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Technologies For Controlling Water Inrushes From Coal Seam Floors Under Flowing Water And Their Water Plugging Performance, Yang Zhibin

Coal Geology & Exploration

Objective Limestone water hazards in coal seam floors represent one of the two primary categories of mine water hazards in China. Limestone aquifers are generally characterized by abundant static water reserves and considerable dynamic water recharge. To reduce economic losses and casualties caused by water inrushes from limestone aquifers, post-disaster emergency rescue through grouting for water plugging is frequently carried out under flowing water.Methods Based on numerous cases of water inrush control under flowing water in China and the fundamental requirements for control scheme design, this study presents a systematic review of existing technologies for water inrush control under …

Joint Inversion For Heat Transfer Parameters Of Porous Media With Geothermal-Seepage Coupling Based On A Physics-Informed Neural Network, Zhang Xiao, Yang Duoxing, Cong Lin, Cheng Yimei, Zhang Lianzhong

Coal Geology & Exploration

Background The thermal diffusivity and vertical seepage velocity of porous media are critical to characterizing the mechanisms underlying subsurface heat transfer. These two parameters are typically determined through inversion using temperature data since they are difficult to measure directly. Fiber-optic distributed temperature sensing (FO-DTS) can yield high-resolution, continuous temperature profiles, providing data for parameter identification. However, conventional numerical inversion suffers from limitations such as mesh dependency and sensitivity to initial values when used to process continuous monitoring data. Methods This study proposed a joint geothermal parameter inversion method that integrates FO-DTS data with a physics-informed neural network (PINN). Specifically, the …

Joint Inversion Of Borehole-Surface Direct-Current Resistivity Data, Xu Kaijun, Jin Heran, Cao Danping, Mou Bin, Hu Zuzhi

Coal Geology & Exploration

Objective The conventional inversion of surface direct-current (DC) resistivity data faces challenges such as limited exploration accuracy and depth. This study aims to enhance the accuracy and reliability of exploration in complex engineering and geological settings through the joint inversion of borehole-surface DC resistivity data. Methods First, different geoelectric models were constructed through three-dimensional (3D) forward modeling of full-space DC resistivity. Then, the potential response characteristics under surface and borehole observation methods were systematically analyzed to determine the differences in detection sensitivity between surface and borehole observations. Accordingly, a joint 3D inversion technique for borehole-surface DC resistivity data was developed …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Optical Mechanisms Behind Vitrinite Reflectance Suppression Caused By Strong Anisotropy: A Case Study Of Contact Metamorphic Coals, An Yanfei, He Shuyang, Chen Kaixin, Gao Junhan

Coal Geology & Exploration

Objective For vitrinite with weak anisotropy, which proves uniaxial and optically negative, replacing random vitrinite reflectance (R_ran) with the maximum vitrinite reflectance (R_max) allows for the accurate correction of vitrinite reflectance suppression induced by anisotropy. However, as its anisotropy intensifies, vitrinite exhibits increasingly complex optical properties, rendering it challenging to reflect the thermal metamorphic temperature of vitrinite using R_max. Methods This study investigated the strongly anisotropic vitrinite in coals and natural coke subjected to magma intrusion in the Shitai coal mine, Huaibei City, Anhui Province. Using a reflected-polarized light microscope (R-PLM), an …

Machine Learning-Based Prediction And Experimental Validation Of The Pyrolysis Product Distribution In Tar-Rich Coals, Dong Shuai, Li Hongqiang, Wu Zhiqiang, Yu Zunyi, Lyu Zitao, Guo Wei, Yang Panxi, Fu Keming, Hao Xuanzhi, Liu Gen, Yang Bolun

