Mine tailings dam failures: review and assessment of the phenomenon


There are more than twenty thousand mining tailings dams around the world, which contain tailings from ore exploitation and processing. The failure of these structures is one of the most recorded and destructive ground movement phenomena, both in terms of the number of victims and the environmental impact generated. Since the initial construction work, progress has been made in controlling this risk, particularly in the light of feedback from historical accidents. Nevertheless, many of these structures do not offer sufficient safety guarantees when exceptional events, or even structural or anthropogenic failures, occur.
The risk could be controlled when the mine is in activity and managed by an operator. On the other hand, when the mine is abandoned and return to the natural environment, these dams remain and are likely to be affected by ruptures, the most destructive of which may, under certain conditions, generate a flow phenomenon that may impact the downstream part of the structure.
This report deals with the evaluation of the hazard of ground movement that these dams can generate. It particularly proposes main principles and tools for evaluating the flow-type phenomenon which can be associated to their failure. It is based on this experience feedback from the identified accidentology, as well as a consultation of the bibliography relating to this subject. A number of criteria to assess the phenomenon is proposed, to accompany the assessment work on a specific dam site.