Silesian Coal Basin In Poland Research Articles

Botryoidal and spherulitic hematite as experimental evidence of highly acidic conditions in burning coal-waste dumps and potentially on Mars

In the extreme setting of burning coal-waste dumps in the Upper Silesian Coal Basin in Poland, botryoidal and spherulitic hematite occurs in association with sulphates and chlorides. A series of simple experiments aimed at replicating the conditions leading to the formation of hematite spherules on the burning dumps are described. Goethite synthesised in the laboratory, mixed with various combinations of other reactants, was heated in a heating chamber or a tubular furnace. Temperature, duration of heating, water and oxygen access, and pH were experimental variables. The results show that hematite may form spherules from goethite where access to oxygen is limited and where conditions are strongly acidic. The spherulitic shape of hematite produced due to dynamically changing physicochemical conditions in the burning dumps can be an indicator of an extremely acidic environment during the closing stages of coal-waste self-heating. The conditions of hematitic-spherule formation on burning coal-waste dumps may apply in a variety of other unrelated settings, e.g., waning volcanism, sulphuric acid speleologenesis and even the formation of blueberries on Mars.

Assessing the application of GACOS atmospheric correction for DInSAR-based mining deformation monitoring by using Sentinel-1 data in Upper Silesian Coal Basin in Poland

Assessing the application of GACOS atmospheric correction for DInSAR-based mining deformation monitoring by using Sentinel-1 data in Upper Silesian Coal Basin in Poland

Distribution of Peak Ground Vibration Caused by Mining Induced Seismic Events in the Upper Silesian Coal Basin in Poland

Distribution of Peak Ground Vibration Caused by Mining Induced Seismic Events in the Upper Silesian Coal Basin in Poland

Methane retrievals from airborne HySpex observations in the shortwave infrared

Abstract. Monitoring anthropogenic emissions is a crucial aspect in understanding the methane budget. Moreover, a reduction of methane emissions could help to mitigate global warming on a short timescale. This study compares various retrieval schemes for estimating localized methane enhancements around ventilation shafts in the Upper Silesian Coal Basin in Poland using nadir observations in the shortwave infrared acquired from the airborne imaging spectrometer HySpex. Linear and nonlinear solvers are examined and compared, with special emphasis put on strategies that tackle degeneracies between the surface reflectivity and broad-band molecular absorption features – a challenge arising from the instrument's low spectral resolution. Results reveal that the generalized nonlinear least squares fit, employed within the Beer InfraRed Retrieval Algorithm (BIRRA), can measure enhanced methane levels with notable accuracy and precision. This is accomplished by allowing the scene's background covariance structure to account for surface reflectivity statistics. Linear estimators such as matched filter (MF) and singular value decomposition (SVD) are able to detect and, under favorable conditions, quantify enhanced levels of methane quickly. Using k-means clustering as a preprocessing step can further enhance the performance of the two linear solvers. The linearized BIRRA fit (LLS) underestimates methane but agrees on the enhancement pattern. The non-quantitative spectral signature detection (SSD) method does not require any forward modeling and can be useful in the detection of relevant scenes. In conclusion, the BIRRA code, originally designed for the retrieval of atmospheric constituents from spaceborne high-resolution spectra, turned out to be applicable to hyperspectral airborne imaging data for the quantification of methane plumes from point-like sources. Moreover, it is able to outperform well-established linear schemes such as the MF or SVD at the expense of high(er) computing time.

Geomechanical and tectonophysical conditions of mining-induced seismicity in the Upper Silesian Coal Basin in Poland: a case study

Geomechanical and tectonophysical conditions of mining-induced seismicity in the Upper Silesian Coal Basin in Poland: a case study

Initial Assessment of Variability in the Modes of Occurrence of Some Trace Elements in Coal Seams with Vertical Profiles in the Upper Silesian Coal Basin in Poland

Initial Assessment of Variability in the Modes of Occurrence of Some Trace Elements in Coal Seams with Vertical Profiles in the Upper Silesian Coal Basin in Poland

Ground Motion Prediction of High-Energy Mining Seismic Events: A Bootstrap Approach

Induced seismicity has been a serious problem for many coal mines in the Upper Silesian Coal Basin in Poland for many decades. The occurring mining tremors of the rock mass generate seismic vibrations that cause concern to the local population and in some rare cases lead to partial damage to buildings on the surface. The estimation of peak ground acceleration values caused by high energy mining seismic tremors is an important part of seismic hazard assessment in mining areas. A specially designed bootstrapping procedure has been applied to estimate the ground motion prediction model and makes it possible to calculate the confidence intervals of these peak ground acceleration values with no assumptions about the statistical distribution of the recorded seismic data. Monte Carlo sampling with the replacement for 132 seismic records measured for mining seismic tremors exceeding 150 mm/s2 have been performed to estimate the mean peak ground acceleration values and the corresponding upper limits of 95% confidence intervals. The specially designed bootstrap procedure and obtained ground motion prediction model reflect much better the observed PGA values and therefore provide more accurate PGA estimators compared to the GMPE model from multiple regression analysis. The bootstrap analysis of recorded peak ground acceleration values of high-energy mining tremors provides significant information on the level of seismic hazard on the surface infrastructure. A new tool has been proposed that allows for more reliable determination of PGA estimators and identification in the areas in coal mines that are prone to high-energy seismic activity.

