Hard Coal Mining Research Articles

A Low-Cost Web Application System for Monitoring Geometrical Impacts of Surface Subsidence

This paper develops a low-cost web application system for monitoring geometrical impacts of surface subsidence. In many of the developing countries, the method of extraction of minerals such as coal is often impractical and uneconomical, especially with surface mining. With global warming, rapid population growth, and fast-growing urbanization with a disregard for sustainability, the overall subsidence risk has significantly increased. Despite the maturity of Differential Interferometric Synthetic Aperture Radar (DInSAR) for timely monitoring of subsidence hazards, the potential of SAR constellations has been under-exploited, as most applications focus mainly on mapping unstable areas. The developed web application system exploits Sentinel-1 SAR constellation and Small-BAseline Subset (SBAS-DInSAR) technique, to provide new streamlines of information for monitoring solutions and improve disaster risk decision making. We illustrate the model by investigating and measuring potential surface subsidence caused by underground hard coal mining activities and exponential urban population growth within a major coalmine in Nigeria. Results of the yearly cumulative amount of horizontal and vertical deformation between 2016 and 2020 range from −25.487 mm to −50.945 mm and −24.532 mm to −57.161 mm, for high and low risks, respectively. Under the influence of external factors such as rising poverty and fast-growing urbanization, the destruction of in situ stress distributions will likely increase nonlinear deformations.

COAL WORKERS’ PNEUMOCONIOSIS: A COMPARATIVE ANALYSIS OF LIGNITE AND HARD COAL MINE WORKERS

Physical and chemical properties of coal and its relationship with coal workers’ pneumoconiosis (CWP) have been studied previously. However definitive conclusions have not been reached, primarily due to the complex nature of coal mine dust. It remains unclear exactly which properties of coal mine dust related to the grade of coal cause differences in the exposure–response relationship. The aim of the study is to identify the coal mine environmental factors, and personal factors affecting the severity of CWP. This study was a retrospective cross-sectional study and included total of 116 coal mine workers diagnosed as CWP in a tertiary hospital between January 1, 2014, and December 31, 2021. Of the cases, 77 (66.4%) worked in a hard coal mine and 39 (33.6%) worked in a lignite mine, and mean age was 60.2 ± 11.5 years. There was a significantly higher prevalence of concomitant pulmonary disease in hard coal mine workers compared to lignite mine workers (p= 0.005). In addition, the prevalence of progressive massive fibrosis (PMF) was higher in hard coal mine workers compared to lignite mine workers, and a statistically significant difference was found (p= 0.004). The value of FEV1 and FEV1/FVC were significantly lower in hard coal mine workers than in lignite mine workers (p= 0.005, p= 0.002). As a conclusion, concomitant lung disease, presence of PMF and impairment in lung functions, which are important causes of mortality and morbidity for CWP, were found to be more common in hard coal mine workers than in lignite mine workers. Therefore, taking into account the type of coal mine while making protective arrangements to prevent pneumoconiosis in coal mines may contribute to reduce the burden of CWP.

Analysis of the Scope for Reducing the Level of Energy Consumption of Crew Transport in an Underground Mining Plant Using a Conveyor Belt System Mining Plant

One of the main elements that shape the production process in an underground mining plant is, in the broadest sense of the word, transport. Currently, a large amount of rolling stock from cable cars or suspended railways is maintained in mining plants, along with extensive infrastructure used for transporting crew and materials. The development of conveyor belt transport systems, as well as system process management, is increasing efficiency levels. Mining transport is a complex process, requiring large amounts of energy, which incurs significant production costs. We conduct a comparative analysis of the human transport system using a suspended railway with belt transport at Lubelski Węgiel “Bogdanka” Spółka Akcyjna (the largest hard coal mine in Poland), in terms of energy efficiency levels. We found that the process of transporting the crew in an underground mining plant to the production site using a conveyor belt system was less energy-intensive, and therefore created less emissions than the currently used model based on suspended queues. The analyses for the above project were conducted according to a model that was based on the study and analysis phase of the project through to its implementation and transfer to operational activities. The analysis was carried out based on the created simulation model, taking into account all elements of the crew transport process to and from the mining area. The implementation of the technical solution allowed for nearly a threefold reduction in the level of energy consumption and emissivity. In the analyzed model, the energy consumption in the first phase of production was 3.04 kWh per employee using the diesel rails system and 1.13 per employee using the belt conveyor system.

