Challenges with Upstream Tailings Dams

In the wake of the Brazilian tailings dam failures, the safety of upstream dams is coming under intense scrutiny by the communities, investors and the mining companies. Upstream tailings dams depend upon the strength of the deposited tailings and there can be a wide range of conditions and variabilities within the deposited tailings. The strength of the tailings varies with the type of tailings (e.g. Fine tailings to Coarse tailings), deposition practices and changing ore types. Static liquefaction of tailings has been the cause of recent failures and although it is a long-recognized phenomenon, the conditions that can ‘trigger” static liquefaction are not well understood, and the awareness of these conditions are not widespread in the technical community. Common problems with assessment of stability of upstream dams are discussed along with practices to improve the safety of upstream dams.