Search Results (28)

Bed separation is a common geological phenomenon in the overburden strata during coal mining, which easily induces water inrush hazards, surface subsidence hazards, and other engineering disasters, thus seriously threatening the safety and efficiency of coal mining operations. This paper presents the spatiotemporal evolution characteristics and dynamic prediction of bed separation. The different boundary conditions before and after coal mining disturbance are considered to calculate and predict the location, spatial dimension and spatiotemporal evolution process of bed separation development. Theoretical analysis and scale model tests are used to study the distribution and process of bed separation development with comparisons made between the pre- and post-mining conditions. Formulas for the dynamic prediction of bed separation and a criterion for identifying bed separation development locations are proposed. The vertical propagation coefficient (K_s) and the horizontal development coefficient (K_l) of bed separation are proposed to quantitatively predict the vertical propagation extent and horizontal expansion scale of bed separation space with the advancement of the panel, providing key indicators for the dynamic prediction of bed separation evolution. The results show that the size and duration of bed separation space increase abnormally in the presence of thick and hard strata. This study provides a theoretical basis and practical guidance for the design and optimization of bed separation water hazard prevention and overburden grouting for subsidence control. Full article

Large-scale surface subsidence induced by extra-thick seam longwall top-coal caving (LTCC) is strongly amplified by thick unconsolidated overburden, posing serious serviceability risks to overlying linear infrastructure. Taking the S103 Provincial Highway above Panel 6118 in Inner Mongolia, China, as the engineering background, this study integrates theoretical analysis, numerical simulation, and in situ monitoring to investigate the subsidence-control mechanism of directional presplitting roof cutting. The results show that roof cutting mitigates surface subsidence by reconstructing the overburden structural system and weakening the stress-transfer chain, thereby transforming key-stratum deformation from integral bending to segmented block movement and narrowing the subsidence-affected zone. An equivalent mining-depth model for subsidence-boundary convergence is proposed to characterize the inward migration of the subsidence-basin boundary under thick unconsolidated cover, and a segmented probability-integral model is developed to explain the kink-like high-gradient feature in the post-cut subsidence profile. Parametric simulations of roof-cutting positions (p = 0, 2, 4, …, 32 m) show that the most effective mitigation occurs in the range p = 4–12 m; using minimum–maximum highway subsidence together with profile flattening as the optimization criteria, the representative optimum is identified at p ≈ 10 m, for which the maximum highway subsidence is approximately 57 mm, about 76% lower than that in the non-cutting case. The results further indicate that, although roof cutting significantly reduces subsidence and deformation gradients, fissure localization and possible discontinuous deformation near the pre-split weak plane still require careful field monitoring. Full article

To address the challenges of designing geologically compatible, large-scale gas drainage strategies in gassy coal mines, this study introduces an integrated workflow combining detailed gas-geological unit subdivision with the Analytic Hierarchy Process (AHP) for the Baode Coal Mine. This approach aims to transform gas drainage technology selection from empirical judgment to a systematic, quantitative decision-making process, thereby enhancing control precision and mine safety. First, the No. 8 coal seam was refined into ten distinct gas-geological units (II-i to II-x), forming the foundation for a targeted management strategy. For these units, a quantitative evaluation index system was constructed, integrating key factors such as permeability, structural characteristics, and unit area. The AHP was then employed to assess the adaptability of four primary drainage technologies: ULB-uni/bi (underground long borehole unidirectional/bidirectional drainage), UULB (underground ultra-long directional borehole drainage), UDLB-SHF (underground directional long borehole drainage with staged hydraulic fracturing), and FHWS (fractured horizontal wells drilled from the surface). The decision analysis reveals significant regional differentiation in technical suitability. FHWS ranks highest in structurally complex and water-rich zones. UDLB-SHF and UULB serve as viable, cost-effective alternatives to FHWS in various scenarios, with UULB being particularly advantageous for “large-area pre-drainage” in extensive panels with relatively simple geology. ULB-uni/bi is confirmed as the most economical option but is suitable only for minor blocks with simple conditions. Consequently, the study proposes a hierarchical, zone-specific strategy: prioritizing surface-based FHWS for high-risk zones, employing UDLB-SHF for active permeability enhancement in low-permeability resource-rich areas, utilizing UULB for efficient large-area drainage, and restricting ULB-uni/bi to small, geologically normal blocks. Ultimately, this research establishes a robust technical selection system that integrates fine geological subdivision, AHP-based multi-criteria evaluation, and targeted technology matching. It provides a scientific basis for balancing risk control and cost optimization in gas drainage design for the Baode Coal Mine. In summary, the methodological framework proposed in this study provides a systematic approach for coal mine gas control under complex geological conditions. Its core value lies in achieving the unity of scientificity and practicality in gas control technology decisions through standardized analysis logic and differentiated adaptation mechanisms, thereby providing support for the precise and efficient development of coal mine gas control. Full article

