Search Results (133)

This study determined the influence of experimental factors such as current density, surface-to-volume ratio (S/V), and contact time on the removal of Chemical Oxygen Demand (COD) and energy consumption during electrocoagulation, aiming to optimize the efficiency of a coaxial electrocoagulator for the co-treatment of municipal wastewater and acid mine drainage. After identifying the optimal volumetric ratio between both types of effluents, a Box–Behnken design and response-surface methodology were employed to identify the conditions that maximize COD removal while minimizing energy consumption. Under optimal conditions (current density of 2.42 A·m⁻², S/V = 300 m²·m⁻³, 60 min), a COD removal of 91.13% was achieved with a specific energy of =2.59 kWh·kgCOD⁻¹. The statistical model for COD removal demonstrated a good fit (R² = 0.87), though its predictive power was limited (predicted R² = 0.53). In contrast, the model for energy consumption exhibited an outstanding fit (R² = 0.99) and high predictive consistency (predicted R² = 0.98), confirming the decisive influence of current density on energy demand. Additionally, the S/V ratio emerged as the most impactful factor in COD removal variability. Overall, the findings highlight the importance of balancing removal efficiency with the economic feasibility of the process, contributing to the design of more sustainable and effective strategies for integrated wastewater treatment. Full article

Mine Thermal Energy Storage (MTES) offers a promising solution for sustainable heating by repurposing abandoned, water-filled mines as underground thermal reservoirs. This study assesses the feasibility of implementing MTES in Nova Scotia, with a focus on the Sydney coalfield region, particularly Glace Bay. The research combines geological analysis, residential heat demand estimation, thermal storage capacity estimation, and cost–benefit evaluation to determine whether abandoned coal mines can support district heating applications. Results show that MTES can deliver substantial heating cost reductions compared to oil-based systems, while significantly lowering greenhouse gas emissions. The study also explores the integration of MTES with local renewable energy sources, including wind and solar, to enhance energy system flexibility and reliability. International case studies from Springhill (Canada), Heerlen (Netherlands), and Bochum (Germany) are referenced to contextualize the analysis and demonstrate how the findings of this study align with broader MTES scalability, performance, and operational challenges. Key technical barriers, such as water quality management, infrastructure investment, and seasonal variability in heat demand, are discussed. Overall, the findings highlight MTES as a viable and sustainable energy storage approach for Nova Scotia and other regions with legacy mining infrastructure. Full article

This work investigated the ion exchange technique for selective separation of rare earth elements (REE) from acid mine drainage (AMD), using different column systems, pH values, and eluent concentrations. Systematic analysis of pH and eluent concentration showed that an initial pH of 6.0 and 0.02 mol L⁻¹ NH₄EDTA are the optimal conditions, achieving 98.4% heavy REE purity in the initial stage (0 to 10 bed volumes). This represents a 32-fold increase compared to the original AMD (6.7% heavy REE). The speciation of REE and impurities was determined by Visual Minteq 4.0 software using pH 2.0, which corresponds to the pH at the inlet of the fractionation column. Under this condition, La and Nd and the impurities (Ca, Mg, and Mn) remained in the fractionation column, while Al was partially retained. In addition, the heavy REE (Y and Dy) were mainly in the form of REE-EDTA complexes and not as free cations, which made fractionation more feasible. The fractionation column minimized impurities, retaining 100% of Ca and 67% of Al, generating a liquor concentrated in heavy REE. This sustainable approach adopted herein meets the critical needs for scalable recovery of REE from diluted effluents, representing a circular economy strategy for critical metals. Full article

