricity consumption, flow measurements, and control of grain moisture. It could be useful for manufacturers who could use this method to generate more reliable data in their product datasheets, and it could also be legally regulated as an appropriate tool for calculating the energy consumption of agricultural grain dryers. According to the approach presented in this paper, the S428.CS construction powered by LPG gas had an energy consumption that was 6.14% lower than the DT2532 dryer construction, which used hard coal.

The paper presents the practical use of a solidifying hydro-mixture based on ashes from fluidized bed boilers under hard coal mine conditions for filling an incline connecting the headgate and tailgate of a longwall running along the strike with roof caving. The reason for filling the incline with a material of preset strength parameters was to minimize the methane hazard in the extracted coal seam. Due to a great demand for fill material, which translates into economic considerations, the option of applying fine-fraction waste material was selected. Preliminary laboratory tests of the physical and mechanical properties of hydro-mixtures based on ash obtained from a fluidized bed boiler of a power plant, allowed us to select a specific hydro-mixture meeting the requirements. After 95 days, the incline filled with the proposed hydro-mixture was subjected to exploitation along with the advance of longwall working. This enabled the in-situ collection of a number of fill material samples from various places along the entire length of the incline. Then their strength was tested and the results compared with the obtained test results of identical material seasoned under laboratory conditions. The obtained results constitute a unique research material since it is practically impossible to verify the laboratory-determined strength parameters of the solidifying fine-fraction hydro-mixtures under in-situ conditions. Thsis results mainly from the lack of technical capabilities and poor access to the places where fine-fraction hydro-mixtures are applied, mostly abandoned cavings or parts of workings separated by dams.

German hard coal production ended in 2018, following the termination of subsidies. This paper looks at 60 years of continuous decline of an industry that employed more than 600,000 people, through a case study comparing Germany’s two largest hard coal mining areas (Ruhr area and Saarland). Although predominantly economic drivers underlay the transitions, both provide valuable lessons for upcoming coal phase-outs induced by stricter climate policies, including beyond Germany. The analysis identifies the main qualitative and quantitative characteristics of the two regions. It then discusses policy instruments implemented to guide the transition, including measures for the conservation of coal production, regional economic reorientation, and the easing of the transition’s social impacts. The success of these policies is evaluated using economic, social, and geographical indicators that were developed within three interdisciplinary research projects running from 2016 to 2019. A key lesson from the examined case studies is the importance of combining not only policies addressing unemployment and the attraction of new energy corporations and investments, but also measures improving infrastructure, education, research facilities and soft location factors. Protecting a declining industry for decades caused increased transition costs compared to an earlier phase-out. Economic reorientation and changing regional identities have proven most difficult in the past. However, the German example illustrates that the complexity of the challenges of a transition can be mastered if city, regional, and national governments and institutions cooperate in a polycentric approach. Key policy insightsA faster and more pro-active hard coal mining phase-out in Germany would have been much less expensive and paved the way for new industriesA just and in-time transition needs to: be jointly managed in a polycentric approach by city, regional, national, and international governments and institutions.combine climate, energy, social, and structural policies, whilst recognizing both local specifics and global connections.consider long-term effects, external independent advice apart from the incumbent regime and beyond-border thinking, while aiming to diversify the economy and enabling broad stakeholder participation.address unemployment, the economy, and the energy system, as well as measures to improve infrastructure, universities, research facilities, and soft location factors. A faster and more pro-active hard coal mining phase-out in Germany would have been much less expensive and paved the way for new industries A just and in-time transition needs to: be jointly managed in a polycentric approach by city, regional, national, and international governments and institutions.combine climate, energy, social, and structural policies, whilst recognizing both local specifics and global connections.consider long-term effects, external independent advice apart from the incumbent regime and beyond-border thinking, while aiming to diversify the economy and enabling broad stakeholder participation.address unemployment, the economy, and the energy system, as well as measures to improve infrastructure, universities, research facilities, and soft location factors. be jointly managed in a polycentric approach by city, regional, national, and international governments and institutions. combine climate, energy, social, and structural policies, whilst recognizing both local specifics and global connections. consider long-term effects, external independent advice apart from the incumbent regime and beyond-border thinking, while aiming to diversify the economy and enabling broad stakeholder participation. address unemployment, the economy, and the energy system, as well as measures to improve infrastructure, universities, research facilities, and soft location factors.

