EMBREA-MUD a tool for the simulation of tailings dams breaching

Failure of a tailings dam can have disastrous consequences. However, to date, it cannot be accurately simulated. Therefore, the EMBREA-MUD model was developed to fill this gap within the DAMSAT project which is funded by the UK Space Agency. The model is a two component breach modelling tool that simultaneously takes into account outflows of both water and mud (i.e. tailings). The model can also represent erosion of dam material by both water and tailings, erosion of tailings by water as well as dynamic forces between water and tailings layer. There are however some challenges related to simulation of tailings dam breaching and in particular the breach initiation which can be due to overtopping, piping or other mechanisms, such as foundation failure or sliding. As dams are designed to be stable, these initial failures are un-foreseen and therefore cannot be accurately quantified based on available data. In this paper, these mechanisms were investigated to check whether they could be reproduced assuming an initial notch in the dam crest. The case of Mount Polley was used, where the dam failed initially due to foundation failure. The results showed that the “initial notch” approach indeed produced similar peak outflows and time intervals