Underground Coal Mines
Jiskani et al. (4) studied the physical and environmental working conditions of underground coal mines and discovered mining design was inappropriate were workers had to deal with excessive job.
When the 1969 Coal Mine Health and Safety Act was enacted, U.S. coal production was about 600 million tons with about 60 percent underground mining and 40 percent surface mining. Longwall mining accounted for less than 1 percent of the underground production room-and-pillar continuous mining accounted for about 50 percent of the underground.