Coal Geology & Exploration

Background Tar-rich coals serve as an important coal-based oil and gas resource in China, while their pyrolysis product distribution is governed by the coupling effects of coal properties and reaction conditions. Therefore, rapidly identifying the pyrolysis product distribution patterns holds great significance for the resource evaluation and experimental design of tar-rich coals.Methods Existing studies on tar-rich coals suffer from the insufficient integration of exclusive data and limited synergistic prediction capacities for multiple products. To address these issues, this study constructed a dedicated dataset involving proximate analysis, ultimate analysis, elemental molar ratios, maceral composition, and pyrolysis conditions by systematically collecting …

Parameter Optimization And Field Application Of Roof Volume Fracturing Using Horizontal Wells For Coalbed Methane Extraction From Broken-Soft Coal Seams, Zhang Qingli, Sun Siqing, Li Haozhe, Wu Xiaoxuan, Yang Fan, Zheng Yuqi, Li Wenbo

Coal Geology & Exploration

Objective and Method To achieve rapid coalbed methane (CBM) extraction from broken-soft coal seams using surface horizontal wells, this study proposed a volume fracturing technology for coal seam roof using horizontal wells. Focusing coal seam 4-1 in a mining area, this study established a numerical model using finite element analysis (FEA) software Abaqus Using this model, the impacts of in-situ stress on the cross-layer propagation characteristics of multiple fractures were investigated. Through true triaxial hydraulic fracturing experiments, the multi-fracture propagation patterns under varying injection rates of fracturing fluids, perforation cluster numbers, and cluster spacings were analyzed. Using 3D fracturing design …

Evaluation And Research Progress Of Co2 Sequestration In Deep Coal Seams, Xiong Yucan, Xu Shi’Ang, Zhang Pingsong, Lu Haifeng, Jia Yunzhong, Ge Binbin, Li Baiqiang, Liu Chang, Lei Jian, Fu Wenyu

Coal Geology & Exploration

Background With increasing pressure for global carbon emission reduction, geologic CO₂ sequestration has emerged as a critical technical approach to achieving the goals of peak carbon dioxide emissions and carbon neutrality. Owing to their high CO₂ adsorption capacity and favorable sealing conditions, deep coal seams are considered one of the most promising media for CO₂ sequestration, following saline aquifers and depleted hydrocarbon reservoirs. Therefore, the exploitation and utilization of deep coal seams hold significant strategic importance for the green, low-carbon transformation of the coal industry. Methods Based on literature analysis and a review of outcomes from cutting-edge …

Dynamic Prediction On Goaf Surface Subsidence For The Last Two Periods Based On The Erf Time Function, Ren Lianwei, Li Shihui, Wang Wenchang, Li Zhenhua, Chen Shaojie, Dun Zhilin

Coal Geology & Exploration

Background The surface subsidence induced by coal seam mining represents a continuous dynamic evolution process. Constructing a full-time perdition model for surface subsidence in goafs holds significant theoretical and practical values for the rational utilization of land resources, the safety guarantee of engineering construction, and the transformation and development of resource-based cities. Methods To accurately predict the surface subsidence in goafs during its decline and residual periods, this study proposed a prediction model based on the error function (Erf). First, the evolution characteristics of Erf were analyzed, verifying that the subsidence, as well as its velocity and acceleration, predicted using …

Exploring Water Migration Patterns In Reconstructed Soil Layers For Waste Dumps Of Open-Pit Coal Mines Based On Ct Scanning, Fan Tingyu, Zhang Xinghui, Lu Akang, Yang Changde, Wang Shun, Wang Xingming, Sun Xueliang, Ji Quancai

Coal Geology & Exploration

Objective In the arid regions of western China, the ecological restoration of waste dumps within open-pit coal mines plays a key role in green mine construction, while creating a suitable soil profile structure serves as a prerequisite for the ecological restoration.Methods This study investigated the reconstructed soils with a three-layer sponge-like structure consisting of the topsoil, sandy-soil, and mudstone layers for the waste dump of the Hongshaquan open-pit coal mine in Xinjiang. Using computed tomography (CT) scanning, a three-dimensional (3D) pore network model (PNM), and water migration simulation, this study systematically analyzed the pore structures and water migration characteristics …

