Comparação do quantitativo de elementos construtivos de barragens de rejeito alteadas à montante e à jusante

Abstract

Tailings dams are important for the maintenance of the mining industry in Brazil and in the world, executed to carry out in order to carry out the containment of the surplus of the ore beneficiation process, in a safe and efficient way. Upstream, Downstream and Center Line raising techniques are used, however, since the Mariana-MG and Brumadinho-MG ruptures, which occurred in 2015 and 2019, respectively, the ANM (National Mining Agency), together with the competent regulators, banned construction of new dams by the method and creating a plan to un-characterize these dams until 2030. Recurrence of accidents involving them is mainly due to the relatively lower cost compared to other techniques. The question here is to know which elements make up such a cost. The objective of this work is to compare the constructive elements that directly influence the construction cost of a dam with heightening upstream and a dam with heightening downstream, both with equivalent tailings containment volume, determined by Autodesk AutoCAD software. For this purpose, the safety factors for the stability of the downstream slopes of the two types of dams were analyzed using the software Slope/W, from GeoStudio. At the end of the analyzes and comparison of the constructive elements in relation to costs, the hypothesis was confirmed that the downstream dam has a greater quantity, when comparing the volumes of materials than the upstream dam, mainly due to the costs linked to the foundation and construction of the massif.