This study proposes a feature-level fusion method that integrates Differential Interferometric Synthetic Aperture Radar (D-InSAR) and Unmanned Aerial Vehicle photogrammetry (UAV-P) for monitoring mining-induced subsidence basin (MSB). The method begins by extracting key subsidence characteristics based on the patterns of coal-mining-related surface displacement; the centimeter-level subsidence boundary is determined from D-InSAR data, while the meter-scale deformation at the subsidence center is derived from UAV-P. These extracted features are then used to invert the parameters of the probability integral method (PIM). The subsidence basin predicted by the inverted parameters serves as a criterion to select the superior dataset between the D-InSAR and UAV-derived results. Finally, the selected subsidence data are fused to generate a composite subsidence map. The proposed method was applied to the 2S201 panel in the Wangjiata Coal Mine using eight Sentinel-1A images and two UAV surveys. The fusion results were evaluated for their regional and overall accuracy against 30 ground control points measured by total station and GPS. The results demonstrate that the fusion method not only accurately extracts large-scale deformations in the mining area, with a maximum subsidence of 2.5 m and a root mean square error (RMSE) of 0.277 m in the subsidence center area, but also precisely identifies the subsidence boundary region with an accuracy of 0.039 m. The fused subsidence basin exhibits an overall accuracy of 0.182 m, which represents a significant improvement of 83.6% and 27.8% over the results obtained using D-InSAR and UAV alone, respectively. This method effectively reconstructs the complete morphology of the mining-induced subsidence basin, confirming its feasibility for practical applications. Full article

The accelerated closure of hard coal mines across Europe contrasts with Poland’s continued structural reliance on coal extraction and coal-based power generation, increasing the urgency of credible post-mining development models. This article investigates the potential transformation of the end-of-life Bobrek coal mine in Bytom (Poland), drawing on methodological and business-model insights from the European Union (EU) Research Fund for Coal and Steel (RFCS) POTENTIALS and GreenJOBS projects. A combined methodological framework is applied, including structural analysis to identify key transformation variables, morphological analysis to explore alternative redevelopment pathways, and multicriteria assessment to configure coherent scenarios integrating renewable energy systems and circular-economy activities. The results show that an industrial eco-park backed by a virtual power plant (VPP), comprising photovoltaic installations, a mine-water-based geothermal heating system, and small-scale wind turbines, is technically feasible and environmentally sustainable. In parallel, three circular-economy business lines, the recycling of end-of-life photovoltaic panels, waste electrical and electronic equipment (WEEE), and refrigeration units, were assessed as possible economic cores of the envisaged eco-park. Overall, the proposed model enables effective reuse of mining infrastructure, supports low-emission industrial activity, and aligns with EU climate policy objectives. The Bobrek site may serve as a reference for post-mining redevelopment in other coal regions. Full article

Underground coal mining leads to surface subsidence and ground deformation, which may affect the accuracy of cadastral data. This study evaluates mining-induced displacement caused by longwall VIII-E-E1 extraction in seam 703/1 and examines its potential impact on the Polish EGiB cadastral register. In 2018–2021, precise GNSS observations were collected on a specially designed geodetic monitoring polygon located in the affected area. These measurements enabled a detailed assessment of surface deformation during and after exploitation. The maximum subsidence was recorded above the extracted longwall and decreased outward, forming a typical post-mining deformation basin. Although boundary-point displacements remained generally within acceptable limits, the cumulative reduction of parcel areas reached about 43 m² in total. Five parcels (0.8% of the dataset) showed area changes exceeding 1 m². The results indicate that a single longwall has a limited effect on cadastral data integrity; however, continued multi-panel mining may lead to progressive boundary shifts, compromising the spatial and legal reliability of cadastral resources. The study confirms the effectiveness of integrated geospatial monitoring in detecting mining-related deformation and highlights the need for continuous control of cadastral datasets, especially in the Upper Silesian Coal Basin, where large-scale mining remains active. Full article

