The opencast mining of previously underground.mlned coal seamsDec 12, 1985 . several potential methods of mining the coal. The paper . The sequence of mining operations is . 1-The sequence of operations In method 1.method of operation of a coal,Coal - Ohio History CentralCurrently, there are about 90 active coal-mining operations in 15 eastern Ohio . to the older room-and-pillar method where up to half the coal remained in the.
method of operation of a coal