CASE STUDY OF INPIT DUMP INSTABILITY AT PIT M PT XYZ

• Main Author: LUTFIAH (NIM : 12114093), IFFAH
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27918
• Institution: Institut Teknologi Bandung

PT XYZ is a coal company located in Tapin, South Kalimantan. One of the active pit of PT XYZ, Pit M, is used as an inpit dump. The in-pit dump which is located in the southern part of Pit M is suffering a failure. Based on the site investigation, failure is still occuring and the in-pit dump material is still moving. To anticipate a bigger movement, a stabilization method is needed to handle the failure so the backfilling activity can be safely continued. <br /> <br /> The stability analysis is carried out with the limit equilibrium method using Slide 6.0 on 2 vertical cross sections along Pit M. The result of the analysis, for both vertical section H and vertical section I, show that different shape of failure are occured. Failure in vertical section H occurs above the embankment of the insitu material so that redesign slope can be done to handle the failure. While, the failure in vertical section I occurs at the end foot of the slope so the best stabilization method is creating the counterweight. <br /> <br /> Redesign of dumping material slope above the material embankment can be carried out with the slope angle of 25o, height of 4.4 m, and bench of 20 m width. While the counterweight design can be carried out with the slope angle 18o and height of 7.9 m. These stabilization methods will give safety factor for vertical section H and I 1.43 and 3.79 respectively. Therefore, the backfilling activity can be continued in Pit M with slope angle 18o, height of 8.4 m, and bench of 60 m width. This design will give safety factor 1.36.