Note: Intro -- Supervisor's Foreword -- Parts of this thesis have been published in the following journal articles: -- This research was supported by the following projects: -- Contents -- Executive Summary -- 1 Introduction -- 1.1 Research Background and Significance -- 1.2 Current Research Status -- 1.2.1 Research on Water-Bearing and Water-resisting Properties of the TOL in NCCs -- 1.2.2 Pertinent Research on Grouting Reconstruction of the TOL -- 1.3 Major Limitations of Current Research -- 1.4 Research Content and Technical Approach -- 1.4.1 Research Content -- 1.4.2 Research Method and Technical Approach -- References -- 2 Paleosedimentary Environments and Karst Characteristics of Ordovician Limestone in North China Coalfields -- 2.1 Paleotectonic Movement in NCCs -- 2.2 Evolution of the Paleosedimentary Environments in NCCs -- 2.3 Characteristics of Karst Development of Ordovician Limestone in NCCs -- References -- 3 Water-Bearing and Water-resisting Properties of Top of Ordovician Limestone in North China Coalfields -- 3.1 Research on Planar Division of Water Yield Property of TOL in NCCs -- 3.1.1 Analysis on the Influencing Factors of Water Abundance of the TOL -- 3.1.2 Comprehensive Evaluation Method of Water Abundance of the TOL -- 3.1.3 Case Study of Water Abundance of the TOL -- 3.2 Research on Vertical Zonation of Water-Bearing and Water-resisting Properties of the TOL in NCCs -- 3.2.1 Three Vertical Zones in the TOL -- 3.2.2 Case Study of Vertical Zoning of Water-Bearing and Water-resisting Properties of the TOL -- References -- 4 Utilizability of Weathered and Filled Zone of Top of Ordovician Limestone in North China Coalfields -- 4.1 Formation, Evolution, and Spatial Distribution Characteristics of the Weathered and Filled Zone of the TOL -- 4.2 Experimental Study on the Utilizability of the Weathered and Filled Zone of TOL as Aquifuge. , 4.2.1 Rock Strength Test -- 4.2.2 Rock Permeability Test -- 4.2.3 Water-resisting Capacity and Rock Strength Test of TOL -- 4.3 Utilizability of the Weathered and Filled Zone of the TOL as Aquifuge -- References -- 5 Criterion for Utilization and Grouting Reconstruction of Top of Ordovician Limestone -- 5.1 Criterion for Utilization and Grouting Reconstruction of the TOL -- 5.2 Thickness of Grouting Reconstruction of the TOL -- 5.3 Prediction Methods of Damage Depth in Coal Seam Floor -- References -- 6 Technical System of Grouting Reconstruction of Top of Ordovician Limestone -- 6.1 Experimental Study on Grouting Material Formula Using Pulverized Coal Ash -- 6.2 Dispersion Properties of Grout in Karst Fractures of the TOL -- 6.3 Surface Automatic Grouting System Using Fly Ash-Based Grouting Materials -- References -- 7 Case Study of Utilization and Grouting Reconstruction of Top of Ordovician Limestone -- 7.1 Background of Tested Working Face 3105 in Sangshuping Coal Mine, Hancheng Mining Area -- 7.2 Karst Characteristics and Water Yield Properties of TOL in Sangshuping Coal Mine -- 7.3 Utilization of the TOL in Working Face 3105 -- Reference -- 8 Conclusions and Innovation Points -- 8.1 Conclusions -- 8.2 Innovation Points.

Note: Intro -- Preface -- Contents -- 1 Water Hazards in Coal Mines and Their Classifications -- 1.1 Introduction -- 1.2 Water Inrush Conceptual Site Models for Coal Mines of China -- 1.2.1 Development of Water Inrush Conceptual Site Models -- 1.2.2 Benefits of Water Inrush Conceptual Site Models -- 1.3 Classification of Water Inrush for Coal Mines of China -- 1.3.1 Principles for Classification of Mine Water Inrush -- 1.3.2 Types of Mine Water Inrush -- 1.3.3 Characteristics of Mine Water Inrushes -- 1.4 Hydrogeological Classification for Mine Water Hazard Control -- 1.4.1 Criteria of Hydrogeological Classification -- 1.4.2 Hydrogeological Classification of Coal Mines in China -- 1.4.3 Hydrogeological Characteristics of Mines -- 1.5 Advances in Prevention and Control Technologies of Mine Water Hazards -- 1.5.1 Updated Mining Principles -- 1.5.2 Evolution of Water Inrush Coefficient -- 1.5.3 Supplemental Investigation and Water Inrush Prediction -- 1.5.4 Advanced Detection