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In this study, the radioactivity contents of Carboniferous Zonguldak-Kozlu hard coals, Carboniferous Antalya-Pamucakyayla hard coals and Pliocene Konya-Karapınar lignites were determined, then compared with the limit values determined by the authorized institutions and their hazard indexes were determined. The range of measured activity concentrations was from 16.2 Bq·kg−1 to 227.6 Bq·kg−1 for 238U, 20.6 Bq·kg−1 to 67.5 Bq·kg−1 for 232Th and 211.9 Bq·kg−1 to 515.5 Bq·kg−1 for 40K. The calculated mean absorbed gamma dose rate (D), radium equivalent activity (Raeq) and annual equivalent dose (AED) were 105.7 nGy·h−1, 227.9 Bq·kg−1 and 129.6 μSv·h−1, respectively. Although 238U and 232Th radionuclide activity concentrations are comparable to literature values, 40K activity concentrations were around three or four times higher than in UNSCEAR (2000) reports. As it poses a radiological risk, it is necessary to take the necessary precautions to reduce the negative effects on the environment and human health due to use of coals from Konya-Karapınar, Antalya-Pamucakyayla basins and to burn in a controlled manner. [ABSTRACT FROM AUTHOR]

The volatility of raw material prices and the rising prices of CO2 emission allowances when using fossil fuels to produce electricity and heat are still relevant problems for owners of generating units. The decision-making tools are used in the fuel purchase process. However, these tools should also consider environmental issues. The article’s main objective is a quantitative analysis of the potential for reducing costs associated with supplying and using hard coal in public power plants as a result of considering the costs of environmental protection and CO2 emission allowances in the process of planning this fuel supply. A mathematical model was developed to optimize the supply of hard coal for the power industry. The tool and elaborated research scenarios made it possible to calculate and analyze the impact of considering the costs of emissions of harmful substances into the environment and CO2 emission allowances on the planning of coal supplies and the reduction of costs related to acquiring and using coal by public power plants. The calculation results were presented on the example of the Polish power sector. The model’s results confirm that the appropriate selection of coals, taking into account the quality parameters determining the amount of emissions of harmful substances, reduces the amount of these emissions and the total costs of acquiring and using coal in electricity production. However, depending on the considered scenario, the scale of this impact varies. The results of the optimization of coal supplies to power plants and their proper interpretation may constitute an important contribution to making management decisions in energy companies. [ABSTRACT FROM AUTHOR]

This study presents the results of concentrations of rare earth elements and yttrium (REY), uranium (U), and thorium (th) in ashes from combustion/co-combustion of biomass (20%, 40%, and 60% share) from the agri-food industry (pomace from apples, walnut shells, and sunflower husks) and hard coal. The study primarily focuses on ashes from the co-combustion of biomass and hard coal, in terms of their potential use for the recovery of rare earth elements (REE), and the identification of the sources of these elements in the ashes. Research methods such as ICP-MS (inductively coupled plasma mass spectrometry), XRD (X-ray diffraction), and SEM-EDS (scanning electron microscopy with quantitative X-ray microanalysis) were used. The total average content of REY in ash from biomass combustion is 3.55-120.5 mg/kg, and in ash from co-combustion, it is from 187.3 to 73.5 mg/kg. the concentration of critical REE in biomass combustion ash is in the range 1.0-38.7 mg/kg, and in cocombustion ash it is 23.3-60.7 mg/kg. In hard-coal ash, the average concentration of Rey and critical REY was determined at the level of 175 and 45.3 mg/kg, respectively. In all samples of the tested ashes, a higher concentration of th (0.2-14.8 mg/kg) was found in comparison to U (0.1-6 mg/kg). In ashes from biomass and hard-coal combustion/co-combustion, the range of the prospective coefficient (Coutl) is 0.66-0.82 and 0.8-0.85, respectively, which may suggest a potential source for REE recovery. On the basis of SEM-EDS studies, yttrium was found in particles of ashes from biomass combustion, which is mainly bound to carbonates. The carriers of REY, U, and th in ashes from biomass and hard-coal co-combustion are phosphates (monazite and xenotime), and probably the vitreous aluminosilicate substance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Mining of hard coal creates large underground cavities, which significantly affect the subsurface and land surface. Observations of land surface behaviour after the closure of mines demonstrate that these threats do not disappear. During mine water rebound in the post-mining phase of underground coalmines, the water flows into the open mine workings and other altered or fissured areas. This paper provides early observations from the PostMinQuake project, which is designed to identify mechanisms, relevant parameters and dependencies of mining and geological parameters causing post-mining seismicity in several European coal regions. It also presents the correlation between seismicity and water table level in the studied basins that has been observed during the post-mining phase and shows the necessity of implementing new procedures to monitor these seismic events. [ABSTRACT FROM AUTHOR]

The content of natural methane in hard coal seams, called methane-bearing capacity, is the basic parameter that enables the level of methane hazard to be determined in hard coal mines. This parameter is also used to determine the potential quantities of methane that can be collected and used for energy purposes and the amount of its harmful emission to the atmosphere. Direct methods are most often used to determine methane-bearing capacity. An important aspect that has a great influence on the final result of the research is the gas losses generated at the stage of sampling. Under the conditions of the Polish mining industry, the direct drill cuttings method is used to determine the methane-bearing capacity. Gas losses are compensated for in this method with the use of the coefficient 1.12, by which the obtained result is multiplied. In this paper, a multi-parameter analysis of gas loss in the determination of methane-bearing capacity in hard coal seams has been carried out. Several experiments were performed to identify the most important aspects to be taken into account to obtain a correct result. A methane-bearing capacity test was conducted using two direct methods: the direct drill cuttings method, otherwise known as the single-phase vacuum degassing method, and a method based on the United States Bureau of Mines standards. Sorption studies, such as methane sorption kinetics tests, were also conducted in which sorption properties, such as sorption capacity, effective diffusion coefficient, and half sorption time, were determined. Methane sorption isotherms were also determined, and pore structure was analysed. Based on the obtained test results, an analysis was carried out which made it possible to present appropriate conclusions concerning the gas losses during the methane-bearing capacity test, generated at the stage of sampling. The final result of the work was the proposal of a new gas loss coefficient for the direct drill cuttings method of methane-bearing capacity determination. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An impact assessment of the run-of-mine dilution on hard coal production efficiency is presented in the article. The data were taken from three longwall faces, conducted in a thin seam. Empirical data were subject to a statistical analysis aiming at the development of a mathematical model of an advance of longwalls depending on a quality structure and an amount of the run-of-mine from the ploughequipped longwall faces. The Monte Carlo method, an analysis of agglomerations and an analysis of scenarios enabled to develop a mathematical model. Afterwards, an analysis of the economic efficiency of the mining process, bearing in mind scenarios assuming an improvement of the run-of-mine quality, was conducted. [ABSTRACT FROM AUTHOR]

