Influence of Recirculation Flow on the Dispersion Pattern of Blasting Dust in Deep Open-Pit Mines

The recirculation within a deep open-pit mine is a significantfactor contributing to the deterioration of the atmospheric environment.However, the underlying mechanisms of how recirculation influencesthe dispersion pattern of dust clouds within the deep open-pit minehave not been clearly elucidated. In this research, the dispersionpatterns of blast dust clouds were investigated in a deep open-pitmine located in northern China. This research initially conducteda similar experiment to verify the existence of recirculation flowin the experimental mine, which can cause dust particles to aggregatetoward the upwind slope. In response to the dust pollution issue indeep open-pit mine blasting operations, this study conducted a numericalsimulation analysis based on on-site measurement data to investigatethe effects of varying natural wind velocity, natural wind direction,and blast location on the diffusion pattern of blasting dust. Theresults indicate that natural wind velocity (v),natural wind direction (& alpha;), and blast location (d) affect the distance between the blast location and the recirculationcenter point (D (recir)), subsequently influencingthe diffusion pattern of blasting dust. The recirculation flow effectinfluences the diffusion of dust toward the upwind slope under smaller D (recir) values, leading to widespread and long-termpollution within the mine. Under larger D (recir) values, dust diffuses toward the downwind slope with the straightflow of wind, resulting in less pollution within the mine. Throughorthogonal experiments, the equation D (recir) = -120.61v (2) + 237.27v + 0.82d - 0.07 & alpha;(2) + 6.75 & alpha; + 151.08 was established inthis deep open-pit mine, which provides a basis for predicting thediffusion pattern of blasting dust and control strategy in this deepopen-pit mine.