Abstract: The ash of the coarse clean coal product of the plant is considerably high because of the high content of high-ash fine slime in coarse-grained slime. As a result, the heavy medium separation process has to reduce the ash of its clean coal product to an unnecessarily low level. To address the knotty problem, it is proposed to use a stacked-type high-frequency vibrating fine screen for desliming and ash reduction of coarse slime. Practice shows that the application of the screen can lead to effective reduction of the ash of coarse clean coal product.