Failures of sand tailings dams in a highly seismic country

Chile is one of the main copper producers in the world. It is located in a geographical area where mega-earthquakes occur and this fact, together with the development of larger and higher sand tailings dams (with some facilities currently under development having final heights in excess of 250 m), requires that careful attention be paid to the safety and security of these facilities. In this paper, the main failure mechanisms of these sand tailings dams that have generated incidents of different magnitude involving loss of human life, significant environmental damage, and economic losses are described. Some key characteristics of reported incidents in Chile are presented, including failures resulting from the mega-earthquake that occurred on 27 February 2010 (Maule Region, Chile). Finally, the engineering practice and present Chilean regulatory framework, which have allowed progressive improvements in the construction, operation, and closure of such deposits, are described.