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Articles 69871 - 69900 of 294487

Full-Text Articles in Physical Sciences and Mathematics

Influence Of Surrounding Rock Changes On The Coal Seam Reflected Wave Under Thin Interbed Condition, Chang Suoliang, Zhang Sheng, Liu Jing, Liu Zuiliang, Chen Qiang, Liu Bo Oct 2021

Influence Of Surrounding Rock Changes On The Coal Seam Reflected Wave Under Thin Interbed Condition, Chang Suoliang, Zhang Sheng, Liu Jing, Liu Zuiliang, Chen Qiang, Liu Bo

Coal Geology & Exploration

In order to study the influence of the changes of surrounding rock on the reflected wave of coal seam under the condition of thin interbeds, the coal-bearing strata in the λ/4 thin layer range in seismic exploration is taken as the research object, and three types of models of surrounding rock lithology, thickness and structure change are established. By Brekhovskikh equation in the theory of thin-bed reflection coefficient spectrum, the influence of surrounding rock changes on the AVO curve, attributes and gathers of coal seams are calculated and summarized. The research results show that the changes of surrounding rock …

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Research On Three-Component Response Of Ground-Airborne Tem Considering Emission Current Waveform, Hou Yanwei, Guo Jianlei, Si Yinnyu, Jiang Tao Oct 2021

Research On Three-Component Response Of Ground-Airborne Tem Considering Emission Current Waveform, Hou Yanwei, Guo Jianlei, Si Yinnyu, Jiang Tao

Coal Geology & Exploration

The ground-airborne TEM has received more and more attention in coal goaf exploration and other fields. In order to provide a theoretical basis for the processing and interpretation of ground-airborne transient electromagnetic data, it is necessary to study the influence of the transmitted current waveform parameter on the three-component response characteristics of ground-airborne TEM. Taking trapezoidal waves as an example, this article firstly studies the frequency distribution of different emission current waveform, and then investigates the effects of the rising edge time, pulse width and turn-off time of the transmitted waveform on the three-component magnetic field response of ground-air transient …

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Research And Application Of Horizontal Wire-Line Directional Deviation Correction While Drilling, Wu Jinsheng, Huang Xiaolin, Jiang Bing, Zhang Chi, Wu Wanjiong Oct 2021

Research And Application Of Horizontal Wire-Line Directional Deviation Correction While Drilling, Wu Jinsheng, Huang Xiaolin, Jiang Bing, Zhang Chi, Wu Wanjiong

Coal Geology & Exploration

In wire-line core drilling of horizontal holes, the rotation axis of the drilling tool is not in a straight line with its own gravity direction; with the ground hole pressurized, the drilling trajectory will be deviated due to the soft and hard formation or the occurrence of the rock formation. At present, there is no effective way to achieve directional deviation correction while drilling. This paper studies the pushing, fixing and fishing technologies of small-diameter horizontal wire-line directional instruments while drilling. A set of horizontal rope directional drilling tools and directional technology are developed and applied in directional deviation correction …

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Design And Application Of Pdc Bit For Large Diameter Directional Drilling Of Coal Seam Roof With Double Stage And Double Speed, Gao Xiaoliang, Ju Pei, Zhao Jianguo Oct 2021

Design And Application Of Pdc Bit For Large Diameter Directional Drilling Of Coal Seam Roof With Double Stage And Double Speed, Gao Xiaoliang, Ju Pei, Zhao Jianguo

Coal Geology & Exploration

The development of large diameter directional drilling technology has provided technical support for the extraction of gas in the upper corner of the goaf by "replacing roadway with borehole". At present, conventional large-diameter drilling mainly adopts the step-by-step hole-forming method, which solves the problem of insufficient power of large-diameter drilling equipment in underground coal mines. However, step-by-step reaming requires multiple times of lifting and lowering, long auxiliary time and intensive labor of the workers. In order to improve the drilling efficiency of large-diameter holes in the coal roof, a double stage drilling process with two speeds was developed. The process …

