Search Results (782)

In response to ground pressure problems such as an abnormal increase in working face support resistance and severe roadway floor heave induced by the lateral composite structure of the multi-layer thick and hard roof in the 11,223 working face of Xiaojihan Coal Mine, based on the triangle area slip theory, this study reveals that the lateral triangle area forms a composite structure of “cantilever beam + masonry beam”. The stress transfer and unloading mechanism of the high- and low-position thick and hard rock stratum fracturing was clarified. A technical scheme is proposed and implemented to weaken the high- and low-position thick and hard rock strata through horizontal Long Directional Borehole synergistic fracturing and optimize stress transfer. The results show that (1) the lateral overlying rock forms a triangular slip area under the clamping of the cantilever and masonry beam structures. This composite structure is the main reason for the increase in the support resistance at the end of the working face and the stress concentration of the roadway surrounding rock. (2) The influence law that the load of the triangular slip area is mainly influenced by the length of the broken block, and the breaking angle was clarified. The distribution characteristics of the load in the lateral triangle area under the fracturing of thick and hard rock strata at different horizons are mastered. When the length of the key block is reduced by 40%, the supporting force F₁ of the rock mass below the broken block on it is reduced by 62.5%, and the supporting force F₂ and the frictional force F₃ of the end part on the broken area of the triangle area are reduced by 34.6%. (3) The fracturing of high- and low-position thick and hard rock strata can collaboratively weaken the stress accumulation at high and low positions. Fracturing the low-position thick and hard rock strata can cut off the low-position “cantilever beam” structure, and fracturing the high-position thick and hard rock strata at the same time can transfer the load of the “masonry beam”. Through simulation, it is seen that the stress peaks at the end of the working face and the roadway surrounding rock during synergistic fracturing are, respectively, reduced by 12.2% and 28.9%. (4) An industrial test of directional drilling hydraulic fracturing of lateral thick and hard rock strata is carried out, achieving the regulation effect that the average value of the support resistance at the end of the cycle is reduced from 27.2 MPa to 22.7 MPa, and the floor heave amount of the reused roadway is reduced by 62.3%. The research results can provide a reference for the advanced treatment of the strong ground pressure area of the multi-layer thick and hard roof. Full article

The enrichment laws and key controlling factors of coalbed methane (CBM) in the Xishanyao Formation of the Hedong mining area remain unclear, restricting exploration progress. Based on well data and experimental analyses, this study investigates CBM enrichment characteristics and geological controls using genetic identification diagrams. Results demonstrate that CBM exhibits a “high in northwest and low in southeast” planar distribution. Vertically, CBM content is extremely low above 360 m due to weathering oxidation and burnt zone effects, increases within the 360–950 m interval (peaking at 750–950 m), and declines from 950 to 1200 m because of limited gas contribution. Genetic analysis indicates predominantly primary biogenic gas, with a minor component of early thermogenic gas. Enrichment is controlled by structure and hydrogeology: the medium-depth range (358–936 m) on the northern syncline limb and western part of the northern monoclinal zone forms a high-efficiency enrichment zone due to compressive stress from reverse faults and high mineralization groundwater (TDS > 8000 mg/L). While the southern limb, characterized by high-angle tensile fractures and active groundwater runoff, suffers gas loss and generally low gas content (<3.5 m³/t). This study clarifies CBM enrichment laws and enrichment mechanisms, supporting exploration of low-rank CBM in the Hedong mining area. Full article

The U.S. municipal solid waste recycling rate has remained near 32% for two decades, placing the country 30th globally. In response, the U.S. Environmental Protection Agency (EPA) has set a national goal of achieving a 50% recycling rate by 2030, yet concrete strategies for reaching this target remain limited. Persistent challenges—such as low public participation and inadequate dissemination of effective practices—highlight the potential importance of recycling education. This study has two aims. First, we assess federal investment in recycling education through the EPA’s Environmental Education Grants Program (1992–2023) using a large language model (LLM)-assisted text-mining approach to identify recycling-focused projects. Second, we examine the factors that shape state-level recycling rates, including policy, demographic, infrastructure, and education variables. Our results show that states with bottle bills—deposit–refund laws for beverage containers—and states with higher levels of educational attainment exhibit significantly higher recycling rates. By contrast, federal investments in recycling education, as measured through the grants program, were not statistically associated with state-level recycling performance. This study introduces a novel analytic approach for evaluating how policy and educational factors contribute to state-level recycling outcomes and to national recycling performance. Full article