Sixteen samples were designed for analysis (hard coal, aggregate - barren rock, hard coal sludge). The total mercury content and the amount of mercury leaching were determined. The percentage of leachable form in the total content was calculated. The studies were carried out under various pH medium. The leachability under conditions close to neutral was determined in accordance with the PN EN 12457/1-4 standard. The leachability under acidic medium (pH of the solution - approx. 3) was determined in accordance with principles of the TCLP method. The mercury content was determined by means of the AAS method. For hard coal the total mercury content was 0.0384-0.1049 mg/kg. The level of leaching on mean was 2.6%. At the acidic medium the amount of leaching increases to an mean 4.1%. The extractive waste of aggregate type features a higher total mercury content in the finest fraction < 6 mm (up to 0.4564 mg/kg) and a lower content in the fraction 80-120 mm (up to 0.1006 mg/kg). The aggregate shows the percentage of the leachable form on mean from 1.4 to 2.2%. With pH decreasing to approx. 3, the amount of leaching grows up to mean values of 1.7-3.2%. Coal sludge features the total mercury content of 0.1368-0.2178 mg/kg. The percentage of mercury leachable form is approx. 1.8%. With pH decreasing the value increases to mean value of 3.0%. In general, the leachability of mercury from hard coals and extractive waste is low, and the leachability in an acidic medium grows approx. twice. Such factors as the type and origin of samples, their grain composition, and the pH conditions, have basic importance for the process. The time of waste seasoning and its weathering processes have the greatest impact on increasing the leaching of mercury from the extractive waste. [ABSTRACT FROM AUTHOR]

The zoning of the coal seam gas is zonal, which has a significant impact on the prominent prediction indicators, resulting in different prediction results for the same prominent prediction indicators in the same coal seam soft and hard coal. In this paper, the hard coal and soft coal in the coal seam are highlighted. The adsorption and desorption rules of the soft coal and hard coal in the outburst coal seam and its influence on the sensitivity of the outstanding prediction index are studied. The results show that: (1) the initial desorption of soft coal is larger than that of hard coal; (2) the outstanding prediction index has an exponential function relationship with gas pressure; (3) the sensitivity of prediction indicators is different. And concluded that: (1) the initial desorption rate of soft coal is faster than that of hard coal; (2) the outburst prediction index K1 and Δh2 increase with the increase of gas adsorption equilibrium pressure; (3) outburst prediction index K1 is more reliable than Δh2. [ABSTRACT FROM AUTHOR]

The authors concentrated on some issues related to the sustainable development of the mining industry, i.e. on the management of fossil fuels deposits to achieve economic efficiency, environmental, as well as social acceptance. It should be borne in mind that Poland still belongs to the countries in which electric energy production and thermal energy production are based on hard coal and lignite. The research work results described in the article present efficiency assessment aspects in the case of different longwall technological systems in the LW Bogdanka. Advantages and disadvantages resulting from using shearer and plow systems are given. An impact of dilution in the run-of-mine on the coal quality is analyzed, and some recommendations emerging from this analysis are suggested. On the basis of the conducted in situ experiments, technical possibilities of reducing dirt are described. As an efficiency assessment is a multi-criterion process, so it requires continuous monitoring of production parameters. The article also contains an analysis of longwall systems in the aspect of dust control. An impact of mining, technical and technological parameters on generated dust amount, in particular in the case of a shearerequipped longwall face, is discussed. In the conclusions, it is highlighted that an efficient assessment process in the case of longwall systems is complicated as an impact of different factors should be taken into consideration. It is suggested to use the data integration platform based on the Service Oriented Architecture (SOA). Due to the SOA, any mistakes in the scope of the functionality of individual systems can be detected very quickly. Such an approach is fundamental for the realization of the TPM (Total Productive Maintenance), leading to the creation of the socalled Mine of Smart Solutions. [ABSTRACT FROM AUTHOR]

A method for drying hard coals using an impinging stream dryer has been proposed in the article. A series of screening tests were conducted, seeking optimum process parameters of an innovative coal impinging stream dryer using flue gas as the drying medium. The article addresses measurement results obtained for the flue gas and feedstock flow rate, feedstock sort, and initial moisture content on the specific energy consumption, volumetric water evaporation rate, and moisture reduction. The maximum volumetric water evaporation rate was found to be around 230 kgwater/m3·h and the maximum volumetric heat transfer coefficient came to ca. 2.5 kW/m3·°C. In terms of specific energy consumption, the lowest specific energy consumption was found to be around 1.79 kWh/kgwater. It was established that the relation between specific energy consumption and a product of the flue gas flow rate and the initial water (in the feedstock) flow rate is a power function. The best performance of the impinging stream dryer was achieved for high-moisture coal and high flue gas flow rates. The impinging stream dryer proved to be suitable for surface moisture removal from particulate materials that contain very high moisture. The initial tests conducted at the pilot plant successfully demonstrated reliable operation and promising results. [ABSTRACT FROM AUTHOR]

This paper deals with issues related to tribological processes occurring as a result of excessive wear of the surface of scraper conveyor components caused by the impact of the mined material created during drilling of development or exploitation galleries. One of the most common types of tribological wear is abrasive wear. W ear tests were carried out for hard coal - based abrasive using dry carbon abrasive and a hydrated mixture with 76 and 58% hard coal. Based on the conducted research, it was established that the effects of wear processes are associated with damage typical of wear mechanisms: micro-scratching and micro-fatigue. For the wear variant in the presence of dry coal abrasive, individual scratches caused by the abrasive grains were observed on the surface of the samples. The main reason for this type of damage was the aggregation of quartz, which is one of the basic components of the mineral substance present in the tested hard coal. When hydrated carbon mixtures were used as an abrasive, the surface of the samples also displayed scratches characteristic of the aggregate quartz. A small part of the carbon abrasive was pressed into the scratches. Under the influence of the wear caused by friction, small depressions were also formed, where coal penetrated. The effect of coal pressing into micro-scratches is related to its plastic properties. T ests of the abrasive conducted after the conclusion of wear tests have shown that under the influence of the local increase in temperature and pressure, the hard coal contained in the abrasive can undergo transformations. In the abrasive transformed under friction, small, but measurable changes in the content of the C element in relation to the initial hard coal sample were exhibited. [ABSTRACT FROM AUTHOR]

