Many ultra-thick coal seams exist in Xinjiang and the northern part of the Inner Mongolia. These coal seams are more than 30～40m thick. This kind of the thick coal seam is too difficult to extract in one slice, so the top-coal caving longwall mining method was designed for this purpose. In order to study the movement characteristics of the overburden strata and the development of the "three zones" in ultra-thick coal seams, the physical and numerical simulations were carried out based on the in-site condition of Baiyinhua coal mine. The result shows that, when extracting the upper part of the 15m thick coal seams, the first weighting interval was 50～58m and the periodic weighting interval was 18~20m. The caving zone, fractured zone and bending and sinking zone were 38m, 92m, and 50m respectively in height. The fractured zone height increased with the advancing distance of the face, but in some localities, a ladder-like distribution due to the periodic weighting existed. When extracting the lower part of the 25m thick coal seams, the roof was extremely broken and the collapse range of overlying strata continued to increase in irregular form.
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