Performance Optimization Of Superfine Cement Through Composite Modification Using Coal-Based Solid Waste And Modifiers, Kang Zhipeng, Luo Yong, Xiao Diancai, Ren Shuai, Cai Zhiliang, Gao Xiang, Zhang Kunzhe

Coal Geology & Exploration

Objective Superfine cement-based grouting materials generally suffer from limitations including high bleeding rates, unfavourable rheological properties, poor stability, and strength retrogression. These issues can be mitigated by incorporating modifiers, which allows for the reutilization of coal-based solid waste while enhancing the performance of composite, superfine cement-based grouting materials. Methods Superfine cement-based grouting materials with different mixing ratios were prepared by using superfine cement as the basic material, fly ash (FA) and mineral fines (MFs) as primary admixtures, and modified bentonite, methyl cellulose ether (MCE), U-type expansive agent (UEA), and magnesium oxide (MgO) as modifiers. These grouting materials and pure superfine …

Mine Data Fusion Technology Based On Multi-Feature Joint Decision Making, Han Shanshan, Zhang Jifeng, Fan Tao, Liu Qiang, Song Xiaojiao, Qi Zhipeng, Zheng Hangzhou

Coal Geology & Exploration

Background In the field of geological exploration of coal mines, methods such as in-seam seismic exploration, the transient electromagnetic method, and audio-frequency electrical penetration offer unique technical advantages. However, each of these methods can only reflect a single physical property of a medium, suffering from limitations including the one-sidedness of information and the multiple solutions of interpretations, thus failing to adapt to the new situations of current coal mine exploration. Multi-source data fusion promotes a technological development by leaps from one-sided detection to comprehensive analysis through mechanisms of information complementation, feature enhancement, and field-source integration. Therefore, this technology can enhance …

Oil-Based Mud Electrical Imaging Logging Responses Of Carbonate Strata, Wu Yuyu, Lai Qiang, Pan Feng, Zhao Zuo’An, Wang Xiaoxing, Wang Yue, Cheng Lu, Wang Zeyu, Yin Rong

Coal Geology & Exploration

Objectives This study aims to characterize the oil-based mud (OBM) electrical imaging logging responses of carbonate strata, highlighting the response characteristics of dissolution vugs, fractures, stratigraphical structures, and special minerals. Methods Tests were conducted on logging data acquisition of a drilled well within the Dengying Formation in the Sichuan Basin before and after OBM was replaced with water-based mud (WBM). Based on the fine-scale core-to-log (CTL) calibration, this study compared the WBM and OBM electrical imaging logging responses of different geological and pore structures. Furthermore, the characteristics of OBM electrical imaging logging responses were further discussed from the measurement principles …

A Cutting Trajectory Planning Technology Driven By Coal Seam Data In A Comprehensive Mining Face, Guo Yifeng, Xue Xusheng, Ma Hongwei, Zhang Guangming, Su Hao, Qi Ailing, Nie Zhen, Ma Kexiang, Wu Xuefei

Coal Geology & Exploration

Objective Currently, the insufficient full-element digitization and the prevalence of “data silos” in fully mechanized mining faces (FMMF) result in poor cutting precision and operational instability of shearers under complex undulating and abrupt geological conditions. These factors pose significant challenges to high-precision proactive trajectory planning. Methods Guided by the academic philosophy that “mining is data acquisition”, this paper proposes a coal seam data-driven cutting trajectory planning method for FMMFs. It elaborates on three core technologies: high-precision digital coal seam modeling, generative model updating and digital twin construction, and data-driven trajectory planning.To address low modeling precision, an intelligent interpolation-based digital coal …

Image Processing Technique To Find The Burden Rock Velocity And Its Interdependency On Bench Blasting Parameters – A Case Study, Channabassamma N, Akhil Avchar, Sahas V Swamy, Vedala Rama Sastry, Hemant Agrawale

