Abstract: The star-wheel extractor of the YTG-3 jigging machine used in the Nantong section of Nantong Coal Preparation Plant is frequently jammed up in operation due to treatment of a raw coal feed with an extended upper size limit. To tackle this problem, the clearance between the wheel extractor and the movable hanger plate is readjusted. Practice shows that through the readjustment made, apart from a thorough elimination of the frequent blocking of the extractor wheel, there can be seen a noticeable improvement of working performance which is well up to the requirement.