Mining Publication: Behavior of a Coal Pillar Prone to Burst in the Southern Appalachian Basin of the United States

One of the more pressing engineering problems for deep longwall mines in the southern Appalachian Basin is to design longwall systems that will eliminate catastrophic coal pillar failure from the working environment. The purpose of this U.S. Bureau of Mines study is to quantify the behavior of a particular size abutment pillar prone to burst or bump (local terminology). Because of the 24.4-M (80-ft) square abutment study pillar is within the pillar size commonly used in this region, understanding the behavior of this pillar should aid in future efforts to design optimum mining strategies. This research has attempted to construct the stress and convergence profiles of the pillar in order to evaluate the ultimate strength, pillar deformation modulus, visco-elastic deformation, and violent failure characteristics during longwall mining. This information reflects the overriding influence of the local geologic characteristics on bursts, provides the field measurements needed to verify concurrent modelling studies, and suggests some basic mechanisms associated with the coal pillar bursts discussed in this paper.