New geologic studies suggest that underground mining of coal may cause more environmental damage over long periods of time than surface strip mining followed by proper reclamation, according to the U.S. Geological Survey (USGS). While underground mining initially disturbs only a small portion of the surface above a mined area, long-term effects from ground subsidence can be more severe and widespread than the effects from modern strip mining and reclamation.

USGS geologists C. Richard Dunrud and Frank W. Osterwald emphasized that their investigations involved only coal beds with no more than 60 meters of overlying rock and soil, although other studies show that subsidence and consequent environmental damage can occur from mining coal deeper than 60 meters.