Abstract: The surface collapse of Shizhuyuan Mine has brought a series of problems to the underground production，such as the surface mud water mixed into the underground leads to ore dilution and affects mineral processing，the high steep cliffs in the north and northeast of the collapse area lead to the surface rolling stones and landslides，the large-span cantilever empty area in the south，the formation of high-risk goaf groups between unstable pillars and large goafs， and the ore bearing blocks block the ore roadway，etc..According to the field survey，field survey mapping and rock movement research，through 3Dmine software modeling，the collapse area，transition type goaf， high-risk open goaf and peripheral goaf are accurately divided.In order to solve the production problem of the mine，the technical scheme of synergetic mining of underground and open pit is put forward:firstly，the low-grade ore is used to fill the high-risk empty area around the collapse area；secondly，it is forbidden to mine ore underground in the south of the subsidence area， and the cantilever ore-rock is collapsed by the deep hole blasting technology on the surface； then the high steep cliffs in the north and northeast of the collapse area are stripped on the surface and the subsidence area is backfilled with low-grade ore；finally，the transition from underground mining to open-pit mining in 6~8 years， and tentative mining of large ore in the subsidence area.In order to reduce the investment in the early stage of stripping and ease the difficulty of road construction beyond the boundary of stripping，combing with the idea of arranging spiral step-by-step stripping steps around the mountain and embedding the road into the step of the hillside stripping boundary，the 720 stripping boundary is optimized and determined by using 3Dmine software modeling study.At the same time，through the technical measures such as marking the production plan on the map， updating the cooperative operation area in time，monitoring the underground mining area with real-time micro earthquake and monitoring the rock movement in the subsidence area with GPS，the synergetic mining operation of the mine has realized the dynamic monitoring and early warning. The study results show that the idea of optimizing stripping boundary and a series of technical schemes of open-pit and underground synergetic mining are put forward，which solve the current production problems of the mine，provide safety guarantee for the open-pit and underground synergetic operation of the mine，and provide useful reference for similar mines.

Key words: Synergetic mining, High-risk goaf group, Underground to open-pit mining, Isolated pillar, Microseismic monitoring