Approximation parameters of mining area curvatures induced by an operation of the 338/2 seam of hard coal

Article presents a method of determination of an approximation parameters of average graphs of mining terrain curvatures caused by an exploitation of the 338/2 hard coal seam in the Upper Silesian Coal Basin in Poland. Approximation by the use of the higher orders polynomials has been done. An order of polynomial and a number of its segments belong to the parameters of approximation. Both values on the basis of minimization of a variability coefficient of random dispersion of observed curvatures have been determined. Parameters of approximation for the average graphs of curvatures measured after the end of an operation of one, two, three and four longwalls in the 338/2 seam have been calculated.

UAV Applications for Determination of Land Deformations Caused by Underground Mining

This article presents a case study that demonstrates the applicability of unmanned aerial vehicle (UAV) photogrammetric data to land surface deformation monitoring in areas affected by underground mining. The results presented include data from two objects located in the Upper Silesian Coal Basin in Poland. The limits of coordinate and displacement accuracy are determined by comparing UAV-derived photogrammetric products to reference data. Vertical displacements are determined based on differences between digital surface models created using UAV imagery from several measurement series. Interpretation problems related to vegetation growth on the terrain surface that significantly affect vertical displacement error are pointed out. Horizontal displacements are determined based on points of observation lines established in the field for monitoring purposes, as well as based on scattered situational details. The use of this type of processing is limited by the need for unambiguous situational details with clear contours. Such details are easy to find in urbanized areas but difficult to find in fields and meadows. In addition, various types of discontinuous deformations are detected and their development over time is presented. The results are compared to forecasted land deformations. As a result of the data processing, it has been estimated that the accuracy of the determination of XY coordinates and the horizontal displacements (RMS) in best case scenario is on the level of 1.5–2 GSD, and about 2–3 GSD for heights and subsidence.

Spatial Macroscale Variability of the Role of Mineral Matter in Concentrating Some Trace Elements in Bituminous Coal in a Coal Basin—A Case Study from the Upper Silesian Coal Basin in Poland

As there are numerous claims that the mode of occurrence of trace elements in coal influences the quality of the substrates as well as the course and results of the coal preparation processes, it is necessary to analyse the differences in the mode of occurrence of the elements in coal within a coal basin or a coal deposit. With the use of concentration distribution functions and the Pearson correlation coefficient, it was concluded that (1) mineral matter plays a significant and nearly constant or constant role in concentrating V, Cr, Co, As, Rb, Sr, Ba, and Pb in coal; (2) organic matter plays a stable role in concentrating Sn; and (3) there are significant differences in the role of organic and mineral matter in concentrating Mn, Ni, Cu, Zn, Mo, Cd, and Sb in coal throughout the USCB (Upper Silesian Coal Basin). Moreover, there was observed a difference in the mode of occurrence of Cr, Mn, Co, Ni, Cu, Zn, Mo, Cd, Sn, and Sb in coal in the vertical profile of the USCB. At the same time, there were observed no differences and a stable significant role of mineral matter in concentrating V, As, Rb, Sr, Ba, and Pb in coal, while the role of the petrographic groups of the coal components in concentrating the elements in raw coal was differentiated. It is believed that the difference in the mode of occurrence of the trace elements in coal within coal seams and coal deposits is a geochemical regularity.

Simulation of ground motion in a polish coal mine using spectral-element method

Mining seismic events have been associated with the mining of hard coal in the Upper Silesian Coal Basin in Poland for many years. These seismic events pose a threat to people working underground and cause damage to construction facilities on the surface. It is possible to predict seismic vibrations from mining seismic events using numerical calculations. One such method is the spectral element method (SEM). In this method, synthetic seismograms that enable the imaging of the full waveform are calculated. A complex mechanism of the source is assumed by applying the seismic moment tensor, which best reflects the balance of forces in the source. This paper presents the results of SEM modeling of ground motions of a seismic event which occurred on November 8, 2018, in the Budryk mine with a magnitude of 3.8 on the Richter scale. The modeling results show that even if the calculated synthetic seismograms do not fully correlate with real vibration registrations, it is possible to determine the peak values of seismic vibrations at any point in the model. This method can be a good complement to the analytical methods used to assess seismic hazard caused by mining seismic events.

