Abstract: The critical medium column′s theory is used to determine critical medium column′s height using lateral pressure and predict surface subsidence range. Past lateral pressure tests usually lead to inaccurate forecasts without considering the influence of ore drawing on lateral pressure. So an experimental test on lateral pressure of bulk-solid medium was performed to measure the lateral pressure under ore drawing， and the effects of releasing bulk-solid medium on lateral pressure were got through the comparisons among the different heights. The result shows that the lateral pressure is effected at the vicinity of drawing hole under ore drawing， and the effects′ range is little by releasing bulk-solid and lateral pressure increases with the consolidation of bulk-solid medium. Combined the critical medium column′s theory and the classical Janssen theory， the calculation of the critical medium column′s height under the effect of ore drawing was obtained. Then considered the relationship between mining height and the disturbed angle， reference for prediction of surface subsidence range was provided.

Key words: critical medium column′s theory, lateral pressure, surface subsidence range, experimental study, critical medium column′s height, ore drawing