Back-Analysis of the 2015 Fundão Tailings Runout using TUFLOW Software

January 7, 2026

This paper presents a back-analysis of the 2015 Fundão (Brazil) tailings dam failure using TUFLOW’s nonNewtonian flow simulation capabilities, supported by rheological testing and field observations carried out by Machado (2017). While TUFLOW is considered an industry-standard software, its usage in North America is relatively limited and peer-reviewed research on tailings flow case study validation is sparse. The Fundão event, the largest tailings release in history by volume, provides an opportunity to evaluate the applicability of TUFLOW in TDBAs. Despite data limitations (primarily the absence of design information for Santarém Dam), this study produced a hydrograph using the release volume from the Fundão facility and inundation extents at Santarém Dam, which when modelled with rheological parameters from in-situ test samples, suitably reproduce the observed inundation extent. Iterations during the modelling process concluded that simulations with a higher solids concentrations (Cv) resulted in a greater inundation extent and depth of final tailings deposition. The range of modelled solids concentration (Cv range of 49-54%) produced limited influence on the modelled inundation extent and time to peak flow depth. This finding has been attributed to the unique downstream topography (channelized topography to a natural basin with a downstream hydraulic control) and the large release volume. In other contexts, where lower release volumes and/or unconfined terrains were to be applied, the Cv and rheology parameterisation could have a larger influence upon the runout extent and dynamics. TUFLOW’s Advection-Dispersion (AD) module allows for simulation of flows with dynamic Cv, but its performance may depend on accurate parameterization of dispersion coefficients, settling velocity, and decay rate. Future work could involve testing the AD module’s performance on other case studies and sensitivity analyses to evaluate how AD parameters could affect simulation results and TDBA projects.

Machado, N., Rana, N., Palmen, L. 2025 " Back-Analysis of the 2015 Fundao Tailings Runout using TUFLOW Software,” in Proceedings of the Tailings and Mine Waste 2025 Conference, 2-5 November 2025, Banff, Alberta: University of Alberta Geotechnical Centre