Predicting the Remaining Useful Life (RUL) of engine oil is critical for proactive maintenance and fleet reliability. However, irregular and noisy single-point sampling presents challenges for conventional prognostic models. To address this, a hierarchical physics-informed transfer learning (TL) framework is proposed that reconstructs nonlinear degradation trajectories directly from non-time-series data. The method uniquely integrates Arrhenius-type oxidation kinetics and thermochemical laws within a multi-level TL architecture, coupling fleet-level generalization with engine-specific adaptation. Unlike conventional approaches, this framework embeds physical priors directly into the transfer process, ensuring thermodynamically consistent predictions across different equipment. An integrated uncertainty quantification module provides calibrated confidence intervals for RUL estimation. Validation was conducted on 1760 oil samples from dump trucks, dozers, shovels, and wheel loaders operating under real mining conditions. The framework achieved an average R² of 0.979 and RMSE of 10.185. This represents a 69% reduction in prediction error and a 75% narrowing of confidence intervals for RUL estimates compared to baseline models. TL outperformed the asset-specific model, reducing RMSE by up to 3 times across all equipment. Overall, this work introduces a new direction for physics-informed transfer learning, enabling accurate and uncertainty-aware RUL prediction from uncontrolled industrial data and bridging the gap between idealized degradation studies and real-world maintenance practices. Full article

Taking Yujialiang Coal Mine as the engineering background, aiming at the actual demand of 5-2 coal seam mining and 4-4 coal seam upward mining, the temporal evolution and spatial distribution characteristics of overburden failure height after 5-2 coal seam mining are systematically investigated by using multi-source field detection technology such as ground drilling, logging, and borehole peeping, combined with a numerical simulation method. The field detection results show that after the 5-2 coal seam is mined, the development height of the water-conducting fracture zone (WCFZ) is 116.25–129.92 m, and the height of the caving zone is 9.32–21.56 m. The 4-4 coal seam is located within the fracture zone, 15.99–22.88 m above the caving zone. The strength of the 4-4 coal seam and its surrounding rock affected by mining is reduced, with a more significant decrease in the middle of the goaf. The numerical simulation further reveals the law of overburden movement and deformation. After the 5-2 coal seam mining, the maximum subsidence of the 4-4 coal seam floor reaches 4.57 m, and there is stress concentration above the remaining coal pillars. The maximum vertical stress after mining all three working faces (52,204, 52,205, 52,206) is 4.10 MPa, and the stress environment above the goaf is better. The results show that the average distance between the 4-4 coal seam and 5-2 coal seam is about 39.45 m, and the upward mining is feasible, but the stability of the rock strata in the fracture zone should be paid more attention to. Based on the movement law of overlying strata and the characteristics of stress distribution, it is suggested that the mining gateway of the 4-4 coal seam should be arranged in the middle of the remaining coal pillar of the 5-2 coal seam or the corresponding area in the middle of the goaf so as to ensure the stability of the roadway surrounding the rock during mining. The research results provide a reliable theoretical basis and technical support for the upward mining design of the 4-4 coal seam in Yujialiang Coal Mine and have important reference value for the upward mining projects of coal mines under similar conditions. Full article

This research conducts a comparative analysis of the Environmental Impact Assessment’s (EIA’s) legal frameworks in Laos and China, utilising a qualitative methodological approach rooted in comparative law. This research systematically examines primary legal documents, case studies from the hydropower and mining sectors, and recent government data to evaluate the two systems based on three core criteria: the robustness of the legal structure, the effectiveness of enforcement mechanisms, and the depth of public participation. The analysis indicates that although both countries require Environmental Impact Assessments (EIAs), China’s framework is more structured and efficient, as demonstrated by its clearer legal hierarchy, strict penalties for non-compliance, and established public disclosure procedures. In contrast, Laos’s framework, although established, is marked by its early stage of development, evident in fragmented legislation, limited enforcement due to capacity constraints, and reduced public engagement. The study contributes by providing a direct bilateral comparison and empirically demonstrating how institutional divergences account for disparities in environmental outcomes and foreign investment. Recommendations are provided to improve transparency, enforcement capabilities, and substantive public engagement in both nations. This research is based on comparative legal theory and institutional analysis to transcend a mere descriptive narrative. It utilises a qualitative comparative methodology that combines doctrinal research of legal texts with practical case studies from the hydropower and mining industries. This method enables us to systematically investigate how differing institutional capacity, enforcement mechanisms, and governance models between an emerging and a developed system account for variations in EIA outcomes. The study questions are formulated to evaluate theoretical claims regarding the influence of legal frameworks and administrative authority on the attainment of good environmental governance, providing a transferable analytical model for analogous developing environments. Full article

