They represent the number one cause of death and injury in abandoned mines. Because no light enters a mine shaft, the depth is difficult to assess. The shaft collar may be loose and unconsolidated. This material can break away, causing individuals to fall into the shaft. Darkness, loose debris, false floors, rotten timbers, and water can hide vertical openings.
Explosives become highly unstable with time and when exposed to the elements.
Old dynamite often contains nitroglycerine, which can explode with the slightest disturbance. Perhaps the most dangerous explosives are blasting caps. Rodents can scatter blasting caps on the mine floor. If stepped on, they will explode. Highwalls are vertical cliffs.