The coal in Heishan coal mine is mainly long flame coal and non stick coal. The tar content is up to 18.6%, which is the best raw material for semi-coke. The average altitude of the mining area is more than 2000 meters, which belongs to continental arid and alpine climate, so the traditional wet coal preparation method cannot be used. In October 2017, ZM400 plateau dry separation system was selected to discharge rejuect and improve the quality of 80-20mm mixed lump coal. The reject content of cleaned coal after separation was controlled within 2% ~ 5%, which fully meets the needs of semi-coke plant.