Using Battery-Powered Suspended Monorails in Underground Hard Coal Mines to Improve Working Conditions in the Roadway

Transporting materials and mine staff is a vital link necessary to the production process in underground mines. Deteriorating climatic conditions, mainly due to the increasingly deep mining and the usage of machines, force us to look for solutions to improve the underground mine environmental situation. Another essential factor responsible for deteriorating working conditions is harmful substances and exhaust fumes emitted from diesel engines. Supplying the workplaces with air quantity exceeding requirements such as the minimum velocity of air movement or gas and climatic conditions will allow for maintaining the gas concentration at the appropriate level. One possible way to solve the problems mentioned above is to replace suspended monorails powered by internal combustion engines with new solutions of electrically battery-powered monorails. Electric monorails are not yet widely used in mines; nevertheless, they have many advantages. This article analyzes the exhaust gas parameters from monorail locomotives operating in a hard coal mine and determines the required airflow to maintain permissible concentrations of harmful gases. It also focuses on a comparative analysis of climatic conditions in the development heading, considering the roadway’s functioning with and without using diesel or electric monorail. The study consists of the methodology for predicting climate conditions. Based on the performed analysis, it was shown that using electric monorails could significantly improve working conditions.

Perceptions on mine water and mine flooding – An example from abandoned West German hard coal mining regions

For the first time, this paper describes the climate of opinion of mine water and mine flooding in three German hard coal post-mining regions, Ibbenbüren, the Ruhr area and the Saarland. Each region has unique geographical, political and mining-historical characteristics, and the underground mines were closed in 2018 (Ibbenbüren and Ruhr area) and 2012 respectively. People’s prevailing opinion and emotions regarding mine water, mine water treatment, mine flooding as well as the level of acceptance of the remediation measures and the mining company was investigated. The study is based on a representative telephone and online survey with 1527 participants for the respective regions.Results show that the local public opinion towards mine flooding and mining issues are not substantially different, but generally more positive in the Ibbenbüren area compared to the Ruhr area and the Saarland. In general, interest in mining related issues as well as environmental or renewable energy issues is low, but those interested in one of the subjects are also interested in the others. Participants indicated that they wanted more information about mine flooding. Of the actors dealing with mine water, the mining company is thought to be best situated to solve potential problems, whilst politicians were least expected to solve them.People see the term mine flooding slightly more positive than the term mine water rebound, but based on the Student’s t-test, there are no statistically significant differences. Compared with other surveys worldwide, the results are similar, indicating that experience with the mining company influence the emotions towards remediation measures and the risks people attribute to them. However, people want transparent and understandable information, feel positive towards mine water treatment and oppose mine flooding in general.

The impact of the mountain barrier on the spread of heavy metal pollution on the example of Gorce Mountains, Southern Poland

The main objective of this study was to determine the content, mobility, and the variability of concentration of zinc, lead, and cadmium in soils from the Gorce Mountains (south Poland), located over 100 km south-east from the potential industrial sources of contamination—zinc-lead sulfide ore mine and smelter in Bukowno, as well as hard coal mines of Silesia region and Kraków Nowa-Huta steelwork. The abovementioned problem is crucial in the context of the traditional mountain farming still extant in the region, as well as intensively developing tourism. The geoaccumulation index and potential ecological risk index were adopted to evaluate soil pollution in the study area and the BCR sequential extraction technique to assess mobility of the abovementioned elements. The obtained results clearly show that the pollution from distant industrial sources in the mountains is detectable. Apart from the increased concentrations of the tested metals in the soil (especially available forms), there is also a strong correlation between the concentrations of lead, zinc, and cadmium, which proves their common source of origin. The main evidence is the fact that differences in the concentrations of the tested metals on the windward and leeward sides were statistically significant. This also means that the studied mountain area, despite relatively low altitudes (up to 1310 m above sea level), constitutes a measurable barrier to the spread of atmospheric pollutants.

