If you have access to OneMine as part of a member benefit, log in through your member association website for a seamless user experience.
|High-extraction mining of coal and other stratified minerals has a predictable effect on the surface and subsurface. Impacts on ground waters in overlying strata and on surface waters, that are associated with overlying sequential zones of collapse, fracturing, aquiclude, constrained strata, and surface disturbances can be anticipated. Since first quantified around 1979 in Bureau of Mines sponsored contract research work and others (and often adopted by state regulators), with zone extents based upon multiples of mined seam height of 24 to over 60 for the fractured zone, much new data have become available. In examining the sources of data and the methods and intents of the researchers of over 65 case histories, it became apparent that the strata behaviors were being confused with overlapping vertical extents reported for the fractured zones and aquiclude zones depending on whether the researcher was interested in water intrusion into the mine or in water loss from surface or ground waters. These more recent data, and critical examination of existing data, have led to the realization that the former "Aquiclude Zone" defined for its ability to prevent or minimize the intrusion of ground or surface waters into mines has another important character in increasing storage of surface and shallow ground waters in response to mining with no permanent loss of waters. This zone is here named the "Dilated Zone." The existence of the dilated zone explains the ratios of up to 60 times the mined thickness. Surface and ground waters can drain into this zone, but seldom into the mine, and can eventually be recovered through closing of dilations by mine subsidence progression away from the area, or filling of the additional void space created, or both. A revised model has been developed which accommodates the available data, by modifying the zones as follows: ? collapse and disaggregation extending 6 to 10 times the mined thickness above the panel ? continuous fracturing extending approximately 24 times the mined thickness above the panel, allowing temporary drainage of intersected surface and ground waters ? development of a zone of dilated, increased storativity, and leaky strata with little enhanced vertical permeability from 24 to 60 times the mined thickness above the panel above the continuous fracturing zone, and below the constrained or surface effects zones, whose thickness or existence is dictated by the zones above and below ? maintenance of a constrained but leaky zone above the dilated zone and below the surface effects zone, whose thickness or existence is dictated by the zones above and below ? limited surface fracturing in areas of extension extending up to 50 ft or so beneath the ground surface|
Additional chapters/articles from the SME-ICGCM book Proceedings of 12th International Conference on Ground Control in Mining
|Bolting Practice In Longwall Gateroads At The Miike Colliery||Cable Supports For Improved Longwall Gateroad Stability||Comparisons Of Active Versus Passive Bolts In A Bedded Mine||Flexibolt Flexible Roof Bolts: A New Concept For Strata Cont||The Design And Application Of Hercules Cribs For Underground||Cyprus Shoshone Tailgate Roof Control: Case Study||Engineering Methods For The Design And Employment Of Wood Cr||The Use Of Foamed Cement Cribs At American Electric Power Fu||A Comparison Of Support Reactions To Retreat Longwall Front||Entry Design For Optimum Stability In A Multi-Seam Environme||Gate Entry Design For Longwalls Using The Coal Mine Roof Rat||A Test Of Predictive Numerical Models To Simulate Entry Desi||The Coal Mine Roof Rating (CMRR) A Practical Rock Mass Class||Comparative Analysis Of Longwall Gateroad Designs In Four De||Further Improvements In The Roof Beam Tilt Method Of Gateroa||Application Of A Static And Geophysical Monitoring System Fo||Flexible Support Design For Gateroads Of Retreating Longwall||Longwall Support Monitoring||Case Studies Using Mine-Wide Monitoring Systems For Geotechn||An Application Of Tree Classification Method In Analysis Of||Image Analysis Development And Application To Fracture Patte||Mathematical Modeling Of Strong Roof Beds In Longwall Mining||Load Deformation Behavior Of Simulated Longwall Gob Material||Monitoring Of The Interaction Effects Over A Longwall Panel||Design, Monitoring And Evaluation Of A Pre-Driven Longwall R||Ground Control And Safety Considerations During Longwall Rec||Utilization Of Polymer Grid Structures In Shield Recovery Op||The Impact Of Variability In Coal Strength On Mine Planning||Underground Application Of Optimization||Modern Geotechnical Exploration And Mine Design||A New Method For Longwall Pillar Design||A Rock Mass Strength Concept For Coal Seams||Techniques To Increase Yield Pillar Residual Strength||Application Of Seismic Tomography For Assessing Yield Pillar||Structure, Strength And Relaxation Of Interbuden For Input I||Rock Compaction Caused By Dewatering In Poorly- Consolidated||Correlation Between The Effect Of Confining Pressure On Comp||Characterization Of Structural Integrity And Stress State Vi||Rock Mechanics Property Data Bank For Coal Measure Strata||Failure Modes Of Mine Tunnels In Stratified Rock Structures||Determination Of Plate Size Effect On Ultimate Bearing Capac||Development And Evaluation Of A Floor-Bearing Capacity Test||Investigation Of Blast Damage And Underground Stability||Development Of A Slope Stability Program For Improved Quarry||Material Instability Hazards In Mine Processing Operations||Mine Design Considerations For Surface Subsidence Control||Surface Fracture Development From Mine Subsidence In Eastern||An Integrated Approach To Subsidence Modelling And Predictio||Effect Of High-Extraction Coal Mining On Surface And Ground||Economic Evaluation Of Subsidence Damage Mitigation Techniqu|