The enrichment of hard coal is one of the stages of mineral resources management. It is aimed at adapting its quality parameters to different recipients' requirements, considered as a stage of mineral resources management. This process is treated as a stage of clean coal technologies or as a process of improving the economics of mining plants, which takes place in the Mechanical Coal Processing Plant (ZMPW). Adaptation of the quality of commercial coal products to the needs of specific recipients consists of removing useless components of the excavated material. In this publication, factors having a negative impact on the environment as a result of the refining process of useful minerals carried out at the Mechanical Coal Processing Plant were analysed. All departments and workstations in the Mechanical Coal Processing Plant (ZMPW) were analysed. The measurement results and proposals of solutions which have an impact on reducing the nuisance of working conditions on people working in these places were presented. The analysis results show that noise is an important factor influencing work comfort. The actions taken by the Plant will allow eliminating the negative impact of equipment emitting excessive noise on the environment. The process related to the processing and adaptation of coal to market requirements was also analysed. This analysis of the production process allowed to determine the impact that this process has or may have on the natural environment. The presented results were obtained from one of the Hard Coal Mines of the Polish Mining Group S.A. [ABSTRACT FROM AUTHOR]

The aims of this work were (1) the determination of the efficiency of isolating by hand two lithotypes concentrates, vitrain and durain, from original coal sample of low rank bituminous coal, (2) the evaluation of the relation between macro- and microscopically distinguishable components of samples under investigation and their physicochemical properties and (3) the assessment of the effect of maceral composition of low rank coal on carbon dioxide sorption capacity and desorption process. To address the first issue a petrographic analysis was performed for separated components and the original raw sample. A significantly higher vitrinite content in vitrain concentrate and much lower in durain concentrate in regard to basic coal confirmed that the separation process was satisfactory. The second aspect comprised an investigation into selected physical and chemical properties of original coal and two lithotypes concentrates including helium density, methanol density, FTIR spectra, the amount of oxygen functional groups and swelling properties using pyridine as solvent. The results show that in the case of material under study the coal rank does not preponderate the effect of maceral composition. This third issue was addressed by performing adequate sorption experiments carried out at 298 K at low pressure on basic coal sample and two lithotypes concentrates. The tendency of adsorption capacity of CO2 to depend on maceral composition was confirmed as it increases with the content of vitrinite. The Dubinin–Radushkevich equation shows a very good agreement with all the experimental data obtained for both lithotypes concentrates and basic coal under investigation. [ABSTRACT FROM AUTHOR]

In the Czech part of the Upper Silesian Coal Basin, there are records of rockbursts dating back as early as the beginning of the last century. Since then, 450 such rockbursts of varying intensities have been recorded. This article is a vignette of our recent opinion on rockburst issues in the Ostrava–Karvina Coalfield. It comments on the main causes of rockbursts and summarises the strategic measures taken against them. It highlights the main mistakes in mine design in rock mass that lead to a rockburst risk and supports these arguments with illustrative examples from Czech hard coal mining. Long-term analyses of the causes of rockbursts provide recommendations on proper mining techniques for excavation of a rock mass with rockburst risk. [ABSTRACT FROM AUTHOR]

The purpose of the research was mapping, inventorization, and valorization of coal mining waste dumps from the mines of JSW SA company, for the needs of recovery of coal from the dump material as well as the reclamation and management of examined facilities. The valorization of post-mining waste dumps has been carried out using a methodology which considers the problems of reclamation, management, accessibility of the dumps as well as environmental hazards connected with disposing of mining and preparation wastes on the ground surface. An inventorization of 10 coal mining waste dumps coming from 6 mines of JSW SA including in their range 7 deposits: Borynia, Jastrzębie, Zofiówka, Budryk, Knurów, Szczygłowice and Pniówek was carried out. The source material within the localization of particular dumps was obtained from archival materials coming from coal mines and municipalities where the dumps are located. Verified data has been drawn on topographical map, which results in the map of coal mining waste dumps. The results of the valorization of the dumps comprise the defining of: the name of the dump, state of the dump, surface of the dump, accessibility, name of the coal mine from where the wastes come from, type of technical and biological reclamation and possibilities of coal recovery, which have been brought on the drawn map. Basing on collected and elaborated data, an attempt of defining of potential possibilities of recovery of coal from the dumps and connection of coal quality in the deposits of JSW SA and in waste material was made. The results of the research showed that in spite of preliminary information that a majority of the investigated dumps may be considered as potential facilities for coal recovery, ultimately the recovery is economically justified only in several cases (5 facilities). [ABSTRACT FROM AUTHOR]

The restoration of soil fauna on a spoil heap is a strong indicator of successful reclamation. The studies were conducted on two types of materials: bare rock (BR) and BR with topsoil (TS) which were applied during coal spoil reclamation and three vegetation types. Four variants investigated included natural forest succession on BR (Succession_BR) and TS (Succession_TS), afforestation (Reclamation_TS) and afforestation with Robinia pseudoacacia (Robinia_TS). Soil pH, soil organic carbon (SOC) and total nitrogen (TN) content, and soil texture were measured in 0–10 cm layers. Earthworms were collected using hand sorting method, and enchytraeids were collected using wet extraction with the heating method. The investigated soil had varying pH values from 5.3 in a BR to 7.2 in Robinia_TS. The highest content of SOC and TN were in Successinon_BR, and the lowest was in Succession_TS. Enchytraeids density was in the following increasing order: 275, 2982, 3001 and 4548 ind m−2 for Succession_BR, Robinia_TS, Succession_TS and Reclamation_TS, respectively. Earthworm density ranged from 0 ind. m−2 in the Succession_BR through 116 ind m−2 and 120 ind m−2 in Reclamation_TS and Succession_TS, respectively up to 162 ind m−2 in the Robinia_TS. The reclamation treatment was a major driver for soil fauna development while vegetation type was of secondary importance. Investigated soil fauna was positively related to pH value and clay content. The most stimulating variant for the development of earthworms and enchytraeids was the application of reclamation with various tree species and the planting of Robinia pseudoacacia on the topsoil. [ABSTRACT FROM AUTHOR]