Quantifying CH4 emissions in hard coal mines from TROPOMI and IASI observations using the wind-assigned anomaly method

Abstract. Intensive coal mining activities in the Upper Silesian Coal Basin (USCB) in southern Poland are resulting in large amounts of methane (CH4) emissions. Annual CH4 emissions reached 448 kt according to the European Pollutant Release and Transfer Register (E-PRTR, 2017). As a CH4 emission hotspot in Europe, it is of importance to investigate its emission sources and make accurate emission estimates. In this study, we use satellite-based total column-averaged dry-air mole fraction of CH4 (XCH4) from the TROPOspheric Monitoring Instrument (TROPOMI) and tropospheric XCH4 (TXCH4) from the Infrared Atmospheric Sounding Interferometer (IASI). In addition, the high-resolution model forecasts, XCH4 and TXCH4, from the Copernicus Atmosphere Monitoring Service (CAMS) are used to estimate the CH4 emission rate averaged over 3 years (November 2017–December 2020) in the USCB region (49.3–50.8∘ N and 18–20∘ E). The wind-assigned anomaly method is first validated using the CAMS forecast data (XCH4 and TXCH4), showing a good agreement with the CAMS GLOBal ANThropogenic emission (CAMS-GLOB-ANT) inventory. It indicates that the wind-assigned method works well. This wind-assigned method is further applied to the TROPOMI XCH4 and TROPOMI + IASI TXCH4 by using the Carbon dioxide and Methane (CoMet) inventory derived for the year 2018. The calculated averaged total CH4 emissions over the USCB region is about 496 kt yr−1 (5.9×1026 molec. s−1) for TROPOMI XCH4 and 437 kt yr−1 (5.2×1026 molec. s−1) for TROPOMI + IASI TXCH4. These values are very close to the ones given in the E-PRTR inventory (448 kt yr−1) and the ones in the CoMet inventory (555 kt yr−1), and are thus in agreement with these inventories. The similar estimates of XCH4 and TXCH4 also imply that for a strong source, the dynamically induced variations of the CH4 mixing ratio in the upper troposphere and lower stratosphere region are of secondary importance. Uncertainties from different error sources (background removal and noise in the data, vertical wind shear, wind field segmentation, and angle of the emission cone) are approximately 14.8 % for TROPOMI XCH4 and 11.4 % for TROPOMI + IASI TXCH4. These results suggest that our wind-assigned method is quite robust and might also serve as a simple method to estimate CH4 or CO2 emissions for other regions.

Good Practices to Counteract Epidemic Emergency in Mining Companies in Poland

The date assumed as the beginning of the pandemic in Poland is 4 March 2020, the date of the first confirmed case of the virus. This article presents the actions undertaken by the management of underground hard coal mining plants concerning the risk of epidemic related to SARS-CoV-2. This work shows a set of implemented recommendations, guidelines and decisions, which were established after the appearance of the first wave of cases in Poland. What is more, it discusses measures aiming at reducing the risk of spreading the coronavirus among the mineworkers. The suggestions for different variants of the decision-making process concerning the pandemic and which have an enormous impact on the operating expenses of the company are also made. The paper presents the results of the study on actions taken in individual mining companies and good work practices recommended to be applied.

The Impact of Two Years of the COVID-19 Pandemic on the Functioning of a Mine Restructuring Company in Poland

The article presents the most important changes in the strategic sector, which is hard coal mining, and shows the effects of industry transformation. The results of the research on the COVID-19 pandemic on the functioning of the mine restructuring company Spółka Restrukturyzacji Kopalń S.A. (SRK S.A.), which is the body whose main goal is the mine liquidation process, are presented. Restructuring activities have been carried out in the Polish mining industry since the end of the 20th century so as to adjust the industry to the market economy. The liquidation of the mine is the last and natural stage of mining activity. The investment process leading to the liquidation of the mine is complex and costly. The changes that are taking place in the mining environment caused by the pandemic of Covid-19 cause both current and long-term economic effects in the operations of most economic entities. The publication analyzes the implementation of the restructuring processes in a closed mine. The analysis showed the main factors disrupting the course of the mission of a mine restructuring company (SRK S.A.), and the most important movement problems. The experience was presented and conclusions were indicated. The procedures used in the mine can also help other mining enterprises so as to cope more easily with the technical difficulties of the pandemic.

