Exploring Dynamic Parameters And Tooth Structure Of Self-Propelled Borehole Repairing Drill Bits,
2024
State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China; State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization, Henan Polytechnic University, Jiaozuo 454000, China
Exploring Dynamic Parameters And Tooth Structure Of Self-Propelled Borehole Repairing Drill Bits, Liu Yong, Li Yang, Wei Jianping, Yuan Yongwang, Dai Shuo, Li Linyu
Coal Geology & Exploration
Self-propelled borehole repairing drill bits provide an effective technique for repairing long boreholes that have failed. In order to further improve the borehole repair speed and gas drainage efficiency, based on the theory of jet recoil, the relationship between the jet recoil force and nozzle parameters was analyzed, and a theoretical model was established for rotational mechanics of self-propelled borehole repairing drill bits. Subsequently, the coal-breaking processes of drill bits with different tooth structures were simulated using LS-DYNA, the failure modes in coal mass broken by cutting teeth and the rules of variation in the volume of coal broken by …
Prediction Of Mine Water Inflow Along Mining Faces Using The Ssa-Cg-Attention Multifactor Model,
2024
Hebei State Key Laboratory of Mine Disaster Prevention, North China Institute of Science and Technology, Beijing 101601, China
Prediction Of Mine Water Inflow Along Mining Faces Using The Ssa-Cg-Attention Multifactor Model, Ding Yingying, Yin Shangxian, Lian Huiqing, Liu Wei, Li Qixing, Qi Rongrong, Bu Changsen, Xia Xiangxue, Li Shuqian
Coal Geology & Exploration
Predicting mine water inflow plays an important role in ensuring mine safety, optimizing resource allocation, and improving work efficiency. This study aims to improve the accuracy and stability of the predicted mine water inflow. Given their strong correlations with water inflow, borehole water level and microseismic energy were chosen as multifactor characteristic variables. Using these variables, this study developed the SSA-CG-Attention multifactor prediction model for mine water inflow along mining faces. The new model extracted effective nonlinear local features of data utilizing a new network structure, which was formed by integrating a convolutional neural network (CNN) based on the time …
Intelligent Identification Method For Overburden Three Zones Of A Goaf,
2024
CCTEG Ecological Environment Technology Co., Ltd., Beijing 100013, China
Intelligent Identification Method For Overburden Three Zones Of A Goaf, Li Jianwen, Zhao Wen, Wu Zhenkun, Xu Xiaobing, Wang Qingtao, Duan Longchen
Coal Geology & Exploration
In this paper, an intelligent identification method was proposed to ascertain overlying strata failure types and fracture development in the overlying strata of a goaf, and identify three zones (sagging zone, fractured zone and caving zone) quickly and accurately. This method is expected to be a basis in later development of goaf treatment plans. A coal mine goaf in Shandong Province was introduced for case study, where the Bayesian Online Changepoint Detection (BOCD) algorithm was employed to analyze the changes and response characteristics of the drilling fluid loss and drilling rate over the drilling process at the boundaries of three …
Mechanism And Application Of Cross-Interface Fracturing For Permeability Enhancement Through The Roof Blasting Of Tectonic Coal Seams,
2024
School of Safety Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China; Scientific and Technological Research Platform for Disaster Prevention and Control of Deep Coal Mining, Anhui University of Science and Technology, Huainan 232001, China
Mechanism And Application Of Cross-Interface Fracturing For Permeability Enhancement Through The Roof Blasting Of Tectonic Coal Seams, Gao Kui, Wang Youwei, Qiao Guodong, Tian Yu, Fu Shigui
Coal Geology & Exploration
Deep coal mining is challenging due to deteriorating geological conditions. After undergoing multiphase tectonic movements, primary coals have evolved into soft tectonic coal seams with low permeability and high gas content, complicating drilling in coal seams. In this case, the blasting-induced fractures are not well-developed and are prone to be re-compacted. So far, no fundamental breakthrough has been achieved in the key technology of fracturing for permeability enhancement technology through the roof blasting of tectonic coal seams. Given this, this study established test models for similar simulation tests and numerical analysis on the roof blasting of coal seams. By monitoring …
