La Subsidenza nelle coltivazioni sub level stoping: il caso della miniera di Acquaresi (Sardegna)

The article illustrates the study of the subsidence phenomenon occurred in the Acquaresi mine district (South west of Sardinia) and the monitoring program set up for its control. The analysis has been developed on the base of the investigations carried on in the last 15 years together with the aim of the numerical simulation. Two different mechanisms of collapse have been finally individuated: the slipping of the limestone blocks constituting the horizontal pillars of the mine rock structure and the collapse of the vertical walls of the extraction chambers. The system adopted for monitoring the stability evolution of the rock pillars is based on the measurement of the energy released during the slipping process in the form of micro seismic waves. After 5 years, the monitoring system has proved to be suitable for controlling the behaviour of the pillars stability but its reliability has still to be improved.