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Articles 13051 - 13080 of 291673

Full-Text Articles in Physical Sciences and Mathematics

2025 Revised Draft Final Insufficiently Reclaimed Sites Quality Assurance Project Plan (Qapp), Pioneer Technical Services, Inc. May 2025

2025 Revised Draft Final Insufficiently Reclaimed Sites Quality Assurance Project Plan (Qapp), Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


The Quaternary Fluvial-Lacustrine System In The Akarçay Basin (Sw Anatolia): Depositional Environments And Paleoclimatic Interpretation, Koray Aktürk, Sevi̇nç Kapan May 2025

The Quaternary Fluvial-Lacustrine System In The Akarçay Basin (Sw Anatolia): Depositional Environments And Paleoclimatic Interpretation, Koray Aktürk, Sevi̇nç Kapan

Turkish Journal of Earth Sciences

The Akarçay Closed Basin, located in southwest Anatolia, contains deformed formations and the drying Akşehir and Eber lakes. This study aimed to interpret the paleoenvironmental and paleoclimatic conditions of the Akşehir and Eber lakes, which are reported to have been connected during the Pleistocene. Based on sedimentological and mineralogical data, three different depositional subenvironments were defined, corresponding to the formation and development stages of the lake. Sedimentary facies analysis of the Pleistocene deposits in the basin revealed the following facies associations, listed from bottom to top: 1) an alluvial fan and fluvial facies association, representing the formation stage of the …


First Record Of Scyphocrinoids In Türkiye And Recognition Of The Silurian/Devonian Boundary Interval (Halevikdere Section, Eastern Taurides), Eberhard Schindler, Reimund Haude, Mehmet Namik Yalçin, Rainer Brocke, Ati̇ke Nazi̇k, Emine Şeker Zor, Volker Wilde, Achim Wehrmann May 2025

First Record Of Scyphocrinoids In Türkiye And Recognition Of The Silurian/Devonian Boundary Interval (Halevikdere Section, Eastern Taurides), Eberhard Schindler, Reimund Haude, Mehmet Namik Yalçin, Rainer Brocke, Ati̇ke Nazi̇k, Emine Şeker Zor, Volker Wilde, Achim Wehrmann

Turkish Journal of Earth Sciences

During the Silurian/Devonian (S/D) boundary interval, scyphocrinoids (Crinoidea, Echinodermata) flourished on a global scale. The first record of scyphocrinoids from Türkiye, especially represented by their bulbuous loboliths, is now described from the Halevikdere Section in the Eastern Taurides. The Devonian part of the section is more than 1300 m thick and covers a time span from the S/D boundary interval to the Late Devonian (Famennian). It consists mainly of fine-grained to sandy siliciclastics, event-driven conglomerates/fanglomerates and biogenic carbonates deposited in deep shelf to shallow-water coastal settings. The S/D boundary interval was measured and studied in great detail. The dominant lithology …


Integrated Geochemical, Geoelectrical, And Uav-Based Methods For Analyzing The Güzelyalı Landslide (Çanakkale, Türkiye), Oya Erenoğlu, Emi̇n Ulugergerli̇, R. Cüneyt Erenoğlu, Abdullah Akbaş, Ahmet Evren Ergi̇nal May 2025

Integrated Geochemical, Geoelectrical, And Uav-Based Methods For Analyzing The Güzelyalı Landslide (Çanakkale, Türkiye), Oya Erenoğlu, Emi̇n Ulugergerli̇, R. Cüneyt Erenoğlu, Abdullah Akbaş, Ahmet Evren Ergi̇nal

Turkish Journal of Earth Sciences

The number of reactivations increased in the Güzelyalı-Erenköy landslide area after 2013 in Çanakkale, Türkiye, where historical landslide activity has been recorded since 1875. This area is home to numerous summer residences and experiences ongoing slow-moving landslide activity along a 400-m-long slope, extending from the heavily trafficked Çanakkale-İzmir highway to the coastline. In this study, the nature of the reactivations was evaluated by considering the conditioning and triggering factors that contributed to the landslide. The evaluation was based on geochemical analyses, field observations, geoelectric measurements, and unmanned aerial vehicle (UAV) data. The results revealed that the sliding occurred along a …


