Use of geoprocessing in the simulation of mining tailings dam rupture

Abstract

The study of hypothetical dam rupture aims to understand the flow through the valley downstream of the volume released by a tailing dam rupture to seek preventive actions in the event of a real rupture. In this research, the open and free program for simulating dam ruptures, called HEC-RAS (Hydrologic Engineering Center-River Analysis System), software developed by the US Army Corps of Engineers Hydrologic Engineering Center is used for simulation dam ruptures. A hydrodynamic simulation of the rupture of dam B1, in Brumadinho, Minas Gerais, Brazil, was applied, is developed for this test area. Six simulation scenarios are defined, for the configuration of the hydrodynamic model of the valley downstream of the B1 dam, where all the input data identical besides the DTMs that are configured from a rescaling process of an original DTM obtained from a LiDAR (Light Detection and Ranging) survey, ranging the spatial resolution from 1 m to 25 m. Each of these DTMs is introduced into the simulation processes in HEC-RAS. A direct comparation with data obtained from the real rupture event is made to validate the results of these simulation scenarios. The flooded areas obtained in the model were assessed using the performance indicator F that considers the under and overestimated areas. The other results are subjected to a descriptive statistical analysis through the coefficient of variation (Cv) to verify the discrepancies between the values ​​for each scenario. Form the the results, it is concluded that the scenarios presented very similar performance, in terms of the rupture of the studied dam, with the velocity being the variable most sensitive to the spatial resolution change, without presenting a very discrepant response in relation to the other metrics analyzed.