At the Grasberg Block Cave mine in Indonesia, Drainage Drift 4 encountered a wide fault fracture zone, extremely poor rock quality, roadway collapse, and a large void. The structural instability threatened the continuous operation of critical mining infrastructure.
To address these high-risk conditions, a specialized rebar-reinforced shotcrete arch (RRSA) system was engineered. This modular solution provided immediate temporary support during installation and evolved into a permanent high-capacity structural lining capable of bridging the 33-35m wide fault zone.