Evaluating Bump Control Techniques Through Convergence Monitoring.
Coal Mining 1987 Jul; 24(7):42-46
This paper describes bump control techniques employed at the Olga Mine in McCowell County, West Virginia. Stress reduction techniques such as shot firing and auger drilling were evaluated using convergence monitoring, and roof and floor extensometer data confirmed that convergence is generally caused by a coal pillar yielding under stress rather than by separations in the roof or the heaving of the floor.
Coal Mining, V. 24, No. 7, July 1987, PP. 42-46