The applicability of the in-situ pyrolysis of oil-rich coal is highly dependent on regional geological conditions. In this study, six major geological factors and 19 key parameters influencing the in-situ pyrolysis of oil-rich coal were systematically identified. An analytic hierarchy process incorporating index classification and quantification was employed in combination with the geological features of the Tiaohu mining area to establish a feasibility evaluation index system suitable for in-situ development in the study region. Among these factors, coal quality parameters (e.g., coal type, moisture content, volatile matter, ash yield), coal seam occurrence characteristics (e.g., seam thickness, burial depth, interburden frequency), and hydrogeological conditions (e.g., relative water inflow) primarily govern pyrolysis process stability. Surrounding rock properties (e.g., roof/floor lithology) and structural features (e.g., fault proximity) directly impact pyrolysis furnace sealing integrity, while environmental geological factors (e.g., hazardous element content in coal) determine environmental risk control effectiveness. Based on actual geological data from the Tiaohu mining area, the comprehensive weight of each index was determined. After calculation, the southwestern, central, and southeastern subregions of the mining area were identified as favorable zones for pyrolysis development. A constraint condition analysis was then conducted, accompanied by a one-vote veto index system, in which the thresholds were defined for coal seam thickness (≥1.5 m), burial depth (≥500 m), thickness variation coefficient (≤15%), fault proximity (≥200 m), tar yield (≥7%), high-pressure permeability (≥10 mD), and high-pressure porosity (≥15%). Following the exclusion of unqualified boreholes, three target zones for pyrolysis furnace deployment were ultimately selected. Full article

Facing the support challenges of short-wall working face (15–40m) roadways in the ‘excavation–backfill–retention’ tunneling method for section coal pillars, traditional equipment struggled to achieve stable, reliable, and efficient support. This paper designed a temporary support robot for the excavation and mining system of section coal pillars to ensure the safety of equipment and personnel in short-wall working faces. The support requirements of the section coal pillar excavation and mining system were analyzed, and a general ‘driving under pressure’ temporary support scheme was proposed. The working principle of the temporary support robot was analyzed. A mechanical model for the stable support of the temporary support robot was established. The mechanical properties of the surrounding rock were analyzed, and the allowable range of the temporary support robot’s supporting force was determined while ensuring the stability of the surrounding rock. Based on the Stribeck friction theory, a dynamic model of the temporary support robot in the driving under pressure state was constructed. The boundary conditions of the dynamic model were set, and the corresponding relationship between the temporary support robot’s supporting force and its maximum static friction force was determined. This accurately described the influence of the supporting force and pushing (pulling) force on the movement during the process of driving under pressure. Through finite element simulation, the stress conditions of the temporary support robot and the floor under maximum load were analyzed, indicating that this load condition would not cause damage to the temporary support robot or the surrounding rock. Through multi-body dynamics simulation, the pushing (pulling) forces required for the temporary support robot’s movement under different supporting force conditions were obtained, verifying the feasibility of the driving under pressure action under different supporting force conditions. Moreover, the model-predicted and simulated values of the required pushing (pulling) forces during the process of driving under pressure were consistent, validating the accuracy of the driving under pressure dynamic model. This research provides a new theoretical framework for the design and dynamic analysis of temporary support equipment for short-wall working faces in section coal pillar mining, holding significant academic value and broad application prospects. Full article

The forced-air self-aspirating flotation machine is the core equipment for achieving a horizontal configuration in a large-scale flotation circuit. During scale-up, power consumption increases significantly due to the requirement for a greater pulp suction volume, while flotation dynamics deteriorate. Therefore, it is difficult to meet the horizontal configuration requirement for a large-scale flotation process. In this study, the key factors influencing pulp suction capacity were analyzed, revealing that as impeller submergence depth increases, pulp suction capacity decreases sharply, while power consumption rises, which was determined to be the main limitation in scaling up a forced-air self-aspirating flotation machine. To address these challenges, a new design concept for large-scale forced-air self-aspirating flotation machines was developed, featuring an impeller–stator system positioned in the middle of a trough. This design eliminated the issue of the impeller moving farther from the overflow weir and prevented increasing pulp suction resistance during scale-up. Additionally, an independent design of the upper blades was introduced based on pulp suction demand, and the design method and scale-up equations for the new impeller were established. An industrial experiment system based on a 50 m³ forced-air self-aspirating flotation machine was established to verify the developed design schemes. The new impeller with a middle placement design achieved the best separation performance, exhibited low unit pulp suction power consumption, and demonstrated the most favorable overall performance. Using CFD simulations, the flow pattern and dynamic performance were calculated, including the pulp suction volume, circulation volume, and gas–liquid dispersion for large-scale forced-air self-aspirating flotation machines. The first and largest 160 m³ large-scale forced-air self-aspirating flotation cell was successfully developed and applied in a copper–sulfur mine, where the function of self-absorbing pulp was achieved and power consumption was effectively controlled. Finally, the feasibility and accuracy of the new large-scale forced-air self-aspirating flotation machine design and scale-up method were verified. In this paper, a large forced-air self-aspirating flotation machine is designed and developed which is capable of supporting horizontally configured large-scale flotation processes. This innovative approach significantly simplifies the processing layout and reduces both the equipment configuration complexity and energy consumption, offering a more efficient and cost-effective solution for large-scale mineral processing operations. Full article

