The El Teniente tailings dam failure, 1928
The second known disaster due to the failure of mine tailings dams took place on 1st December 1928 in the mining village of Sewell, Chile, where a similar incident had already taken place in 1915.
The Barahona sand tailings dam, a facility serving the El Teniente copper mine, located in the Andes south of Santiago, was over 2 km long, 63 m high and contained 29.5 million tons of mine waste material. Following a very strong earthquake, the outer embankment of the tailings dam suddenly collapsed.
As a consequence, millions of tons of mud flowed into the riverbeds of the Barahona and Coya rivers, destroying several square kilometres of farmland and causing the death of many people.