In the rapidly evolving digital economy, the expansion of business-to-business e-commerce ecosystems has compelled traditional industries to integrate into digital supply chains to achieve sustainable development. Industrial e-commerce is no longer limited to online transactions but extends to the digital transformation of backend operations. Drawing upon the perspective of the digital business ecosystem, this study investigates how digital supply chain integration, manifested through digital transformation, impacts energy efficiency. By utilizing a panel fixed effects model and advanced text mining techniques on a dataset of 721 listed firms in the resource-intensive sectors of China spanning from 2011 to 2023, this research constructs a novel index to quantify corporate digital maturity based on semantic analysis. The empirical results demonstrate that digital transformation significantly enhances energy efficiency by facilitating optimized resource allocation and data-driven decision making required by modern digital markets. Mechanism analysis reveals that green innovation functions as a pivotal mediator that bridges the gap between digital investments and environmental performance. Furthermore, this relationship is found to be contingent upon corporate social responsibility strategies, ownership structures, and the scale of the firm. This study contributes to the electronic commerce literature by elucidating how traditional manufacturers can leverage digital technologies and green innovation to navigate the twin transition of digitalization and sustainability, offering theoretical implications for platform governance in industrial sectors. Full article

Addressing the challenge of efficient gas control in high-gas coal mines with ultra-long panels, this study focuses on the No. 8 coal seam in the Baode Mine. A multi-parameter integrated methodology was developed to establish a hierarchical classification system of Gas Geological Units (GGUs), aiming to identify regions suitable for large-scale gas extraction. The results indicate that the overall structure of the No. 8 coal seam is a simple monocline. Both gas content (ranging from 2.0 to 7.0 m³/t) and gas pressure (ranging from 0.2 to 0.65 MPa) generally increase with burial depth. However, local anomalies in these parameters, caused by geological structures and hydrogeological conditions, significantly limit the effectiveness of large-scale drainage using ultra-long boreholes. Based on key criteria, the seam was classified into three Grade I and ten Grade II GGUs, distinguishing anomalous zones from homogeneous units. Among the Grade II units, eight (II-i to II-viii) were identified as anomalous zones with distinct geological constraints, while two (II-ix and II-x) exhibited homogeneous gas geological parameters. Practical implementation of large-scale gas extraction strategies—including underground ultra-long boreholes and a U-shaped surface well—within the homogeneous Unit II-x demonstrated significantly improved gas drainage performance, characterized by higher methane concentration, greater flow rate, enhanced temporal stability, and more favorable decay characteristics compared to conventional boreholes. These findings confirm the critical role of GGU delineation in guiding efficient regional gas control and ensuring safe production in similar high-gas coal mines. Full article

Geological modeling is generally based on deterministic models, which provide a single representation of reality. Probabilistic modeling is more appropriate when quantifying or understanding the uncertainty associated with a parameter of interest as it considers several equally probable geological scenarios. The object of this study is to quantify the uncertainty in the estimation of the minerals in the Punta Alegre gypsum deposit, by applying a new method based on the simple normal equation geostatistical simulation technique. The Punta Alegre gypsum deposit is a sedimentary deposit of clastic origin, formed by the complex redeposition of salts, gypsum and other sediments. To carry out this research, 50 equiprobable scenarios were simulated, reproducing overburden, gypsum series (different types of gypsum) and intercalated non-mineral lithologies (limestone and other rocks) in a network of nodes measuring 5 × 5 × 5 m, using a training image, composites and prior probability maps as input data. As a result of scaling the previously simulated geological units, three-dimensional models of volume proportions and estimation error for gypsum were obtained for panels measuring 10 × 10 × 5 m. The quantification of the uncertainty of the gypsum volume, determined by the root mean square error, established that the volume estimation error is small at a global scale (6.51%), given that there is no significant variation when comparing the deterministic model with the gypsum proportion model obtained from the 50 simulated scenarios. Conversely, at the local scale, there is a significant variation in gypsum volume of 42% in the 10 × 10 × 5 m panels with a future impact on recoverable mining resources, given the uncertainty at a local scale, which will cause an increase in mining dilution due to the inclusion of non-mineral lithologies within the extracted mineral that will be sent to the processing plant. On the other hand, it will cause changes in the mining company’s plan in areas where there are panels that were previously accounted for by the deterministic model as minerals and are not actually exploitable. Full article

