Dust dispersion and prevention in deep concave open-pit coal mines

To address dust diffusion in deep concave open-pit coal mines, this study examined Fushun East open-pit coal mine in Liaoning Province, a deep concave open-pit coal mine. Employing theoretical analyses, field testing, numerical simulation, and experimental validation, we comprehensively investigated the mechanisms of dust generation, migration, and effective control strategies, revealing the mine dust migration patterns and providing practical foundations for dust control systems. Based on field measurements, road transportation was identified as the primary source of dust emissions. Atmospheric flow within the deep concave open-pit mine follows a complex recirculation pattern. Using COMSOL numerical simulation software, a fluid-solid coupling dust dispersion model was established based on the scale conditions of deep concave open-pit mines, revealing the formation mechanism of negative pressure dust accumulation zones induced by the inclination angle of the pit’s lateral slopes, while the pit’s shape illustrated dust migration trajectories. The air flow inside the pit was vortex-induced, primarily concentrated near the intake air areas of the pit. The study simulated air flow and dust particle trajectories in the flow field around mining vehicles, determining that the air disturbance range during vehicle movement extends to 1.5 times the vehicle’s volume. It is found that under low-speed driving conditions, dust dispersion behavior is mainly controlled by external wind speed and direction, with relative speed playing a dominant role in affecting the dust dispersion rate around mining vehicles. This in-depth study of dust sources, generation mechanisms, dispersion patterns, and precise control measures in deep concave open-pit coal mines has significant implications for achieving coordinated development between economic benefits and environmental protection.