Mining for coal creates topography that can be hazardous to visitors. Highwalls are large vertical surfaces (steep drop off) that are the outer limit of mining activities. These steep cliffs have been subject to movement in the past, and are less stable than natural cliffs, posing a danger to those walking on the surface or below.
In 2018 and 2019, a massive project was undertaken to remove highwalls. These areas were graded to create gentle slopes, and have been vegetated with seed mixtures to reduce erosion.
Mining can also create subsidences which are caused by the collapse of rock layers above an abandoned coal mine. Subsidences can manifest as sinkholes or troughs. In addition, vertical shafts and abandoned mine openings can pose a threat and have been sealed before the area is opened to the public.