https://phys.org/news/2018-07-mountaintop-coal-yearly-appalachia.html

The tool uses satellite imagery to identify and map the annual extent of mining activity across a four-state area including portions of Kentucky, Tennessee, Virginia and West Virginia.

In the journal PLOS ONE, researchers estimate that between 1985 and 2015, an average of 21,000 acres was converted to bare earth and rubble in central Appalachia each year—an area about half the size of Washington, D.C.