NOUFERROUS METALLURGICAL EQUIPMENT

The fragmentation and weakness of surrounding rock under complex stress conditions in underground metal mines pose significant challenges to tunnel support design. This study focuses on a copper-gold mine in Serbia, employing the FLAC3D finite difference software to conduct numerical simulations on three types of tunnels and two levels of fractured rock masses. The research evaluates the rationality of the existing support design and proposes optimized support parameters tailored to varying surrounding rock conditions. The results indicate that the instability of the -200m level tunnels is primarily caused by the combined effects of high geostress, deformation of the exposed rock surfaces, and rock corrosion. Typical failure modes include roof settlement within the permissible range for IV and V grade surrounding rock tunnels, whereas the cumulative relative displacement of the two sides generally exceeds the allowable limit, highlighting deficiencies in the current support design for controlling sidewall deformation. The optimized support parameters for the IV and V grade surrounding rock tunnels at the -200m level include an anchor bolt spacing of 0.8m×1.0m, an anchor cable spacing of 2.0m×3.0m, and a shotcrete thickness of 125mm, meeting safety requirements. These findings provide theoretical support for optimizing support systems for fractured rock masses in underground metal mines.