Investigations on the possibility of heavy metal immobilization in soils contaminated by mining activities

A variety of technologies is available for the environmental remediation of soils contaminated by mining activity. These methods consist in removing contaminants by means of in-situ or ex-situ processes (soil-washing, physical separation, phytoremediation, leaching, etc.) or in immobilizing metals so as to minimise their release into the environment. Here the possibility is explored of applying metal immobilization techniques to soils severely contaminated by heavy metals in land down-valley from the tailings pond of the Montevecchio-Levante mine in SW Sardinia (Italy). The results of tests on low value materials such as ore processing wastes demonstrated the immobilization ability of "red muds", bauxite ore processing waste, and fly-ash produced by coal fired power stations. The main features of a site set up for pilot tests under natural climatic conditions are described.