Abstract: Controlling roof falling hazard was the key safety technique of synchronous mining in upper and lower mining areas.Taking Xiaowanggou iron mine that was divided into three areas in ore-body extending direction for example,and based on theoretical analysis,the main types of roof falling hazards were shown in three mining areas,falling rocks and collapse for upper mining area,airblast wave and falling rocks for middle mining area,and falling rocks for lower mining area.Meanwhile,according to the location feature of three mining areas and the orebody condition,mining sequence was adjusted for controlling roof falling forms by continuous mining area.And,to avoid from the disasters of the air-blast wave,falling rocks,collapse,a series of technical measures were proposed,including keeping 5m safe distance between working site and the falling edge,and setting 6m thick granular medium as isolation cushion,non worker allowed to entering the mined out area,and piling rocks on surface to forbid worker entering subsidence area.These measures were applicable for the safe mining under different caving conditions,and had good application.It provides technical support for synchronous caving in upper and lower mining areas.

Key words: Synchronous mining in upper and lower mining areas, Caving,Roof falling forms, Controlling roof falling hazards