Abstract
This study presents an analysis of open-pit bench stability based on laboratory strength testing of limestone and kinematic analysis of rock mass fracturing. The Hoek-Brown criterion was applied to determine the uniaxial compressive strength (UCS) of intact rock samples and the internal friction angle using RocData_v5. The UCS was measured at 82 MPa, with additional consideration given to the D factor, which accounts for blast-induced rock mass damage. Stability analysis was conducted using Dips and SWedge software, revealing that planar sliding and wedge failures dominate on the northeastern slope. The results indicate that 35% of fracture intersections fall within the critical wedge failure zone, and the actual bench stability is below the internationally accepted threshold (25–50%). To mitigate these risks, it is recommended to adjust the pit slope orientation to an azimuth of 325–310°, revise the Stage 2 pit design by reducing the bench angle to 60°, avoid bench strike directions between 330–360°, employ controlled blasting techniques, or increase berm width to 12 meters.