## 1 Introduction
After validating the reliability of Particle Flow Code (PFC) for draw simulations, [PERSON] constructed various numerical models to examine the flow behaviors of caved ore and rock under multiple drawpoint conditions. The findings indicate that the influence of the particle size, drawpoint size, and caved ore column height on the IEZ shape is negligible, being primarily governed by draw control. The ore loss rate decreases with increasing drawpoint size and caved ore column height but increases with larger drawpoint spacing. [PERSON] et al. (2019) proposed a method for generating irregular particle clusters using PFC and explored the variation patterns of IEZ shape and caved ore/rock fragment size under conditions considering secondary fragmentation. [PERSON] et al. (2019) employed the Particle Flow Code (PFC) to define different block categories to characterize the irregularity of caved rock shapes. Using numerical analysis, they studied the influence of rock particle shape on the morphology and quality of the IEZ. [PERSON] et al. (2019) utilized discrete element numerical simulation to assess the rock mass cavability under various factors prior to far-field mining initiation. They reported that in situ stress and the hydraulic radius are the primary factors influencing rock cavability in block caving. [PERSON] et al. (2019) established a void diffusion model based on stochastic medium theory, introducing the concept of the draw fragmentation index. Programming algorithms were then used for simulations to analyze the flow characteristics of caved rock under varying draw heightsand fragmentation conditions. [PERSON] et al. [20] conducted numerical simulations using PFC2D to investigate the evolution characteristics of force chains within granular media flow beneath a flexible isolation layer. By integrating contact mechanics and statistical mechanics, they studied the evolution of internal force chain attributes--including length, quantity, strength, orientation, and quasi-linear count--during multi-drawpoint mining. [PERSON] [21] applied the discrete element numerical simulation method to analyze the effects of ore friction and fragmentation on ore dilution and recovery. [PERSON] et al. [22] constructed a caved rock model with uniformly distributed block sizes via PFC3D. They explored the optimization of sublevel caving method structural parameters, the shape of the extraction zone under different granular medium conditions, and the optimal cave step distance. Previous research has predominantly focused on the shape of the extraction zone in caving methods. However, most studies characterize release points based on single-hole configurations, neglecting drawbell conditions. In the block caving method, ore is drawn from both ends of the drawbell. The flow mechanisms induced by the interaction between these two outlets create a distinct extraction zone morphology, inevitably differing from prior conclusions drawn under single-hole conditions. Additionally, variations in rock mass structure lead to differences in fragmented rock sizes across zones. Such size disparities directly impact rock flowability, thereby altering the extraction zone dimensions above the drawbell and resulting in divergent overlap patterns. Consequently, designing ore extraction drift spacing in block caving must account for these influences. Investigating the migration laws of caved ore and rock during the draw process is therefore of paramount importance for refining the ore draw methodology in block caving operations.