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Application And Development Of Advanced Drilling Technology For Coal Mine Roadway Heading, Zhang Youzhen, Fan Tao, Kan Zhitao, Wei Hongchao, Chen Hongyan Oct 2021

Application And Development Of Advanced Drilling Technology For Coal Mine Roadway Heading, Zhang Youzhen, Fan Tao, Kan Zhitao, Wei Hongchao, Chen Hongyan

Coal Geology & Exploration

With the development of intelligent and fast roadway heading in coal mines, the demand for advanced and fine exploration of heading face is becoming increasingly urgent. Considering the technical characteristics of roadway heading and tunnel drilling, this paper firstly analyzes the technical characteristics and technical requirements of roadway heading advanced drilling under the background of intelligent green mining of coal mines and describes the innovative practice of technology and equipment, such as the integration of excavation and exploration, dual-arm advanced drilling and comprehensive exploration based on directional drilling to effectively solve the contradiction of exploration and excavation and improve the …

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Remediation Techniques For Cadmium-Contaminated Dredged River Sediments After Land Disposal, Zhang Changsong Oct 2021

Remediation Techniques For Cadmium-Contaminated Dredged River Sediments After Land Disposal, Zhang Changsong

Coal Geology & Exploration

The remediation of heavy metal Cd contamination in municipal waste is one of the urgent environmental problems in China. To determine the best Cd pollution remediation technology, this paper investigates the applicability of various cadmium(Cd) remediation techniques in river treatment. These remediation methods are compared and analyzed based on the dredged river sediments after land disposal in a city in East China. Three remediation techniques of stabilization, soil leaching, and phytoremediation, are compared by analyzing the performance of the techniques for Cd-contaminated soil remediation. The experimental results show that the stabilization technique reduced the leaching rate of soil Cd from …

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Mgrre_Pureoilscouttickets_Robertson_1_21127021230000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Robertson_1_21127021230000, Mgrre

Legacy Scout Tickets from Pure Oil Company

No abstract provided.

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Tracking Secondary Lahar Flow Paths And Characterizing Pulses And Surges Using Infrasound Array Networks At Volcán De Fuego, Guatemala, Ashley R. Bosa, Jeffrey B. Johnson, Silvio De Angelis, John J. Lyons, Amilcar Roca, Jacob F. Anderson, Amando Pineda Oct 2021

Tracking Secondary Lahar Flow Paths And Characterizing Pulses And Surges Using Infrasound Array Networks At Volcán De Fuego, Guatemala, Ashley R. Bosa, Jeffrey B. Johnson, Silvio De Angelis, John J. Lyons, Amilcar Roca, Jacob F. Anderson, Amando Pineda

Geosciences Faculty Publications and Presentations

Lahars are one of the greatest hazards at many volcanoes, including Volcán de Fuego (Guatemala). On 1 December 2018 at 8:00 pm local Guatemala time (~2:06:00 UTC), an hour-long lahar event was detected at Volcán de Fuego by two permanent seismo-acoustic stations along the Las Lajas drainage on the southeast side. To establish the timing, duration, and speed of the lahar, infrasound array records were examined to identify both the source direction(s) and the correlated energy fluctuations at the two stations. Co-located seismic and acoustic signals were also examined, which indicated at least five distinct energy pulses within the lahar …

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Automated Identification Of Stages In Gonotrophic Cycle Of Mosquitoes Using Computer Vision Techniques, Sherzod Kariev Oct 2021

Automated Identification Of Stages In Gonotrophic Cycle Of Mosquitoes Using Computer Vision Techniques, Sherzod Kariev

USF Tampa Graduate Theses and Dissertations

In this paper, we design Computer Vision techniques to determine stages in the Gonotrophic cycle of mosquitoes. The dataset for our problem came from 125 adult female mosquitoes - each of which belonged to one of three species - Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi. The mosquitoes were raised in a lab and passed through all fourGonotrophic stages (Un-fed, Fully-fed, Semi-gravid, and Gravid). At each stage, their images were captured on a plain background via a Xiaomi smartphone, resulting in a dataset of 1784 images. The images were then augmented using standard techniques to generate a larger dataset of …

