Dynamic dispersion and high-rise release of coal dust in the working surface of a large-scale mine and application of a new wet dust reduction technology

Abstract

To determine the dynamic dispersion process of coal dust in a working surface characterized by a large mining height, as well as the formation time and the dispersion range of a heavy pollution area of coal dust in the same working surface, we restored the field production conditions and performed a simulation analysis by using the FLUENT software. The results of our analyses showed that: within 30–120 m from the lower wind side of the hydraulic support's advancing point, the minimum airflow speeds along the machine passage and the sidewalk were 0.41 m/s and 0.24 m/s, respectively. At T = 60 s, coal dust initially formed at ⁓ 40 m from the downwind side of the front drum and the average mass concentration in the high-concentration coal dust contaminated area was 1840 mg/m3. At T = 600 s, coal dust diffusion achieved a dynamic balance, at 60 m from the downwind side of the front drum; in this case, the average coal dust mass concentration in the high-concentration coal dust dispersion area reached 1470 mg/m3. A new wet dust reduction technology was installed at the starting location of a highly polluted area: the average coal dust reduction rates were 73% and 82%. These results confirm the efficiency of the proposed technology in reducing the spread of coal dust pollution and in avoiding the problem of high coal dust concentration in large mining environments.