and Dewatering Technologies -- 1.5.5 Early Warning Technique -- 1.5.6 Innovated Grouting Technique -- References -- 2 Mine Water Inrush Mechanisms and Prediction Methods -- 2.1 Overview of Water Inrush Studies -- 2.2 Water Inrush Mechanisms in North China's Coalfields -- 2.2.1 Hydrogeological Background -- 2.2.2 Relationship Between Aquiclude Thickness and Groundwater Pressure -- 2.2.3 Impact of Mining Activities on Geologic Barrier -- 2.2.4 Laboratory Experiments on Failure of Geologic Barrier -- 2.2.5 Initial Conductive Zone in Geologic Barrier -- 2.2.6 In-Situ Hydrofracturing Tests -- 2.3 Water Inrush Mechanism Through Karst Collapse Columns -- 2.3.1 Karst Collapse Columns and Their Relationship with Mining -- 2.3.2 Hydrogeological Characteristics of Karst Collapse Columns -- 2.3.3 Water Inrushes Through Karst Collapse Columns -- 2.4 Prediction Methods. , 2.4.1 Water Inrush Coefficient Method -- 2.4.2 Vulnerability Index Method -- 2.4.3 Three-Map and Two-Prediction Method -- 2.4.4 Five-Map and Two-Coefficient Method -- References -- 3 Modeling of Groundwater Flow in Karst Aquifers for Mine Water Control -- 3.1 Inputs to Karst Hydrogeological Systems -- 3.1.1 Discharge-Storage Method -- 3.1.2 Recession-Curve-Displacement Method -- 3.1.3 Meteorological Model -- 3.2 Groundwater Flow in Karst Hydrogeological Systems -- 3.2.1 Groundwater Flow Patterns in Karst Aquifers -- 3.2.2 Influenced Flow Patterns -- 3.2.3 Confluent Flow in Karst Aquifers -- 3.2.4 Siphon Karst Flow -- 3.3 Water Budget Analyses -- 3.3.1 Discharge Hydrograph -- 3.3.2 Discharge Recession Analysis -- 3.3.3 Discharge Chemograph -- 3.3.4 Groundwater Level Hydrograph -- 3.4 Statistical and Stochastic Methods -- 3.4.1 Regression Analysis -- 3.4.2 Kernel Analysis -- 3.4.3 Threshold Autoregressive Analysis -- 3.5 Mixing-Cell Models -- 3.5.1 Discrete-State-Compartment Model -- 3.5.2 Water Tank Models -- 3.6 Physics-Based Models -- 3.6.1 Equivalent-Porous-Medium Models -- 3.6.2 Discrete-Fracture Models -- 3.6.3 Double-Continuum Models -- 3.6.4 Determination of Hydraulic Parameters at Respective Scales -- 3.7 Quantitative Analysis of Tracer Tests -- 3.7.1 Tracer-Breakthrough Curves -- 3.7.2 Estimation of Hydraulic Parameters of Karst Conduits -- 3.7.3 Evaluation of Dynamic Dispersion in Karst Aquifers -- 3.8 Application of Dual-Porosity Model to Groundwater Simulation in the Ordovician Limestone in Jiaozuo Coalfield, China -- 3.8.1 Introduction to Jiaozuo Coalfield -- 3.8.2 Karst Conduit Distribution -- 3.8.3 Calibration of the Dual-Porosity Model -- References -- 4 Prevention and Control of Mine Water Hazards from Underlying Aquifers. , 4.1 Water Prevention and Control Technology in Mining Lower Coal Seams Under Potentiometric Pressure in Xingtai Dongpang Mine -- 4.1.1 Mine Background -- 4.1.2 Application of Water Prevention and Control Technology to Mining Under Potentiometric Pressure -- 4.2 Grouting Technology in Thin-Bedded Limestone to Prevent Water Inrushes from Underlying Aquifers in Zhuzhuang Coal Mine of Huaibei Coalfield -- 4.2.1 Background -- 4.2.2 Large-Scale Advance Grouting Technology in Transforming Limestone into Water Barrier -- 4.3 Utilization of the Top of the Ordovician Limestone in the Sangshuping Mine of Hancheng and the Underground Grouting Transformation Technology -- 4.3.1 Mine Background -- 4.3.2 Utilization of Top of the Ordovician Limestone and Underground Grouting Transformation Technology -- 4.4 Emergency Mitigation Technology of Water Inrush Induced Mine Flooding in Luotuoshan Coal Mine in Wuhai Energy Co., Ltd. -- 4.4.1 Overview -- 4.4.2 Emergency Water-Plugging Technology in #16 Coal Seam Air Return Lane -- 4.4.3 Comprehensive Investigation Technology of Water Inrush Point -- 4.5 Characterization and Remediation of Karst Collapse Columns in Renlou Coal Mine, China -- 4.5.1 Mine Background -- 4.5.2 Water Source Discrimination by Temperature and Hardness Measurements -- 4.5.3 Geophysical Investigations -- 4.5.4 Borehole Exploration and Grouting -- 4.5.5 Summary -- 4.6 Design and Construction of Watertight Plugs in Permeable Karst Collapse Columns in Restoration