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Comments On The Holographic Description Of Narain Theories, Anatoly Dymarsky, Alfred D. Shapere Oct 2021

Comments On The Holographic Description Of Narain Theories, Anatoly Dymarsky, Alfred D. Shapere

Physics and Astronomy Faculty Publications

We discuss the holographic description of Narain U(1)c × U(1)c conformal field theories, and their potential similarity to conventional weakly coupled gravitational theories in the bulk, in the sense that the effective IR bulk description includes “U(1) gravity” amended with additional light degrees of freedom. Starting from this picture, we formulate the hypothesis that in the large central charge limit the density of states of any Narain theory is bounded by below by the density of states of U(1) gravity. This immediately implies that the maximal value of the spectral gap for primary fields is ∆1 = …

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Application Of Surface Nuclear Magnetic Resonance Technology In Detecting Water Abundance In Concealed Burnt Zone, Hou Enke, Fan Jiangwei, Gao Lijun, Wang Jianwen, Chen Dehai, Chi Baosuo, Wang Hongke Oct 2021

Application Of Surface Nuclear Magnetic Resonance Technology In Detecting Water Abundance In Concealed Burnt Zone, Hou Enke, Fan Jiangwei, Gao Lijun, Wang Jianwen, Chen Dehai, Chi Baosuo, Wang Hongke

Coal Geology & Exploration

The overlying bedrock composite aquifer(including weathered bedrock and burnt rock aquifer) in the concealed burnt zone of coal seams is one of the main threats to coal mining. It is of great significance to clarify the water enrichment of the concealed burnt zone for the prevention and control of coal mine water hazards. Ningtiaota Coal Mine, which has experienced a large water inrush accident, was used as the research object, and the Surface Nuclear Magnetic Resonance(SNMR) was used to detect the water enrichment of the aquifer in the concealed burnt area. The results show that there are two aquifers in …

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Beware Of Ips In Sheep's Clothing: Measurement And Disclosure Of Ip Spoofing Vulnerabilities, Alden Douglas Hilton Oct 2021

Beware Of Ips In Sheep's Clothing: Measurement And Disclosure Of Ip Spoofing Vulnerabilities, Alden Douglas Hilton

Theses and Dissertations

Networks not employing destination-side source address validation (DSAV) expose themselves to a class of pernicious attacks which could be prevented by filtering inbound traffic purporting to originate from within the network. In this work, we survey the pervasiveness of networks vulnerable to infiltration using spoofed addresses internal to the network. We issue recursive Domain Name System (DNS) queries to a large set of known DNS servers world-wide using various spoofed-source addresses. In late 2019, we found that 49% of the autonomous systems we tested lacked DSAV. After a large-scale notification campaign run in late 2020, we repeated our measurements in …

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Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam Oct 2021

Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam

USF Tampa Graduate Theses and Dissertations

Barrier islands shield the mainland coast from the effects of extreme storms such as increased wave energy and storm surge. During these events, however, barrier morphology can be altered by erosive forces. Thus, compromising the protection offered and leading to increased impact on the mainland. The St. Joseph Peninsula, located in the Northwest of the Gulf of Mexico, is one such barrier at threat from storm-induced erosion. Presented here is an assessment of morphology change induced by two major storms to impact the peninsula, Hurricanes Dennis 2005 and Michael 2018. These changes characterize the erosive/depositional patterns that can be expected …

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Confirmation Of Carbon Emissions In Coal Mining Areas And Research On Low-Carbon Green Development Path, Wang Meng, Ma Ruying, Dai Xuguang, Shan Yadi Oct 2021

