Abstract: In consideration of all particle size thermal coal washing process causing a lot of difficult-to-separate coal slime with lower calorific value,the coal slime reduction-producing technology is proposed by analyzing existing slime processing system in Jinfeng,Hongliu,Shuangma branch of Ningdong mine coal preparation plant. Raw coal is sized at 6 mm by flip-flop screen in these plants,and then + 6mm raw coal is delivered to separation system. The result shows that coal slime is reduced by 33% to 70%,while calorific value of fine coal is increased by 438. 57 k J/kg. This technology can not only drop construction investment and operating costs,but improve quality of coal product,as well as can be a new approach to other thermal coal preparation plants.