Coal Mine Subsidence and Structures

Gray, Richard E.; ,

Coal Mine Subsidence and Structures

by Richard E. Gray, GAI Consultants Inc, Monroeville, PA, USA,

Document Type: Proceeding Paper

Abstract:

Underground coal mining has occurred beneath 32 multiplied by 10**9m**2 (8 million acres) of land in the United States and will eventually extend beneath 162 multiplied by 10**9m**2 (40 million acres). In areas of abandoned mines where total extraction was not achieved, roof collapse, crushing of coal pillars, or punching of coal pillars into softer mine floor or roof rock is now resulting in sinkhole or trough subsidence tens or even hundreds of years after mining. Subsidence due to total extraction can be predicted fairly reliably with regard to both areal extent and downward displacement of the ground surface, whereas subsidence associated with abandoned mines is unpredictable in both magnitude and extent. Differences in geology, in mining, and building construction practice between Europe and the United States preclude direct transfer of European subsidence engineering experience. Building damage cannot be related simply to tensile and compressive strains at the ground surface. Recognition of the subsidence damage role played by ground-structure interaction and by structural details is needed.

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