Confirmation Of Carbon Emissions In Coal Mining Areas And Research On Low-Carbon Green Development Path, Wang Meng, Ma Ruying, Dai Xuguang, Shan Yadi

Coal Geology & Exploration

Analysis was carried out on the issues such as unclear boundaries of carbon emission sources in coal mining areas, lack of accounting models, and development directions in the context of carbon neutrality. Based on the previous researches and through literature review, data collection and other methods, the boundaries of carbon emission sources in coal mining areas have been clarified and accounting model has been established, clarifying the low-carbon and green development direction of coal mining areas. The sources of carbon emissions(CH4 and CO2) in coal mining areas are divided into two major categories: natural emission and anthropogenic …

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Slippage Effect And The Seepage Mechanism Considering The Compaction And Embedding Action Of Proppant, Cheng Qiaoyun, Li Bobo, Li Jianhua, Gao Zheng, Wang Bin Oct 2021

Slippage Effect And The Seepage Mechanism Considering The Compaction And Embedding Action Of Proppant, Cheng Qiaoyun, Li Bobo, Li Jianhua, Gao Zheng, Wang Bin

Coal Geology & Exploration

Hydraulic fracturing technology is an effective method to improve the efficiency of coalbed methane drainage, but the universal embedding of proppant under stress will change the width of the fractures, which will affect the gas slippage effect and the permeability mechanism. In order to explore the gas slippage effect and coal seepage law under the background of hydraulic fracturing, the Hertzian contact theory is used to quantify the embedding depth of proppant, and the gas slippage coefficient calculation equation and permeability model of the combined effect of proppant and effective stress are constructed. The results show that under different gas …

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Study On P-Wave Velocity And Mechanical Response Characteristic Of Rock In Coal Seam Roof With Supercritical Co2 Injection, Chen Chen, He Xingyi, Niu Qinghe, Yu Hongxu, Xie Xiangyu Oct 2021

Study On P-Wave Velocity And Mechanical Response Characteristic Of Rock In Coal Seam Roof With Supercritical Co2 Injection, Chen Chen, He Xingyi, Niu Qinghe, Yu Hongxu, Xie Xiangyu

Coal Geology & Exploration

Deep coal seam CO2 geological sequestration and enhanced CH4 recovery(CO2-ECBM) can both increase CBM recovery and achieve carbon emission reduction, possessing dual benefits of energy and environment. The geochemical reactions between supercritical CO2(ScCO2), water and coal seam roof can change its physical-mechanical properties and increase the risk of CO2 leakage. In this paper, taking the roof rock of No.3 coal seam in Hudi Mine from Qinshui Basin as the research area, the ScCO2-water-rock geochemical reaction simulation experiment was carried out to explore the geochemical reaction process of ScCO2 …

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Adsorption Phase Density Characteristics Of Supercritical Methane Of Granular Coal, Zhang Mingjie, Liu Hao, Jia Tianrang, Gong Ze, Yang Mingxin Oct 2021

Adsorption Phase Density Characteristics Of Supercritical Methane Of Granular Coal, Zhang Mingjie, Liu Hao, Jia Tianrang, Gong Ze, Yang Mingxin

Coal Geology & Exploration

Finding out the characteristics of supercritical methane adsorption phase density of granular coal is the basis of studying the influence of temperature and pressure on methane adsorption amount of coal sample. Granular coal samples collected from Hebi No.6 Mine and Longshan Mine in Anyang-Hebi Coalfield were used to measure the isothermal adsorption lines at temperatures of 308 K, 313 K and 318 K, and pressures of 1-24 MPa by magnetic suspension balance isotherm adsorption device. The intercept method, Langmuir ternary model fitting method and liquid phase density method were used to calculate the adsorbed phase density at adsorption saturation and …

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Optimization Of Regional Advanced Coal Floor Water Hazard Prevention And Control Technology And Its Application, Zheng Shitian, Ma Hewen, Ji Yadong Oct 2021