Journal of Sustainable Mining

In any rock engineering or excavation project, optimizing blast design is essential for controlling post-blast phenomena such as flyrock, burden throw, and burden rock velocity (BRV). This study investigates the dynamic response of BRV in bench blasting operations by employing a high-speed camera and ProAnalyst software to quantify rock displacement. The relationships between BRV and key blast parameters, number of holes (NH), explosive charge per hole (EPH), total explosive charge (TEC), stiffness ratio (K), and stemming ratio (STR), were analyzed to identify linear or non-linear trends. Non-linear trends, …

Analysis And Study Of Telemetry Systems For Directional And Horizontal Well Drilling, Jahongir Abdiganiyev Erkin Ugli, Sherali Halloqovich Umedov

Technical science and innovation

The article discusses the issues of reducing non-productive drilling time during the construction of directional and horizontal wells. The main focus is on the analysis of drilling conditions in complex geological and high-temperature environments. Particular attention is paid to drilling conditions in the territory of the Republic of Uzbekistan, with a specific study of data from the Boysun and Ustyurt regions. An analysis and study of the performance of telemetry systems available on the market, as well as their main technical characteristics, have been conducted. Key factors affecting the accuracy of wellbore trajectory measurements under various geological and technical conditions …

A Method To Accelerate Rock Breakage With Soundless Chemical Demolition Agents, Patrick A. Darko, Hani S. Mitri

Journal of Sustainable Mining

Soundless chemical demolition agents (SCDA) are recognized as a safe and sustainable alternative for rock breakage, with the potential to reduce reliance on explosives in mining. However, their mechanical performance is considerably hampered in the extreme cold climate, with slow or no rock fracturing observed. To overcome this deficiency, two methods were developed in recent studies by 1) electric heating the SCDA borehole with high-temperature wire, and 2) increasing the SCDA mixing water temperature. Good results were obtained with both methods. This paper explores the merits of a hybrid approach combining the two methods to further enhance the SCDA efficiency …

Research Status And Development Trend Of Acidification And Permeability Improvement Technology For Low-Permeability Coal Seam, Shaochuan Chen, Yun Lei, Fuchao Tian, Jie Kang

Journal of Sustainable Mining

Low-permeability coal seams in China are often characterized by mineral-clogged pore-fracture systems, severely limiting coalbed methane (CBM) extraction efficiency. Acidification technology, which involves injecting acidic solutions into coal seams to dissolve minerals and enhance permeability, has emerged as a promising approach. This paper systematically reviews the mechanisms, laboratory findings, and field applications of acidification technology for permeability enhancement in low-permeability coal seams. Key findings include significant improvements in pore connectivity, reductions in gas adsorption capacity, and enhanced gas extraction rates post-acidification. Field tests demonstrate that acid fracturing can increase gas extraction volume by 4-7 times. The study also identifies current …

Improving Energy Reliability In Mining Areas Through Modelling And Control Of Resonance Phenomena In Solar-Integrated Power Systems, Yurii Papaika, Gennadiy Pivnyak, Maksim Malyshko, Yuliya Pazynich, Natalia Howaniec, Adam Smolinski

Journal of Sustainable Mining

This study addresses the emergency and operational transient processes that arise when integrating large-scale solar power plants (SPPs) into electrical load nodes, particularly under conditions of limited power system capacity. With the increasing penetration of distributed generation in Ukraine's energy landscape, challenges related to electromagnetic compatibility and harmonic resonance are becoming more prominent. The research builds upon the foundational work of leading Ukrainian scientific schools and focuses on the specific resonance phenomena observed during the operation of solar inverters in medium-voltage networks, especially in regions with high industrial and mining Energy demand. A novel algorithm is proposed for determining the …

Feasibility Study Of Barite Sourcing From Sediments Emerging Due To Treatment Of Waste Water From Coal Mining, Hubert Makuła, Zbigniew Bzowski, Bogusław Michalik

Journal of Sustainable Mining

The accumulation of mine water in settling ponds, which is discharged due to coal mining, allows them to be cleaned out of suspension, and it is the reason for the accumulation of hundreds of thousands of tons of sediments. One interesting mineral enclosed in these sediments is barite, which is considered in the EU as a critical raw material, but it also contains radium originating from formation water.

