Numerical simulation investigation for the pollution characteristics of dust particles in the fully mechanized mining face under different air humidity conditions

In this study, airflow and dust particle diffusion in the 3401 fully mechanized mining face of Xin’an Coal Mine considering the humidity field was numerically simulated. Based on the simulation results, the influence of relative humidity on dust migration and diffusion was revealed from two aspects, namely, dust concentration and dust diffusion distance. The following findings were obtained. Under seven relative humidity conditions, the degrees of dust pollution to the sidewalk vary notably. When the relative humidity is 45%, 55% and 65%, the dust concentration at the sidewalk ranges from 763 mg/m3to 1301 mg/m3. When the relative humidity is 95%, the dust concentration at the sidewalk is below 700 mg/m3, and the pollution is the slightest. As the relative humidity in the fully mechanized mining face rises, the dust diffusion distance generally shows a decreasing trend. Under different humidity conditions, the maximum differences of the dust diffusion distances at the sidewalk and the machine roadway are 20.36 m and 33.2 m, respectively. Finally, 75%− 85% is selected as the optimal relative humidity environment for coal mining, in accordance with the “people-centered” idea in ergonomics and the simulated dust pollution characteristics.