An independent panel of academics, engineers and other experts, in November 2019, released a draft set of international standards for tailings storage facilities (TSF). During mining operations, ore is reduced into sand-sized particles and mixed with water before the valuable minerals are removed and the remaining milled rock slurry—called tailings—flows to the TSF, an engineered impoundment. It is estimated there are over 3,500 TSFs globally.
The driver for these draft international standards is two recent catastrophic failures of TSFs in Brazil. In January, a TSF owned and operated by Vale in the state of Minas Gerais, near Brumadinho, collapsed, sending a tidal wave of mid and other debris downstream that killed over 250 people. Another TSF owned and operated by Samarco failed in Minas Gerais at Mariana in November 2015, killing 19 people and spreading pollutants over 400 miles of surface waters, eventually reaching the Atlantic Ocean.