Laboratory coking test is very often used for prediction of produced coke quality. The second route for results utilisation is differentiation of products and determination of its yield. There were not carried out many tests to check if mass balance sums to one. In addition to this there were not performed test to control elements balance if there were made further ultimate analysis of products. In order to control mass and elements balance there were carried out laboratory coking tests of several coals with ultimate analysis of coals, coke and by-products. There were found good correlations between some products and volatile matter in origin coal. It confirms that for them there is rational for its prediction from quality parameters of coal.

The emission of gaseous pollutants and particulates from domestic heating sources, DHS, can be especially troublesome in winter when the smog effect is enhanced. One of the possible ways to solve this problem is the use of fuel that emits significantly lower gaseous pollutants and particulates compared to hard coal. A major feature of this solution is the possibility of its immediate effect compared with other solutions that need more time to move toward a system change. This paper presents the findings from a laboratory and a full-scale operational pilot investigation into a smokeless fuel application (charcoal known as “Blekitny Wegiel”, BW) that is used for residential heating. Pilot experiments in users’ homes were carried out using 34 heating devices. A significant decrease of gaseous pollutants [NOₓ, SO₂, total organic carbon, PAHs, and B(a)P] and particulate emissions from the heating devices was obtained when BW was applied, and this was even the case for boilers with outdated constructions.

This paper reports on a full-scale investigation of a possible increase of the SO2 capture ratio in current semi-dry flue gas desulphurization (FGD) technology. The FGD unit is used for two 130 t/h steam PC boilers burning a blend of lignite and hard coal with dry ash-free sulphur content at 1.83%. The FGD unit has been designed to reach an SO2 emission limit of 1350 mg/Nm3. The aim of the experimental work presented in this paper was to investigate the possibility of reaching SO2 emission targets of 500 and 200 mg/Nm3. The investigation sought to determine the real correlation of SO2 capture ratio with Ca/S and with the difference of dry-bulb temperature and dew point in the absorber ΔtAD. Generally, the SO2 capture correlation with Ca/S has flat characteristics at a capture ratio >90%, which is required to reach the 200 mg/Nm3 target. In this case, lowering the ΔtAD in the absorber has only a weak effect. The 500 mg/Nm3 target requires an SO2 capture ratio of about 80%; in this case lowering the ΔtAD by about 7 °C increases the SO2 capture by 10% points at the same Ca/S ratio.

The subject of the article is the quantitative–qualitative characterization of unburned carbon in fly ash, occured in power plants in southern Poland, fired with hard coal. Significant differences ...

In this study, a total of 26 hard coal sample (either clean or original) from Zonguldak Coal Basin (17 from Zonguldak, 9 from Amasra) and a total of 17 low grade Turkish coals from various locations in Turkey were collected. So, a total of 69 samples were analyzed initially with standard method of coal grindability, i.e. HGI values were determined. In addition, an alternative method (does not require a standard HGI mill) for grindability measurement was proposed in this study. The abovementioned alternative method includes a ring mill with specified conditions and Malvern Mastersizer. As regards to the procedure of the new proposed method for the determination of coal grindability, samples were prepared in the size range of -1.7 + 1.18 mm size group and they were ground in ring mill. Here, ring mill was chosen because of the fact that it is very widely used for sample preparation and it is very commonly available in every laboratory. Procedure proposed includes placing abovementioned specified samples in ring mill (See Material and Method) and having the samples ground in a previously determined time period. After this grinding process (with ring mill) they have rather different size distribution at the end depending on their nature of grindability. For better understanding, having the ground samples of (-1.7 + 1.18 size group for 20 s for 50 g samples) and analyzing their size distributions with Malvern Mastersizer, ground samples have different D10, D50, D90, D32 and D43 at the end. Comparing these size parameter results with previously determined HGI values, it can be claimed that coal grindability can be easily determined with this method, since evaluated HGI values with the method proposed are ±0.05% different than the determined HGI values. © 2019 The Society of Powder Technology Japan, British Association for Psychopharmacology, Author of this study would like to thank to coal producer companies for providing samples, and would like to specially thank to professors (Sait Kizgut, İhsan Toroglu, Dilek Cuhadaroglu), researchers (Baris Akkaya, Mehmet Bilen) and M.Sc. students (Erman Kıran, Cemil Emre Yilmaz and Alper Oktem) of Mineral Processing Division of Mining Engineering Department of Zonguldak Bülent Ecevit University. Their contribution on this paper is highly appreciated. Authors also would like to express their appreciation to the BAP Research Coordinatorship of Bülent Ecevit University financial support, and coordinatorship staff.