To study the mechanical properties and displacement evolution of rock masses near coal-seam normal faults under mining disturbances; this paper utilizes fiber optic monitoring and distributed strain measurement techniques to achieve the fine monitoring of the entire process of stress–displacement–strain during mining. The experimental design adopts a stepwise mining approach to systematically reproduce the evolution of fault formation; slip; and instability. The results show that the formation of normal faults can be divided into five stages: compressive deformation; initiation; propagation; slip; and stabilization. The strength of the fault plane is significantly influenced by the dip angle. As the dip angle increases from 30° to 70°, the peak strength decreases by 23%, and the failure mode transitions from tensile failure to shear failure. Under mining disturbances, the stress field in the overlying rock shifts from concentration to dispersion, with a stress mutation zone appearing in the fault-adjacent area. During unloading, vertical stress decreases by 45%, followed by a rebound of 10% as mining progresses. The rock layers above the goaf show significant subsidence, with the maximum vertical displacement reaching 150 mm. The displacement between the hanging wall and footwall differs, with the maximum horizontal displacement reaching 78 mm. The force chain distribution evolves from being dominated by compressive stress to a compressive–tensile stress coupling state. The fault zone eventually enters a stress polarization state and tends toward instability. A large non-uniform high-speed zone forms at the fault cutting point in the velocity field, revealing the mechanisms of fault instability and the initiation of dynamic disasters. These experimental results provide a quantitative understanding of the multi-physics coupling evolution characteristics of coal-seam normal faults under mining disturbances. The findings offer theoretical insights into the instability of coal-seam normal faults and the mechanisms behind the initiation of dynamic disasters. Full article

Investigating the evolution mechanism of overlying strata fractures during mining and identifying the key factors that influence the development height of water-conducting fracture zones (WCFZs) are essential for preventing roof water inrush disasters, protecting mine water resources, and ensuring safe and sustainable mine development. To investigate the height of WCFZs and the evolution law of roof water inflow in a syncline structure working face under high-confined aquifer conditions, the 203 working face of Gaojiapu Coal Mine in Binchang Coalfield is selected as the engineering case. This paper analyzes the characteristics and control mechanisms of roof water inflow in a syncline structure mining area using UDEC 7.0 and COMSOL Multiphysics 6.0 multiphysics numerical simulation software. The results indicate that under different mining heights and advancing speeds, the height of the WCFZ in the overlying strata of a syncline structure working face continuously increases during the downward mining stage and in areas below the axis, and decreases thereafter, eventually stabilizing after reaching its maximum value at the initial stage of upward mining. When the WCFZ communicates with the strong aquifer of the Cretaceous Luohe Formation during the mining process, roof water inflow into the working face increases abruptly. The effectiveness of controlling water inflow by adjusting mining height is superior to that of controlling mining speed. Based on the response relationship between mining height, mining speed, and roof WCFZ, an on-site drainage prevention strategy was implemented involving reduced mining height and increased mining speed. Consequently, the roof water inflow at the working face has decreased from an initial rate of 950 m³/h to 360 m³/h. This study is of great significance for the safe and efficient extraction of coal seams under high-confined aquifers in the Binchang Coalfield, supporting the efficient development of coal resources while safeguarding regional water resources, thereby offering considerable engineering and practical value in promoting green mining and sustainable mining practices in large-scale coal production bases with similar geological conditions. Full article

