SOIL GEOCHEMICAL SURVEY IN PANASQUEIRA MINE SURROUNDINGS (CENTRAL PORTUGAL): MINING, METAL(LOID)S AND RELATED ENVIRONMENTAL IMPACT

Mining activity is one of the industrial activities that produce more residues, most of then left in piles and/or tailing dams. Mine wastes containing high sulphide concentrations produce acid mine drainage, that will leach contaminants, resulting in pollution of soils. Soils can be easily contaminated by meta(loid)s due to their direct contact with the chemical processes of metal liberation and mobilization that result from mining operations. These consequences are very problematic when the mining and ore treatment operations are performed in the vicinity of villages. The economic exploitation of Panasqueira Sn–W mine has been focused on wolframite, cassiterite, chalcopyrite, several sulphides, carbonates and silver sulphosalts. The beneficiation processes have given rise, during a long production period, to a large amount of sulphide-rich waste, contained in tailing ponds.