Application of a dry cover system to remediate acid rock drainage generation in the uranium mining and milling site of Pocos de Caldas, Brazil

摘要

This paper addresses the remediation of acid rock drainage originated in one of the waste rock piles of the mining and milling site of Pocos de Caldas. The dump consists of a total amount of 29.8 x 10~6 tons corresponding to a volume of 12.4 x 10~6 m~3. It was estimated that acid drainage generation will last for 600 years and because of that permanent remedial solutions will have to be considered. In this paper the efficiency and costs of a dry cover system was assessed. It was found that the application of a material with a diffusion coefficient to oxygen of 10~(-9) m~(-2) and with a thickness of 1.0 m would reduce the pollutant loads to acceptable values. The overall costs of this remediation scheme would amount US$ 10 million.