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Multiple-seam interactions are a major ground control hazard in many U.S. underground coal mines. In some U.S. coalfields, particularly in central Appalachia and the West, the majority of today's mines are operating above and/or beneath previously mined seams. The effects of multiple-seam interactions can include roof falls, rib spalling, and floor heave. These can seriously disrupt mining operations and threaten the safety of miners. In early 2006, a West Virginia coal miner was killed by rib roll that occurred in a high-stress zone beneath a remnant structure in an overlying mine. Fortunately, not every multiple-seam situation results in hazardous conditions. Indeed, the vast majority do not. For the past several years, the National Institute for Occupational Safety and Health has been conducting research to develop better techniques for predicting the location and severity of multiple-seam interactions. During this investigation, more than 50 mines were visited across the U.S. coalfields. Nearly 300 case histories were collected and analyzed using multivariate statistical techniques. The study also employed the numerical model LaM2D to estimate the multiple-seam stress, the Analysis of Longwall Pillar Stability (ALPS) and the Analysis of Retreat Mining Pillar Stability (ARMPS) programs to determine pillar stability factors (SFs), and the Coal Mine Roof Rating to measure roof quality. The study focused on the two most common types of multiple-seam interactions: 1. Undermining, where stress concentrations caused by previous full extraction in an overlying seam is the main concern; and. 2. Overmining, where previous full extraction in an underlying seam can result in stress concentrations and rock damage from subsidence. The study confirmed that overmining is much more difficult than undermining, and isolated remnant pillars cause more problems than gob-solid boundaries. For the first time, however, it was possible to quantify these effects in terms of the equivale

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Zaradenie knihy Knihy po anglicky Society & social sciences Politics & government

• Celý názov: Proceedings
• Podnázov: New Technology for Ground Control in Multiple-Seam Mining
• Autor: Department of Health and Human Services, National Institute for Occupational Safe
• Jazyk: Angličtina
• Väzba: Brožovaná
• Počet strán: 98
• EAN: 9781288506767
• ISBN: 9781288506767
• ID: 08258613
• Nakladateľ: Bibliogov
• Hmotnosť: 191 g
• Rozmery: 246 × 189 × 5 mm
• Dátum vydania: 02. January 2013

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