Hydrochemistry of pit lakes in the Portuguese sector of the Iberian Pyrite Belt

Abstract

The Iberian Pyrite Belt (IPB) is a world-class metallogenic province with volcanogenic massive sulphide ore deposits. Most ore exploitation occurred since pre-Roman time, creating extensive galleries, wells, waste-dumps and pit lakes. These last structures are a concern for their potential environmental impact because they accumulate large volumes of mine water affected acid mine drainage. The present work classifies the pit lakes based on the surface water hydrochemistry. Using the Ficklin diagram for classification, pit lake waters vary from acid, high-metal to high-acid, extreme-metal and exhibit similarities with other pit lakes from the Spanish sector of the IPB.