Аңдатпа
Open stope mining systems are highly susceptible to stope wall overbreak and unplanned dilution. The equivalent linear overbreak slough (ELOS) graph is a widely used empirical method for open stope design; however, its performance can be compromised when geotechnical domain data carry low confidence, a common issue in practice. The inherent variability of key design input parameters, such as rock mass properties, leads to this limitation, which requires explicit consideration to enhance design reliability. Properly accounting for this variability could significantly enhance open stope design. Yet, most existing studies on open stope design do not adequately address this limitation. Motivated by these aspects, this study applies the First-Order Reliability Method (FORM) to quantify the reliability index and the probability of unplanned dilution associated with stope designs across various geotechnical domains. To validate and generalize the approach, a comprehensive database of stope overbreak cases was compiled. The input parameters for the analysis included the Modified Stability Number (N’), Hydraulic Radius (HR), and ELOS or dilution values, along with their coefficients of variation (CoV), which were determined based on the compiled data. The results indicate that reliability indices and the probability of unplanned dilution are highly sensitive to changes in CoV, with responses varying by rock domain. The outcomes align well with field observations, supporting the robustness of the method. Additionally, a reliability index classification is proposed. Overall, the findings demonstrate that a reliability-based design framework can serve as an effective tool for optimizing open stope design and mitigating unplanned dilution. The proposed classification enables uncertainty to be directly incorporated into design decisions, yielding a more reliable design process and contributing to improved dilution control, enhanced safety margins, and more favorable cost outcomes.