Abstract: Chengchao Iron Mine enters the deep mining environment with complex and changeable surrounding rock properties， and the movement and change patterns of the collapse pits are different from those in the shallow ones， so that，it is impossible to accurately predict the stability of important surrounding structures on the ground.In order to ensure the safety of the new auxiliary shaft and the important surface structures around the subsidence area， based on the indoor similar simulation test and numerical simulation method，the movement regularity of the collapse pit in the deep mining below -500 m is studied， and the variation regularity of the movement angle of collapse pit and the surrounding rock of far and near surface with mining depth is analyzed.The study results show that:① the surface collapse and deformation caused by the mining of ore bodies below -500 m gradually transfer to the hanging wall，the moving angle of the hanging wall shows an increasing trend， and the range of surface movement does not exceed the initial design value；②In the early stage of mining， the bottom plate was greatly affected， and as the mining progressed， the impact gradually weakened；③Throughout the mining stage， the surrounding rock strains in the near and far surface regions show different patterns of change；④At the end of mining， the inclination value of the new auxiliary well on the surface reached 0.017 mm/m， exceeding the critical impact standard value， indicating that mining will have a certain degree of impact on the new auxiliary well.According to the degree of influence of different mining stages on the new auxiliary shaft， the stability control measures of the new auxiliary shaft are proposed. The study results have certain guiding significance for the deep safety mining project of Chengchao Iron Mine.

Key words: deep mining, caving mining, moving angle, surface stability, similar simulation, numerical simulation