SPONTANEOUS INRUSHES OF WATER IN UNDERGROUND MINES.

Several water inrushes occurring in Italian underground mines were carefully observed in order to study causes and circumstances, of such events and to investigate the possibility of predicting these inrushes. It turned out that whereas the spontaneous inrushes, i. e. those determined by natural episodes, are accompanied by clear warning signals linked with changes in the water regime and, possibly, of mine gases. However, the inrushes caused by the mining activities are accompanied by few and indistinct warnings. With respect to the spontaneous inrushes, the observation of events prior to the occurrence of inrushes suggest that the gas flow rates can be correlated to the hydrodynamics activities around the mine, whereby possible inrushes can be forecasted by means of the gas flow rates. With respect to mining induced inrushes, however, since clear warning signals are lacking, it is proposed that preventive measures may be used rather than forecasting.