Abstract: The coarse coal washing system of the plant is working under the designed capacity. To tackle this problem, work is made on renovation of the raw coal sizing screen, blending coal scraper conveyor, middling product transfer belt conveyor and overflow weir of heavy medium vessel. Practice shows the renovation work has led to a rise of treating capacity of coarse coal washing system to 1 400 t/h, a surge of yield of clean coal by around 5 percentage points, and an additional gain of 7 million yuan a year, creating a favorable economic benefit for the plant.