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Mining Publication: The Unpredictable Life Cycle of a Coal Pillar

NOTE: This page is archived for historical purposes and is no longer being maintained or updated.

Original creation date: July 2007

Image of publication The Unpredictable Life Cycle of a Coal Pillar

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.

Authors: SC Tadolini, P Zhang

Conference Paper - July 2007

NIOSHTIC2 Number: 20032433

Proceedings of the 26th International Conference on Ground Control in Mining, July 31 - August 2, 2007, Morgantown, West Virginia. Peng SS, Mark C, Finfinger G, Tadolini S, Khair AW, Heasley K, Luo Y, eds., Morgantown, WV: West Virginia University, 2007 Jul; :90-96