In Europe, renewable energy sources such as photovoltaic panels and wind power plants are developing dynamically. The growth of renewable energy is driven by rising energy prices, greenhouse gas emission restrictions, the European Union’s Green Deal policy, and decarbonization efforts. Photovoltaic farms generate energy intermittently, depending on weather conditions. Given the increasing number of new installations, ensuring the power balance and transmission capacity of the electrical grid has become a major challenge. To address this issue, the authors propose a technical solution that allows the energy generated by photovoltaic systems to be stored in the form of heat. Thermal energy from solar power and wind energy offers significant potential for energy storage. It can be accumulated during summer in specially designed sand-based heat storage systems and then used for heating purposes in winter. This approach not only reduces heating costs but also decreases greenhouse gas emissions and helps balance the power grid during sunny periods. Post-industrial areas, often located near city centers, are suitable locations for large-scale heat storage facilities supplying, among others, public utility buildings. Therefore, this article presents a concept for utilizing high-temperature sand-based heat storage systems built in decommissioned underground mining excavations. Full article

With the strategic background of accelerating the transformation of the low-carbon economy in China, how to better help the new energy automobile industry realize green and high-quality development under the goal of “dual-carbon” with the strengthening of science and technology has become one of the most important issues nowadays, and it is of great significance to explore the relationship between financial technology (fintech) and the environmental, social, and governance (ESG) performance of the new energy automobile (NEV) industry. Using panel data from NEV companies listed on the Shanghai and Shenzhen A-share markets between 2011 and 2022, this study applies text mining techniques to construct a fintech index and analyze the transmission mechanisms through which fintech influences ESG performance. The findings show that fintech directly improves ESG outcomes for NEV companies, a result that remains robust across a series of validation tests. The analysis reveals that fintech reduces financing constraints and enhances corporate environmental information disclosure, which in turn drives better ESG performance. Furthermore, the impact of fintech is particularly pronounced in state-owned enterprises, large-scale firms, and technologically advanced NEV companies, as evidenced by heterogeneity analysis. This study provides empirical insights into fintech’s role in advancing sustainable development in the NEV sector, offering guidance for policymakers and industry stakeholders aiming to align technological progress with environmental and social governance objectives. Full article

The neutralization of high-density sludge (HDS) effluent is a required process involved in the treatment of acid mine drainage (AMD). In their last treatment stage, effluents with high pH values are acidified to reach legal standards before being released to the environment using hydrochloric or sulfuric acid. In this investigation, CO₂ was tested as an alternative way to decrease the pH of the HDS effluent, together with an economic analysis comparing the results with the use of strong mineral acids, considering a full-scale 300 m³/h plant. HDS samples were collected from a PAN American Silver operation in Cajamarca, northern Peru. Four acidification tests were carried out on 20 L containers, with a subsequent evaluation of reaction time and CO₂ consumption to regulate the final pH of the treated solution. The results suggest that by adding CO₂ (0.5 L/min) to the solution, the pH was successfully decreased from 10–10.5 to 6.5–7.5 (which falls within the legal limits) in a matter of minutes. An average of 130 g of CO₂ was sequestrated per m³ of solution to decrease the pH within legal limits, representing around USD 0.031/m³ in terms of treatment cost for a full-scale plant. While this is more expensive than using other acids, with a CO₂ credit of USD 100/ton, sequestrated CO₂ neutralization is 12% cheaper and only 6% more expensive than using H₂SO₄ and HCl, respectively. Moreover, in terms of the costs per ton of avoided CO₂ of USD 133 and USD 262 for replacing hydrochloric and sulfuric acid, respectively, it is markedly lower than the cost of other CO₂ abatement technologies, like, for instance, solar photovoltaic panels (PV) that can cost between USD 368 and USD 684/ton of avoided CO₂ in Peru and require substantial capital investments. Moreover, the use of CO₂ implicates a series of additional safety, operational, and environmental advantages that should be considered. Therefore, the use of CO₂ to decrease HDS effluent’s pH should be further explored in Peru and elsewhere as a sustainable alternative. Full article

