Abstract: Aiming at the reliability of large-scale mining with Large and thick steeply inclined orebody, the southern district orebodies of Sijiaying Iron Mine are divided into two step bord which are mined at intervals by the open stoping with subsequent filling method,and one-step goaf filled with cement and two-step goaf filled with tailings.The recovery process is simulated numerically by using UDEC software.The results show that the pressure arch structure which arch loss is equal to the total length of recovery is found in the roof rock strata during the stoping and filling process of the mine house,and the filling body and ore pillar and surrounding rock are collaborative stability;at the same time,high stress concentration phenomenon occurs in the lower plate and upper plate of ore bodyabout 40~50 MPa),and in the consolidated packabout 15MPa), ant there are 0.5~2 m down and 0.2~0.28 m down respectively between the top of the stope and the earth's surface,in addition,a high pressure stress concentration zone and long belt main tensile stress zone are derived from the junction of the fourth system and the weathering belt and the weathering zone.The above study results further indicated that the roof and surrounding rock of upper and lower disk should be supported before mining,and the groundwater and fault fissure zone should be monitored as the roof and earth surface,so as to ensure the safety mining of the mine.

Key words: Large and thick steeply inclined orebody, Open stoping with subsequent filling method, Step by step mining, Structural parameters, Numerical simulation