Optimization Of Regional Advanced Coal Floor Water Hazard Prevention And Control Technology And Its Application, Zheng Shitian, Ma Hewen, Ji Yadong

Coal Geology & Exploration

In order to optimize the grouting process, improve the effect of the technology, and promote its application, this paper presents an investigation on the application of the regional advanced coal floor water hazard prevention and control technology in Huaibei mining area. The investigation shows that the pressure control in low pressure diffusion and medium pressure strengthening stages plays a major role in controlling the total grouting volume, which directly affects the limestone aquifer reformation. The prediction formula for grouting volume for strata with different karst fractures can provide guidance to the grouting engineering design. In addition, the horizontal layout method …

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Performance Deterioration Law Of Retarded Cement Slurry And Its Mixed Slurry In Freezing Borehole Mud Replacement, Li Qiang, Wang Yansen, Wang Chunlin, Xu Shengji, Fan Zhiqiang Oct 2021

Performance Deterioration Law Of Retarded Cement Slurry And Its Mixed Slurry In Freezing Borehole Mud Replacement, Li Qiang, Wang Yansen, Wang Chunlin, Xu Shengji, Fan Zhiqiang

Coal Geology & Exploration

The mud replacement of freezing hole has become a necessary part of freezing shaft sinking in rock strata, but in the lowering process, the freezing pipe is prone to excessive slurry viscosity resistance, and even be locked, leading to borehole failure. In order to deeply understand the performance deterioration law of cement slurry and its mixture in deep hole environment, the laboratory tests of retarded cement slurry and mixed slurry are carried out respectively, taking the apparent viscosity as the measurement index and considering the factors such as curing time, temperature, water loss state and volume ratio of mixed slurry. …

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Friction Law Of Compound Drilling Along The Coal Seam With Super-Long Directional Drilling, Xu Chao, Jiang Lei, Wang Xian, Fang Jun, Chen Pan, Liu Zhi Oct 2021

Friction Law Of Compound Drilling Along The Coal Seam With Super-Long Directional Drilling, Xu Chao, Jiang Lei, Wang Xian, Fang Jun, Chen Pan, Liu Zhi

Coal Geology & Exploration

The internal friction is the main factor affecting the drilling rate and drilling efficiency in super-long directional drilling in coal mines. In order to meet the objective demand of gas drainage mode in big panels, the friction and its influence law in drilling process are studied. To provide a basis for the selection of friction reduction process parameters of compound drilling along coal seam with super-long directional drilling, the drill string motion characteristics and stress state under the condition of near-horizontal compound drilling in the coal mine are analyzed. With certain conditional assumptions, the mechanical models of axial frictional resistance …

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Table Of Contents, The Editors Oct 2021

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

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Medium Conditons And Influence Mechanism Of High Salinity Mine Water Transfer And Storage By Deep Well Recharge, Li Xin, Sun Yajun, Chen Ge, Wang Houzhu, Zhang Zhijun Oct 2021

Medium Conditons And Influence Mechanism Of High Salinity Mine Water Transfer And Storage By Deep Well Recharge, Li Xin, Sun Yajun, Chen Ge, Wang Houzhu, Zhang Zhijun

Coal Geology & Exploration

In the arid and semi-arid regions of the Western China, there is not only a shortage of water resources, but also the problems of large mine water inflow and high salinity of mine water. In order to reduce the waste of water resources in the mining activities and protect water ecological environment in the region, it is proposed to treat the mine water by deeper well recharge to the aquifers under the coal seam based on the theories and technical methods such as mine water transfer and storage, water-preserving mining and coal-water dual resource coordinated mining. A test well project …

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Medium Characteristics And Hydrodynamic Evolution Law Of High Salinity Mine Water Recharge In Deep Well, Liu Qi, Wang Weijun, Luo Bin, Wang Houzhu, Zhang Zhijun Oct 2021

Medium Characteristics And Hydrodynamic Evolution Law Of High Salinity Mine Water Recharge In Deep Well, Liu Qi, Wang Weijun, Luo Bin, Wang Houzhu, Zhang Zhijun