The accumulation and improper management of mining tailings represent significant environmental and public health challenges globally, due to their potential for water contamination and the presence of heavy metals. In recent years, various studies have explored the feasibility of using mining wastes, such as tailings sludge, as partial replacements for cement in concrete mixes. The literature highlights the pozzolanic properties of mining tailings attributable to their silica and alumina content, which contribute to the improved structural characteristics, chemical resistance, and enhanced durability of concrete. This research evaluates the specific potential of gold mining tailings sludge (REMI) from the municipality of Vetas, Santander, Colombia, as a sustainable substitute in cementitious materials. Characterization methodologies including X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed the pozzolanic behavior of REMI due to its high content of silica- and alumina-rich amorphous phases and verified negligible contamination levels (Hg and cyanide below detectable limits). Concrete mixes with varying cement substitution levels (0% to 50%) were formulated and systematically evaluated to determine optimal substitution ranges based on criteria such as density, workability, setting time, and compressive strength. Consistent with previous studies, the results revealed an optimal replacement rate between 10% and 20%, with a particular emphasis on the 20% substitution achieving mechanical strengths comparable to traditional concrete. These findings underscore the technical viability and environmental benefits of using mining tailings sludge, contributing both to sustainable waste management and the advancement of eco-efficient concrete technologies. Full article

To address the feasibility of gob-side entry retaining in the shallow-buried three-soft coal seam fully mechanized mining face (SB-TSCS FMMF) of Xindeng (Zhengzhou, China) Coal Industry, we established a mechanical model of post-mining roof–coal-rock interaction in shallow-buried three-soft coal seams. This study reveals the quantitative relationships between the fracture position of the main roof and parameters such as coal seam thickness and immediate roof elastic modulus, and determines the parameter conditions required for implementing gob-side entry retaining in SB-TSCS FMMF. Critical parameters for the main roof fracture under this geological condition were first identified through particle flow simulation. The results indicate that there exist quantitative relationships between the main roof fracture position and parameters of the coal seam and the immediate roof. The influence degree on the maximum force exerted by the main roof on underlying coal-rock strata decreases in descending order as follows: immediate roof elastic modulus, coal seam thickness, immediate roof thickness, and coal seam elastic modulus. Similarly, the influence degree on the maximum bending moment follows the same order: immediate roof elastic modulus, coal seam thickness, immediate roof thickness, and coal seam elastic modulus. Based on the roof fracture laws, parameter thresholds suitable for gob-side entry retaining in three-soft coal seams are proposed, such as coal seam thickness (≤4 m) and immediate roof thickness (≤8 m). It is found that the main roof fracture position in shallow-buried three-soft coal seams is concentrated within the 0.3–0.6 m stress-sensitive zone at the edge of the goaf, providing key parameter thresholds for the support design of gob-side entry retaining. Full article

Heart disease is a serious threat to human health. Accurate prediction is very important for disease prevention and treatment. The purpose of this study is to establish a more suitable prediction model of heart disease. Based on LightGBM, we have deeply integrated bootstrap sampling and weighting technology. We repeatedly use multiple parameters of LightGBM to perform bootstrap sampling on the original training set. Through this process, we not only obtain training sub-models for various training subsets but also mine rich data features. In the process of cross-validation, the weight coefficient for each sub-model is carefully determined by comprehensively evaluating multiple key performance indicators, including accuracy, precision, recall, and the F1 score. This approach effectively highlights the role of high-quality sub-models. In the test stage, each sub-model is weighted according to the weight corresponding to its specific parameter combination, and finally, an accurate prediction result is obtained. Compared with the traditional prediction model, the model shows better comprehensive performance in terms of various performance metrics such as accuracy, precision, recall, and F1 score, and also performs better in the paired t-test. Moreover, compared with the baseline model, the phenomenon of overfitting is obviously reduced. Although the model has not been verified by external data sets, it has, to a certain degree, significantly boosted its predictive ability, universality, and stability. Moreover, it has provided a feasible scheme for heart disease prediction, which is expected to play a crucial role in clinical auxiliary diagnosis and disease management. The research shows that this model has obvious advantages in heart disease prediction and can effectively enhance the accuracy and reliability of prediction. Full article

