d Valley-unloading stress trends, Coal Mining Geology, Kentucky Geological Survey, University of Kentucky

Valley-unloading stress trends

Valley-unloading fractures can be anticipated and planned for by making topographic overlays of mine areas to determine sections of planned mines that might be beneath valley axes, especially valleys with steep walls. Many stream valleys are oriented along preferred regional trends in Appalachia (Overbey and others, 1973; Jansky and Valane, 1983; Hylbert, 1984).

Example of roof falls (red) in a underground coal mine (A) concentrated beneath a valley. (B) Cross section of the valley showing the position of the coal mine and (C) concentration of stresses beneath the valley bottom. The coal bed is at a depth of 160 ft beneath the valley floor (modified from Molinda and others, 1992, Figs. 7 and 21).
Example of roof falls (red) in a underground coal mine (A) concentrated beneath a valley. (B) Cross section of the valley showing the position of the coal mine and (C) concentration of stresses beneath the valley bottom. The coal bed is at a depth of 160 ft beneath the valley floor (modified from Molinda and others, 1992, Figs. 7 and 21).


 

 

 

 

 

 

 

Last Modified on 2025-11-17
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