Abstract: With the improvement of mechanization, the content of slime in raw coal is increasing. There are some problems in most coal preparation plants, such as low separation accuracy of coarse slime and serious tailings running away from coal. Through screening test and interference bed separation test of raw coal with large slime volume, the difference of interference settling state of coarse slime with different particle size is analyzed. At the same time, aiming at the limitation of traditional jamming bed sorting, the technical route of twice sorting to improve the accuracy is put forward, and a three-product jamming bed testing machine is developed. The results of industrial practice show that the separation accuracy of coarse slime is greatly improved after three-product interference bed separation, and the ash content of coarse and concentrate products is reduced by 3%. At the same time, the tailings are effectively avoided and the recovery rate of concentrate is improved.