Soil Geochemistry Characteristics Of Bimodal-Mafic Type Vms Deposits In The Central Pontides: Importance Of Data Investigation In Exploration And Following Discovery, Buğra Çavdar, Kurtuluş Günay May 2025

Soil Geochemistry Characteristics Of Bimodal-Mafic Type Vms Deposits In The Central Pontides: Importance Of Data Investigation In Exploration And Following Discovery, Buğra Çavdar, Kurtuluş Günay

Turkish Journal of Earth Sciences

Çangaldağ Metamorphic Complex is defined with low grade metamorphic equivalents of mafic to felsic intrusive and extrusives, clastics and volcanoclastics. The Au-Cu-Zn Say Yayla (deeply-seated; West Zone) and the Au-dominant Büyük Hill (gossan related; East Zone) deposits are classified as bimodal-mafic type VMS in that complex and they are hosted in the metafelsic ensimatic arc volcanics. These were investigated by soil samples developed over each mineralization to examine the soil characteristics with different textural features. A total of 274 soil samples were collected and they have been geochemically analysed and examined using various statistical methods. The results reveal that both …


Apatite Chemistry From The Xv Ioa Deposit, The Bafq–Saqand Metallogenic Province (Bsmp), Central Iran: Constrains On The Genesis Of Ioa Deposits, Sakine Amraei, Majid Ghasemi Siani, Mohammad Yazdi, Liang Qiu, Chang–Zhi Wu, Minghua Ren, Shahrokh Rajabpour May 2025

Apatite Chemistry From The Xv Ioa Deposit, The Bafq–Saqand Metallogenic Province (Bsmp), Central Iran: Constrains On The Genesis Of Ioa Deposits, Sakine Amraei, Majid Ghasemi Siani, Mohammad Yazdi, Liang Qiu, Chang–Zhi Wu, Minghua Ren, Shahrokh Rajabpour

Turkish Journal of Earth Sciences

In this study, we present petrographical and microanalytical (EPMA, LA–ICP–MS) results of apatites associated with Fe–Ti±P mineralization in the XV deposit in the BSMP. Apatite is predominantly observed as subhedral to euhedral, homogeneous grains, with no zoning or inclusions. Geochemically, apatite is fluorapatite of magmatic origin, with Cl/OH and Cl/F ratios of <0.05 and 0.01 to 0.07, respectively. Apatites from XV and other IOA deposits in the BSMP display a high F/Cl ratio, which is likely the main characteristic of IOA–type deposits such as the Kiruna-type deposit. Apatites from both rock types (gabbro and pyroxenite) exhibit similar rare earth elements (REEs) and multitrace element patterns, indicative of a shared origin. The highly light rare earth elements (LREEs)–enriched pattern in chondrite–normalized fractionation trends, along with positive Eu and slight negative Ce anomalies, as well the high (La/Sm)N and (La/Yb)N ratios of XV apatite, further corroborates the magmatic genesis of fluorapatite. The Eu/Eu* and Ce/Ce* ratios in XV rocks imply a high oxidation condition, as well as other IOA deposits in BSMP. The sulfur content is less than 1 wt% and shows a positive correlation with SiO2, implying coupled dissolution–reprecipitation of primary fluorapatite. Considering the geological setting of XV and other IOA deposits in the BSMP, the parental magma(s) appear to have originated from oxidizing Fe-Ti±P-rich magma(s), likely formed within an extensional postcollisional setting, influenced by the Proto–Tethys and Central Iranian Microcontinent (CIMC) convergence events.


