Hello Virtual Section members,
Join us for a complimentary Henry Krumb lecture on Tuesday, June 22 at 9:00 am MDT.
Henry Krumb Lecturer Mark Alexander Van Dyke presents:
Moderate Cover Bleeder Entry and Standing Support Performance in a Longwall Mine: A Case Study
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Title & Abstract
Moderate cover bleeder entry and standing support performance in a longwall mine: a case study
Bleeder entries are critically important to longwall mining for the moving of supplies and miners and the dilution of mine air contaminants and must stay open for many years. Standing support in moderate cover bleeder entries were observed, numerically modeled, and instrumented by researchers at the National Institute for Occupational Safety and Health (NIOSH). The measurements of the installed borehole pressure cells (BPCs), standing support load cells and convergence meters, and roof extensometers are presented in this paper in addition to the numerical modeling results and visual observations made by the NIOSH researchers in the bleeder entries. The results include the effects of multiple panels being extracted in close proximity to the instrumented site as well as over one and a half years of aging. As expected, standing supports closer to the longwall gob showed the greatest load and convergence. The roof sag appeared generally independent of the proximity to the longwall gob. The BPC readings were driven by both the proximity to the gob and the depth into the pillar. The results of this study demonstrated that the entry roof can respond independently of the pillar and standing support loading. In addition, the rear abutment stress experienced by this bleeder entry design was minimal. The closer the mine development, pillar, or supports are to the gob, the greater the applied load due to rear abutment stress.
About the Speaker
Mark Alexander Van Dyke | Physical Scientist (Geologist) NIOSH/PMRD, Ground Control Branch | Pittsburgh, Pennsylvania, United States
Mark is from Morgantown, West Virginia, He enlisted in the Navy in 2000 as an electronics technician and served 5 years on the submarine USS Boise, and deployed for Operations Enduring and Iraqi Freedom. After the military he graduated with a B.S. in Geology from West Virginia University in 2009. As a geologist for the West Virginia Geological Survey, Mark worked on the Marcellus Shale gas well GIS database and bedrock mapping project. He worked for CONSOL Energy as a ground control geologist for 6 years covering 12 longwalls in the Pittsburgh and Pocahontas coal seams. He is currently working for NIOSH as a geologist with four years of service and is involved with many projects such as Design Methodology for Rib Control in Coal Mines, Design Procedures for Gateroad Ground Control and Underground Stone Mine Pillar Design in Challenging Conditions.
Rachel Grimes, SME Sections Coordinator
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