of Flooded Dongpang Mine, China -- 4.6.1 Mine Background -- 4.6.2 Construction of the Watertight Plug -- 4.6.3 Completion Criteria of Grouting -- 4.6.4 Grout Intake Distribution -- 4.6.5 Evaluation of Plug Effectiveness -- 4.6.6 Summary -- 4.7 Utilization of Paleokarst Crust of Ordovician Limestone in Water Inrush Control in Sihe Coal Mine, Shanxi Province. , 4.7.1 Introduction to Paleokarst Crust -- 4.7.2 Characteristics of Paleokarst Crust at Sihe Mine -- 4.7.3 Hydrogeogical Properties of Fengfeng Formation -- 4.7.4 Thickness of Aquifuge in Fengfeng Formation -- 4.7.5 Summary -- 5 Prevention and Control of Mine Water Hazards from Overlying Aquifers -- 5.1 Water Control Technology for Overlying Thick-Bedded Sandstone Fissure Aquifer in Hujiahe Mine, Binchang, Shaanxi -- 5.1.1 Mine Background -- 5.1.2 Exploration and Prevention Techniques for Water Hazards Posed by the Overlying Thick Sandstone Fissure Aquifer -- 5.1.3 Exploration and Prevention Technologies of Water Hazards from Overlying Thick Sandstone Fissure Aquifers -- 5.2 Prevention and Control Technology for Water Disaster from Bed-Separation Voids of Overlying Formations in Hongliu Coal Mine, Ningdong Coalfield -- 5.2.1 Mine Background -- 5.2.2 Investigation and Mitigation of Bed-Separation Water Inrush -- 5.2.3 Summary of Bed-Separation Groundwater Control -- 5.3 Prevention Technology on Water and Sand Inrush in Halagou Coal Mine, Shendong Coalfield -- 5.3.1 Mine Background -- 5.3.2 Mechanism and Conditions of Water and Sand Inrush -- 5.3.3 Prevention and Control Technology of Water and Sand Inrush -- 6 Investigation and Prevention of Water Hazards from Old Mine Pools in Ordos -- 6.1 Background of Mining Area -- 6.2 Technical Approaches -- 6.3 Geophysical Methods -- 6.3.1 High-Density Electrical Resistivity Imaging -- 6.3.2 Transient Electromagnetic Method -- 6.3.3 Shallow Seismic Method -- 6.3.4 EH4 Magnetotelluric Method -- 6.3.5 Control-Source Audio Magnetotelluric Method -- 6.3.6 Magnetic Method -- 6.4 Achievements by Electrical and Magnetic Imaging -- 6.4.1 Geophysical Survey Layout -- 6.4.2 Results of Electrical Resistivity Imaging Survey -- 6.4.3 Results of Transient Electromagnetic Survey -- 6.4.4 Results of Magnetic Survey. , 6.5 Experience with Reconnaissance of Coal Mine Goafs in Ordos -- 6.5.1 Unified Organization and Implementation Led by Government -- 6.5.2 Reliance on Technical Institutions to Improve Reconnaissance Effectiveness -- 6.5.3 Active Cooperation of Coal Mine Enterprises -- 6.5.4 Concerted Efforts from All Parties -- 7 Technologies in Sealing Massive Karst Conduits in Restoration of a Flooded Open Pit Quarry in West Virginia, United States -- 7.1 Mine Background -- 7.2 Water Source and Pathway Investigations -- 7.3 Concept of Remediation Design -- 7.3.1 Selection of Cut off Methodology -- 7.3.2 Selection of Grouting Concepts -- 7.3.3 Evolution of the Remediation Program -- 7.4 Execution of Mitigation -- 7.4.1 Drilling -- 7.4.2 Grouting -- 7.5 Drilling and Grouting Quantities -- 7.6 Impact of Grouting Program on Quarry Inflow Characteristics -- 7.7 Summary -- References -- 8 Environmental Impact Assessment in Hongliulin Coal Mine -- 8.1 Mine Background Setting -- 8.1.1 Geographical Location -- 8.1.2 Mining History -- 8.1.3 Resources and Reserves -- 8.2 Geoenvironmental Background -- 8.2.1 Physical Geography -- 8.2.2 Topography -- 8.2.3 Stratum Lithology and Geological Structure -- 8.2.4 Aquifer and Aquiclude -- 8.2.5 Groundwater Flow, Recharge, and Discharge -- 8.2.6 Analysis of Groundwater Recharge Conditions in the Mine -- 8.2.7 Geotechnical Conditions -- 8.2.8 Characteristics of Coal Seam -- 8.2.9 Other Human Engineering Activities in the Mine and its Vicinity -- 8.3 Geoenvironmental Impact Assessment -- 8.3.1 Evaluation Scope and Level -- 8.3.2 Assessment of Background Conditions -- 8.3.3 Soil Erosion Intensity -- 8.3.4 Vegetation and Coverage -- 8.3.5 Summary -- 8.4 Predictive Geoenvironmental Assessment -- 8.4.1 Predictive Assessment of Geological Disasters -- 8.4.2 Predictive Assessment of Aquifers. , 8.4.3 Evaluation of Impact on Topography and Landscape.