Ground Conditions That Can Shut Down a Longwall--how They Can Be Predicted, Avoided, and Controlled.
Longwall USA PP 119-134 :119-134
Ground control failures continue to create safety hazards on many U.S. longwalls, often resulting in expensive downtime. In the course of a recent series of geotechnical surveys, the U.S. Bureau of Mines identified a number of geologic structures and conditions that contribute to ground control failures during longwall mining. This paper describes those structures and conditions, their effects, and the coal basins in which they can be expected to cause the most problems. Based on the experiences reported by the surveyed mines, suggestions are given for predicting when these features might occur, and how they might be avoided or controlled.
Longwall, USA, PP. 119-134