Analysis of dust pollution effect of cutting dust and ventilation control parameters at the heading face in plateau mines

To reduce dust pollution at the heading face of plateau mines and improve the working environment at the heading face,a numerical simulation software was used to analyze the change law of viscous fluid and particle motion characteristics according to the change of environmental parameters after the altitude increases.This study investigated the pollution effect during dynamic coal cutting by roadheader,analyzed the diffusion and settlement characteristics of particles at different altitudes,and determined the ventilation technical parameters of “dust control” and “dust extraction” at the heading face according to the law of particle transport.The results show that the dust generated by cutting is affected by the motion of the cutting head and the vortex of the heading face,and mainly moves along the cutting arm to the return air side.When cutting the rock body in left side,the dust is more than that when cutting right side,and the dust particle size is mainly below 40 μm.When the altitude increases,the fluid properties change,leading to the change of particle force and trajectory,and the diffusion distance becomes smaller,the deposition is accelerated,among which the effect on particles above PM5 is more obvious.Although the ability of fluid to carry dust is weakened by altitude increase,leading to a decrease in dust concentration along the heading face,the amount of dust deposition will increase and there is a risk of secondary fly-away.After the installation of pressed-in “wall-mounted air duct”,a clockwise rotating vortex air curtain will be formed at the heading face,which can effectively control the dust in the front section of the heading face,while the “dust removal fan” on the other side will discharge the dust gathered at the head in time.When the radial and axial air volume ratio of the wall-mounted air duct is greater than 0.7 and the pressure-extraction ratio is less than 1,the dust concentration in the area after 20 m from the head is reduced by more than 70% under the effect of “jet,convergence and rotating air curtain”,which effectively reduces the damage of dust to the personnel and mechanical equipment during the heading process.