Formation Of Holocene Paleosols In A Relict Sand Dune Sequence At Kıyıköy, Türkiye, Ahmet Evren Ergi̇nal, Mustafa Bozcu, Nuretti̇n Yakupoğlu, Abdullah Akbaş, Hakan Kaya, İsmai̇l Onur Tunç May 2025

Formation Of Holocene Paleosols In A Relict Sand Dune Sequence At Kıyıköy, Türkiye, Ahmet Evren Ergi̇nal, Mustafa Bozcu, Nuretti̇n Yakupoğlu, Abdullah Akbaş, Hakan Kaya, İsmai̇l Onur Tunç

Turkish Journal of Earth Sciences

The paleoclimatic indicators from a relict dune and paleosol sequence observed south of Kıyıköy Port, NW Türkiye, provide insights into the variable paleoclimatic conditions in the western Black Sea coastal zone over the last 4700 yrs BP. The relict dune- paleosol sequence consists of reddish-brown coarse sands with abundant shells and overlying paleosol. Radiocarbon dating of Donax trunculus shells collected from the lowest part of the relict dune revealed the onset of sand deposition 4689 ± 123 yrs ago. The dark-colored paleosol layer, with an Rb/Sr ratio of 0.008, yielded an age of 287 ± 32 yrs cal BP. These …


U-Pb Calcite Geochronology, Epr, Geochemistry, And C-O-Sr Isotopes Of Africanomarbles In The Seferihisar (İzmir, Türkiye) U-Pb Calcite Geochronology, Epr, Geochemistry, And C-O-Sr Isotopes Of Africano Marbles In The Seferihisar (İzmir, Türkiye), Fatma Şi̇şman Tükel, Namik Aysal, İpek Deni̇z Yildirim, Marcel Guillong, Tonguç Uysal, Si̇nan Öngen, Emre Erdem May 2025

U-Pb Calcite Geochronology, Epr, Geochemistry, And C-O-Sr Isotopes Of Africanomarbles In The Seferihisar (İzmir, Türkiye) U-Pb Calcite Geochronology, Epr, Geochemistry, And C-O-Sr Isotopes Of Africano Marbles In The Seferihisar (İzmir, Türkiye), Fatma Şi̇şman Tükel, Namik Aysal, İpek Deni̇z Yildirim, Marcel Guillong, Tonguç Uysal, Si̇nan Öngen, Emre Erdem

Turkish Journal of Earth Sciences

The Africano marbles (Africano Verde and Bigio Africano) extracted from the region of Sığacık (ancient Teos) region and its surroundings were widely used and even traded in construction and decorative items throughout the Roman period due to their brecciated and colourful appearance. There are two different types of Africano marble, the first consisting of marble breccias embedded in a dark matrix. In this type, the marble breccias show micritic, microsparitic, and sometimes sparitic textures formed by coarse-grained calcite, while the dark matrix consists of chlorite and/or serpentine minerals. The second type is Bigio Africano, which consists of grey-blue homogeneous limestones, …


Math 115: College Algebra Instructor Guide, Seth Lehman May 2025

Math 115: College Algebra Instructor Guide, Seth Lehman

Open Educational Resources

OER instructor guide for Math 115, College Algebra, Queens College


Calculating Moment Magnitude Using The Coda Calibration Technique To Update The Earthquake Catalog Of Iraq (1900-2021), Muntadher Al-Kaabi May 2025

Calculating Moment Magnitude Using The Coda Calibration Technique To Update The Earthquake Catalog Of Iraq (1900-2021), Muntadher Al-Kaabi

Theses and Dissertations

The first comprehensive earthquake catalog for Iraq based on moment magnitude (Mw) ‎was compiled by Onur et al. (2017). It spanned the period from 1900 until the end of ‎‎2009, covered the region between 26°–40° N latitudes and 36°–51° E longitudes, and ‎included more than 18,000 earthquakes, of which roughly 4,000 are of Mw 4.0 or larger. ‎With the ongoing efforts of updating the probabilistic seismic hazard assessment ‎‎(PSHA) and the Iraqi building code, the need for an updated earthquake catalog for Iraq ‎in terms of moment magnitude (Mw) has been raised. Robust estimation of moment ‎magnitude (Mw) can be …


Wildlife Road Mortalities During Covid-19 Pandemic-Related Lockdown In South Texas: A Comparative Survey, Bradley Evan Beer, Kevin W. Ryer, Md Saydur Rahman, John H. Young Jr., Richard J. Kline May 2025

Wildlife Road Mortalities During Covid-19 Pandemic-Related Lockdown In South Texas: A Comparative Survey, Bradley Evan Beer, Kevin W. Ryer, Md Saydur Rahman, John H. Young Jr., Richard J. Kline

