# Research Progress and Typical Case of Open-Pit to Underground Mining in China
## 2 Analysis of Key Technologies for the Transition from Open-Pit to Underground Mining
### Current Status of Slope Stability Research in Open-Pit Underground Mining  
Slope stability in open-pit to underground mining is a critical safety concern throughout the entire lifecycle of the mine [39]. The interaction between open-pit and underground mining, which differs significantly in orebody occurrence conditions, stress redistribution patterns, and rock mass disturbance mechanisms, forms a dynamic composite system. This interaction leads to highly complex and uncertain slope stability challenges. During the transition period, underground mining-induced rock loosening, stress concentration, and structural deformation frequently compromise the original stability of open-pit slopes, significantly increasing the risk of geological hazards such as landslides and collapses. Statistics indicate that approximately 65% of safety incidents in typical open-pit to underground mines in China are directly related to slope stability issues, underscoring the urgency and importance of further research in this area. In the investigation of instability mechanisms, [PERSON] [40] introduced the progressive slope instability theory, which outlines the evolution of slope failure from local initiation to overall instability. [PERSON] et al. [41] constructed a multi-factor interaction model for slope instability by coupling external triggering mechanisms with the physical and mechanical properties of the soil and rock mass. [PERSON] et al. [42], based on the theory of complexity classification, systematically discussed the application range and technical advantages of numerical simulation methods in slope stability analysis. These theories provide a crucial theoretical foundation for a deeper understanding of slope instability mechanisms. In the field of technical methodology research, numerical simulation and physical similarity experiments have become the predominant approaches, offering substantial application value in understanding slope stability mechanisms. Initially, [PERSON], [PERSON]. [43] employed the finite difference method to evaluate slope stability in the Cao Shan open-pit mining area in Vietnam. [PERSON] et al. [44] applied the stochastic finite element method to analyze the probability of stability for slopes and underground mining rock masses, presenting a novel perspective on how underground mining affects slope stability. [PERSON] et al. [45], through centrifugal modeling and numerical simulation, identified that underground mining induced overturning failures in overlying rock masses, providing experimental evidence for further studies on the effects of underground mining disturbances on rock mass stability. [PERSON] and [PERSON] [46] utilized the three-dimensional discrete element method to simulate the crack propagation process in fractured rock masses, offering vital technical support for analyzing failure mechanisms in such formations. [PERSON], [PERSON] [47] developed a numerical analysis model based on the geological conditions of the Anjialing open-pit mine to investigate the evolution of slope stability during bench mining. [PERSON] and [PERSON] [48] categorized rock slope failure modes into four types and created a direct model for evaluating the probability of slope instability. With advancements in computational technology, three-dimensional numerical analysis has emerged as the mainstream approach, enabling more accurate simulations of complex geological conditions and stress distributions. For example, [PERSON] et al. [32] developed a three-dimensional finite difference model for the Jinfeng gold mine, systematically assessing the effects of mining disturbances on shaft stability and surface deformation, thereby validating the practical utility of three-dimensional models in mine stability assessments. [PERSON] and [PERSON] [49] proposed a FLAC3D strength reduction method, based on the Hoek-Brown criterion, which successfully analyzed the stability of three-dimensional rock slopes and provided a scientific basis for slope stability design in engineering practice. Additionally, [PERSON] et al.