Análise de sensibilidade dos parâmetros reológicos em software bidimensional para estudos de ruptura de barragem de rejeito

Abstract

The number of mining dams worldwide has increased, reflecting the growth in demand and technological advances, which in turn have led to faster tailings generation. The increase in tailings volume requires storage alternatives, whether surface, underground, or underwater disposal. The focus, however, is on surface disposal, more specifically in earth dam reservoirs. This type of structure undergoes rigorous safety controls; nevertheless, two major accidents in Brazil have brought it into the spotlight, leading to a loss of public trust among downstream communities. Brazilian legislation has been revised and now requires the geotechnical and rheological characterization of stored tailings to develop action plans that ensure the safety of all those involved in the event of a dam failure. The selection of parameters for these analyses is not yet well established in the literature. Although rheology is not a new field, it has gained more attention in recent studies. In this context, two-dimensional numerical simulations were performed using RiverFlow 2D software for a hypothetical tailings dam failure scenario that complies with current legislation. The simulations used real values obtained from rheological characterization tests of two iron ore tailings samples taken from a reservoir. All scenarios were developed using identical input data in the numerical model, modifying only the rheological parameters based on the volumetric concentration (CV). The results showed differences starting from the models with 30% CV. Variations in velocity, depth, wave arrival times, and flood extent demonstrated the impact of solids concentration and rheological properties on flow behavior. Furthermore, the influence of rheological parameters from the two samples on the results was evident, indicating that only two samples were insufficient for this study. This finding suggests the need for more detailed criteria for the rheological characterization of tailings in hypothetical dam failure studies. Additionally, further research is needed on this topic, considering the many uncertainties, variables, and social and environmental impacts involved.