On 25th January 2019, at Brumadinho in the State of Minas Gerais, Brazil, a mine waste deposit, made up of several tailings dams, serving the Córrego de Feijão iron mine, collapsed and generated a huge mudflow. First, it struck the mine facilities and after a few minutes the town of Brumadinho, located some 7 km downstream. 259 people lost their lives and 11 persons went missing.
The mudflow, with a total volume of 12 million cubic metres, caused severe environmental damage and the destruction of numerous buildings and a railway bridge. There was fear that a fourth tailings dam, damaged by the mudflow, might also fail.
The Stava 1985 Foundation and the “19 luglio Val di Stava” Association pinpoint the fact that the risk of failure of tailings dams is still underestimated. Unfortunately, this risk is growing with the passing of time, since many unsafe tailings dams, which should be closed and reclaimed, are still in use.
In order to reduce the risk of failure of mine waste deposits, the use of mechanical filtering systems and other mud dehydration methods, such as “dewatering”, should be made compulsory. By means of these methods, it is possible to eliminate the water in the final deposition and storing processes of tailings in waste disposal earth structures.