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Design parameters of roof support systems for predriven longwall recovery rooms.
Trans Soc Min Metall Explor 2006 Jan; 318:87-96
Reduction in the recovery time required and improvements in safety during a longwall face move have compelled coal mine operators to examine and use predriven longwall recovery rooms. The recovery entry is developed at the longwall stop position and supported ahead of time so that the required combinations of standing and internal supports can be installed before the longwall face approaches. A calibrated three-dimensional finite-element model, developed in conjunction with an underground test area, provided the critical component and design principles for a comprehensive parametric study. The study indicates that vertical, horizontal, and shear stresses concentrated on the outby abutment pillar corner of the recovery room, resulting in deformations in the immediate roof above the primary roof support anchorage level. The results of the numerical model and field site observations indicated that the combination of the internal bolting system and the standing concrete supports are critical for the successful and safe extraction of the longwall equipment. Cable supports installed at and angled over the pillars can help stabilize the disturbed zone above the adjacent fender and outby pillars; however, standing supports are required in most sedimentary roof conditions to increase stability and assure a safe longwall extraction.
Mining-industry; Coal-mining; Underground-mining; Longwall-mining; Ground-control; Ground-stability; Geology; Injuries; Safety-research
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Transactions of the Society for Mining, Metallurgy, and Exploration
Page last reviewed: March 11, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division