Assertion: mountaintop removal mining | /r/CapableOf | begin in 1970
Facets:
Source sentences:
text: Less expensive to execute and requiring fewer employees, mountaintop removal mining began in Appalachia in the 1970s as an extension of conventional strip mining techniques.
text: Less expensive to execute and requiring fewer employees, mountaintop removal mining began in Appalachia in the 1970s as an extension of conventional strip mining techniques.