Characterization and modeling of acid mine drainage in a highly acidic stream (Trimpancho Mining Complex, SW of Spain)

Abstract

The Trimpancho mining complex is a group of abandoned mines affected by acid mine drainage. The present work was focused on studying the hydrochemical behavior of the receiving stream and the secondary phases associated with potential natural attenuation processes. The results indicate extreme acidity conditions, with pH in the range of 1,97 to 2,87. At the time of the sampling campaign, no clear spatial distinction was observed in relation to the different sources of acid mine drainage. Several secondary minerals were identified, mainly close to the waste dumps or suspended in the watercourse. Besides the ability to immobilize pollutants through precipitates, this abandoned area requires rehabilitation as it still has a high environmental risk of water contamination.