Study on the characteristics of dust diffusion during a truck travelling in an open-pit coal mine affected by the vertical wind shear.

Heavy trucks in open-pit mines are significant sources of dust. The diffusion of dust is primarily influenced by wind flow. The surface wind speed exhibits an exponential distribution as height increases. To investigate dust diffusion under the influence of wind shear, a numerical model was developed using real-scale data through computational fluid dynamics. The results indicate that wind shear significantly affects near-ground wind speeds. The ground-level wind speed near the rear of the truck exceeds the dust lift-off speed, reaching over 6 m/s. The acceleration of the ambient wind speed leads to extensive areas of turbulence with increased intensity. The location of the vortex zone represents the primary area of negative pressure. A higher ambient wind speed accelerates the dust discharge and generates a greater negative pressure, reaching -68 Pa at a wind speed of 9 m/s. The dust concentration behind the truck initially increases before subsequently decreasing. Notably, the local dust concentration at a wind speed of 9 m/s is lower than that at a wind speed of 5 m/s. The obstruction of airflow by the truck cab can result in elevated dust levels on the driver's side. Furthermore, high dust concentrations along driving paths necessitate appropriate truck spacing to protect operator health.