In onler to study the safety of coking coal preparation system of coking plant,the samples from dust removal pipeline of crusher and coal conveyor belt are collected and analyzed in industrial analysis and grain size. The results show that the total moisture of dust from crusher is over 6%,higher than that of coal conveyor belt,which is less than 3%. The both grain size is approaching and the most is beyond 2 μm. The blending coal can generate some dust when the moisture is below 6%,which is less than the a...