Study on safe and efficient mining method of deep open pit mine during the transition from open pit to underground mining

During the transition from open pit to underground mining, mines are usually faced with the problem of reducing production.Generally, mines will be mining hanging-wall ore-body to supplement production capacity during this period.Traditional mining methods for hanging-wall ore-body have a series of problems such as poor safety, low efficiency and low production capacity, which make it difficult to fundamentally reverse the dilemma of reducing transition.With a deep open pit transition into underground mining as an engineering background, on the basis of comprehensive analysis for hanging-wall ore-body distribution location, mining conditions and the ore-rock characteristics, the technology scheme of mining hanging-wall ore-body in south slope by induced caving method was proposed in transition period.In order to ensure the safety of open-pit mining, the unstable slope is induced to slide towards the goaf rather than to the open pit floor by controlling the mining sequence, so as to realize the open pit and underground safe and efficient cooperative mining in the transitional period.Finally, the numerical simulation method is used to study the induced caving mining scheme of hanging-wall ore-body in south slope.The results show that it is safe and feasible to use the induced caving method to mining hanging-wall ore-body under the condition of deep open-pit mine.