The effective barite separation and its beneficiation could constitute a win-win solution because then it would be possible to obtain the valuable radium concentrate for further processing, e.g., in nuclear medicine, and …

Wettability Evaluation Via Contact Angle And Data Mining For Enhanced Oil Recovery, Syasya Wadihah Md. Ja’Afar, Bashir Busahmin

Journal of Sustainable Mining

The oil industry has used many enhanced oil recovery (EOR) strategies to increase crude oil production from reservoirs, particularly as production begins to fall. With a significant quantity of hydrocarbon reserves still existing in the reservoirs, improved oil recovery techniques have the potential to increase oil production, with wettability alteration playing a significant role. To date, there has been no comprehensive investigation of wettability in Brunei's sandstone reservoir. The goal of this research is to determine wettability by contact angle measurement and data mining approaches based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) algorithm. …

Owning Geothermal Energy, Gabriel Eckstein

Michigan Journal of Environmental & Administrative Law

Geothermal energy holds vast potential for decarbonizing the U.S. energy system, yet the sector remains significantly underdeveloped, supplying only 0.4% of the nation's electricity. A principal barrier to growth is the fragmented and ambiguous legal landscape currently governing ownership of geothermal resources: thirty-three states lack any clear statutory or common-law framework identifying who owns subsurface thermal energy. This Article examines the physical characteristics of geothermal energy, recent developments in the U.S. geothermal sector, and the principal doctrinal approaches that might govern ownership of subsurface heat, including the ad coelum doctrine, common-pool and open-access frameworks, the rule of capture, and public …

Recovery Of Bioenergy From Industrial Wastewater Using Microbial Fuel Cell, Syed Wamiq Ali, Ghulam Mujtaba, Manzoor Ahmed Sanjrani, Falak Shad

Journal of Bioresource Management

Water problems and Energy demands are increasing particularly in developing countries. Researchers are looking for sustainable technologies that can address increasing energy and environmental concerns. Major reasons behind those emerging concerns are industrialization and rapid development. There is need of sustainable technology which can solve wastewater issues and fulfill energy demand. One of the emerging technologies that have been studied comprehensively is Microbial Fuel Cell (MFC). It is a bio-electrochemical conversion technology that converts organic substrate into electrical energy. Chemical Oxygen Demand (COD) is removed as a result of microbial metabolism of organic substrate. Even through technical and economic aspects …

Coupling Mechanisms Of Fracture Propagation And Proppant Transport Indeep Coalbed Methane Reservoirs, Guo Xiaodong, Zhang Shicheng, Zhang Jingchen, Zhou Changjing, Zhang Chengsheng, Qiu Shixin, Xi Xiangrui

Coal Geology & Exploration

Objectives and Methods Deep coalbed methane (CBM) reservoirs commonly exhibit well-developed beddings, strong mechanical heterogeneity, and high in-situ stress gradients. These characteristics result in pronounced nonlinear fracture propagation and strong multi-field coupling effects during hydraulic fracturing. Consequently, it is challenging to accurately describe the mechanisms governing fracture complexity in deep coal reservoirs using conventional mechanical models for fractures. Using a super-large true triaxial system with dimensions of 2.0 m × 2.0 m × 1.0 m, this study conducted physical simulation experiments on hydraulic fracturing under varying injection rates and viscosities of fracturing fluids. In combination with fracture mechanics and energy …

Advances In Research On Mechanisms And Prevention And Control Technologies For Solid-Phase Production In Hydraulically Fractured Coalbed Methane Wells, Zhang Fengsan, Wu Jinqiao, Lin Jin, Li Yu, Zhang Ying, Li Bing, Zhang Guobiao, Sun Ying, Gan Yuke

