Avaliação numérica do dimensionamento de sistemas de cobertura para reservatórios de disposição de resíduos de mineração

Abstract

The mine tailings consisting of sulfide minerals in the presence of water and oxygen can generate an acidic aqueous solution called acid mine drainage. The most commonly technique used to prevent this problem is to cover the tailings deposit with soil in a controlled manner. This thesis reviews the concepts, fundamentals and equations related to the design of soil cover systems applied to the closure of mining waste disposal sites. It also introduces the types of cover systems and current technologies available. A hypothetical study of a tailings dam closure case was conducted to describe the main design stages of a soil cover system. This study concluded that the design of soil cover systems applied to closure mining waste disposal facilities is complex, multidisciplinary and requires a large amount of input data that are not always easy to obtain. The influence of parameters variation and use of different methodologies to design soil covers was quantified and it was also indicated how these variations affect the results. Finally, numerical simulations were done considering different Brazilians tailings as a cover material. It was found that the use of tailings as a building material of cover systems can be accepted, bringing environmental and economic advantages.