| Popis: |
The Ingurtosu Pb-Zn mine, situated in the southwestern part of Sardinia, has been in production from the beginning of the last century up to 1968. The orebody consists of galena/sphalerite/barite/siderite veins in Ordovician arenaceous and phyllitic sediments, near the contact with a Hercynian batholith. Abundant tailings were collected in a pond from which they were discharged during the winter months into the sea via the Rio Naracauli stream. Today this area of outstanding scenic beauty, is degraded by tailings and waste rock scattered all along the stream. Material derived from mining activities was studied for grain size, mineralogical and geochemical composition. The Rio Naracauli was sampled over a length of ten kilometers at regular intervals. The results can be summarized as follows: (a) tailings contain a varying, but often quite high, percentage of Pb; lower percentages were found for Zn and Cd; (b) a sharp increase in dissolved Zn, Cd and Pb was observed in the Rio Naracauli where it leached the tailings; and (c) tailings and waste rocks should be recycled or revegetated. |