School of Earth, Environmental, & Marine Sciences Faculty Publications

Mortalities of wildlife caused by collisions with vehicles along roads are increasing in prevalence, threatening the existence of various species and populations. The COVID-19 pandemic-related lockdown provided an opportunity to gain a better understanding of how wildlife vehicle mortality occurrences change in response to anthropogenic variables and how varying survey methods influence obtaining mortality data. In this study, data were collected in three observation periods: pre-lockdown (PreL), during lockdown (DL), and post-lockdown (PostL) in south Texas. There were 194 wildlife mortalities recorded during weeks 4–27 of 2020. Results of this study showed that road mortality survey counts did not change …


A Phase Transition-Induced Fracturing Permeability Enhancement Technology Using Carbon Dioxide Capsules For Low-Permeability Coal Seams And Its Application, Li Mao, Fan Xinchuan, Fu Hui May 2025

A Phase Transition-Induced Fracturing Permeability Enhancement Technology Using Carbon Dioxide Capsules For Low-Permeability Coal Seams And Its Application, Li Mao, Fan Xinchuan, Fu Hui

Coal Geology & Exploration

Objective and Methods To address engineering challenges like high gas content, high pressure, and low drainage efficiency in the mining of low-permeability coal seams, this study developed a phase transition-induced fracturing and permeability enhancement technology using carbon dioxide (CO2) capsules for low-permeability coal seams. This technology leverages the feature that CO2 transitions into the supercritical state under high pressure. A capsule encapsulating critical CO2 is placed into a conduit, which is then placed within a coal seam. Subsequently, phase transition-induced blasting is triggered using a heating blasting start device. Consequently, liquid CO2 vaporizes rapidly and …


Characteristics And Control Modes Of Geothermal Fields In Deep Coal Reservoirs In The Linxing-Shenfu Block, Xu Lifu, Bai Yuhu, Xu Bingxiang, Hu Weiqiang, Chen Jianqi, Li Yong May 2025

Characteristics And Control Modes Of Geothermal Fields In Deep Coal Reservoirs In The Linxing-Shenfu Block, Xu Lifu, Bai Yuhu, Xu Bingxiang, Hu Weiqiang, Chen Jianqi, Li Yong

Coal Geology & Exploration

Objective Geothermal fields serve as a crucial geological condition controlling the phases and seepage of deep coalbed methane (CBM). Investigating geothermal fields facilitates the assessment and efficient development of deep CBM resources.Methods This study explored the Nos. 8 and 9 coal seams in the Linxing-Shenfu block using data from drilling, well logging, well tests, and experiments. Specifically, this study summarized the regional distribution patterns of geothermal fields in deep coal reservoirs in the block, analyzed the impacts of the geothermal fields on the gas-bearing and physical properties of the reservoirs, and revealed the controlling factors and mechanisms of the …


Dynamic Evolutionary Patterns Of High-Temperature Steam Seepage And Thermal Strains Of Coals During Heat Injection, Li Zhiqiang, Zhang Ningchao, Chen Jinsheng, Chen Liwei, Feng Wenxiang, Liu Longwei, Wang Yungang May 2025

Dynamic Evolutionary Patterns Of High-Temperature Steam Seepage And Thermal Strains Of Coals During Heat Injection, Li Zhiqiang, Zhang Ningchao, Chen Jinsheng, Chen Liwei, Feng Wenxiang, Liu Longwei, Wang Yungang

Coal Geology & Exploration

Background Thermal stimulation of coal seams using high-temperature steam is recognized as a highly promising technology used to increase gas production. Steam permeability serves as a critical parameter for characterizing the injection capacity of thermal fluids. However, the seepage patterns and evolutionary mechanism of steam in coals remain unclear, and exploring these issues holds critical scientific significance for gas production enhancement via heat injection. Methods Through experiments on the seepage and thermal strains of coals during the injection of high-temperature steam performed using the steady-state method, this study investigated the dynamic time variation patterns of the steam permeability and thermal …