Assessment of post-mining terrain suitability for economic use

Upper Silesian Coal Basin in Poland is subjected to underground mining for several hundreds of years. Due to intensive extraction, land surface has been widely transformed, causing a lot of mining damages. Of great importance is the issue of recovering the surface to its previous conditions after mining activity is finished. In specific conditions, a threat of mining damages may rest for several years after mine closure. In this paper, some chosen issues connected with assessment of post-mining terrain suitability for economic use have been discussed. Two important elements of such threat have been described: determining the possibility of discontinuous deformations creation and the evaluation of active subsidence process duration. In the introductory part of the paper some theoretical base has been given. Next, the example of probability assessment of sinkhole creation has been presented, together with determination of subsidence process cease time. For determination of subsidence process duration, own empirical formulas have been utilized. They can be used in cases, when there is a lack of survey results from the area of interest.

Tests to Ensure the Minimum Methane Concentration for Gas Engines to Limit Atmospheric Emissions

During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as ‘mine gas’. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane–air mixture captured in the methane drainage system is not emitted to the atmosphere, but burned as fuel in systems, including cogeneration systems, to generate electricity, heat and cold. However, in order for such use to be possible, the methane–air mixture must meet appropriate quality and quantity requirements. The article presents an analysis of changes in selected parameters of the captured methane–air mixture from one of the hard coal mines in the Upper Silesian Coal Basin in Poland. The paper analyses the changes in concentration and size of the captured methane stream through the methane capturing system. The gas captured by the methane drainage system, as an energy source, can be used in cogeneration, when the methane concentration is greater than 40%. Considering the variability of CH4 concentration in the captured mixture, it was also indicated which pure methane stream must be added to the gas mixture in order for this gas to be used as a fuel for gas engines. The balance of power of produced electric energy in gas engines is presented. Possible solutions ensuring constant concentration of the captured methane–air mixture are also presented.

Polish underground coal mines as point sources of methane emission to the atmosphere

The Upper Silesian Coal Basin in Poland is one of the major European hotspots of CH4 release. Until now, no data concerning short-term CH4 emissions from coal mines have been accessible worldwide. They are available only on a yearly timescale. No values are provided on a higher temporal scale, that’s why the measurements presented here are of great importance. This paper discusses short-term CH4 emissions from ventilation shafts of three mining fronts (Mf) divided into two periods. The concentrations of CH4 in shafts varied from 0.05 to 0.4 %. The highest levels occurred in Shaft IV (Mf I) and Shaft VI (Mf II): from 0.15 to 0.38 % (Period 1). These values correspond to emission levels ranging from 27 to 75 m3/min (Shaft IV) and from 18 to 40 m3/min (Shaft VI). In Period 2, the highest concentrations of CH4 occurred in Shaft VI (Mf II and III): from 0.2 to 0.4 %. The most significant CH4 emissions were recorded for Shaft VI (Mf II) and ranged from 29 to 54 m3/min. Presented data have been used to validate the measurements obtained in the CoMet campaign, which aimed at verifying the sensitivity of the test equipment operating from aircraft. During the test flights of HALO in 2015, the CoMet team achieved a remarkable consistency of measurements conducted with airborne equipment (26 ± 3m3/min) and the emission data (24.34 m3/min), for Shaft VI (Mf II). The analysed short-term data for individual shafts are more reliable and can improve CH4 flux estimates during the CoMet campaign in 2018.

Permeability measurements of raw and briquette coal of various porosities at different temperatures

Temperature is one of the main factors influencing the parameters describing the phenomena of sorption, diffusion and filtration of gases occurring in the pore space of coal. While the influence of temperature on sorption capacity and the diffusion coefficient of coal is known, changes in the coal permeability coefficient due to temperature changes are undetermined. The main objective of this work was to study and explain the influence of temperature on the permeability of raw and briquette coals with various porosities. In order to describe coal permeability, the Klinkenberg equation was used, as it takes into consideration the slippage effect, typical of porous media characterized by low permeability. The experiments on coal permeability to helium and nitrogen were carried out using an original measurement stand. They were performed on five samples prepared from the same bituminous coal material (two raws and three briquettes samples) from Budryk coal mine, located in the Upper Silesian Coal Basin in Poland. On the basis of the obtained results, it was established that as the temperature rises, the value of absolute permeability of raw coal to nitrogen and helium drops significantly. The influence of temperature changes on briquette coal permeability changes could be neglected, and it could be compensated by the changes in the value of the dynamic viscosity factor, which is present in the Darcy permeability equation. The results show that in the case of raw and briquette coals, the influence of temperature on permeability is ambiguous.

