Transport model of radon in blind roadway with forced ventilation after blasting

In order to guide the design of ventilation in the blind roadway under uranium mine, based on the theories of mass conservation and displacement ventilation, the calculation models for the variation of radon activity concentration with ventilation time after blasting in the throwing-space and in the wind end were firstly built. With the models, the calculation method of the theoretical shortest ventilation time for eliminating radon in the blind roadway which meets radon activity concentration limit was obtained, and the influences of different parameters on the activity concentration of radon in the wind end and the shortest ventilation time to eliminate radon were both analyzed. The results show that after blasting radon activity concentration in the wind end suddenly rises up to peak value after keeping stable for certain ventilation time, and it finally decays gradually to steady value. With other parameters unchanged, the start moment that radon activity concentration suddenly rises up decreases with the increase of the length of the blind roadway, but increases with the ventilation volume. The decay speed for radon activity concentration in the wind end increases with the ventilation volume. The peak value of radon activity concentration increases with the uranium grade of the driving face. The shortest ventilation time to eliminate radon increases with the length of the blind roadway and the uranium grade of the driving face, and decreases with the increase of the ventilation volume. (authors)