Análise do potencial de risco de rompimento em barragens de rejeito de mineração do Estado do Pará utilizando a metodologia Risk-Based Profiling System (RBPS).

Abstract

The serious and very serious socioenvironmental disasters related to disruption in mining tailings dams have been exhibiting worldwide, a growing tendency since the 1960s and this is directly related to the increasing production of waste. In this context, there is a fundamental necessity for risk and safety analyzes of these dams, which can be done through methods that estimate the probability occurrence of disruption events, in order to make the decision to have a process more focused and safe. One of these analyzes is the so-called Risk-Based Profiling System (RPBS), which allows us to gauge, from qualitative data, the probability of a disruption and its probable consequences, which comes from the four most frequent scenarios (static, hydrological, seismic and operation and maintenance). This analysis was applied to six mining dams in the State of Pará, municipalities of Parauapebas, Paragominas and Canaã dos Carajás. The results showed, in the universe of analysis, dam B3 was the one with the highest failure rate (455.18), followed by the dam B1 (428.63) and the dam B2 (375,66). However, the dam with the highest risk for downstream areas was B2 with a Total Risk Index of 969.20 points, mainly due to the large number of possible people affected (12,900 people). This same dam is the one that would affect the greatest number of socioenvironmental components, defined then with possible cause of extreme damages. Compared with the risk analysis established in law, the RBPS analysis showed similarities, but more detailed in function of the four scenarios of analysis that will be generated, rather than just one. A risk analysis guide for dams was created as well, which came out from this present study.