Benfeng Zhang, Kang Yang, Kai Zhang, Qibao Wang, Nianqing Wu
{"title":"Migration transformation, prevention, and control of typical heavy metal lead in coal gangue: a review","authors":"Benfeng Zhang, Kang Yang, Kai Zhang, Qibao Wang, Nianqing Wu","doi":"10.1007/s40789-023-00656-8","DOIUrl":"https://doi.org/10.1007/s40789-023-00656-8","url":null,"abstract":"<p>Coal gangue is one of China’s main industrial solid wastes, which contains various harmful heavy metal elements, such as lead (Pb). The long-term accumulation of coal gangue causes Pb to migrate to the surrounding environment due to weathering and rain erosion, eventually endangering human life and health with its continuous accumulation in the food chain. This review discusses the migration and transformation process of Pb in coal gangue under different conditions and summarizes the available forms and mechanisms of Pb in coal gangue. The current prevention and control and comprehensive utilization methods of Pb in coal gangue are comprehensively reviewed, and the characteristics of each method are discussed. In order to realize the economical, efficient, and high resource utilization of coal gangue, this paper provides favorable suggestions and support for subsequent in-depth research and the implementation of heavy metal prevention and control measures.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138560681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jin Luo, Yingming Li, Xiangrui Meng, Qingbiao Guo, Guangming Zhao
{"title":"Influence of coupling mechanism of loose layer and fault on multi-physical fields in mining areas","authors":"Jin Luo, Yingming Li, Xiangrui Meng, Qingbiao Guo, Guangming Zhao","doi":"10.1007/s40789-023-00640-2","DOIUrl":"https://doi.org/10.1007/s40789-023-00640-2","url":null,"abstract":"<p>Coal mining under the geological conditions of a loose layer will lead to the intensification of surface movement and deformation, and mining under the geological conditions of a fault will lead to the living slip of a fault. Mining under both conditions will have a great impact on the safety of coal production. To reveal the evolution law of the coupling mechanism of loose layer and fault on the multi-physical fields of overburden, the numerical simulation method is used to simulate the coupling of loose layer and fault with different thicknesses, analyze the changes of vertical stress on the key strata, the changes of surface subsidence, the evolution of elastic energy on the fault zone and the changes of activated slip area of the fault zone. The simulation analysis shows that the vertical stress change trend of the key strata gradually changes from the \"V\" shape to the \"W\" shape at the beginning of mining, and the vertical stress concentration will occur at the fault. The loose layer will promote surface subsidence, and the fault will hinder the surface subsidence to a certain extent. The loose layer and the fault alternately affect the surface subsidence. The elastic energy accumulation on the key strata is mainly concentrated on both sides of the goaf. The elastic energy in the center of the goaf is dissipated. The elastic energy accumulation in the fault zone starts from the shallowly buried fault and gradually develops to the deeply buried fault. The instability of fault activation has gone through the initial stage of activation—the intensification stage of activation—the stable stage of activation. Under the working conditions of no loose layer, thin loose layer, and thick loose layer, the fault zone is the first to undergo living slip, and under the action of an extra-thick loose layer, there is a certain lag in the activation slip of the fault zone.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138560541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JiangJiang Yin, Jiangyang Lei, Kaixin Fan, Shaofeng Wang
{"title":"Integrating image processing and deep learning for effective analysis and classification of dust pollution in mining processes","authors":"JiangJiang Yin, Jiangyang Lei, Kaixin Fan, Shaofeng Wang","doi":"10.1007/s40789-023-00653-x","DOIUrl":"https://doi.org/10.1007/s40789-023-00653-x","url":null,"abstract":"<p>A comprehensive evaluation method is proposed to analyze dust pollution generated in the production process of mines. The method employs an optimized image-processing and deep learning framework to characterize the gray and fractal features in dust images. The research reveals both linear and logarithmic correlations between the gray features, fractal dimension, and dust mass, while employing Chauvenel criteria and arithmetic averaging to minimize data discreteness. An integrated hazardous index is developed, including a logarithmic correlation between the index and dust mass, and a four-category dataset is subsequently prepared for the deep learning framework. Based on the range of the hazardous index, the dust images are divided into four categories. Subsequently, a dust risk classification system is established using the deep learning model, which exhibits a high degree of performance after the training process. Notably, the model achieves a testing accuracy of 95.3%, indicating its effectiveness in classifying different levels of dust pollution, and the precision, recall, and F1-score of the system confirm its reliability in analyzing dust pollution. Overall, the proposed method provides a reliable and efficient way to monitor and analyze dust pollution in mines.