Mining is associated with specific heavy metals (HMs), including cadmium (Cd), lead (Pb), copper (Cu), iron (Fe), and other toxic metals. These metals contaminate water and accumulate in both children and adults at varying concentrations, resulting in severe health implications. This paper examines the impact of barite mining on water quality, human well-being, and the environment. It evaluates the health implications of natural and anthropogenic activities on the selective liberation of heavy metals at mining sites. The potential environmental impact on mining communities in the extreme dry (April), early or mid-rainy (July), and optimum rainy (October) seasons of the year is also elucidated. Ponds within six barite mining sites were analysed using an Atomic Absorption Spectrometer (AAS) to identify these metals in water samples. The implications of HM concentrations on the well-being of the young and adults were examined and assessed using relevant mathematical expressions, and the outcome was compared with national and international environmental standards. Results show that the ponds within the barite mining sites are contaminated with copper (Cu), barium (Ba), cadmium (Cd), lead (Pb), and iron (Fe). The HM concentration exceeds the reference dose (RfD) or tolerable daily intake (TDI) stated by global and national standards for water quality and healthy living. Statistical assessments indicated that the non-carcinogenic risks of Pb and Cd are higher in children than in adults. In addition to mining, farming activities may increase HM contamination within the areas. It is anticipated that existing policy frameworks and water laws will be reviewed to support efforts for the early detection of HMs in water through medical examinations, water quality assessments, and non-carcinogenic risk (NCR) assessments. Full article

Sparse unmixing (SU) has become a research hotspot in hyperspectral image (HSI) analysis in recent years due to its interpretable physical mechanisms and engineering practicality. However, traditional SU methods are confronted with two core bottlenecks: Firstly, the high computational complexity of the abundance matrix inversion severely limits algorithmic efficiency. Secondly, the inherent challenges posed by large-scale highly coherent spectral libraries hinder improvement of unmixing accuracy. To overcome these limitations, this study proposes a novel sub-abundance map regularized sparse unmixing (SARSU) framework based on dynamic abundances subspace awareness. Specifically, first of all, we have developed an intelligent spectral atom selection strategy that employs a designed dynamic activity evaluation mechanism to quantify the participation contribution of spectral library atoms during the unmixing process in real time. This enables adaptive selection of critical subsets to construct active subspace abundance maps, effectively mitigating spectral redundancy interference. Secondly, we innovatively integrated weighted nuclear norm regularization based on sub-abundance maps into the model, deeply mining potential low-rank structures within spatial distribution patterns to significantly enhance the spatial fidelity of unmixing results. Additionally, a multi-directional neighborhood-aware dual total variation (DTV) regularizer was designed, which enforces spatial consistency constraints between adjacent pixels through a four directional (horizontal, vertical, diagonal, and back-diagonal) differential penalty mechanism, ensuring abundance distributions comply with physical diffusion laws of ground objects. Finally, to efficiently solve the proposed objective model, an optimization algorithm based on the Alternating Direction Method of Multipliers (ADMM) was developed. Comparative experiments conducted on two simulated datasets and four real hyperspectral benchmark datasets, alongside comparisons with state-of-the-art methods, validated the efficiency and superiority of the proposed approach. Full article

Despite the existence of human rights legislation in Canada, equitable access to these rights remains elusive in many workplaces—particularly in traditionally male-dominated sectors such as engineering and mining. This paper argues that the proactive application of human rights frameworks can drive meaningful workplace culture transformation by addressing both overt and systemic inequities. While Canadian human rights laws offer legal remedies for discrimination, underrepresented groups continue to face barriers, especially in non-unionized environments where support mechanisms are limited. This paper presents a novel analysis of Canadian workplaces through a human rights lens, emphasizing the need for policies that go beyond reactive measures. It advocates for increased public awareness, targeted allyship training, and leadership accountability to foster inclusive and equitable work environments. The findings have broad implications for advancing decent work across sectors and for building representative and inclusive workforces. Full article

Based on the problem of water and sand inrush caused by the infiltration and failure of the clay layer at the bottom of the loose layer in shallow coal seam mining in eastern China, this study adopts the Particle Flow Code numerical simulation method to conduct multi-physics field coupling analysis. Based on the geological conditions of Taiping Coal Mine in Shandong Province, a two-dimensional water sand clay coupling model was constructed to systematically simulate the entire process of permeability failure of clay layers under different mining crack widths (5–20 mm). The permeability failure mechanism was revealed through porosity distribution, particle contact number, and contact force evolution laws. The numerical simulation results show that with the increase in crack width, the speed of contact reduction is faster, the speed of water and inrush is faster, and the time is shorter. The process of infiltration failure can be divided into two stages: the first stage is the clay infiltration deformation stage, and the second stage is the water inrush and sand collapse stage. In addition, the larger the width of the crack, the greater the contact force, and the shorter the time of infiltration failure and water and sand bursting experienced. The quantitative relationship between the width of mining induced cracks and permeability failure was revealed, and a critical discrimination index for permeability failure in clay layers was established, providing theoretical support for optimizing safe mining parameters and preventing water and sand inrush disasters in porous aquifers. Full article

