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|Clay veins, also referred to as clay elastic dikes, have been responsible for numerous underground injuries and fatalities. These hazardous structures are also responsible for increased production costs during all phases of mining. For these reasons, the Bureau of Nines has investigated the physical characteristics of and roof instability problems associated with clay veins in order to make support and other mining recommendations. In addition the occurrence and origins of clay veins were examined to determine whether or not the structures could be projected into unmined portions of the coalbed. This investigation included portions of the Arkoma, Illinois, Northern Appalachian, Southern Appalachian, and Uarrior Coal Basins. Virtually a11 clay veins observed or documented occurred in the Illinois and Northern Appalachian Basins. Observed clay veins ranged in sire from 1 inch to 16 feet In cross-section and were found under shale, siltstone, sandstone, and limestone roof rock. Individual clay veins were predominantly composed of claystone; however, limestone. siltstone. and sandstone infilled clay veins do occur. Clay vein formation has been associated with the infilling of fissures which result from compressive, tensile, or shear ground failures. These gaping fissures were propagated by compactional processes and/or tectonic stresses active during and subsequent to coal iff cation. Associated fault, fracture, and slickenside planes commonly parallel clay veins and disrupt the lateral continuity of the immediate and, sometimes, main roof. When clay veins parallel or subparallel the direction of face advance the roof is segmented into cantilever beams causing unstable conditions. Therefore, the strata on either side of the clay vein must be bolted and strapped together to form a beam.|
Additional chapters/articles from the SME-ICGCM book Proceeding of the Fourth Conference on Ground Control in Mining (ICGCM)
|Truss Bolting On-Cycle in Jane Mine Lower Freeport Seam||Design Of A Roof Truss Bolting Plan For Bear Mine||Tension-Torque Relationship For Mechanical Anchored Roof Bol||A Novel System For Automatic Installation Of Cement Grouted||Load Transfer Mechanics In Fully-Grouted Roof Bolts||An Investigation Of Longwall Pillar Stress History||Impact Of Horizontal Load On Shield Supports||Interaction Between Roof And Support On Longwall Faces With||Roof Control With Polyurethane For Recovery Of Kitt Energy?s||First Caving And Its Effects--A Case Study||Staubbekampfung An Schildausbau In Bruchbaustreben (Combatin||Yield Pillar Applications--Impact On Strata Control And Coal||Constraint Is The Prime Variable In Pillar Strength||Massive Pillar Failure--Two Case Studies||Investigations Of Underground Coal Mine Bursts||Destressing Practice In Rockburst-Prone Ground||Statistical Characterization Of Coal-Mine Roof Failure: Sugg||Pillar Design - Continuous Miner Butt Section And Longwall D||Design Factors In Near-Seam Interaction||Remote Sensing For Roof Control And Mine Planning: An Overvi||Design, Construction And Performance Of A Single Pass Lining||Computer Modelling And In Situ Instrumentation Techniques: A||A Sonic Wave Attenuation Technique For Monitoring Of Stress||The Radio Imaging Method (RIM) -- A Means Of Detecting And I||Clay Veins: Their Physical Characteristics. Prediction, and||Evaluation of the Point Load Strength for Soft Rock Classifi||Ground Control Experiences in a High Horizontal Stress Field||Horizontal Stresses and Their Impact on Roof Stability at th||Ground Control Problem Associated with Longwall Mining of De||Geotechnical Aspects of Subsidence over Room and Pillar Mine||Proposed Criteria for Assessing Subsidence Damage to Surface||Surface Subsidence. in Longwall Mining--A Case Stud||An Integrated Approach to the Monitoring and Modeling of Gro|