Consideration of Overburden Lithology for Subsidence Prediction.
Proc Workshop on Surface Subsidence Due to Underground Mining Morgantown West Virginia, 1981 :17-33
Geological differences among various coalfields restrain the applicability of subsidence prediction using existing European methods. To modify these methods for domestic conditions, the Bureau of Mines developed a method of assessment to evaluate the lithological effects on subsidence in the northern Appalachian Basin by examining data collected from 16 longwall panels in the coalfield. The assessment is partially completed, and the results to date show that the ratio of maximum subsidence to the extraction thickness, known as the subsidence factor, can be expressed in terms of the width-to-depth ratio by a simple exponential equation that has a coefficient tentatively considered as the subsidence index. This index varies with the lithology of a particular site and can be expressed in terms of the percent distribution of weak and strong rocks in the overburden.
Proc. Workshop on Surface Subsidence Due to Underground Mining, Morgantown, West Virginia, 1981, PP. 17-33