Employers in South Africa are mandated by labour laws to implement systems of work for the maintenance and promotion of health and safety at work. In response, companies have adopted and implemented occupational health and safety management systems (OHSMSs) whose effectiveness should be continuously monitored through performance measurement. However, there remains no national convention on the specific performance measurement indicators for companies to use. The objective of this study was to determine, characterise and compare lagging indicators adopted and reported by the top 150 Johannesburg Stock Exchange (JSE)-listed companies in South Africa. This qualitative study evaluated annual reports and data books from these companies by analysing textual data through qualitative document analysis. Only 87 of the 150 case companies reported performance using lagging indicators. The basic materials, consumer goods, consumer services and industrial sectors had the most companies which reported performance metrics. Fatality count and lost time injury frequency rate (LTIFR) were the most commonly reported performance metrics and were reported by 64 and 41 companies, respectively. There was variation in the number, type and form of adopted lagging indicators by the case companies. Companies in the manufacturing and mining sectors were more likely to report OHS performance, in general, than those in other sectors. The observed variation across sectors emphasises the need for harmonised indicators to measure and report OHS performance in South Africa. Full article

The transition from open-pit to underground mining entails significant risks associated with rock mass deformation and surface subsidence, which pose critical challenges in mining engineering practice. To investigate and control the deformation behavior of overlying strata under mining-induced disturbances, a three-dimensional numerical model is developed for the goaf area at the Sijiaying Iron Mine. Deformation indicators, combined with calculations of rock movement angles and collapse angles, are utilized to elucidate the deformation characteristics and controlling mechanisms of the mine surface. The results indicate the following: (1) slope deformation in the open-pit mine exhibits notable spatial heterogeneity, characterized by a “large displacement–small deformation” phenomenon, with peak values of total displacement and total deformation reaching 92.86 mm and 3.28 mm/m, respectively; (2) the critical ranges of surface movement angle and collapse angle are determined, enabling quantitative delineation of the influence zones of underground mining on surface deformation; and (3) the dip angle of the ore body is the primary controlling factor influencing the surface subsidence. Specifically, gently dipping ore bodies predominantly exhibit vertical subsidence (associated with larger movement angles), whereas steeply dipping ore bodies display pronounced directional sliding (correlated with smaller movement angles). Full article

Focusing on the mining-induced fracture development characteristics of Weakly Cemented Overburden (WCO) in Ultra-Thick Coal Seam (UTCS) extraction, this study, based on the 1101 first mining face in Xinjiang’s Zhundong Coalfield, systematically investigates the dynamic evolution law of the water-conducting fracture zone (WCFZ) in WCO by employing similarity simulation, quantitative characterization using Fractal Dimension (D), and surface borehole exploration and borehole imaging technology. The results show that existing prediction equations for the WCFZ have poor applicability in the study area, with significant fluctuations in prediction outcomes. Similarity simulation reveals that Thick Soft Rock Layers (TS) guide and control fracture development, with the D exhibiting a “step-like” evolution. After the first rupture of TS1, the peak D reaches 1.49, stabilizing between 1.36 and 1.37 after full extraction. The height of the WCFZ increases non-linearly with the advance of the working face, reaching a maximum of 189 m, with a fracture-to-mining ratio of 10.5. Based on D fluctuations and extension patterns, the fracture development is divided into three stages, initial development, vertical propagation, and stabilization, clarifying its spatial evolution. Field measurements indicate a WCFZ height ranging from 161 to 178 m, with a fracture-to-mining ratio of 9.73–12.18, showing only a 6.2% error compared to the simulation results, which verifies the reliability of the experiment. This study reveals the evolution mechanism of the WCFZ during mining in UTCS and WCO in the Zhundong area, providing a theoretical basis and practical guidance for mine disaster prevention and control, as well as safe and efficient mining. Full article