Assessing The Potential And Suitability Of Geothermal Resources Using Monte Carlo Simulation And Game-Based Combination Weighting Method, He Yixiang, Ding Pengpeng, Liu Shaohua, Wang Mingzhu, Zhu Lei May 2025

Assessing The Potential And Suitability Of Geothermal Resources Using Monte Carlo Simulation And Game-Based Combination Weighting Method, He Yixiang, Ding Pengpeng, Liu Shaohua, Wang Mingzhu, Zhu Lei

Coal Geology & Exploration

Background Geothermal energy in porous sandstone reservoirs is recognized as stable, efficient clean energy. However, these reservoirs feature heterogeneity and exploration uncertainty, posing serious challenges to probabilistic resource assessment and the identification of suitability for resource development.Methods This study investigated the geothermal resources in the Guantao Formation within the northwest Shandong plain. Using the volumetric method and Monte Carlo simulation, this study assessed the uncertainty of the resource potential. Then, considering the characteristics of geothermal resources, the attributes of geological structures, and the social economy, this study developed a multi-dimensional evaluation index system for the suitability of sandstone geothermal …


Table Of Contents, The Editors May 2025

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.


Sedimentary Patterns And Exploitation Practices Of Tight-Sand Gas Reservoirs In Coal Measure Strata: A Case Study Of The 3rd Submember Of The Second Member Of The Permian Shanxi Formation In The Daning-Jixian Block, Zhang Lei, Huang Li, Zhao Longmei, Wang Feng, Zhang Yixin, Shi Shi, Zhang Wen, Zhao Haoyang, Chen Tong, Tong Jiangnan May 2025

Sedimentary Patterns And Exploitation Practices Of Tight-Sand Gas Reservoirs In Coal Measure Strata: A Case Study Of The 3rd Submember Of The Second Member Of The Permian Shanxi Formation In The Daning-Jixian Block, Zhang Lei, Huang Li, Zhao Longmei, Wang Feng, Zhang Yixin, Shi Shi, Zhang Wen, Zhao Haoyang, Chen Tong, Tong Jiangnan

Coal Geology & Exploration

Background The third submember of the second member of the Permian Shanxi Formation (also referred to as the Shan 23 submember) in the Daning-Jixian block along the eastern margin of the Ordos Basin is identified as a primary target layer for tight-sand gas production in the block. In the early stage of the block development, play fairways were initially identified through fundamental studies on provenance areas and sedimentary systems. Accordingly, a gas field with an annual production of 10 × 108 m3 was constructed in the block. However, further exploitation reveals that the sandstones in the Shan …


Application Of A Uav-Borne Gpr System In The Detection Of Water Bodies And Cavities, Wang Ying, Sun Chenchen, Zhang Lu, Chen Yifei, Lu Song, Zhou Feng May 2025

Application Of A Uav-Borne Gpr System In The Detection Of Water Bodies And Cavities, Wang Ying, Sun Chenchen, Zhang Lu, Chen Yifei, Lu Song, Zhou Feng

Coal Geology & Exploration

Objective and Methods The unmanned aerial vehicle (UAV)-borne ground-penetrating radar (GPR) system, enjoying the advantages of high resolution and non-contact detection, is applicable to the detection of water accumulation in coal seams and goaves in mines. Therefore, this study proposed a rapid detection method based on a UAV-borne air-coupled GPR system to enhance the exploration efficiency of mining areas and reduce the time and risks of manual explorations. Given the limitations of the test scenarios in actual coal mines, this study investigated the water body of the Fanxiong reservoir in Ezhou City and surrounding drainage culverts for equivalent validation, aiming …


Mat 301 - Applied Statistics And Data Analysis, Eric Aragundi May 2025

Mat 301 - Applied Statistics And Data Analysis, Eric Aragundi

Open Educational Resources

Data analysis using standard statistical methods and relevant computer software. Emphasis on real-world data, interpretation, and misinterpretation of computer output.

This syllabus contains open source notebook about data analysis content.


