Abstract: The coal washery used to operate with a series of troubles, such as high moisture of raw coal feed, liability of raw coal to pile up on or spill out from belt conveyor, high labor intensity of handpicking workers, difficulty of reduction of clean coal ash and excessively high calorific value of middlings. To cope with the problems as described above, improvement is made of the washing system, which involves, among others, dewatering of raw coal, introduction of high-frequency vibrating screen and rewashing of crushed middlings. Application of the improved washing sytem has enabled the plant to operate in a more flexible manner and produce more consistent products, thanks to its ability to lower raw coal moisture to 13%, reduction of clean coal ash by one percentage point and decrease of calorific value of middlings by 4 MJ/kg.