Abstract: In order to explore the spatiotemporal evolution law of dust diffusion when the underground comprehensive excavator
cuts coal and rock during the dynamic excavation process,taking the 31116 main transportation and slot comprehensive
excavation face of Lijiahao Mine as an example,the dynamic process of the cutting head of the comprehensive excavator cutting
coal and rock was simulated by combining Fluent modeling software,CFD simulation software with the dynamic grid theory. The
spatiotemporal evolution law of dust diffusion and the dust pollution at the position of the driver of the comprehensive excavator
were explored when the cutting head cuts coal and rock at different times (moving to different positions). The results show that
the high-concentration dust mass generated by the cutting coal will move with the movement of the cutting head during the dynamic
coal cutting process of the comprehensive excavator. When the cutting head moves to the return air side to cut the coal
and rock,the dust generated will quickly spread to the position of the driver of the comprehensive excavator with the return air
flow,which seriously affects the physical and mental health and working environment of the driver. In addition,the study of the
whole tunneling workflow of the comprehensive excavator shows that the movement (position change) of the cutting head of the
comprehensive excavator has a great influence on the dust diffusion in the roadway within the space range of 0 m to 7 m in the
front section of the comprehensive excavation work. After that,as the dust particles continue to diffuse to the exit of the roadway,
the dust gradually fills the roadway,and the influence of the position change of the dust source (cutting head) on the dust
pollution distribution at the rear of the roadway is greatly weakened.