Recirculation of air at injection airing of blind faces as a cause of their gassing

Abstract

The phenomenon of air recirculation during the operation of partial ventilation fans as a cause of gasification of dead-end excavations is insufficiently studied. As is known, recirculation at partial ventilation is a harmful phenomenon, and in gas mines dangerous, as it leads to an increase in methane concentration in the workings above the established standards. In workings where blasting operations are carried out, recirculation prolongs the time of face ventilation and can lead to an increase in the concentration of harmful gases. I. A. Babokin, analyzing the causes of methane accumulation before blasting over a ten-year period, came to the conclusion that in 8% of cases the accumulation was due to recirculation. The current Coal and Shale Mine Safety Regulations provide a number of restrictions that preclude the possibility of recirculation.