Mines without good safety culture were often lethal to the workers in centuries past, and although the per capita rates of injuries and deaths are lower in modern mining, they are still nonzero.
Personal protective equipment lessens this risk, but maintaining adequate protection is not easy, especially as advancing mining technologies have made mechanized fracturing of the rock and coal more efficient on a per-worker basis, making more dust to control in tighter spaces and time frames.
Coal mines use a combination of boreholes and high-resolution seismic reflection data to identify the larger faults and avoid the most faulted areas at the mine planning stage.
If the seam splits, due to a delta collapsing, sand and silt sediments pile up on top until that area is covered.
This may make all or part of the coal seam uneconomic to mine as it is too thin.