A dual-continuum model (TOUGH2) for characterizing flow and discharge in a mechanically disrupted sandstone overburden

Underground hard coal mining usually disrupts the mechanical equilibrium of rock sequences, creating fractures within minor permeable rocks. The present study employs a dual-continuum model to assess how both fractured and porous sandstone media influence the percolation process in postmining setups. To test the approach, the software TOUGH2 was employed to simulate laminar fluid flow in the unsaturated zone of the Ibbenbüren Westfield mining area. Compared to other coal mining districts in Germany, this area is delineated by the topography and local geology, leading to a well-defined hydrogeological framework. Results reveal good agreement between the calculated and measured mine water discharge for the years 2008 and 2017. The constructed model was capable of reproducing the bimodal flow behavior of the adit by coupling a permeable fractured continuum with a low-conductivity rock matrix. While flow from the fractured continuum results in intense discharge events during winter months, the rock matrix determines a smooth discharge limb in summer. The study also evaluates the influence of individual and combined model parameters affecting the simulated curve. A detailed sensitivity analysis displayed the absolute and relative permeability function parameters of both continua among the most susceptible variables. However, a strong a priori knowledge of the value ranges for the matrix continuum helps to reduce the model ambiguity. This allowed for calibration of some of the fractured medium parameters for which sparse or variable data were available. However, the inclusion of the transport component and acquisition of more site-specific data is recommended to reduce their uncertainty.

ROLLERS FOR BELT CONVEYORS IN TERMS OF ROTATION RESISTANCE AND ENERGY EFFICIENCY

The paper shows the results of researching the rollers used in belt conveyors working in a hard coal mine. Rollers should be characterized by low rotation resistance, which results in low power consumption of the propulsion unit. The tests conducted aimed to assess the technical condition of the new C-type rollers after several years of operation in a hard coal mine. The research was carried out from the new approach to the standard issues of roll testing and verification in a hard coal mine. Laboratory tests were combined with testing the entire belt conveyor in terms of power demand. The research was carried out for 3 years and it was monitored how the dynamic resistance of the working rollers changed and how this translates into the power demand consumed by the belt conveyor in a hard coal mine. The aim of the research was a new approach to the research of rollers used in conveyors operating in a mine.

Use of machine learning algorithms to assess the state of rockburst hazard in underground coal mine openings

The risk of rockbursts is one of the main threats in hard coal mines. Compared to other underground mines, the number of factors contributing to the rockburst at underground coal mines is much greater. Factors such as the coal seam tendency to rockbursts, the thickness of the coal seam, and the stress level in the seam have to be considered, but also the entire coal seam–surrounding rock system has to be evaluated when trying to predict the rockbursts. However, in hard coal mines, there are stroke or stress-stroke rockbursts in which the fracture of a thick layer of sandstone plays an essential role in predicting rockbursts. The occurrence of rockbursts in coal mines is complex, and their prediction is even more difficult than in other mines. In recent years, the interest in machine learning algorithms for solving complex nonlinear problems has increased, which also applies to geosciences. This study attempts to use machine learning algorithms, i.e. neural network, decision tree, random forest, gradient boosting, and extreme gradient boosting (XGB), to assess the rockburst hazard of an active hard coal mine in the Upper Silesian Coal Basin. The rock mass bursting tendency index W TG that describes the tendency of the seam–surrounding rock system to rockbursts and the anomaly of the vertical stress component were applied for this purpose. Especially, the decision tree and neural network models were proved to be effective in correctly distinguishing rockbursts from tremors, after which the excavation was not damaged. On average, these models correctly classified about 80% of the rockbursts in the testing datasets.

