Critérios operacionais para redução da contribuição de sedimentos gerados em pilhas de estéril

Abstract

Failure to construct and / or operate sterile piles can lead to significant environmental impacts due to the management of sediments from erosion processes, especially in the rainy season, making it necessary to prepare mitigation plans that take into account the behavior morphodynamic characteristics of the land, as well as the rate of sedimentation or the sediment load that can be incorporated into the watercourses during the different constructive stages of the structures, in order to guarantee the integrity of the flora around the enterprise, as well as to optimize the destination of the tailings and sediments within the space defined for the mining activities. In this sense, this study aims to analyze the process of sterile disposal and solids generation in iron ore sterile disposal cells from open pit mines, thus indicating operational criteria that subsidize the reduction of the contribution of sediment generated in batteries for the environment. In order to carry out this work, a Vale sterile stack was installed in the Mineral Province of Carajás, called PDE NW II, for which a documentary research and critical analysis of the main factors involved in the erosive dynamics of the structure was carried out. In this context, rainfall histories, soil cover classification, size and morphology of the contribution basin are included, as well as the quantification of sediment carried by the structure to downstream portions. The methodology used was efficient, mainly because it was able to correlate cause and effect, in the evaluation of the routines of implantation and operation of the piles, in order to make preventive actions intuitive, in order to minimize the contribution of sediment to the environment.