Computational Fluid Dynamic Simulation of Inhaled Radon Dilution by Auxiliary Ventilation in a Stone-Coal Mine Laneway and Dosage Assessment of Miners

Inhaled radon status in the laneways of some Chinese stone-coal mines is a cause of concern. In this study, computational fluid dynamics simulations were employed to investigate three flowrates of the dilution gas (2.5, 5, and 7.5 m3/s) and radon distributions at realistic breathing levels (1.6, 1.75, and 1.9 m). The results showed that there are obvious jet-flow, backflow, and vortex zones near the heading face, and a circulation flow at the rear of the laneway. A high radon concentration area was found to be caused by the mining machinery. As the ventilation rate increased, the radon concentrations dropped significantly. An airflow of 7.5 m3/s showed the best dilution performance: The maximum radon concentration decreased to 541.62 Bq/m3, which is within the safe range recommended by the International Commission on Radiological Protection. Annual effective doses for the three air flowrates were 8.61, 5.50, and 4.12 mSv.