Social License for Closure—A Participatory Approach to the Management of the Mine Closure Process

The European Union’s climate policy and the assumptions of the European Green Deal require Poland to take decisive transition efforts. The achievement of climate neutrality is a challenge due to the special role of coal in the Polish economy. Closing mines and abandoning coal is the greatest challenge for local communities in mining regions. This article presents the example of Wałbrzych, a Polish post-mining town, which has been experiencing the accumulation of negative consequences of inadequately planned liquidation since the 1990s. The current activities of mining companies in the face of abandoning coal were also analyzed. The gaps identified in the literature indicate the need to define a new method of managing the liquidation processes, based on the consideration of key risks resulting from decommissioning, to minimize the social costs in the first place. In this regard, it is helpful to diagnose the social concerns of the stakeholders. The social aspects of mine closures remain a challenge and finding effective ways to deal with them has become crucial for the industry. This prompted us to propose an approach based on community involvement in the decommissioning processes and the introduction of the social license for closure (SLC). By engaging the community, the SLC gives it a voice, allowing it to accommodate the individual needs of mining regions and ensure a successful and just transition. This article recognizes the key stakeholders and their fears related to the liquidation of mining. The organizational framework for stakeholder approval of the SLC is presented. The analysis was based on the example of Poland, a country facing the challenge of closing hard coal mines. Conclusions formulated on the basis of the case study complement the existing research in the field of social licensing and involving stakeholders in the mine closure planning process in accordance with the idea of corporate social responsibility.

A Multifaceted Method of Analyzing the Amount of Expenditures on Mine Liquidation Processes in SRK S.A.

Abstract The liquidation of the mine is the last and natural stage of mining activity. The activities related to the revitalization and restructuring of hard coal mines are carried out by Spółka Restrukturyzacji Kopalń S.A. (SRK S.A.), as the legal successor of previous mining operations. The implementation of the mine liquidation process has not been the subject of scientific research so far aimed at rationalization and minimization of the costs incurred. Activities leading to the liquidation of the mining plants are the procedural nature, however, the mine liquidation is always a single case which has a result in diversifying the size of outlays. The support for the implementation of the process approach in the issue of mine liquidation in terms of rationalization and minimization of the costs incurred in SRK S.A. was to develop a method of managing the costs of liquidation processes with the software for evaluation of its size. The proposed method signals to the designer that the estimated cost of the process of liquidation of another mining plant deviates from the average values previously worked out by SRK S.A. The range of acceptable values results from the assumed coefficient of data variation.

Research on the Environmental Impact of Industrial Noise Emitted By Mine and Mining Plants

Abstract The article presents the results of measurements of environmental noise accompanying the operation of devices operated in surface facilities of hard coal mines and noise generated in technological processes related to the loading and transport of spoil and materials necessary for production. The research results presented in the article are part of the program of “Consequences of excessive noise in the mining environment of hard coal mines”, the overarching goal of which is to reduce the emission of industrial noise. The research described in the article, carried out using the sampling method, was introduced in order to determine the actual values of noise levels emitted to the external environment from mines and mining plants, as well as to identify the acoustic power levels of devices and processes constituting the main sources of noise in mines. The obtained results showed that mines and mining plants are often not fully aware of the scale of the environmental impact of undesirable noise they emit. Therefore, the current periodic measurements of environmental noise should be replaced with permanent monitoring, which will be beneficial not only for the environment, residents of housing estates located near mines, but also for the mining plants themselves.

How to avoid unjust energy transitions: insights from the Ruhr region

Abstract Background The transition of the Ruhr region in Germany from a hard coal belt into a knowledge-based economy with a dynamic service sector and state of the art universities over the past 60–80 years has been widely touted as a successful example of how just and fair low carbon energy transitions can unfold. Methods This paper leverages documentary analysis of data across a wide array of sources to test these claims and identify lessons by creating a novel just energy transition framework. Results The study finds economic motivation, mindset and reorientation—not environmental concerns—to be the defining features for at least the first two decades of this shift. The lack of willingness to acknowledge environmental impacts and market realities has delayed the transition and led to wasteful allocation of resources towards supporting the hard coal mining industry. The prominence given to distributional justice cushions the victims of this transition financially, but does not allow a broad based coalition to advance the transition process. It is in the second phase (mid-1980s onwards that we see procedural aspects of justice come forth and support greater ownership and sustainability of the transition to emerge, while the evidence of recognition justice continues to be scant. Conclusions There are many nuanced successes in the Ruhr’s example, along with some failures worth highlighting. It is in the breakdown of this transition into two distinct phases and their nuances (particularly in the domain of justice) that fresh insights emerge and allow for a better understanding of what constitutes a suitable energy transition in a particular socio-economic and political context. As the international community embarks on ambitious greenhouse gas reduction targets, it can maximise the benefits and minimise the damages and costs by considering these realities on the ground.

