Abstract: As lignite is not amenable to wet cleaning, the IDS separator is used by the opencast mine to treat the 300~80 mm raw coal. Practice shows the use of the separator can lead to effective removal of gangue with a removal rate as high as 95.5%, reduction of load and operating cost of subsequent crushing process, reduction of percentage of coal misplaced in refuse to 1.72% and percentage of refuse in coal to 2.77%, effective elemination of gangue in coarse coal, lessening of environmental protection pressure, improvement of economic performance, and realization of comprehensive utilization of coal resources.