The unpredictable life cycle of a coal pillar.
Proceedings of the 26th International Conference on Ground Control in Mining, July 31 - August 2, 2007, Morgantown, West Virginia. Peng SS, Mark C, Finfinger GL, Tadolini SC, Khair AW, Heasley KA, Luo Y, eds., Morgantown, WV: West Virginia University, 2007 Jul; :90-96
A unique circumstance created by monitoring a pre-driven longwall recovery room permitted measuring the stresses of a coal pillar throughout its entire life cycle in less than a week. A fender pillar, created in approximately the middle of a longwall panel at a depth of 650 ft, transformed from a solid barrier pillar - to a yielding pillar - to a residual pillar as 3 ft slices were methodically removed with the longwall shearer. The complete transformation, or life cycle, took place in less than 12 hours. The stresses were quickly transferred from the pillar onto the standing pumpable concrete supports and into the outby pillars. Roof to floor closure measurements, combined with the timing of the pillar behavior, provides a detailed look at the uncontrollable convergence of underground mine openings. Pillars remain the most important form of "primary support" and understanding these life cycles is vital for safe and efficient mine design, in both room and pillar and longwall panel extractions.
Ground-control; Ground-stability; Mining-industry; Underground-mining; Coal-mining; Mine-shafts; Room-and-pillar-mining; Longwall-mining; Injury-prevention; Accident-prevention
Peng-SS; Mark-C; Finfinger-GL; Tadolini-SC; Khair-AW; Heasley-KA; Luo-Y
Proceedings of the 26th International Conference on Ground Control in Mining, July 31 - August 2, 2007, Morgantown, West Virginia