Research On Tar-Rich Coals: Progress And Prospects,
2024
College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, Geological Research Institute for Coal Green Mining, Xi’an University of Science and Technology, Xi’an 710054, China
Research On Tar-Rich Coals: Progress And Prospects, Wang Shuangming, Bao Yuan, Hao Yonghui, Wang Shengquan, Shi Qingmin, Li Dan, Hu Yiliang
Coal Geology & Exploration
Tar-rich coals are a coal-based oil and gas resource that integrates the properties of coal, oil, and gas. Given China's energy endowment of abundant coal resources but limited oil and gas reserves, exploiting tar-rich coals plays a significant role in alleviating China's tight supply of oil and gas resources and achieving green development and low-carbon utilization of coals. Using tar-rich coals as the keyword, we searched the CNKI and Web of Science databases for academic articles and patents published from 1985 to the end of 2023. Based on the search results, we statistically analyzed the process and main aspects of …
Sulphate Contamination In An Abandoned Coal Mine In Light Of Mining Effects,
2024
School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China
Sulphate Contamination In An Abandoned Coal Mine In Light Of Mining Effects, Qi Yueming, Zhou Pei, Zhou Lai, Jiang Dan, Yang Yuqing, Liu Yanzhuo
Coal Geology & Exploration
Abandoned high-sulfur coal mines will become deeply buried acid-producing contamination sites, posing hazards to adjacent aquifers and surrounding environments. Furthermore, mining effects and the complex spatial distribution of abandoned mines complicate the assessment of the contamination processes and degrees in adjacent aquifers. Focusing on a certain abandoned coal mine, this study examined the migration characteristics of SO4 2− pollution in acid mine drainage using numerical simulations by taking sulfate (SO4 2−) as the characteristic contaminant and considering the effects of the fractures formed by the mining of multiple coal seams on the aquifer structure. Furthermore, it analyzed …
Exploring The Pore Structure Of Reconstructed Soils And Its Effects On Water And Salt Transport Based On Ct Scanning,
2024
Anhui Province Engineering Laboratory for Mine Ecological Remediation, Anhui University, Hefei 230601, China
Exploring The Pore Structure Of Reconstructed Soils And Its Effects On Water And Salt Transport Based On Ct Scanning, Li Huakun, Zheng Liugen, Chen Yongchun, Li Bing, Tao Pengfei, Li Hao
Coal Geology & Exploration
Coal gangue serves as a critical material for landfilling and reclamation in the subsidence areas of coal mines. However, due to its rough textures and poor water-holding capacity, soils reconstructed using coal gangue exhibit somewhat different pore structures and water-salt transport from undisturbed soils. To explore the changes in the pore structure of the reconstructed soils and their effects on water and salt transport, this study analyzed the differences in the pore structures between four samples from undisturbed soils, the overburden, mud-gangue mixtures, and gangue using CT scanning and image analysis. Furthermore, an indoor experimental device was designed to simulate …
Response Mechanism Characteristics Of Mining-Induced Fault Activation,
2024
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China; State Key Laboratory of Coal Mining and Clean Utilization, Beijing 100013, China; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
Response Mechanism Characteristics Of Mining-Induced Fault Activation, Sun Wenbin, Hao Jianbang, Dai Xianzheng, Kong Lingjun
Coal Geology & Exploration
In the process of coal mining, mining-induced stress perturbation is a key factor leading to fault activation, which is a primary challenge faced by safe coal mining. Fault activation is prone to induce geological disasters such as rock bursts and floor water inrushes of coal mines. Furthermore, it poses a serious threat to mining safety. Using the Flac3D software for numerical simulations and similar material simulation experiments, this study established a model for faults’ stress-displacement responses under coal mining to analyze the mechanisms behind the evolution of fault structure zones in the process of coal mining. Key findings are …
Laws Of Changes In The Energy Of Gas Hydrate-Bearing Coals Under Different Confining Pressures And Saturations,
2024
School of Safety Engineering, Heilongjiang University of Science and Technology, Harbin 150022, China
Laws Of Changes In The Energy Of Gas Hydrate-Bearing Coals Under Different Confining Pressures And Saturations, Zhu Wei, Gao Xia, Zhang Baoyong, Wu Qiang
