What is Mine Subsidence?
Mine subsidence is the collapse or settlement of the ground surface from failure of an underlying mine. The most common mine subsidence events are from the extraction of coal. However, it also occurs from underground mining of other ores or natural resources as well. This would include mines in gold, iron, zinc, trona, salt, gypsum, limestone, etc. The nature of the mining and depth play a significant role in how the subsidence expresses itself on the ground surface. Based on essentially these two factors the mine subsidence can express itself on the ground surface as pothole sized to large sinkholes and small to very large trough to bowl-shaped depressions.
The mine subsidence movements can be very gradual to rapid depending on the type of mine failure. Example of larger and smaller sinkholes are shown in Figure 1 and 2. Examples of smaller to larger sag depressions of the ground surface are depicted in Figures 3 and 4.
For more information on mine subsidence see: Establishing Mine Subsidence Risk. In selecting a mine subsidence expert see: What to look for in a Geotechnical Engineering Expert.
FIGURE 1 SINKHOLE FROM MINE SUBSIDENCE
FIGURE 2 LARGE SINKHOLE
FIGURE 3 SMALLER SAG DEPRESSION FROM MINE SUBSIDENCE
FIGURE 4 LARGER SAG DEPRESSION FROM MINE SUBSIDENCE