Abstract As the traditional ore-drawing theory does not consider the effects of the low ore height，large opening，inclined drawing and the continuously moving of support，its application in longwall sublevel caving mining of coalmine is limited. Considering the structure and position of hydraulic support and its drawing opening，the problems are analyzed of loose top-coal moving on high-window，middle-window or low-caving- door support. A new concept of arc-ellipsoid is suggested with corresponding equations to describe the transfor- ming relation of drawn body shapes of loose top-coal on high-window support. With the help of co-moving coordinate system and the new concept of average deviation of the drawn body axis，the motion formulas of middle-window of low-caving-door support are also given to present the change of the average contacting position of drawn coal and refuse with different caving quantities.