Ground surface uplift during hardcoal longwall mining

Ground surface uplift was detected during longwall mining in the Lazy Mine, a hard coal mine in the Czech part of the Upper Silesian Coal Basin, Czech Republic. The greatest uplift was 218 mm, based on surface point levelling by comparing surface points with heights of non-mined areas. This uplift occurred during subcritical mining at an average depth of 740 m below the surface. The mined coal seam is situated below the previously mined part of the multi-seam deposit. This study aims to provide a geomechanical explanation for ground surface uplift observed during longwall mining. The source of surface uplifts were deep inside the rock mass, therefore, enabling only the examination of geological, geomechanical, seismic, and technical mining data for uplift occurrence analysis. Therefore, the spatiotemporal evaluation of the observed vertical displacement and induced seismicity data was processed, and the observed ground surface was compared with empirical subsidence . Two time periods with surface uplifts during longwall mining were evaluated. Thick, competent rock layers, together with specific geomechanical conditions, were identified as the main characteristics responsible for the uplift.

The Economic Situation of Polish Cities in Post-Mining Regions. Long-Term Analysis on the Example of the Upper Silesian Coal Basin

The purpose of this article is to identify the long-term economic consequences of mine decommissioning for five selected cities located in Poland in the Upper Silesian Coal Basin. It is carried out over a period of 18 years and covers the period 2003–2020. The economic effects of decommissioning are examined in the context of the budgets of cities where mining plants were closed. In the course of the analyses, the authors of the article attempt to answer the following research questions: (1) has the decommissioning of the mines influenced the current and strategic situation of the examined cities in terms of their budgets? (2) Have the examined cities felt the economic effects of mine decommissioning in a similar way? The assessment of the economic effects of mine decommissioning was carried out from the following two perspectives: (1) operational, relating to the balance of local budgets, and (2) strategic, taking into account the level of long-term liabilities of the examined cities. As part of the research methodology, budget analysis, descriptive statistics, dynamics and trends analysis, correlation and comparative analysis were used. The research carried out in the article shows that the decommissioning of hard coal mines in the examined cities of the Upper Silesian Coal Basin had a negative impact on the balance of local budgets and the level of long-term debt. This was especially true in the cities where all the mines had been decommissioned and which had no way of replacing the mining industry with other economic alternatives. The cities with more diversified economic activity and sources of income were in a better economic condition.

Multi-Parameter Analysis of Gas Losses Occurring during the Determination of Methane-Bearing Capacity in Hard Coal Beds

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.

Radon Concentrations in Dwellings in the Mining Area-Are There Observed Effects of the Coal Mine Closure?

The article presents the results of radon research, carried out in the area of the mining commune in the Upper Silesian Coal Basin (USCB), Poland. Past investigations in the 1990s on radon concentrations in buildings, located within the mining area, showed that the indoor radon concentrations measured in the area affected by mining were higher than in buildings located outside that area. Currently, all underground hard coal mines within the boundaries of the observed commune have been closed. In 2020, after the closure of the last active mine, radon measurements were started again. The current results of indoor radon concentrations were compared with the archival results from the 1990s. It was found that the radon concentration increased significantly in the basements of buildings where measurements were made in 1990, 2020, and 2021: the maximum values were 260 Bq/m3, 644 Bq/m3, and 1041 Bq/m3, respectively. Therefore, these questions were posed: Do the mine closure processes increase radon migration? How long is the period of the occurrence of changes in radon concentrations in buildings after the cessation of mining operations?