Avaliação geotécnica de uma barragem de rejeitos na baixada cuiabana por meio de métodos determinísticos de análise de estabilidade

Abstract

Mining plays a crucial role in the economic development of Brazil, providing essential mineral resources for various sectors of society. With large-scale mining, the benefits come concomitantly with the inconveniences faced in ore extraction, including the waste generated from this operation. Tailings dams aim to contain the waste deposited there. In this study, a stability assessment of a specific section of the BR PYRAMID tailings dam in the lowlands of Cuiabá was carried out, where gold mining waste is stored. The results of the stability analyses were compared with the minimum safety factor values required by Brazilian legislation, based on NBR 13.028/2017, which establishes the minimum safety factors for these structures to be considered stable. The methodology used for these analyses was the slice's method, using the model proposed by Bishop. Triaxial test analysis was used to determine the necessary geotechnical and hydraulic parameters, such as friction angle, cohesion, permeability coefficient, and natural specific weight. The analyses conducted included normal operation, critical operation, seismic demand of normal operation, and seismic demand of critical operation. The safety factors found in the analyses described above are the minimum safety factors required by the standard, both for the upstream and downstream slopes. With these safety factors, it was concluded that the analysed section of the BR PYRAMID dam met the minimum safety factors required and complies with Brazilian norms and legislation regarding dam safety.