Transparent Prevention And Control System For Water Hazards In Mine Floors Under Empowerment Based On Spatiotemporal Information Fusion, Liu Zaibin, Yan Junsheng, Wang Jianghong, Gao Yaoquan, Yang Hui, Bai Baojun, Lu Jingjin, Wang Hongwei, Wang Gang May 2025

Transparent Prevention And Control System For Water Hazards In Mine Floors Under Empowerment Based On Spatiotemporal Information Fusion, Liu Zaibin, Yan Junsheng, Wang Jianghong, Gao Yaoquan, Yang Hui, Bai Baojun, Lu Jingjin, Wang Hongwei, Wang Gang

Coal Geology & Exploration

Background Water hazards in coal mines frequently cause heavy casualties, severely affecting the safe mining of coal mines. Methods With the continuous advancements in both the construction of real scene 3D views and coal mine intelligentization, this study examined the development of the intelligent geological guarantee system for the Tangjiahui Coal Mine in Inner Mongolia, as well as the prevention and control of water hazards in the Ordovician limestones in the coal mine floor. Accordingly, this study elaborated on enhancing the prevention and control capacity against water hazards in coal mines during the mining cycle of a mining face using …


Experimental Study On Unloading Confining Pressure Deformation And Damage Failure Of Multi-Source Coal-Based Solid Waste Cemented Backfill, He Xiang, Wei Longqiang, Yang Ke, Zhang Tong, Zhang Cun, Zhang Zilong, Chen Yanjun May 2025

Experimental Study On Unloading Confining Pressure Deformation And Damage Failure Of Multi-Source Coal-Based Solid Waste Cemented Backfill, He Xiang, Wei Longqiang, Yang Ke, Zhang Tong, Zhang Cun, Zhang Zilong, Chen Yanjun

Coal Geology & Exploration

Objective The preparation of multi-source coal-based solid waste into filling materials for interval strip filling mining is one of the important means of green coal mining. The deformation and failure law of multi-source coal-based solid waste cemented backfill during strip coal pillar mining directly affects the stability of the stope.Methods Five typical solid wastes were mixed with cement to prepare cemented backfill. The conventional triaxial and constant axial pressure unloading confining pressure stress tests of backfill specimens were carried out. The stress-strain curves and failure characteristics of backfill under two stress loading paths were analyzed. The evolution law of …


Fluoride Ion Removal From Mine Water Via Nucleation Crystallization Pelleting Process, Zhang Xiyu, Dong Shuning, Wang Hao, Jin Pengkang, Wang Xiaodong, Wang Qiangmin, Zhang Tao May 2025

Fluoride Ion Removal From Mine Water Via Nucleation Crystallization Pelleting Process, Zhang Xiyu, Dong Shuning, Wang Hao, Jin Pengkang, Wang Xiaodong, Wang Qiangmin, Zhang Tao

Coal Geology & Exploration

Objective The mine water associated with coal mining tends to be rich in fluoride ions. If discharged directly without effective treatment, such water will cause severe pollution to regional ecology, affecting the quality of water resources and the stability of the ecosystem. Methods This study focuses on the challenging treatment of the fluoride pollution caused by coal mining-associated mine water. To overcome the bottlenecks including low efficiency and weak anti-interference of traditional methods for fluoride removal, this study designed a setup for fluoride removal using the nucleation crystallization pelleting (NCP) processing and proposed a novel fluoride removal method—NCP chemical precipitation. …


A Seismic Random Noise Suppression Method Based On Cnn-Mamba, Wei Xiujuan, Liu Xingye, Zhou Huailai May 2025

A Seismic Random Noise Suppression Method Based On Cnn-Mamba, Wei Xiujuan, Liu Xingye, Zhou Huailai

Coal Geology & Exploration

Background Seismic random noise suppression is recognized as a key step to improve the quality of seismic data. Data-driven deep learning provides an intelligent solution for the noise suppression. However, mainstream random noise intelligent methods based on convolutional neural networks (CNNs) are constrained by their local receptive fields. This limitation results in insufficient collaborative optimization between local details and macroscopic structures during denoising, further reducing the noise suppression accuracy. Transformer models, which are widely applied to global feature extraction, can effectively capture long-distance dependencies through the self-attention mechanism, theoretically overcoming the limitations of CNNs in global modeling. However, these models …