This work presents the results of an experimental study on the properties of tar that originated from underground coal gasification (UCG) trials. Two in situ experiments of UCG were performed using oxygen as the gasification agent under the HUGE and HUGE 2 projects. Trials were conducted using different configurations of the fire channel, gasification time and method of raw gas collection and purification. The obtained tars were analysed over a wide range of parameters that are typical for the assessment of the quality of conventional coke oven tar. The results of the analysis showed that in terms of physical–chemical properties, both tars are highly different from each other, as well as from typical coal tar from a coking plant. One characteristic observation of the UCG-derived tars is a higher content of ash as well as toluene and quinoline insolubles compared with a typical coke oven tar. Both tars are susceptible to thermal destruction and degradation to lighter products, and the characteristics of the coking distillation residue after heating to high temperatures is different from coke oven tar. The tested tars vary in boiling range and fractional composition. The analysis also showed that tars from UCG contain more heterocyclic compounds than does coke oven tar, and the tar from HUGE is heavier than tar from HUGE 2. The content of PAHs in the tar from HUGE is many times higher than in tar from HUGE 2 and at a similar level as coke oven tar; however, the naphthalene content in both UCG tars is many times lower compared to typical coke oven tar. The probable reasons for the differences described in this report include the tar residence time in the sampling point, as well as different extents of tar fractionation phenomena, which resulted from the distinct configurations of the gas transportation and purification systems. [ABSTRACT FROM AUTHOR]

Tests of coal samples collected from a borehole drilled in the surrounding of an underground coal gasification georeactor were conducted. This experiment was conducted for the first time in an active coal mine in Poland. The aim of the tests was to determine the extent of heat penetration around the UCG cavity during a nearly two month gasification process. The method of measuring the mean reflectance of the vitrinite index (R o ), which is more generally used to measure the degree of the coalification of organic substances in coal (macerals) under the influence of temperature, was applied. The method is still used to evaluate the usefulness of coal for producing coke. The mean reflectance of the vitrinite index determined for the collected samples and reflectograms, allowed the inference that when the georeactor was operating, the temperature in the UCG cavity reached approximately 1300 °C. Based on R o , the point in a coal seam surrounding the georeactor corresponding to the temperature of approximately 700 °C was also identified, where there were signs of the initial stage of coal transformation. The point was located 1.94  m from the boundary of the UCG cavity. Then, at the distance of 1.73 m from the boundary of the UCG cavity the point with a temperature of approximately 1000 °C was identified. The tests confirmed that it is possible to use the method of determining the mean reflectance of vitrinite index to measure the distance of influence of georeactor temperature on the rock mass. This is particularly important for underground coal gasification conducted in active mines. In the future the results will be used to predict the time of heating needed for coal deposits to become gasified, based on laboratory tests and coal type. [ABSTRACT FROM AUTHOR]

The paper discusses the current situation as well as the perspectives for hard coal extraction in India, a global leader both in terms of hard coal output and import volumes. Despite this, over 300 million people lack access to electricity in this country. The main energy resource of India is hard coal and Coal India Limited (CI L) is the world's biggest company dealing with hard coal extraction. CI L has over 450 mines, employs over 400,000 people, and extracts ca. 430 million tons of hard coal from its 471 mining facilities. India is planning the decisive development of hard coal mining to extract 1.5 billion tons in 2020. Hard coal output in India can be limited due to the occurrence of various threats, including the methane threat. The biggest methane threat occurs in the mines in the Jharia basin, located in East India (the Jharkhand province), where coal methane content is up to ca. 18 m³/Mg. Obtaining methane from coal seams is becoming a necessity. The paper provides guidelines for the classification of particular levels of the methane threat in Indian's mines. The results of methane sorption tests, carried by the use of the microgravimetric method on coal from the Moonidih mine were presented. Sorption capacities and the diffusion coefficient of methane on coal were determined. The next step was to determine the possibility of degassing the seam, using numerical methods based on the value of coal diffusion coefficient based on Crank's diffusion model solution. The aim of this study was the evaluation of coal seam demethanization possibilities. The low diffusivity of coal, combined with a minor network of natural cracks in the seam, seems to preclude foregoing demethanization carried out by means of coal seam drilling, without prior slotting. [ABSTRACT FROM AUTHOR]

This letter deals with the in-situ determination of important inorganic gas phase species in high temperature gasification product gas. The fuels are waste wood and German hard coal which were co-gasified at 1500 °C in lab-scale experiments. The release of the vapour species 34 H 2 S + , 36 HCl + , 56 KOH + , 58 NaCl + , 60 COS + , 64 SO 2 + , and 74 KCl + was determined online by a Molecular Beam Mass Spectrometer. The experimentally determined data sets were compared to calculated data sets in order to distinguish the underlying release mechanisms. The release behaviour of the inorganics 34 H 2 S + , 36 HCl + , 60 COS + , 64 SO 2 + and 58 NaCl + cannot be attributed to simple mixing and dilution effect only. Further, it is shown that the release of these inorganics is significantly influenced by secondary reactions, e.g. competitive reaction with S and Cl. [ABSTRACT FROM AUTHOR]

Mercury is characterized by highly toxic properties. The natural biogeochemical cycle of mercury occurs in the environment, which results in the fact that even a small amount of mercury emitted to the environment is a potential threat to human health. The process of coal combustion is one of the main sources of anthropogenic mercury emissions. For this reason, on 31 July 2017 the European Commission has adopted the mercury emission standards for large combustion plants. The issue of mercury emissions is particularly important for Poland. Forecasts concerning energy consumption in Poland show that coal will be the main source for energy production in the coming decades. Therefore, actions enabling the reduction of mercury emissions from coal-fired power plants will have to be implemented. The mercury emissions from coal-fired power plants may be reduced through the application of a number of methods. These methods can be divided into two main groups: the post-combustion methods which allow for mercury removal from flue gases, and the pre-combustion methods which allow for mercury removal from coal before its combustion. The effectiveness of mercury removal from coal is determined by the mode of its occurrence in coal. In the case of mercury occurrence in the adventitious inorganic constituents of coal, high effectiveness will be obtained in the coal cleaning processes. In the case of mercury occurrence in the organic matter as well as in the inherent inorganic constituents of coal, the effectiveness of this method will be low. Mercury could be removed from such coals through the process of thermal pretreatment at the temperature of 200-400°C (mild pyrolysis). In the paper, the possibility of mercury removal from hard coal through the process of dry deshaling on an air concentrating table was examined. Six raw coals (coal feed), clean coals and the rejects derived from their dry deshaling were analyzed. The mercury content was measured in the examined samples. The content of mercury in raw coals and clean coals were compared. Additionally, the effectiveness of mercury removal from coal with rejects was determined. For the analyzed coals, the effectiveness of mercury removal from coal in the process of dry deshaling on an air concentrating table ranged from 9 to 96%. This effectiveness is similar to the effectiveness of mercury removal from coal in the processes of coal washing. It should be mentioned that, when compared to the coal washing processes, the dry deshaling process is characterized by lower investment and operating costs. Therefore, the dry deshaling process on an air concentrating table should be considered as a competitive method for the coal washing processes. There is also a possibility of an increase in the mercury removal efficiency from coal in the process of dry deshaling as a result of the thermal pretreatment of clean coal derived from dry deshaling. This solution is only recommended for coals in which mercury occurs in the organic matter as well as in the inorganic constituents characterized by a relatively low temperature of mercury release. It should be emphasized that the dry deshaling process allowed for a decrease of mercury content is not suitable for every coal. Although for five of the analyzed coals the mercury content in clean coal was lower in the range from 11 to 53%, for one coal the mercury content was higher by 19%. The effect of decreasing the mercury content in coal is more evident when it is related to the amount of energy contained in coal (i.e. for example to the lower heating value). For five of the analyzed coals mercury content expressed in such a way decreased in the range from 11 to 53 %, and for one coal the mercury content was, however, higher. Nevertheless, the difference was not very significant (ca. 5%). [ABSTRACT FROM AUTHOR]