Geometallurgy seeks to derisk the extraction of primary resources by developing optimal strategies across resource/reserve evaluation, mine planning, mineral processing, environmental management (including waste management), and energy use. Predictive geometallurgy is the crux of modern geometallurgical practice, which leads to a data-rich 3D block model(s). The geometallurgical approach aims to quantify variability through different sample types, including in situ and direct measurements; physical samples; process samples within the plant; and in-line sensor-based measurements. Sampling considerations across sample type, representativity, number of samples required, sample integrity, Quality Assurance/Quality Control, and reporting results in the context of international codes are emphasised. A geometallurgical protocol was developed to obtain multivariate data for highly heterogeneous gold-bearing conglomerate mineralisation. The protocol emphasises the importance of collecting high-quality samples through the use of diamond drill core and early implementation. The programme aimed to acquire an accurate head grade of each core intersection prior to destruction by metallurgical testwork. Core scanning and comminution test work was undertaken prior to the head assay. The protocol was developed so as to allow each core interval to be submitted for comminution testwork, recombined for head grade determination by PhotonAssay™, and subsequently submitted for gold recovery testwork. All core was scanned prior to testwork and assay, which collected digital imagery, geochemistry, and bulk density data. A comprehensive quality assurance and quality control system was implemented for the programme. This paper presents an overview of geometallurgical sampling and the development and implementation of the Beatons Creek testwork programme in support of a Pre-Feasibility Study. Full article

The extraction of minerals continues to face rising costs, but advancements in engineering and technology help reduce these costs, making efficiency improvement a critical goal for mining enterprises. The integration of additional technologies is one approach to achieving increased efficiency, though it presents challenges in accounting for the parameters of these technologies and determining their influencing factors. This paper proposes a methodical approach to developing performance indicators for mining enterprises under such conditions. Based on previous research, the mining enterprise is divided into subsystems, allowing for detailed analysis and the creation of indicators that represent the overall operations. Scientific studies on the definition and application of indicators in production enterprises are examined and adapted to mining enterprises, where the synthesis of multiple technologies is feasible. The paper introduces a methodology for determining integral performance indicators, which is tested through a case study using the “Heroiv Kosmosu” mine, applying both traditional longwall coal mining and coal seam well gasification technologies. This selection of technologies facilitates a detailed description of the necessary equipment, extraction methods, and organizational measures for safe operations. It also offers insights into the potential for scaling the analysis of multiple technologies operating simultaneously. The integration of a consistency coefficient in the model allows for more accurate final values of the indicators, reflecting their qualitative homogeneity. Full article

As intelligent mining develops, utilizing coal mine production monitoring data for early warnings has become a crucial means of ensuring safety in mining operations. Assisting decision-makers in making scientific choices through multi-source and massive data is a complex yet vital task. Based on multi-source information fusion, a model for the coal mine production environment is proposed in this paper. It is designed to provide early warnings regarding the safety status of coal production environments in order to assist management and control personnel in making scientific decisions. Firstly, data integration of multi-source heterogeneous datasets was conducted. Multi-source heterogeneous data collected by various types of monitoring sensors in coal mines were analyzed, including temperature, dust, wind speed, vibration energy, and gas. Based on this, the factors influencing coal mine production safety were identified. These factors were then screened through factor analysis to determine the index. An early warning index system for coal mine production environment safety was established. The index weight was established by the principal component analysis method, and the index system for coal mine production environment safety and early warning systems was established. Secondly, based on BP neural networks, a multi-input single-output feature-level fusion model and a multi-input multi-output feature-level fusion model were constructed. Based on the above model, the safety warning for coal mine production environments was implemented. The accuracy of model was 89.29%. Based on multi-source information fusion, the early warning system for coal mine production environments was constructed. The system exhibited good feasibility. It could assist management and control personnel in making scientific decisions. Full article