Historical Overview, Advancements, And Future Prospects Of Coalfield Structure Research In China, Cao Daiyong, Ju Yiwen, Xia Yucheng, Jiang Bo, Ning Shuzheng, Wei Yingchun, Wang Anmin, Li Xiaoming, Zhan Wenfeng, Li Huantong, Wang Lu, Cai Zhuocheng May 2025

Historical Overview, Advancements, And Future Prospects Of Coalfield Structure Research In China, Cao Daiyong, Ju Yiwen, Xia Yucheng, Jiang Bo, Ning Shuzheng, Wei Yingchun, Wang Anmin, Li Xiaoming, Zhan Wenfeng, Li Huantong, Wang Lu, Cai Zhuocheng

Coal Geology & Exploration

Background Coalfield structures represent a basic aspect of coalfield geology. In China, research into this domain has a history of over a century, yielding numerous results after undergoing exploration, learning, and innovation. These results have played a positive role in the long-term, stable coal supply in China. Amidst the ongoing energy structure optimization and the transformation and upgrading of coalfield geology in China, it is both practically and historically significant to review the history of coalfield structure research, summarize relevant experience, and contemplate future directions of the research under emerging circumstances.Methods Based on literature analysis, as well as the …


Mechanisms And Collaborative Prevention And Control Techniques For Various Disasters In Coal Seam Roofs, Zheng Kaige, Zhang Jian, Sun Siqing, Chen Dongdong, Wang Zeyang May 2025

Mechanisms And Collaborative Prevention And Control Techniques For Various Disasters In Coal Seam Roofs, Zheng Kaige, Zhang Jian, Sun Siqing, Chen Dongdong, Wang Zeyang

Coal Geology & Exploration

Objective The multistage sedimentary and tectonic evolution of coal seams in China has led to the formation of environments with the coexistence of multiple disasters including gas outbursts, water inrushes, and rock bursts. To address the chain evolution of these disasters induced by the coupling of high in situ stress, high water pressure, and intense mining under the condition of deep coal mining, this study systematically investigated the coupling mechanisms and collaborative prevention and control techniques of multiple dynamic disasters in coal seam roofs. Methods Based on the regional tectonic characteristics and the delineation of coal-bearing tectonic units, this study …


Mechanisms And Equation Improvement For Gas Seepage In Coal Seams Around Boreholes Subjected To High-Pressure Co2 Foam Fracturing, Pang Mingkun, Zhang Tianyu, Pan Hongyu, Song Xianfeng, Wu Shan, Zhang Tianjun May 2025

Mechanisms And Equation Improvement For Gas Seepage In Coal Seams Around Boreholes Subjected To High-Pressure Co2 Foam Fracturing, Pang Mingkun, Zhang Tianyu, Pan Hongyu, Song Xianfeng, Wu Shan, Zhang Tianjun

Coal Geology & Exploration

Objective The special low-porosity, low-permeability structures of high-gas-content coal seams restrict efficient gas drainage. To address this issue, this study accurately determined the seepage parameters of annularly fractured coals around boreholes subjected to CO2 foam fracturing to enhance both the design accuracy of boreholes for gas pre-drainage from coal seams and gas drainage efficiency. Methods Using an independently developed apparatus for gas seepage experiments on fractured coals around boreholes, this study investigated the coals with pores and fractures distributed in an annular pattern around boreholes from the perspective of varying initial pore structures. Specifically, this study analyzed the evolutionary …


Classification-Based Point Cloud Denoising And 3d Reconstruction Of Roadways, Chen Denghong, Pang Ning, Nie Wen, Feng Juqiang, Kan Jiliang, Zhang Jinjing May 2025

Classification-Based Point Cloud Denoising And 3d Reconstruction Of Roadways, Chen Denghong, Pang Ning, Nie Wen, Feng Juqiang, Kan Jiliang, Zhang Jinjing

