关键词: 露天地下联合开采, 残留矿石, 采空区, 空场法, 崩落法

Abstract: Due to the previous predatory exploitation in an iron mine in western China，a large number of waste caves with serious safety hazard have been formed and abundant ores are remained.Manual detection has been made in surveying goafs to get its，shape，size，distribution and resources.According to the spatial distribution and mining technical parameters，old goafs are divided into three categories.To make full utilization of the residual resources，the opencast-underground combined mining method was put forward.Based on this scheme，the ores in residual pillars and roof above 954 m level are recovered by open-pit method；After the completion of open pit，the original development system is used to recycle the ores under 954 m level and the slope ores with mining feasibility in open-pit by underground mining method；For the ores between 954 m level to 924 m level，the upper 20 m is drilled up-to-down from open-pit bottom，and the lower 10 m is drilled down-to-up from underground stops.The ores which are produced by blasting are as the lower-middle level covered rocks and are recovered step by step.This scheme fully recovers residual mineral resources in waste caves，but also eliminates large-scale caving hazards in waste caves.So it produces a higher economical and social benefit.

Key words: Open-underground mining method, Residual ore, Mined-out area, Open-stoping method, Caving mining