Design, construction, operation and the effect of fines content and permeability on the seismic performance of tailings sand dams in Chile
The significant growth of the metallic mining industry over the last few decades has made the construction of tailings deposits of large dimensions necessary, tailings being the fine mining waste resulting from the milling and concentration processes. The most common types of tailings dam in mining are the tailings sand dam, a special kind of hydraulic fill dam, for two main reasons: because such dams need to be built over a longperiod of time, and due to the low cost of sand available from the tailings. In particular, this paper analyses the behaviour of tailings dams in Chile, one of the most seismically active countries in the world. The design and construction of tailings dams, as well as the effect of drain gravels and filter materials on the geotechnical behaviour of the tailings sands, are also discussed. The importance of the operational phase is addressed, because in tailings dams this phase can last many years and be the determinant in the final behaviour of the dams. Finally, recommendations to mitigate risks along the complete life cycle of the dams are given, and permeability and fines content effects as well as sand tailings drained and undrained strength are considered.