Simplified approach for rock mass damage around infrastructure for underground mining

ABSTRACT: This study introduces a simplified procedure for the analysis of stress induced damage around infrastructure in a sublevel caving mine, where stress conditions change due to cave propagation. The methodology entails superimposing the mine design with forecasted mining-induced stresses from 3D stress modeling to estimate in-plane excavation-induced stresses, allowing a rapid assessment of extensive infrastructure layouts and the identification of areas that may need relocation or special support. The analysis considers the deviatoric stress and the ore and host rock's Unconfined Compressive Strength (UCS) to calculate damage thresholds such as spalling, severe spalling and moderate and major strain burst. Results from this analysis were compared to results obtained from simple 2D models that used the 3D model induced stresses as in-situ as a validation process, finding similar damage estimates. These 2D models featured different excavation shapes and stress paths. Changes in the infrastructure's layout and/or support can be proposed based on the projected damage.