Rockbursts represent one of the most serious and severe natural hazards emerging in underground copper mines within the Legnica–Glogow Copper District (LGCD) in Poland. The contributing factor determining the scale of this event is mining-induced seismicity of the rock strata. Extensive expertise of the copper mining practitioners clearly indicates that high-energy tremors are the consequence of tectonic disturbances or can be attributed to stress/strain behaviour within the burst-prone roof strata. Apparently, seismic activity is a triggering factor; hence, attempts are made by mine operators to mitigate and control that risk. Underlying the effective rockburst control strategy is a reliable seismicity forecast, taking into account the causes of the registered phenomena. The paper summarises the geomechanics analyses aimed to verify the actual seismic and rockburst hazard levels in one of the panels within the copper mine Rudna (LGCD). Two traverses were designated at the face range and comparative analyses were conducted to establish correlations between the locations of epicentres of registered tremors and anomaly zones obtained via analytical modelling of changes in stress/strain behaviours within the rock strata. The main objective of this study was to evaluate the likelihood of activating carbonate/anhydrite layers within the main roof over the excavation being mined, with an aim to verify the potential causes and conditions which might have triggered the registered high-energy events. Special attention is given to two seismic events giving rise to rockbursts in mine workings. Results seem to confirm the adequacy and effectiveness of solutions provided by mechanics of deformable bodies in the context of forecasting the scale and risk of dynamic phenomena and selecting the appropriate mitigation and control measures in copper mines employing the room-and-pillar mining system. Full article

Agricultural farming problems are the main concerns for states and local governments in stabilizing and increasing food production. Agricultural mechanization is an important element in this scenario. Thus, we conduct a systematic analysis to examine the agricultural mechanization level and its effect on grain production by using panel data and scientific literature mining for the last two decades in northeastern China. For this purpose, the autoregressive distributed lag model, the stochastic frontier model, and bibliometric analysis are employed. The results show that the development level of agricultural mechanization is stable in the region. In terms of scientific research progress in agricultural mechanization, researchers are mainly studying to solve problems related to carbon emissions, green energy, and environmental protection, and overall, a 4.39% growth rate for research publications was found. Also, the statistical analysis shows that variables such as fertilizers (9.808) and agricultural machinery (0.003) have a significant positive impact on the agricultural industry, which indicates that the development of agricultural mechanization has a certain impact on the efficiency of food production. Thus, technological innovation in climate agricultural practices and small-scale farming could be more beneficial to fulfilling the future food demand. Full article

There is a very thick water-bearing key strata above the coal seam in the Binchang mining area. When the mining scale is large, it easily breaks and leads to rockburst with a surge of water gushing in the panel. Adopting the layout pattern of a small panel and a large coal pillar can improve the stability of the main key strata, but at present, the research on the layout pattern of a small panel and a large coal pillar under extra-thick water-bearing key strata is still not perfect. Therefore, taking the second and third panels of a mine in Binchang as the engineering background, the width of the coal pillar and the mining scale of the panel are optimized by means of theoretical analysis, field measurement, and numerical simulation to prevent rockburst and control water inflow. The results show: (1) through theoretical calculation, it is deduced that the critical width of instability of the isolated coal pillar in the current mining scale is 257 m, and the critical mining scale of breaking and instability of the main key strata in the third panel is 537 m; (2) considering the bearing capacity of the isolated coal pillar and the recovery rate of coal resources, the reasonable width of the isolated coal pillar is 210~270 m, and when the width is 200 m and 250 m, the reasonable mining scale of the third panel is 490~550 m and 640~700 m, respectively; (3) the field practice shows that the actual width of the coal pillar between the second and third panels is less than the reasonable width, and the stress concentration in the isolated coal pillar area is relatively high, so the roof deep hole blasting and large-diameter drilling in coal seam are adopted to relieve pressure. After taking pressure relief measures, the stress concentration in the isolated coal pillar area is effectively reduced, and the pressure relief effect is remarkable. Full article