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138580217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical modelling of gas outburst from coal: a review from control parameters to the initiation process","authors":"Fatemeh Soleimani, Guangyao Si, Hamid Roshan, Jian Zhang","doi":"10.1007/s40789-023-00657-7","DOIUrl":"https://doi.org/10.1007/s40789-023-00657-7","url":null,"abstract":"<p>Among all methods for investigating the complex phenomenon of the coal and gas outburst, numerical modelling is the most comprehensive one that can consider all involved parameters and simulate the complex multi-physical phenomenon. The main aim of this paper is to review recent numerical modelling studies concerning this disastrous phenomenon observed in coal mining. The paper aims to analyse these studies comprehensively and identify any existing research gaps that could be addressed in future research endeavours. To this end, the concepts and equations that have been used in previous studies to simulate the solid and fluid behaviour during outburst initiation and how these equations are coupled to consider multiphysical interactions were reviewed. Both strengths and deficiencies in past outburst modelling work were highlighted. Finally, potential research topics for future studies were discussed in three categories; looking into the outburst phenomenon in the scale of the particles which is mostly focused on the discrete element method, conservation of the energy as a method to quantitively assess outburst initiation, and the application of statistics in both applying the heterogeneity in the models and assessing the possibility of the outburst occurrence.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mechanism and key parameters of stress load-off by innovative asymmetric hole-constructing on the two sides of deep roadway","authors":"Dongdong Chen, Zaisheng Jiang, Shengrong Xie","doi":"10.1007/s40789-023-00635-z","DOIUrl":"https://doi.org/10.1007/s40789-023-00635-z","url":null,"abstract":"<p>Traditional dense large-diameter borehole stress load-off techniques reduce the stress levels in the shallow surrounding rock, weaken the bearing capacity of the shallow surrounding rock, and greatly deteriorate the shallow surrounding rock strength and supporting structure, which is not conducive to maintaining the long-term stability of the roadway. Therefore, to address the control problem for the pronounced extrusion deformation in the two sides of a roadway and the overall outward movement of the shallow surrounding rock supported by the sides bolts and anchor cables, as well as to comprehensively consider the on-site construction conditions of the two sides of a test roadway, stress load-off technology for asymmetric hole construction on the two sides of a roadway is proposed. The asymmetric stress load-off technique is a new method; while the shallow surrounding rock of the roadway sides is strongly anchored via a full anchor cable support form, a group of large stress load-off holes near the deep stress peak line of the roadway sides is excavated to relieve pressure and protect the roadway. This technology can transfer the peak stress area of the roadway side deeper into f the surrounding rock without deteriorating the shallow surrounding rock strength and damaging the supporting structure. A numerical simulation analysis of asymmetric stress load-off on the two sides of the roadway was performed, the stress load-off effect evaluation index was established, and the optimal field construction parameters were obtained. The stress load-off parameters obtained from the study are applicable to field engineering practice. Mine pressure data reveal that the test roadway remains intact and stable during the use period when the asymmetric stress load-off technique is adopted.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yongjun Zhang, Meng Xu, Sijia Liu, Fei Liu, Qingsong Wang
{"title":"Rate-dependent constitutive modelling blasting crack initiation and propagation in rock masses","authors":"Yongjun Zhang, Meng Xu, Sijia Liu, Fei Liu, Qingsong Wang","doi":"10.1007/s40789-023-00633-1","DOIUrl":"https://doi.org/10.1007/s40789-023-00633-1","url":null,"abstract":"<p>This study examines the fracture mechanism of cracks and the final blasting effects on defective rock masses under blasting loads. The failure processes of jointed rock with two prefabricated joints are investigated through numerical simulations using a two-dimensional finite element method. Subsequently, simulations are performed to analyze the blasting of granite specimens with various joint arrangements, focusing on the influence of front joint length, inclination angle, and blast hole distance on failure patterns, displacement, velocity, and stress at the joint ends. The numerical results provide a comprehensive summary of various typical failure modes near blast holes and joints for the first time. Specifically, the simulation successfully captures the characteristics of the ring crack zone, wing cracks, and main crack deflection affected by the front joint. Moreover, the results highlight the shielding effect of the front joint, which enhances damage in the medium between the borehole and the joint while exhibiting the opposite effect behind the joint in terms of stress wave propagation. Overall, this study offers objective insights into the mechanics and failure characteristics of jointed rock masses under blasting loads and serves as a valuable reference for the design and optimization of blasting operations.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Longyong Shu, Yankun Ma, Zhengshuai Liu, Hongyan Li