Coal Geology & Exploration
Gas hydration for the solidification of coal seams susceptible to outbursts is a novel technology used to prevent coal and gas outbursts by reducing gas pressure and enhancing coal strength. However, an unclear understanding of the failure characteristics and the energy dissipation law of gas hydrate-bearing coals under different confining pressures and saturations leads to the lack of a theoretical basis for the prevention of dynamic disasters such as field coal and gas outbursts in deep mines. Based on the deviatoric stress-strain curves obtained using triaxial compression tests, this study calculated and analyzed the laws of changes in energy of …
Preliminarily Exploring The Theories And Technologies For Coalbed Methane Production Using Horizontal Wells: Comparison Of Conditions For Coalbed Methane And Shale Gas Exploitation,
2024
PetroChina National Institute of Excellence Engineers, Beijing 102200, China; PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China
Preliminarily Exploring The Theories And Technologies For Coalbed Methane Production Using Horizontal Wells: Comparison Of Conditions For Coalbed Methane And Shale Gas Exploitation, Wang Hongyan, Duan Yaoyao, Liu Honglin, Zhao Qun, Chen Shangbin, Lu Haibing, Shi Zhensheng, Sun Qinping, Chen Zhenhong, Zhou Shangwen, Yang Mingwei, Wang Cong
Coal Geology & Exploration
Through 30 years of unremitting explorations, coalbed methane (CBM) wells in China have gradually transitioned from vertical to horizontal wells. However, the lack of basic theories on CBM production using horizontal wells is the main challenge to current CBM development. Compared to shales, coal seams exhibit heterogeneity and a minor presence of foliations and brittle minerals, hindering the formation of volumetric fracture networks. Nevertheless, the roofs and floors of coal seams have high sealing capacities and mechanical strength, creating excellent conditions for hydraulic fracturing. Some fractures in coals are filled with calcite, rendering acidification conducive to the improvement of reservoir …
Accumulation Characteristics And Exploration Prospects Of Deep Coalbed Methane In The Longtan Formation Of The Nanchuan Block On The Southeastern Margin Of The Sichuan Basin,
2024
Exploration & Development Research Institute, East China Oil and Gas Company, SINOPEC, Nanjing 210011, China; Key Laboratory of Coalbed Methane, SINOPEC, Nanjing 210011, China
Accumulation Characteristics And Exploration Prospects Of Deep Coalbed Methane In The Longtan Formation Of The Nanchuan Block On The Southeastern Margin Of The Sichuan Basin, Guo Tao, Jin Xiaobo, Wu Didi, Xie Fei, Liu Jinxian
Coal Geology & Exploration
Vertical well Y2 in the Nanchuan bloc on the southeastern margin of the Sichuan Basin has yielded daily production of natural flowing gas of 13000 m3, signifying a strategic breakthrough in deep coalbed methane (CBM) exploration on the margin. This study aims to systematically reveal the enrichment and high-yield patterns of CBM in the Nanchuan block. Using data on the regional geology, tests, assays, and production, this study investigated the accumulation characteristic and conducted exploration potential evaluation for deep CBM in the Nanchuan block from the perspective of the quality, pore and fissure characteristics, gas content, and fracability …
Fracture Propagation Mechanism In Directional Perforation And Hydraulic Fracturing Of Coal Seam Horizontal Wells,
2024
China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China
Fracture Propagation Mechanism In Directional Perforation And Hydraulic Fracturing Of Coal Seam Horizontal Wells, Pang Tao, Jiang Zaibing, Hui Jiangtao, Jia Bingyi
Coal Geology & Exploration
Horizontal well perforation and fracturing in complex coal-bearing strata are key to increasing coal seam permeability and enhancing gas extraction efficiency, with the formation structure and perforation location determining fracture propagation. Considering the characteristics of formation structure and perforation locations, a fracturing geological model is established. Based on the finite element method, a numerical model is constructed to study the effects of perforation location, formation conditions, and the difference between vertical stress and horizontal stress on fracture perforation. Engineering verification is conducted, and construction suggestions are proposed. Key findings are as follows: There are three scenarios for the perforation locations: …
