Abstract: In order to reduce the generation of slime, increase clean coal yield, and tackle the problem arising from unchecked going of oversize into undersize product, work is made on renovation of the plant’s coarse slime recovery system.Through the change of the direction of flow of coarse slime sieve bend’s underflow, retaining coarse particles with cyclone classifier which is fitted with densiometer, liquid level meter and manometer and is capable of maintaining an optimum working condition through intelligent adjustment, the coarse slime recovery equipment are made possible to operate always in an optimal state.Practice shows that through two times of recovery of part of the coarse particles contained in the coarse slime screen’s underflow, the volume of coarse particles brought into fine slime is much reduced and effectively controlled, leading to therefore reduced content of coarse slime in thickener and improved economic performance of the plant.