Effect of different sources and local conditions in the post-mining contamination by acid mine drainage: three case studies in Iberian Peninsula (SW Europe)

Abstract

The Iberian Peninsula, comprising Portugal and Spain (SW Europe), has a long tradition of exploiting metals in different metallogenic provinces. The present study shows three cases of mining contamination in different regions of the Peninsula associated with distinctive acid mine drainage sources. Hydrochemical and mineralogical characterizations were performed for the three case studies. The results revealed the influence of ore deposit type, paragenetic, and climate diversity on hydrochemistry. Although different climate conditions and acid mine drainage sources exist, the relationships between physical-chemical indicators are similar for the distinctive sites. However, the magnitude of contamination is different, being highest in the São Domingos mine (Iberian Pyrite Belt). The effect of natural attenuation is also verified, especially by dilution and precipitation. Seasonal variation is more pronounced in the rainiest region under study (Valdarcas mine).