An Intelligent Water Source Discrimination Method For Water Inrushes From Coal Seam Roofs In The Inner Mongolia-Shaanxi Border Region,
2024
China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China; Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard, Xi’an 710077, China
An Intelligent Water Source Discrimination Method For Water Inrushes From Coal Seam Roofs In The Inner Mongolia-Shaanxi Border Region, Wang Hao, Sun Junqing, Zeng Yifan, Shang Hongbo, Wang Tiantian, Qiao Wei
Coal Geology & Exploration
Water hazard on the coal seam proof induced by high-intensity coal mining are increasingly prominent in the Inner Mongolia-Shaanxi border region. The effective, accurate water-source discrimination of the water inrushes is the key to water hazard prevention. This study investigated three typical mines in the Inner Mongolia-Shaanxi border region. To this end, principal component analysis (PCA) was employed to extract principal components from 80 groups of groundwater samples. Then, with inorganic indicators K++Na+, Ca2+, Mg2+, Cl−, SO4 2−, HCO3 − and TDS and organic indicators UV254 …
Experimental Study Of The Thermal Cracking Mechanism Of Limestones During Burning,
2024
School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China; Engineering Research Center of Zero-carbon and Negative-carbon Technology in Depth of Mining Areas, Ministry of Education (China University of Mining and Technology), Xuzhou 221116, China; Geothermal Resources Research Center, China University of Mining and Technology, Xuzhou 221116, China
Experimental Study Of The Thermal Cracking Mechanism Of Limestones During Burning, Zhang Weiqiang, Cao Zhicheng, Zhou Qizhong, Wang Zuoquan, Wu Yun
Coal Geology & Exploration
Spontaneous combustion of coal seams will cause different degrees of structural damage to surrounding rocks at different high temperatures, significantly altering their physical and mechanical properties and engineering geological effects. To delve into the structural evolution patterns of rocks during burning, this study investigated the limestones from the floor of a coal mine in Xuzhou. It conducted thermal cracking experiments under different temperatures, exploring the thermal cracking patterns of rocks on multiple scales. Furthermore, this study revealed the genetic mechanism of thermal cracking by combining numerical simulations and microstructure tests. Key findings are as follows: (1) The thermal cracking temperature …
Exploring The Detection Performance Of Different Array Configurations For Multi-Electrode Resistivity Method Tomography Using A 2.5d Finite Element Method,
2024
College of Earth Sciences, Guilin University of Technology, Guilin 541004, China
Exploring The Detection Performance Of Different Array Configurations For Multi-Electrode Resistivity Method Tomography Using A 2.5d Finite Element Method, Zhao Rongchun, Lyu Yuzeng, Zhang Zhi, Wei Liuye, Pan Hongxu
Coal Geology & Exploration
Multi-electrode resistivity method is equipped with various electrode array configurations. Due to their different electrode arrangements, various electrode array configurations tend to exhibit significantly varying detection effects under different survey environments. Hence, to achieve satisfactory detection effects using high-resolution electrical resistivity tomography, it is necessary to explore the strategy for choosing appropriate array configurations targeting different objects in practical work. Given the high applicability of the method, its forward and inversion calculations remain a critical task. Based on the differential equations to be satisfied by the point source potential in a three-dimensional structure, this study derived the variational problem to …
Three-Dimensional Forward Modeling Using The Transient Electromagnetic Method Under Complex Terrains And The Analysis Of Terrain Effects,
2024
School of Mines, China University of Mining and Technology, Suzhou 221116, China; Shanxi Ningwu Yushupo Coal Industry Co., Ltd., Xinzhou 036700, China
Three-Dimensional Forward Modeling Using The Transient Electromagnetic Method Under Complex Terrains And The Analysis Of Terrain Effects, Qu Shaobo, Zhu Jiao, Jiang Zhihai, Li Maofei, He Zhilong
Coal Geology & Exploration
The ground-based transient electromagnetic method (TEM), with unique advantages, has been extensively applied for hydrogeological exploration in coal mines. However, in field exploration, complex terrains tend to cause variations in geometric shapes of transmitting sources and deviations in signals received, reducing exploration accuracy. Hence, by integrating theoretical analysis and numerical simulations with the analysis of actual terrain data, this study systematically investigated the response characteristics of electrical- and magnetic-source TEM fields under complex terrains. Using the vector finite-element electromagnetic forward modeling technique based on second-order backward Euler discretization, this study delved into the laws of influence of peak and valley …
