## 4 Results and Discussion
### Influence of Wind Velocity on Dust Distribution in the Heading Face  
In this study, dust is described over a period of 600 s after the explosion to analyze its dispersion over time and space within the roadway. As evident from Figures 7-9, the influence of wind velocity within the ventilation outlet on dust dispersion over time and throughout the entire tunnel is apparent. Initially, after the explosion, a high concentration of dust is emitted from the tunnel's face, forming a dense dust cloud concentrated near the tunnel's face for approximately 10 s. Subsequently, due to the interplay between the initial dust velocity and the wind velocity circulating within the tunnel, the dust disperses along the tunnel. For a wind velocity of 9 m/s (Figure 7), it takes about 150 s for the dust to disperse throughout the entire tunnel. The trend of dust concentration decreasing over time is evident from Figure 7, as larger particles settle and dust escapes from the tunnel. Similarly, for a wind velocity of 12 m/s, it takes about 110 s for full dust dispersion, while for 15 m/s (Figure 8), it takes 90 s, and for 18 m/s, it takes about 80 s.  
With a wind velocity of 18 m/s (Figure 8), dust disperses more rapidly, and the dust concentration decreases more quickly compared to the other models. Higher wind velocities lead to a significant reduction in dust concentration. In Figure 9, the graph illustrates the relationship between the distance of dust diffusion within the tunnel over time with various velocity parameters. This relationship is represented by a quadratic function. Higher wind velocities result in faster and more extended dust diffusion at the same time. Figure 6: Graph depicting the average wind velocity across longitudinal cross-sections along the heading face. Figure 7: Dust dispersion results in the tunnel space-time domain for \(V=9\) m/s and \(V=12\) m/s. In Figure 10, at the level of \(y=1.5\), which corresponds to the breathing height of workers, it is evident that higher wind speeds lead to a significant and rapid reduction in dust concentration. Within the first 10 s following the blasting event, larger-sized dust particles quickly settle down or are captured due to gravitational forces, resulting in a rapid decrease in dust concentration. From the contour plot of dust concentration in the horizontal plane at the height of \(y=1.5\), it can be concluded that dust concentration decreases as wind speed increases. Figures 11-14 show the largest variations in dust concentration at positions 1 m, 3 m, and 6 m from the mirror, which are areas where workers are concentrated performing tasks during the furnace excavation process. The figures also indicate that for these three positions, at wind speeds of \(V=18\) m/s, the dust concentration is the lowest, followed by \(V=15\) m/s, \(V=12\) m/s, and finally, \(V=9\) m/s. Considering the relationship between wind speed and dust concentration at the positions at 1 m, 3 m, and 6 m, and at a height of 1.5 m above the ground, Figures 11-14 show that initially, higher wind speeds create areas of high dust concentration and chaotic movement. With \(V=18\) m/s, the highest average dust concentration occurs around 20 s, resulting in higher dust concentrations than the models with other speeds shown in Figures 11 and 12. However, after this time, the dust concentration tends to decrease more rapidly with increasing wind speed. Figures 13 and 14 show that over the entire research period, dust removal efficiency on the furnace  
Figure 8: Dust dispersion results in the tunnel space-time domain for \(V=15\) m/s and \(V=18\) m/s. Figure 9: Dust diffusion graph in time and space. road improves with increasing wind speed. The results of dust concentration at positions 1 m, 3 m, 6 m, and \(y\) = 1.5 indicate that a model with \(V\) = 18 m/s provides the best dust reduction efficiency. Figure 11 shows the highest dust concentration results at the position \(y\) = 1.5 for different wind speeds.