Coal Geology & Exploration

The treatment and discharge of high salt mine water is one of the important factors affecting efficient coal mining in recent years. It is a worth exploring method to reduce the discharge of mine water by selecting the appropriate aquifer under the floor of the coal seam and transferring the high salt mine water to other places. Taking the X mine in the Ordos Basin as an example, the Baotashan sandstone and the deep Liujiagou Formation sandstone formation below the coal seam have transfer storage space. By mercury intrusion experiment and rock mechanics analysis, the two groups of formations were …

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Coupling Simulation Of Groundwater Dynamics And Solute Transfer In The Process Of Deep Reinjection Of Mine Water, Zhao Chunhu, Yang Jian, Wang Shidong, Zhou Jianjun, Xu Feng, Liu Ji Oct 2021

Coupling Simulation Of Groundwater Dynamics And Solute Transfer In The Process Of Deep Reinjection Of Mine Water, Zhao Chunhu, Yang Jian, Wang Shidong, Zhou Jianjun, Xu Feng, Liu Ji

Coal Geology & Exploration

The deep well reinjection of mine water is a main form of "transfer storage" treatment of mine water. According to the geological and mine water characteristics of the coal mine area in Ordos Basin, the paper puts forward the basis for selecting the target layer of mine water reinjection from the perspective of good matching between groundwater and mine water in the target layer of reinjection, the water isolation of upper and lower strata, permeability and sealing of the reinjection layer. Based on Darcy's law of groundwater and Dupuit's theory, a mathematical model of steady flow of water injection well …

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Heavy Metal Pollution Characteristics And Source Analysis Of Water Drainage From A Mine In Inner Mongolia, Wang Tiantian, Jin Dewu, Yang Jian Oct 2021

Heavy Metal Pollution Characteristics And Source Analysis Of Water Drainage From A Mine In Inner Mongolia, Wang Tiantian, Jin Dewu, Yang Jian

Coal Geology & Exploration

Heavy metal pollution evaluation and its source analysis are essential to mine water reuse and protection of ecological environment in mining areas. The objective of this paper is to study heavy metal pollution characteristics and source of heavy metal in mine water. A coal mine from Inner Mongolia Province was chosen as the study area and 49 water samples including surface water, quaternary groundwater, confined groundwater and mine water were collected. Primarily, we detected the concentrations of Zn, Pb, Fe, Mn, As, Cu, Cd, Cr, Hg and Se of water samples to explore heavy metal pollution characteristics and excessive situation. …

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Hydrochemical Characteristics And Genetic Mechanism Of High Tds Groundwater In Xinjulong Coal Mine, Zhang Yuzhuo, Xu Zhimin, Zhang Li, Lyu Weikui, Yuan Huiqing, Zhou Lijie, Gao Yating, Zhu Lulu Oct 2021

Hydrochemical Characteristics And Genetic Mechanism Of High Tds Groundwater In Xinjulong Coal Mine, Zhang Yuzhuo, Xu Zhimin, Zhang Li, Lyu Weikui, Yuan Huiqing, Zhou Lijie, Gao Yating, Zhu Lulu

Coal Geology & Exploration

Based on historical water quality data and sampling test results, using Piper three-line diagram, correlation analysis, hydrogen and oxygen isotope, Gibbs diagram, ion ratio and saturation index, etc., the hydrochemical characteristics and genetic mechanism of the groundwater with high TDS in Xinjulong Coal Mine area were explored. The results show that with the proceeding of mine construction and coal mining, the water chemistry environment in the study area has changed. The water chemistry type is no longer a single SO4-Na type, with SO4·HCO3-Na and SO4-Ca·Mg type appearing in the deep limestone water. …

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Collapse Filling-Based Technology Of Weakening And Danger-Solving By Staged Fracturing In Hard Roof, Zheng Kaige, Yang Junzhe, Li Bingang, Li Yanjun, Dai Nan, Yang Huan Oct 2021

