Abstract: In order to improve the performance in separation of the difficult-to-wash raw coal produced by the mines under the company, a small proportion of the quality coal coming from external sources is blended with such raw coal for improved separation effect. To cater to the specific needs in separation of the blended coal, work is made on optimization of the washing equipment, washing process and flotation reagent regime. The use of the optimized washing system has led to a noticeably improved raw coal treating performance as evidenced by the rise of organic efficiency from 95% to over 98%, bringing about, hence, a favorable economic result for the company.