Recovery modelling and water resources of the abandoned open pit talc-chlorite-feldspar mine excavations at Lasasai-Bonucoro, Central Sardinia, Italy

In the district of Orani, central Sardinia, several talc-chlorite-feldspar bodies, hosted in Palaeozoic metamorphics and granites, have long been mined by open- pit operations. The mining activity has deeply modified the original landscape of the Lasasai-Bonucoro area. Thus the rearrangement of this area, in particular of the open-pit works that are now occupied by newly formed pools, filled with water from aquifers flowing along faults crossed by mining operations, should be considered as an overall project of landscape restoration. In the first phase of this work, the environmental and hydrogeological characterisation and the general definition of different zones characterised by different sets of intervention operations has already been made. The following step will include the detailed definition of the different technological interventions to be performed. In order to attain a rehabilitation of this area, first of all the interventions will include: 1)smoothing and re-modelling of local morphology in its still rough sites, namely a few points of the mine benches and dumps, by removing the volumes in excess and settling them again in the hollows, on the base of the indications obtained from opportunely plotted sections; 2) restoration of the removed soil covers, and rehabilitation of the newly formed surfaces after waste disposal, trough re-vegetation techniques including settlement of vegetal soil and nutrients, herbaceous essence hydro-sowing, temporary automatic sprinkling; 3) rehabilitation of the corrected slopes, and in general of the remaining poorly vegetated surfaces, trough the above re-vegetation techniques. The above operations will result in a slightly modified plane-altimetrical and landscape arrangement. However these interventions will be sufficient to reach a new environmental qualification, characterised by several opportunities of exploitation. Particular conditions, such as the constant outflow of good-quality water and the amenity of the surrounding countryside, are favourable to an easy accomplishment of the above suggestions and perhaps of other ones. Thus the possible utilisation of the resources of Lasasai-Bonucoro at least includes the following opportunities, which do not exclude each other: 1) solace locality; 2) mineral water bottling. In this way, the environmental recovery of Lasasai-Bonucoro will lead to new social-economic, cultural, recreational, and touristy opportunities.