Research On Path Planning Methods For Underground Roadheader Robots,
2024
College of Mechanical Engineering, Xi’an University of Science and Technology, Xi’an 710054, China; Shaanxi Key Laboratoty of Mine Electromechanical Equipment Intelligent Monitoring, Xi’an 710054, China
Research On Path Planning Methods For Underground Roadheader Robots, Zhang Xuhui, Zheng Xili, Yang Wenjuan, Li Yuyang, Ma Bing, Dong Zheng, Chen Xin
Coal Geology & Exploration
In order to solve the problems of difficulty and low efficiency in the movement of robotic roadheaders under conditions of non-full-section roadways in coal mines, the characteristics of unstructured environments in coal mines and the motion characteristics of robotic roadheaders were analyzed, and a path planning method for robotic roadheaders based on deep reinforcement learning was proposed. The tunnel environment was constructed in real time using depth cameras, a virtual model for detecting roadheader-tunnel collisions was established, collision detection was performed in a virtual environment using the hierarchical bounding box method, and an obstacle avoidance strategy under the restrictions of …
Edge Detection Of Low Illumination Image In Cutting Unit Of Shearer,
2024
School of Computer Science and Technology, Xi’an University of Science and Technology, Xi’an 710054, China
Edge Detection Of Low Illumination Image In Cutting Unit Of Shearer, Jia Pengtao, Jin Luwei, Wang Bin, Guo Fengjing, Li Na
Coal Geology & Exploration
In this paper, a fractional differentiation-based edge detection algorithm named Lif is proposed to address the edge detection problems of missing edge and fuzzy details in the cutting unit of shearers working in low-light underground environments. First, the initial fractional mask operator was built using a larger detection template according to the Grünwald-Letnikov definition of the fractional derivative. Then, the weight coefficients at various positions of the mask operator were determined according to the theory of Pascal’s triangle, and the mask operator was extended to four different directions. Finally, the mask operator was convolved with the image, and the local …
Environmental Health Impacts Of Small-Scale Gold Mining In East Indonesia: Mercury Pollution And Nature Conservation,
2024
Universitas Indonesia, School of Environmental Science, Indonesia
Environmental Health Impacts Of Small-Scale Gold Mining In East Indonesia: Mercury Pollution And Nature Conservation, Tri Edhi Budhi Soesilo, Nada Ismita Hawa, Nuraeni Nuraeni
Journal of Sustainable Mining
The expansion of small-scale gold mining impacts environmental health and socioeconomic. Research in Bombana District, one of the gold mining centers in eastern Indonesia, was conducted to explore perceptions of the impact of small-scale gold mining on human health and attitudes towards environmental conservation activities related to small-scale gold mining activities. This research uses a quantitative approach with univariate tests to identify respondent characteristics, bivariate tests (Chi-square) to test relationships and frequency differences, and multivariate analysis (regression) to test the direction and magnitude of the relationship. The perception of the impact of small-scale gold mining on human health was not …
Critical Raw Material In Mineral Elements Found In Fly Ashes From The Czech Republic Power Plant,
2024
Central Mining Institute – National Research Institute, Department of Environmental Monitoring, Poland
Critical Raw Material In Mineral Elements Found In Fly Ashes From The Czech Republic Power Plant, Agnieszka Klupa
Journal of Sustainable Mining
The economic development of EU countries is limited due to limited access to a number of mineral raw materials, which necessitates actions aimed at securing the supply of CRM. For this reason, CRMs constitute elements of particular importance for the EU. The aim of the study was to assess the content of CRMs as a potential source of REY in fly ash resulting from the coal combustion in one of the power plants in the Czech Republic. In the tested ash the main phases are: glassy phase, mullite and quartz. The chemical composition of the tested fly ashes showed dominance …