Coal is a complex geological body that is composed of organic material, gas, and water. Generally, coal with high hardness is commonly considered to be a non-outburst risk; however, several coal mines with hard coal seams in China have experienced coal and gas outbursts. Coals with different degrees of metamorphism have different inherent moisture ranges, which has a strong influence on gas adsorption and desorption. Currently, inhomogeneous moisture wetting remains an issue in traditional preparation methods for preparing coal samples with different moisture levels. In this paper, we chose three typical hard coals with different degrees of metamorphism and systematically studied their pore structure characteristics, effect of approximate inherent moisture on the gas adsorption-desorption characteristics, and gas diffusion of hard coals. The results show that all of the coal samples have an open pore structure, but each coal sample has different development characteristics of their pore structure. The higher the moisture, the shorter the adsorption equilibrium time required and the lower pressure drop. All of the adsorption isotherm curves fit the Langmuir equation well. The gas adsorption capacity of the same coal sample decreases gradually and the amplitude of the gas adsorption capacity decreases with increasing moisture. This relationship indicates that the existence of moisture occupies a certain space of the pore structure and reduces the gas adsorption sites of coal, reducing the adsorption and desorption amount of the coal samples. Moreover, low and middle rank coal can use the bidisperse model to calculate the diffusion coefficient, while high rank coal can use the unipore model. Increasing moisture causes the macropore diffusion coefficient D and micropore diffusion coefficient D of the YZG and YJ samples to decrease. The effective diffusion coefficient D of the WLH samples also reduced gradually, which suggests that moisture has an influence on the gas migration and diffusion channels of coal, reducing the gas adsorption equilibrium time, desorption rate, and diffusion rate of coal seam. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on the degree of faulting of deposits/mining areas of the Upper Silesian C oal Basin having been carried out since the 1970s. The results of these works are comprised of an analysis of the density of faults and an of the faulting index for 26 deposits/mining areas in the borders of the USCB. The statistical presentation of the problem includes three main parameters that characterize the tectonic complication of hard coal deposits in the borders of mining areas: lineal density GUL, surface density GUP and synthetic faulting index WU. The comparison of values of these parameters for particular deposits/mining areas was used for drawing up maps of their changes, whereas the results of the obtained view of variability have been interpolated and extrapolated to the borders of the entire basin. The results of the research showed that the values of GUL vary between 0.2 and 9.4 of faults/m·10-3 and for all four analyzed directions: W-E, N-W, NW-SE i NE-SW, indicate a significant growing tendency in the following directions: N and NW and in SW. According to an analysis of GUP, it was stated that the largest part of the study area is occupied by the area in which there are no faults and the percentage of surface with GUP > 300 m/m²·10-4 is insignificant and does not have an essential influence on the rate and value of the faulting index. WU varies between 1.4 and 131.4 m/m²·10-4 (average for USCB: WU = 52.1 m/m²·10-4) and indicates a significant increasing tendency in the directions: N and NW as well as in the direction of SW. This determines the occurrence of USCB deposits of extreme different grade of tectonic complication in the borders: from not complicated (I grade) to very strongly complicated (VI grade). [ABSTRACT FROM AUTHOR]

The cataloging of over 220 coal mining dumping grounds after hard coal mining was carried out on the area of the Upper Silesian Coal Basin (USCB). Considering the significant content of coal particles in the waste, these object may be perceived as perspective anthropogenic deposits. In order to define the possibilities of recovery, an attempt of linking the quality of coal in the deposit and the in waste material was performed. Another step is the reclamation and use of dumping grounds after completing effective recovery processes. The purpose of the research was the cataloging, mapping and valorization of coal mining waste dumps from Katowicki Holding Węglowy coal mines, for the needs of reclamation and management of examined objects and defining the potential recovery of coal from the dumps. The valorization of the post-mining waste dumps was done with the use of original methodology, considering the problems of: reclamation, management, accessibility of the dumps as well as environmental hazards. The directions of the technical reclamation (e.g. landscape objects, tabular dumps) and biological reclamation (e.g. forest direction, mixed reclamation (grass and tree reclamation), grass cultivation, lack of reclamation) were defined. Accessibility with regard to open access/closing of the dump area and the roads leading towards the object were evaluated. The connection of coal quality in the deposits of KHW S.A. and in waste material enabled the definition and evaluation of the potential possibilities of recovery of coal from the post mining dumping grounds. [ABSTRACT FROM AUTHOR]

In order to determine the suitability of Polish coals for steam gasification, five Polish hard coals and three brown coals, which are used for power and heat production, were examined in this work. The examinations of the process of steam gasification were conducted with the use of a laboratory plant which allows for measurements within a broad pressure range with the thermovolumetric method. reactivity evaluations for the examined coals were conducted on the basis of an analysis of the shape of the kinetic curves of formation of major gasification products and a comparison of the curves of the carbon conversion degree of the examined raw materials. In order to evaluate the reactivity of the examined coals, the following factors were utilized: a comparison of the shape of the curves of the carbon conversion degree and the maximal value of the carbon conversion degree, the time of partial conversion τ0.5, the reactivity index R0.5, as well as the reaction rate constant of carbon conversion. The yields, composition and calorific value of the resulting gas were determined as well as the reaction rate constants of formation of particular gaseous products of gasification. Additionally, for the examined coals, ash fusibility and the content of selected impurities, e.g. sulfur, chlorine and mercury, were given. [ABSTRACT FROM AUTHOR]

