Abstract: To solve the problem of decreasing of clean coal yield due to high quantity of coarse slime with high ash content and which directly recovered and blended into clean coal in Wuhai Kaihong coal preparation plant,the CSS coarse slime separator was used separating 1-0.25mm size fraction produced from jigging process.By taking that measure not only decreased the total ash content of clean coal,but also increased the clean coal yield by 0.55%,obtained better economic benefit.