Compressive Strength, Burst Proneness, and Failure Modes of Model Coal Pillars Related to the End Constraint and Geometry.
Paper in Rock Mechanics A A Balkema Accord Ma 1987 :173-180
This paper describes tests conducted to determine the relationships between strength, constraint, geometry, and failure mode in coal pillars broken under compression. The model pillars used were 54 mm in diameter with varying diameter-to-length ratios and end conditions, and were composed of coals from Colorado and Utah. The study concluded that the roof-pillar-floor sequence, not the pillar geometry alone, should be an important factor in the design of coal pillars.
Paper in Rock Mechanics, A. A. Balkema, Accord, MA, 1987, PP. 173- 180