A Colombian hard coal was stepwise pyrolyzed from 200 to 800 °C, and the resulting changes in surface and material properties were investigated by thermogravimetric analysis and volumetric adsorption techniques as well as by density, surface area, ATR-IR and GC/MS measurements. It was observed that a loss of volatile compounds occurred up to a pyrolysis temperature of 600 °C. These compounds were identified as CO, CO 2 and H 2 O and mainly large substituted aromatic compounds and long-chain hydrocarbons. The loss of functional groups was also monitored by a decrease of related IR bands. The devolatilization was found to cause an increase in density and surface area; the adsorbed amount of CO 2 and O 2 increased in this temperature region as well. The char pyrolyzed at 600 °C was the only sample with a hydrophobic surface. Increasing the temperature to 800 °C led to no further mass loss, but to a structural reorganization of the char indicated by the reappearance of aromatic IR bands. This high-temperature restructuring resulted in a decrease of density, surface area and adsorbed gas amount. [ABSTRACT FROM AUTHOR]

The goal set for this paper was to investigate the relationship between gradation of filler particles content in the epoxy matrix and the gradation of electric properties. In order to characterize the electric properties, the surface resistivity was selected, because it determined the surface ability to electrostatic charging, important in expected applications. In particular, the influence of conditions of centrifugal casting technique and microstructure parameters on electric resistivity was searched. Experimental models were elaborated that juxtapose the dependence of surface resistivity on the volumetric content of the filler, as well as casting rotational velocity. Investigations results confirmed that achieved graded composites were characterized by the reduced ability of electrostatic charging on one side and good insulating properties on the other side. Measured surface resistivities of order 109–1011 Ω allow to classify them as surfaces with reduced susceptibility to static electricity accumulation. These composites may be applied in areas where antistatic properties of the surface, with preservation of insulating properties in the remaining volume of the composite, are beneficial. [ABSTRACT FROM AUTHOR]

In this article, the results from a pilot-scale, underground coal gasification (UCG) experiment conducted in an operating coal mine “Wieczorek” were presented. The 60-day gasification trial demonstrated that through the appropriate selection of the test site and by applying all safety standards essential for the coal mining industry, UCG in an active mine can be conducted safely and efficiently. The idea of the technical realization of the UCG process, as well as selected gasification results, such as the primary mass balance parameters, gas production rate, coal consumption rate, coal gasification efficiency and the changes in gas composition, were presented. [ABSTRACT FROM AUTHOR]

Due to the important role of hard coal in the Polish residential sector, the article traced the changes that have occurred in the use of this fuel in the European Union and in Poland in the years 1990-2014. Throughout the European Union, hard coal has an important place in the structure of primary energy consumption. In the years 1990-2014, primary energy consumption in the European Union (calculated for all 28 Member States) has changed between 1507 and 1722 million toe. Between 2014 and 1990, there was a decrease of primary energy consumption, and the average rate of decline amounted to -0.2%. According to Council Directive 2013/12/EU, by the year 2020 energy consumption throughout the EU is expected to be no more than 1483 Mtoe of primary energy, and already in 2014 total primary energy consumption in the EU28 was higher than assumed by this target by only about 24 million toe (2%). Actions taken to protect the climate result in reducing the consumption of hard coal in the European Union. Between 1990 and 2014, the consumption of hard coal decreased by 41% (a decrease of 126 million toe), and the average rate of decline in consumption of this fuel amounted to -2.1%. Throughout the EU, households are not as significant a consumer of hard coal, as in Poland. Although EU28's coal consumption in this sector in the years 1990 to 2014 varied between 6.5- -15.8 million toe, its share in the overall consumption of this fuel usually maintained at around 3-5%. The changing fuel mix, closing of mines or gradual extinction of coal mining, environmental policy of the individual countries meant that coal has lost its position in some of them. Analyzing the structure of hard coal consumption by households in the EU28 countries in the years 1900 to 2014, one may notice that the leaders are those countries that have their own coal mines. Due to the structure of consumption of hard coal by the customers, the article discussed two countries: Poland and Great Britain in greater detail. In 1990, Poland (50%) and Britain (18%) were close leaders, and twenty-five years later, only Poland has remained in first place (84%) and Great Britain has fallen to fourth place (4%). Between 2014 and 1990, the consumption of hard coal by the British residential sector decreased by 88% to only 0.3 million toe. In the case of Poland, it admittedly decreased by 6%, but still exceeds 6 million toe. The decrease in hard coal consumption in Great Britain was largely a consequence of The Clean Air Act introduced in 1956. In Britain, the process of replacing coal with other fuels (mostly natural gas) lasted several decades. Domestic coal was replaced with another mainly domestic resource - natural gas which ensured the security of its supply. The article also describes the households in the European Union and in Poland. The overall housing stock was taken into account, together with the distribution of population according to the degree of urbanization. Regulations that have a significant impact on the consumption of energy in the European Union were also discussed. [ABSTRACT FROM AUTHOR]

Chemical-looping combustion (CLC) is an emerging carbon capture technology that is characterized by a low energy penalty, low carbon dioxide capture costs, and low environmental impact. To prevent the contact between fuel and air, an oxygen carrier is used to transport the oxygen needed for fuel conversion. In comparison to a classic oxyfuel process, no air separation unit is required to provide the oxygen needed to burn the fuel. The solid fuel, such as coal, is gasified in the fuel reactor (FR), and the products from gasification are oxidized by the oxygen carrier. There are promising results from the electrically heated 100 kWth unit at Chalmers University of Technology (Sweden) or the 1 MWth pilot at Technische Universitat Darmstadt (Germany) with partial chemical-looping conditions. The 1 MWth CLC pilot consists of two interconnected circulating fluidized bed reactors. It is possible to investigate this process without electrically heating due to refractory-lined reactors and coupling elements. This work presents the first results of autothermal operation of a metal oxide CLC unit worldwide using ilmenite as oxygen carrier and coarse hard coal as fuel. The FR was fluidized with steam. The results show that the oxygen demand of the FR required for a complete conversion of unconverted gases was in the range of 25%. At the same time, the carbon dioxide capture efficiency was low in the present configuration of the 1 MWth pilot. This means that unconverted char left the FR and burned in the air reactor (AR). The reason for this is that no carbon stripper unit was used during these investigations. A carbon stripper could significantly enhance the carbon dioxide capture efficiency. [ABSTRACT FROM AUTHOR]

