Geoprocessamento aplicado na conformidade legal dos volumes de bacias de rejeitos de mineradoras

Abstract

After the breach of SAMARCOs tailings dam in November of 2015, it was made clear that a better understanding and inspection of the dams was needed. One of the ways of inspecting eventual irregularities on this structures, that are located in vales of hydrographic basins, is verifying if the mining companys declared volume of the tailings dams are according with the information given in the processes of environmental licenses. With the social and environmental hazards caused by the breaching of the mining dams in the state of Minas Gerais in sight, this academic research offer a methodology for the independent measuring of the tailings volume on the BarragemMaravilhas II, located in the Itabirito county, through a space-time analysis, using geoprocessing tools and geomorphological analysis. For that, the volume of the tailing in the BarragemMaravilhas II was measured through subtraction of the 1977s MDE (before building the dam) and the actual (2017) MDE. The more precise method of measurement was the Grade Regular Retangularand as a result an evaluation of 74.366.812,68 m³ of tailings volume in the BarragemMaravilhas II was obtained. This result shows that the dam is in conformity with the environmental legislation, which foresees a maximum volume of 76.000.000 m³. This methodology can be replicated in other dams to have a more precise surveillance of this kind of structures, minimizing or even avoiding possible environmental, social and economic hazards due of the mining activity.