Coal Geology & Exploration

Background The effective coalbed methane (CBM) exploitation using hydraulic fracturing wells is severely constrained by two major solid-phase production issues: coal fines blockage and proppant flowback. The mechanisms behind both issues are associated with complex interplays between geological conditions and engineering disturbances. This study presents a systematic review of the current status of domestic and international research on the mechanisms of the solid-phase production, as well as relevant prevention and control methods. Furthermore, future research directions are proposed.Advances The solid-phase production in hydraulically fractured CBM wells essentially arises from flow-solid-chemical multi-field coupling processes under interplays between geological conditions and …

Predicting The Risk Of Water-Sand Inrushes From Coal Seam Roofs Based On A Small-Size Sample Dataset, Zhang Wenquan, Li Zixu, Zhu Xianxiang, Qiu Wei, Zhang Chengjie

Coal Geology & Exploration

Objective The eastern and northern regions of China exhibit thick unconsolidated layers and thin bedrocks, with water-sand inrush disasters occurring frequently. Therefore, accurately predicting the risk of water-sand inrushes from coal seam roofs holds great significance for safe coal mining. However, the water-sand inrushes in these regions exhibit complex disaster-causing mechanisms, which involve the coupling effects of multiple factors. Accordingly, the real-time prediction of the water-sand inrush risk in the field poses challenges including high risk and cost. These issues lead to difficult data acquisition and severely insufficient samples, limiting the accuracy and performance of traditional prediction models. Therefore, there …

A Dynamic Prediction Method For Coal Seam Thickness Based On The Kpca-Pso-Svr Model, Yang Tun, Ye Shugang, Ma Ming, Wang Qianyao

Coal Geology & Exploration

Objectives and Methods With the development of high-precision and intelligent seismic exploration techniques, it is necessary to accurately quantify and interpret coal seam thickness to provide reliable data for constructing high-precision three-dimensional geological models. This will help ensure safe and efficient coal mining in coal mines. In coal seam thickness prediction, the comprehensive multi-attribute analysis method faces challenges such as the cumbersome selection of optimal seismic attributes and the low predictive accuracy of regression models. To address these challenges, this study proposed a support vector regression (SVR) prediction model based on kernel principal component analysis (KPCA) and particle swarm optimization …

Positive And Negative Pressure Distributions And Gas Migration Mechanisms Under Gas Drainage From Coal Seams Using Ultra-Long Directional Boreholes, Li Quanxin, Zhao Yuechen, Mou Quanbin, Wang Liang, Fang Jun, Wang Chenghao

Coal Geology & Exploration

Background Gas drainage via ultra-long directional boreholes plays a significant role in gas control in coal mines. To ensure safe and efficient gas drainage using these boreholes, it is critical to determine the mechanisms behind positive- negative pressure coupling, as well as the dominant mechanisms governing gas migration. However, the evolutionary patterns of positive-negative pressure zoning within the boreholes and the primary factors influencing gas drainage efficiency have yet to be accurately characterized. Methods Under the engineering background of the Shendong Baode Coal Mine, this study developed a multi-field coupling model integrating diffusion, seepage, and in-borehole flow fields based on …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Biogasification Potential Of Medium- To High-Rank Coals And Its Controlling Mechanisms At A Molecular Structural Level, Bao Yuan, Li Jiajun, Li Dan, Chen Xueru, Wang Xiaojing

Coal Geology & Exploration

Objective Coals with varying metamorphic grades differ significantly in the potential for methane generation through microbial degradation. Medium- to high-rank coals can generate a substantial volume of methane through microbial degradation. However, key factors governing their biogasification potential remain poorly understood. This study aims to identify the dominant factors controlling the potential of medium- to high-rank coals for methane generation through microbial degradation, as well as relevant controlling mechanisms, from the perspective of molecular structures.Methods The Carboniferous-Permian medium- to high-rank coals along the eastern margin of the Ordos Basin were investigated in this study. Using experiments on the hydrocarbon …