Collapse Filling-Based Technology Of Weakening And Danger-Solving By Staged Fracturing In Hard Roof, Zheng Kaige, Yang Junzhe, Li Bingang, Li Yanjun, Dai Nan, Yang Huan

Coal Geology & Exploration

The working face is easy to induce dynamic disasters such as rock burst, coal and gas outburst, mine earthquake and hurricane in goaf under the condition of hard roof, which seriously threatens the safety of mine production. the pre-weakening and risk-solving technology of staged fracturing in hard roof is proposed based on the mode of advanced weakening by staged fracturing through open holes, combined with the synergetic support concept with "fracturing collapse body+coal pillar+load-bearing rock layer". By using the methods of theoretical analysis, technical research and development and engineering application, the crisis mechanism of advanced weakening of the staged fracturing …

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Development Characteristics And Controlling Factors Of Coal-Measure Source Rocks In The Global Tethys Region, Qu Tong, Huang Zhilong, Wang Rui, Tan Sizhe, Li Zhiyuan, Guo Xiaobo, Zhao Jing, Pan Yongshuai Oct 2021

Development Characteristics And Controlling Factors Of Coal-Measure Source Rocks In The Global Tethys Region, Qu Tong, Huang Zhilong, Wang Rui, Tan Sizhe, Li Zhiyuan, Guo Xiaobo, Zhao Jing, Pan Yongshuai

Coal Geology & Exploration

Under the control of tectonic activity in the Tethys region, a series of basins with coal measure source rocks developed, and the Tertiary coal in the circum Pacific belt is characterized by "hydrogen-rich" and has great hydrocarbon generation potential.This type of coal measure strata is an important source rock in petroliferous basins along the southeast coast of China.Therefore, it is particularly important to systematically analyze the development characteristics and controlling factors of coal measure source rocks under the Tethys background. Based on the systematic analysis of the development age, environments, geochemical characteristics and biomarker characteristics of the coal measure source …

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De-Blocking Technology And Application Of High-Rank Cbm Well In Junlian Region In Sichuan Province, Peng Lisha, Zhang Yimin, Xiong Wei, Zhao Dan, Luo Kai Oct 2021

De-Blocking Technology And Application Of High-Rank Cbm Well In Junlian Region In Sichuan Province, Peng Lisha, Zhang Yimin, Xiong Wei, Zhao Dan, Luo Kai

Coal Geology & Exploration

The coal seams of Leping Formation in Junlian area are high-rank coal reservoir with low porosity and low permeability. The gas production of some coalbed methane wells decreases rapidly in the production process, which seriously restricts the benefit development of coalbed methane wells. Combined with the production data such as drainage, hydrochemistry and pump inspection, this paper analyzes the reasons for the decline of gas production. The main reasons for the decline are coal scaling and coal fines blockage. Targeted measures such as acid pickling, hydraulic shock, plasma pulse and water injection are carried out to remove the blockage. The …

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Mine Water Inflow Modes And Scientific Design Of Drainage Boreholes In Roof Confined Aquifer Of Coal Seam, Hu Weiyue, Ji Yadong, Huang Huan Oct 2021

Mine Water Inflow Modes And Scientific Design Of Drainage Boreholes In Roof Confined Aquifer Of Coal Seam, Hu Weiyue, Ji Yadong, Huang Huan

Coal Geology & Exploration

Aiming at the uncertainty of mine water inflow mode, this paper analyzes the spatiotemporal variation characteristics of mine water inflow at first, and get a conclusion that the mine water is composed of static storage and dynamic recharge. And the static storage is mainly affected by weighting interval, the aquifer thickness of caving and fracture zone height and specific yield; the dynamic recharge is mainly affected by caving and fracture zone height and specific yield, hydraulic gradient in permeable flow field and discharge section area. According to the spatial relationships between water conducted fissure and roof aquifer of coal seam, …

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