In order to solve the problem of insufficient design applicability in the field of lower limb rehabilitation, such as interaction, experience comfort, and modeling color, a biological excitation function system was used to guide the solution of the functional scheme of lower limb rehabilitation products, and the transformation of lower limb rehabilitation products in functional interaction, experience, and morphological color design driven by biological information-driven cross-domain mapping was improved. We used patent knowledge mining to study the product functional requirements of lower limb rehabilitation products. The results were used to screen the required biological prototypes, and the biological incentives were used to guide the design problems. According to the principle of analogy and similarity calculation, the similarity matrix was obtained, and then the strategy was analyzed. Through the analogy of functional system–product technology engineering systems, the engineering relationship between multi-biological and multi-design elements was determined. We realized the biological replacement and upgrading of product functions under biological stimulation to guide the design of lower limb rehabilitation products. The accurate quantitative biological information of multi-biological analogy fit has the significance of optimizing the training effect, improving the operation efficiency, and improving the morphology and modeling of the lower limb rehabilitation product engineering transformation and design. The acquisition rate of the functional design requirements of lower limb rehabilitation products based on text mining reached 95%, and the accuracy of the biological design prototype obtained through similarity calculation was higher than 79%, which verified the feasibility of the accurate bioinformatics design method and improved the rigor of the bioinformatics biomimetic design method. Full article

Deep well injection and storage is an emerging technology for realizing the low-cost treatment of extremely large quantities of three types of waste in coal mines in China, while simultaneously supporting coordinated development that considers its impact on the ecological environment. There has been significant progress in research on the geological storage of carbon dioxide in China. However, the geological storage of fluids such as mine water and high-salinity water needs to be studied further. Based on a comprehensive analysis of the lithology, mineral composition, physical and mechanical characteristics, and spatial structure of the Liujiagou and Shiqianfeng formations in a mining area in the Ordos Basin, we determined the geological storage space for fluids, predicted the storage potential, and evaluated the feasibility of deep geological storage of high-salinity water in coal mines. In the study area, the Liujiagou Formation is dominated by fine sandstone and siltstone, while the Shiqianfeng Formation is dominated by medium sandstone and conglomerate. The main storage space comprises micro-cracks, as well as intergranular, dissolution, and intergranular pores. Among these, the intergranular pores are the most conducive to reservoir development. The burial depth intervals of 1820–1835 m, 1905–1920 m, and 2082–2098 m are favorable for storage and are characterized by high porosities, permeabilities, and storage capacities. The effective storage capacity within a 100 m radius of the storage well was estimated to be 33.15 × 10⁴ m³. The effective storage capacity in the favorable area is 27.69 × 10⁴ m³, accounting for 83.50% of the total storage capacity. The Liujiagou and Shiqianfeng formations thus can serve as favorable reservoirs for deep well injection and storage of high-salinity water in the Ordos Basin. This research provides new ideas for the treatment of high-salinity water in coal mines in the Ordos Basin and technical support for deep well injection and the storage of high-salinity water. Full article

The reuse of by-products as alternative raw materials to traditional construction materials is required in order to ensure sustainable development in the construction sector and is a significant and important focus in the fields of materials science. This study developed geopolymers using by-products from mining, ceramics, and olive industries, including slate stone cutting sludge (SSCS) and chamotte (CH) as aluminosilicate sources, and olive biomass bottom ash (OSBA) as an alkaline activator with sodium silicate. A key novelty of the research lies in the use of SSCS, an underexplored by-product in geopolymerization studies, as a viable aluminosilicate source. The geopolymers were prepared with varying weight ratios of SSCS, CH, and OSBA/Na₂SiO₃ (1.7, 1.9, 2.2, and 2.4). Physical and mechanical tests determined the optimal formulation, while FTIR and SEM analyses revealed the material’s chemical and structural evolution. The FTIR analysis detected the quartz and carbonate phases, indicating incomplete quartz dissolution and carbonate formation during calcination. The SEM analysis revealed a dense microstructure with reduced porosity and enhanced geopolymerization in samples with higher OSBA content. The optimal geopolymer (60% OSBA, 30% CH, OSBA/Na₂SiO₃ ratio of 2.2) achieved a compressive strength of 33.1 MPa after 28 days. These findings demonstrate the feasibility of producing geopolymers using SSCS, CH, and OSBA, promoting the reuse of industrial by-products as sustainable alternatives to conventional binders. Full article