STOPE STABILITY AND SUPPORT DESIGN ANALYSIS ON SQUEEZING ROCK IN STOPE XC 662 CIURUG LEVEL 600 PT ANTAM UBPE PONGKOR

• Main Author: Rizqy Hafizh Banjaransari (NIM : 22117030), Zulnio
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31927
• Institution: Institut Teknologi Bandung

Underground mining will always faced with problems of deformation and rock mass instability around tunnels. PT. Antam conducted underground mining activities in Pongkor, Bogor which faced squeezing rock problems on its production stopes, Stope XC 662 Ciurug. <br /> <br /> Squeezing is a natural phenomenon where the the tunnel is "narrowing" time-dependently during tunnel excavation. This happens because of a combination of induction stress and material characteristics that push the zone around the tunnel for a long time so that it exceeds the stress limit where creep will begin. Stope XC 662 Ciurug is thought to have squeezing because of the very weak rock mass conditions which are in the form of argillic claystones. <br /> <br /> Using the Hoek & Marinos (2000) method, it shows that rock mass conditions in the Stope XC 662 Ciurug have experienced convergence monitoring strain that exceed the strain squeezing criteria so that they can be classified as minor squeezing problems. <br /> <br /> The results using the Burger rheology model get the long-term strength of rock mass around the XC 662 Ciurug stope has decreased by 50% of the strength of intact rock. So that numerical modeling is carried out using these long-term strengths to determine effective support recommendations. <br /> <br /> By looking at the Factor of Safety, Total Displacement, and Plastic Zone Radius values at several points along the tunnel boundary, the most effective support recommendations for the long-term strength of the Stope XC 662 Ciurug rock mass are type 4 support with Splitset, Wiremesh and Shotcrete (thickness 30 cm).