
Dec 02, 2015 suglorbiust.ac.bw. Abstract The availability and the utilisation of drill rigs have great impact on the output of a. mine. These can be optimised While underground mining, which allows coal companies to extract deeper deposits of coal, is viewed as less destructive than strip mining, the effects of mining widespread damage to the environment. In room-and-pillar mines, columns of coal are left to support the ground above during the initial mining process, then they are often taken out and ...