Abstract: The cleaned coarse slime and clean small coal products are sold by Baoshan Coal Mine Washery in a mixed manner for improving the plant's economic performance. To adapt to the property of the coal, the coarse slime is treated with H. M. cyclone, and the effect in separation of the slime with this method is evaluated through testing with a stand-alone H. M. cyclone. Test results show that for treating the coarse power coal slime, the cyclone can operate remarkably well and is capable of meeting production requirement; the cyclone can work with an ecart probable moyen value of merely 0.068 g/cm³ and an organic efficiency as high as 96.77%; and moreover, it can wash down to a lower size limit of around 0.125 mm, and the percentage of refuse misplaced in clean product is as low as 0.48%. The successful application of the coarse slime H. M. cyclone at Baoshan Plant provides a valuable reference for coarse slime cleaning operation at other power coal washeries.