Coal Geology & Exploration

Objective The point cloud denoising and 3D reconstruction of roadways serve as a key step in the digital modeling and analysis of roadways. However, the conventional algorithm based on single filtering fails to effectively remove the noise at varying scales from point clouds. Meanwhile, the existing 3D reconstruction algorithms suffer from low modeling accuracy and high susceptibility to distortion. These necessitate developing methods and technologies to obtain high-quality point cloud data and construct high-accuracy 3D models for roadways. Methods This study proposed an adaptive classification-based point cloud denoising algorithm using neighborhood radius (R), minimum neighborhood point number ( …


Dominant Geological And Engineering Factors Controlling The Productivity Of Horizontal Wells For Deep Coalbed Methane In The Southern Shenfu Block, Guo Guangshan, Liu Yancheng, Zhao Gang, Chen Zhaohui, Li Chen, Kang Lifang, Wang Yuchuan, Wang Jianan May 2025

Dominant Geological And Engineering Factors Controlling The Productivity Of Horizontal Wells For Deep Coalbed Methane In The Southern Shenfu Block, Guo Guangshan, Liu Yancheng, Zhao Gang, Chen Zhaohui, Li Chen, Kang Lifang, Wang Yuchuan, Wang Jianan

Coal Geology & Exploration

Objective The southern Shenfu block along the eastern margin of the Ordos Basin hosts one of the rare gas fields with reserves of over 100 billion cubic meters (bcm) in China, serving as a pilot demonstration area for the exploration and production of deep coalbed methane (CBM) conducted by the China National Offshore Oil Corporation (CNOOC). In this block, the gas production of horizontal wells is 2-10 times that of vertical wells. However, the horizontal wells are challenged by significantly different and rapidly declining gas production. Determining dominant factors controlling the productivity of horizontal wells for deep CBM is the …


Impacts Of The Hydrochemical Characteristics Of Coal Seam Water On The Structures And Metabolic Functions Of Microbial Communities, Wang Gaohao, Duan Shengjie, Wang Bei, Niu Guobin, Liang Yongping, Yu Feilong, Ma Kai, Zhao Weizhong May 2025

Impacts Of The Hydrochemical Characteristics Of Coal Seam Water On The Structures And Metabolic Functions Of Microbial Communities, Wang Gaohao, Duan Shengjie, Wang Bei, Niu Guobin, Liang Yongping, Yu Feilong, Ma Kai, Zhao Weizhong

Coal Geology & Exploration

Background The core of coalbed methane (CBM) bioengineering is to inject bio-fracturing fluids rich in efficient methanogenic bacteria into coal reservoirs to promote the conversion of coals to methane. However, the relationships of the hydrochemical characteristics of coal seam water with the structures and metabolic functions of microbial communities remain unclear. Methods This study investigated coal seam water from 12 typical mining areas in Ningxia. Based on microbial classification and sequencing, as well as statistical analysis, this study explored the relationships of pH, anions, cations, and chemical oxygen demand (COD) of coal seam water with the structures and metabolic functions …


Construction And Application Of A Model For Drainage Via Directional Boreholes Against Water Hazards In Deep Vertical Shafts, Zhao Chunhu, Zhu Mingcheng, Ji Yadong, Wang Shidong, Zhang Wenzhong, Zhu Kaipeng, Liu Yingfeng, Shang Hongbo, Li Chaofeng, Fan Min, Li Kai May 2025

Construction And Application Of A Model For Drainage Via Directional Boreholes Against Water Hazards In Deep Vertical Shafts, Zhao Chunhu, Zhu Mingcheng, Ji Yadong, Wang Shidong, Zhang Wenzhong, Zhu Kaipeng, Liu Yingfeng, Shang Hongbo, Li Chaofeng, Fan Min, Li Kai

Coal Geology & Exploration

Background Vertical shafts are typically employed in the deep mining areas of Jurassic coalfields in western China. However, the direct exposure of extremely thick Cretaceous aquifers frequently leads to significant water inflow in shafts. Meanwhile, the continuous sand-carrying water inflow and scouring in vertical shafts pose serious safety hazards to the overall quality of shaft walls. Methods In underground water exploration and discharge boreholes, water outlets are below the floors of aquifers to be drained. This allows unpowered water discharge. In other words, water can flow out naturally. By fully leveraging this advantage, combined with the favorable condition of spatial …