The article describes the importance of individual client in making level of demand for hard coal in Poland, and points to lack of use this potential by Polish hard coal producers. These arguments were derived firstly on the basis of analysis of the present structure of the hard coal market in Poland, including terms of the competitive situation. Secondly were taken into account characteristics of the level of demand for the product generated by the segment of individual clients. First of all the author focused on the second element, indicating the size and capacity of the quantitative and valuable part of the market for the year 2013. These analyses were carried out on the national level and in terms of individual provinces. In this way the level of the annual capacity of individual clients in Poland is 19.25 million Mg of hard coal. Taking into account prices of coal, calculation of the capacity of value is equal to 15.6 billion złoty per year. In regional terms the author also identified the most attractive in terms of capacity volumes and values Polish province, which included Mazowieckie and Silesia. [ABSTRACT FROM AUTHOR]

The ability of five kinetic equations to describe the sorption kinetics and expansion rate of solid coal samples was investigated. The conducted experiment included the measurements of sorption of methane and carbon dioxide on cuboidal hard coal samples at high pressure using volumetric method. Simultaneously the kinetics of coal sorption induced swelling was monitored. All of the approaches used to fit the experimental sorption and dilatometric data were literature-based equations. Two equations represent the traditional approach for sorption on powder and grain fractions based on the bidisperse gas transport model, and have been used to interpret and quantify the observed gas uptake rates in coal. The other three kinetic equations are the pseudo-second-order kinetic equation, Elovich equation, and stretched exponential (SE) equation. Four of the five equations are suitable to describe the kinetics of methane and carbon dioxide sorption in the porous structure of solid coal samples and the kinetics of coal expansion that accompany the sorption processes. The SE equation gave the best fit to the experimental data. [ABSTRACT FROM AUTHOR]

The paper presents a numerical approach to the analysis of the statistical effect of functional groups on the sorption of methanol and water on hard coal samples. The material used for the analysis was obtained from numerous samples of hard subbituminous and bituminous coals up to anthracite from different Polish coal mines and includes sorption isotherms of water and methanol vapors, as well as carbon dioxide and methane on these samples. Measurements were made of the sorption isotherms of water and methanol vapors and the data set has been supplemented with the sorption isotherms of water, methane and carbon dioxide taken from the literature for the precise estimation of the model parameters. More precise estimation is reached by using a strong setting of the coal structure parameters for a bigger number of sorption system, and in each case the same parameters of coal geometry are constant with an exact fitting of sorption isotherm. The adsorption-absorption model of the sorption in coal (Multiple Sorption Model-MSM) is used in the numerical experiments and the parameters of hard coal structure and the sorption systems are estimated. It has been stated that water as a polar substance together with methanol, as well as carbon dioxide and methane give good estimates of coal structure and let us quantify the polar effect of surface groups present in hard coal. The polar effect is introduced in the model in the range of adsorption and expansion sub-processes. The presence of oxygen groups in the bulk of coal matter has no significant effect and can be neglected. A weak decreasing tendency of polar factors ratio for water and methanol is discovered. [ABSTRACT FROM AUTHOR]

The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutionswas examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibriumtimewas found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coalswere fitted to the Langmuir, Freundlich, Langmuir–Freundlich, Sips and Redlich–Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds. [ABSTRACT FROM AUTHOR]

The article presents the results of tests of porosity of the Upper-Silesian Coal Basin (USCB) hard coals. The porosity was determined for various lithotypes of hard coal, collected in different areas of the Upper-Silesian Coal Basin. Samples of hard coal were collected in 60 seams of 16 coal mines, from the depth of approximately between 350 and 1200 m. There are also presented differences in values of open porosity of coal depending on the depth of occurrence, as well as chronostratigraphic and tectonic correlation of a seam. Uniaxial compression strength of the tested coals falls in the strength class from very low to very high (from 8.1 to 51.5 MPa), open porosity is 0.68-12.5% and total porosity is 3.29-17.45%. With an increase in depth, in general, open porosity of coals decreases. There is an apparent decrease in open porosity correlated with the age of hard coals. It was observed that the lower and upper limits of open porosity ranges of variability shift towards lower values the older the coals are, from the Łaziskie Beds to the Jaklowieckie Beds. The older the coals the greater the average drop in the share of open porosity in total porosity from 60% for the youngest coals to merely several per cent for the oldest ones. The highest values of total porosity (over 10%) were observed in the youngest coals (Cracow sandstone series and siltstone series). Older coals reached more diversified values of total porosity (3.29-17.45%). Based on the conducted tests, zones correlated with tectonics of the basin and with deposition of lithostratigraphic beds of specific age, where values of porosity of hard coals differ, were determined in the area of the USCB. However, in spite of their correlation to a structural unit, the coals demonstrated a decrease in open porosity with an increase in their geologic age. Thus, there is an apparent influence of the deposition depth of coal within a given structural unit on open porosity following the age of coal, i.e. correlation to an older and older chronostratigraphic unit. Porosity tests of hard coal are published in scientific journals yet, most often, there is no information on the type of porosity. Such detailed characteristics of open porosity for coal of the Upper Silesian Coal Basin, as in the article, have not been prepared yet, making our research novel. Such broad tests of porosity of hard coals, correlated with their strength and referring to the deposition depth of seams as well as a correlation to lithostratigraphic units within individual structural units in the USCB, had not been conducted yet. We believe it is a sufficient argument to start detailed research into the open porosity of hard coals. The results of the tests are important from both the research and practical points of view. Knowledge of coal porosity is indispensable in solving many engineering problems of geological engineering, mining geomechanics and mining e.g.: assessing behaviour of coal when it is mined and processed, assessing the possibility of capturing methane, which makes up over 90% of natural gas, from coal in the areas of methane-rich deposits; the possibility of storing various substances in abandoned hard coal mining areas (e.g. CO2 storage within the structure of coal), assessing risk of occurrence of certain natural hazards resulting from mining deposits (e.g. coal and rocks outburst hazard), as well as assessing the possibility of applying unconventional methods of mining hard coal deposits (e.g. underground coal gasification). [ABSTRACT FROM AUTHOR]

In order to further investigate the top-coal caving structural characteristics of extra-thick hard coal seam with shallow bury depth in fully mechanized sublevel caving mining, authors studied the No. 3 coal seam mined in Qian-shuta Coal Mine at Yuyang District, China. The caving structure of hard top coal was studied by using numerical simulation, theoretical analysis, in-site measurement, etc. Cantilever structure of top coal exits at the face end position. The internal stress of cantilever top coal was analyzed, and the cantilever length was also simulated. The results indicate that different broken lengths have an significant impact on the caving and releasing of top coal. When broken length is less than the horizontal projective width of coal caving port,top-coal caving are relatively easy. On the contrary, it is difficult for top-coal caving,and the total time for handling big lump coal increases. The results explains the macro-structural factors of difficulty on hard top coal caving. [ABSTRACT FROM AUTHOR]

