Investigation on the dust migration behavior and safety zone in the fully mechanized mining face.

High dust concentration produced in the fully mechanized longwall mining face is a significant threat to the front-line workers. It is critical to discover the potential safety zone to ensure routine personnel operation. Fluent 2020 R1 is employed to reappear the spatial dust distribution based on the gas-solid coupling theory. The dust migration behavior and safety regional division are illuminated in the spatial longwall mining face. The formation of dust concentration trigonum is introduced with the particle diffusion force analyzed. The YZ plane safety zone area shows an increasing trend at X = 70-95 m. The respirable dust concentration decreases from the peak value to the safe value at sidewalk 4.0-4.6 m. The safety zone area and length both pose a linear growth with the increasing wind velocity. In the XY plane, the safety zone area and length extend by 1.26 times and 1.33 times, respectively. The horizontal plane creates a greater growth rate of safety zone than the vertical plane. The drum rotation creates a wind circumfluence that exerts an obvious effect on the dust distribution around the coal cutter. The sidewalk region mainly situates in the safety zone for the personal squat down, while it is gradually exposed to the dangerous dust pollution situation as the breathing height rises.