Numerical Modeling of CO2 Migration in Saline Aquifers of Selected Areas in the Upper Silesian Coal Basin in Poland

Determining the characteristics of the dynamic behavior of carbon dioxide in a rock mass is a stage in the process of assessing a potential CO2 storage reservoir. The aim of this study was to analyze the process of CO2 storage in saline aquifers of the selected regions of the Upper Silesian Coal Basin in Poland. The construction of dynamic simulation models was based on static models of real deposit structures developed on a regional scale. Different simulation variants of the CO2 storage process were adopted, varying in terms of injection efficiency and duration of individual simulation phases. The analysis examined the influence of the degree of hydrodynamic openness of the structure on the CO2 storage process, in each of the variants. The results of numerical simulations showed that among the three analyzed geological formations, the Dębowiec formation is the most prospective for potential CO2 storage and is characterized by the most favorable geological and hydrogeological parameters. In the best variant of the simulation, in which the safety of CO2 storage in the rock mass was taken into account, the total amount of CO2 injected in a single directional well was approximately 8.54 million Mg of CO2 during 25 years of injection.

Geotechnical characteristics of unburnt colliery spoils after coal-recovery

The aim of the study was to determine the geotechnical characteristics of the unburnt colliery spoils after coal-recovery from the dumping site of one of the mines of the Upper Silesian Coal Basin in Poland. Due to grain-size distribution of tested spoils their geotechnical properties were determined using medium-sized apparatuses. In order to verify the suitability of the studied spoils for the construction of hydraulic embankments, the seepage and stability calculations were conducted for models of hydraulic embankments including the effect of flood wave passage on stress conditions within the construction and their slope stability. The test results revealed, that the studied colliery spoils are characterized by favourable values of geotechnical parameters and they fulfil the requirements for soil materials used in the analysed type of constructions. The spoils are characterized by good compactibility, relatively low water permeability and average susceptibility to mechanical disintegration, which in the case of using this material for the construction of hydraulic embankments and using proper compaction technology, should reduce their susceptibility to weathering. The results of seepage and slope stability calculations for hydraulic embankments built of the studied spoils confirmed their suitability for that type of constructions, retaining the proper inclination of slopes, whereas the variant of embankment without sealing is safer from the stability viewpoint.

Application of geophysical methods for the subsurface treatment of the Piekary highway junction in shallow mining terrain

The study presents the application of geophysical methods in the subsurface treatment of the A-1 highway in the area of the Piekary junction in the terrain of historic zinc and lead ore mining, in the northern part of the Upper Silesian Coal Basin in Poland (USCB). The study area was under threat of discontinuous deformations, mainly sinkholes. This threat resulted from the shallow exploitation of zinc and lead ores, as well as contemporary exploitation of coal seams at greater depths. An original methodology of subsurface treatment has been developed as an adaptation to the geophysical measurement results. The methodology uses the gravimetric method at the initial and final control stages, as well as the seismic and borehole georadar methods during the detailed evaluation stage. The results of the study allowed different categories of sinkhole hazard to be determined in the area of the Piekary junction. The scope of the liquidation works was selected to match the hazard levels. Blasting of varying intensities and the borehole injection of the filling material were performed. The combination of substrate treatment methodologies and highway construction protection systems have proved to be effective.

Sorption rate of CH4 and CO2 in coal at different pressure ranges

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

An evaluation of processing InSAR Sentinel-1A/B data for correlation of mining subsidence with mining induced tremors in the Upper Silesian Coal Basin (Poland)

The Satellite Radar Interferometry is one of the common methods that allow to measure the land subsidence caused by the underground black coal excavation. The interferometry images processed from the repeat-pass Synthetic Aperture Radar (SAR) systems give the spatial image of the terrain subjected to the surface subsidence over mining areas. Until now, the InSAR methods using data from the SAR Systems like ERS-1/ERS-2 and Envisat-1 were limited to a repeat-pass cycle of 35-day only. Recently, the ESA launched Sentinel-1A and 1B, and together they can provide the InSAR coverage in a 6-day repeat cycle. The studied area was the Upper Silesian Coal Basin in Poland, where the underground coal mining causes continuous subsidence of terrain surface and mining tremors (mine-induced seismicity). The main problem was with overlapping the subsidence caused by the mining exploitation with the epicentre tremors. Based on the Sentinel SAR images, research was done in regard to the correlation between the short term ground subsidence range border and the mine-induced seismicity epicentres localisation.