The aim of the experimental works presented in this paper was to develop a method using wavelength dispersive X-ray fluorescence spectrometry (WDXRF) in order to determine the content of 16 rare earth elements (REEs) and the concentration of the said elements in 169 samples of combustion ash of coals coming from ten Polish coal mines, as well as to validate the method. It was found out that there is a clear diversity in the levels and ranges of the variability of REEs occurrence in coal ashes. The average content of cerium, lanthanum , and scandium amounts to 198.8 μg ∙ g − 1 , 76.5 μg ∙ g − 1 , and 52.4 μg ∙ g − 1 respectively, whereas for such metals as europium, holmium, lutetium, terbium, and thulium, the average content does not exceed the level of 5 μg ∙ g − 1 (the average content for these metals amounts to 1.2 μg ∙ g − 1 , 1.4 μg ∙ g − 1 , 0.3 μg ∙ g − 1 , 1.3 μg ∙ g − 1 , and 0.6 μg ∙ g − 1 , respectively). In addition, this paper presents an analysis of data obtained by means of hierarchical clustering analysis. Simultaneous interpretation of the dendrogram of objects (coal ash samples) and the color map of the experimental data allowed a more in-depth analysis of the relationships between the clustered coal ash samples from different coal mines and the content of the rare earth elements. [ABSTRACT FROM AUTHOR]

When comparing two steam generators first thing we think about is their effectiveness. As the environmental impact of industrial activities is a topic becoming more actual lately, an analysis of steam generators from this point of view was considered appropriate. Two steam generators were chosen based on their long-term operation period, almost the same construction and different fuel types used to power them. The results show the need for the replacement of the steam generators as both have exceeded the pollutant concentration limits, and modern steam generators have higher efficiency. [ABSTRACT FROM AUTHOR]

The study presents the method of determining constant coefficient b2, occurring in general filtration equation (1), in the second part of the denominator, that is in the expression for deposit resistance In the considerations, lack of the deposit's compressibility was assumed, which means that the deposit porosity is constant. With such an assumption, constant coefficient b2 is equivalent with transmission coefficient, which occurs in commonly known and accepted equation - as the baseline equation - for fluid flow through a porous layer according to Darcy (Piecuch 2009, 2010). This study is another publication in the cycle of basic tests of the filtration process which constitute next publications of the authors, published in Rocznik Ochrona Środowiska [ Annual Set the Environmental Protection] as well as in the magazine Gospodarka Surowcami Mineralnymi [ Mineral Resources Management], to which the reader interested in these problems can refer. Another study will be the publication discussing the filtration process with the creation of sediment on the filtration deposit, hence in the general filtration equation (1) the value of sediment resistance RO will appear in the denominator. Relevant cycle of publications will study the possibilities of use of gravitational deposit filters in which the porous deposit will be the set of coal grains, while the fed mixture will also be the post-production suspension of coal grains. [ABSTRACT FROM AUTHOR]

W powyższej publikacji, opisując badania o charakterze podstawowym, zaprezentowano jeden ze sposobów wyznaczenia stałych współczynników w filtracji grawitacyjnej, występujących w ogólnym równaniu filtracji (Piecuch 2009, 2010). Wykonano badania laboratoryjne dotyczące filtracji grawitacyjnej, stosując jako zmienne: objętość nadawy (1 dm3; 1,5 dm3; 2 dm3), stopień jej zagęszczenia (10 g/dm3, 20 g/dm3, 30 g/dm3, 40 g/dm3) oraz napór średni słupa cieczy. Jako zanieczyszczenie nadawy użyto węgla kamiennego o klasie ziarnowej zawartej w granicach od 0,315 do 0,5 mm, która była większa od średnicy oczek na siatce filtracyjnej. Przy tak modelowanym doświadczeniu zagęszczenie filtratu było równe zero. Jest to ważne dla przeniesienia badań o charakterze podstawowym na badania o charakterze aplikacyjnym. Na podstawie otrzymanych wyników sporządzono ich graficzne oraz tabelaryczne zestawienie. W pierwszej serii badań oraz obliczeń określono wartość stałej siatki filtracyjnej t', która rosła wraz ze wzrostem ciśnienia filtracji. W drugiej serii badań oraz obliczeń określono wartość stałego współczynnika b, występującego w równaniu oporu osadu i w ogólnym równaniu filtracji (Piecuch 2009, 2010). Stwierdzono, że wraz ze wzrostem zagęszczenia nadawy, wzrasta wartości stałego współczynnika filtracji grawitacyjnej określanego symbolem b, natomiast proces filtracji grawitacyjnej przebiega wolniej. Z wrócono uwagę, że dla przyjętego w obliczeniach układu jednostek SI, wartości obydwu wyznaczonych współczynników t' oraz b stanowią liczby wielocyfrowe o wartościach bardzo dużych ( t') oraz bardzo małych ułamków ( b). W tym odniesieniu obliczenia nie są łatwe. In the above publication describing the research of a fundamental nature presents one of the methods for determining the constant coefficients a gravity filtration. occurring in the general equation filtration (Piecuch 2009, 2010). The laboratory tests concerning the gravitational filtration were performed, applying variables: capacity of the feed (1 dm3, 1.5 dm3, 2 dm3), a degree of density (10 g/dm3, 20 g/dm3, 30 g/dm3, 40 g/dm3) and medium pressure of the column of liquid. As polluting the feed they used the hard bituminous coal about the determined faction entered into within the limits of by 0.315 mm up to 0.5 mm which was larger than the diameter of eyes on the mesh filter. With such experience modeled density of the filtrate was zero. This is important for the transfer of a basic research on studies of an application. Based on received results prepared graphical and tabular statement. The first series of tests and calculations is set to a constant mesh filter t', which has risen with the increase in pressure filtration. In the second series of tests and calculations is set to a constant coefficient b in the equation of resistance occurring sediment and the general equation of filtration (Piecuch 2009, 2010). They stated, that along with the height of thickening the feed, a value of the constant coefficient of the gravity filtration is growing determined with b symbol, however the process of the gravity filtration is proceeding more slowly. It was noted that for assumed in the calculations SI, the value of both set of coefficients t' and b represent the number of multi-valued very large ( t') and a very small fraction ( b). In this regard calculation is not easy. [ABSTRACT FROM AUTHOR]