{"title":"Study and application of a continuous inversion model of coal seam gas pressure in front area of heading face","authors":"Longyong Shu, Yankun Ma, Zhengshuai Liu, Hongyan Li","doi":"10.1007/s40789-023-00646-w","DOIUrl":"https://doi.org/10.1007/s40789-023-00646-w","url":null,"abstract":"<p>The gas pressure in front area of heading face is essential to dynamically evaluate coal and gas outburst during coal mining. In this work, a novel inversion model of gas pressure in front area of the heading face was established on premise of the hypothesis that a time-dependent zone of steady flow exists within newly exposed face. The key parameters in the inversion model were obtained based on the gas emission models and field data of gas emission rate in different times, which were used to calculate the volumes of gas emission from different sources. The results show that the percentage of gas emission from the heading face, coal wall and collapsed coal ranges from 7% to 47%, 47% to 82% and 2% to 11%, respectively. Based on the calculated volumes of gas emission and gas pressure inversion model, the gas pressure was obtained and transformed to the gas content. The absolute errors between the gas content tested and transformed in every hour is 0.4%–33%, which proved the rationality of gas pressure inversion model. Furthermore, the daily drifting footage, the radius of gas pressure boundary and the gas permeability coefficient of coal seam were confirmed to have a great effect on the result of gas pressure inversion. The inversion results verify that the speedy excavation can increase the risk of coal and gas outburst. This work produces a useful method for gas disaster prevention and control that converts the gas emission rate to an index of gas pressure within coal seam.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparative study on the flame retardancy of CO2 and N2 during coal adiabatic oxidation process","authors":"Xiyang Fang, Bo Tan, Haiyan Wang","doi":"10.1007/s40789-023-00652-y","DOIUrl":"https://doi.org/10.1007/s40789-023-00652-y","url":null,"abstract":"<p>To test the effectiveness of N<sub>2</sub> and CO<sub>2</sub> in preventing coal from spontaneously combusting, researchers used an adiabatic oxidation apparatus to conduct an experiment with different temperature starting points. Non-adsorbed helium (He) was used as a reference gas, and coal and oxygen concentration temperature variations were analyzed after inerting. The results showed that He had the best cooling effect, N<sub>2</sub> was second, and CO<sub>2</sub> was the worst. At 70℃ and 110℃, the impact of different gases on reducing oxygen concentration and the cooling effect was the same. However, at the starting temperature of 150℃, CO<sub>2</sub> was less effective in lowering oxygen concentration at the later stage than He and N<sub>2</sub>. N<sub>2</sub> and CO<sub>2</sub> can prolong the flame retardation time of inert gas and reduce oxygen displacement with an initial temperature increase. When the starting temperature is the same, N<sub>2</sub> injection cools coal samples and replaces oxygen more effectively than CO<sub>2</sub> injection. The flame retardancy of inert gas is the combined result of the cooling effect of inert gas and the replacement of oxygen. These findings are essential for using inert flame retardant technology in the goaf.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Water–rock two-phase flow model for water inrush and instability of fault rocks during mine tunnelling","authors":"Dan Ma, Hongyu Duan, Qiang Li, Jiangyu Wu, Wen Zhong, Zhen Huang","doi":"10.1007/s40789-023-00612-6","DOIUrl":"https://doi.org/10.1007/s40789-023-00612-6","url":null,"abstract":"<p>Water inrush hazard is one of the major threats in mining tunnel construction. Rock particle migration in the seepage process is the main cause of water inrush pathway and rock instability. In this paper, a radial water–rock mixture flow model is established to study the evolution laws of water inrush and rock instability. The reliability of the proposed model is verified by the experimental data from a previous study. Through the mixture flow model, temporal-spatial evolution laws of different hydraulic and mechanical properties are analysed. And the proposed model’s applicability and limitations are discussed by comparing it with the existing water inrush model. The result shows that this model has high accuracy both in temporal evolution and spatial distribution. The accuracy of the model is related to the fluctuation caused by particle migration and the deviation of the set value. During the seepage, the porosity, permeability, volume discharge rate and volume concentration of the fluidized particle increase rapidly due to the particle migration, and this phenomenon is significant near the fluid outlet. As the seepage progresses, the volume concentration at the outlet decreases rapidly after reaching the peak, which leads to a decrease in the growth rate of permeability and porosity, and finally a stable seepage state can be maintained. In addition, the pore pressure is not fixed during radial particle migration and decreases with particle migration. Under the effect of particle migration, the downward radial displacement and decrease in effective radial stress are observed. In addition, both cohesion and shear stress of the rock material decreased, and the rock instability eventually occurred at the outlet.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":null,"pages":null},"PeriodicalIF":8.3,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}