Sentinel-1 Data for Monitoring a Pre-failure Event of Tailings Dam

In the present work, an Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) technique has been used to detect the displacements of the upstream tailing dam of Vale’s Córrego do Feijão. The study area is located to 9 km east of Brumadinho, Minas Gerais, Brazil, where on 25 January 2019 the Dam was affected by a catastrophic failure causing a huge flood that destroyed the mining officers, houses, roads and 257 people died as a result of the collapse. The dam was built in 1976 by Ferteco Mineração using the upstream heightening method, the latter consists to build the dam body using the deposited tailings. The Vale’s dam height was 86 m and its crest length was 720 m. The tailings occupied an area of 249.5 thousand square meters and the disposed volume was 11.7 million cubic meters. The study has been carried out using the 64 descending satellite images acquired as Single Look Complex (SLC) from Europe Space Agency of the Copernicus Programme. The data have been processed by means of Coherent Pixels Technique (CPT) algorithm. The result consisted of a map of displacements on the body dam from the 2016 to 2019, in the period before the collapse. Furthermore, the study of the time series of displacements allowed to assess the evolution of dam structure deformations. The study confirms that the A-DinSAR technique could be very useful tool for monitoring tailings dam and to reduce the risks.