Influence of tailings from a sulfide mine on drainage water quality, 60 years after its abandonment. Case study in SW Portugal.

Abstract

The GeoMatRe project aims to find low-cost solutions for water and sediment rehabilitation using raw geomaterials, in abandoned mines of the Iberian Pyritic Belt. One of our case studies is the Caveira mine in southwestern Portugal, where large piles of mining waste, containing significant amounts of metals, record the long history of its exploitation for Au and Ag. After the exhaustion of its reserves, the extraction of the remaining metals (Cu, Pb, Zn) and S continued, until its abandonment during the 60s of XX century. This work has two objectives: (i) to study the influence of mine and mine tailings drainage on water quality by analyzing the dissolved and particulate material in drainage waters, and (ii) to determine whether there are differences in these waters according to the different climatic conditions of the last two winters. Therefore, we will conduct a new sampling campaign, which will allow us to make a comparative study.