Study on temporal and spatial evolution law for dust pollution in double roadway ventilation system of short wall...

To explore the laws of variations in the evolution of dust pollution within a double tunnel ventilation system at a short wall continuous mining face, a numerical simulation of air flow movement was conducted in this study. Results showed that after the wind flowing in the supporting and heading tunnels reached the head, the wind sides returned at speeds of 6.5 and 10.3 m/s, respectively. Affected by the air volume and pressure differences between the two tunnels, part of the air flow entered the connecting tunnel at an average speed of 0.8 m/s and moved to the heading tunnel. Affected by the turbulence at the driving face, a high dust concentration zone with a maximum dust concentration of 1700 mg/m³ was formed in the tunnels at a distance of 15 m from the heading. Dust blocked by the shuttle car accumulated and settled near it and formed a dust zone with an approximate average concentration of 750 mg/m³ at a distance of 19-23 m from the heading. The dust produced by the bolt machine formed a dust mass with an average concentration of 900 mg/m³ at a distance of 0.5-4.5 m from the head. Quantitative analyses of the changes in dust concentration with time at the position of a driver of the continuous mining machine, shuttle car, and anchor bolt machine were conducted, and functional formulae for the quadratic distribution were obtained. Suggestions for dust control were then proposed.