#TITLE_ALTERNATIVE#

• Main Author: LESMANA BASKARI (NIM 22106001), TONNY
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/9502
• Institution: Institut Teknologi Bandung

Slope stability in an open mine is an important matter as it is related to human's safety, mining equipment and another infrastructure located surrounding excavation area. PT. Berau Coal is one of coal mining company which applies an open mining system. Slope stability problem in Binungan Mining Operation of PT. Berau Coal was observed after 9 months excavation activity. Based on experience, up to the year of 2007, there has been one landslide and four times crack happened in the excavation area. In order to acknowledge relation between rock mass classification and slope stability, and long term strength of material that formed the slope, a research should be carried out. Research area is located in Pit K because it has a complex geological structure variation. From field observation result, research area is geologically divided into four lithology unit which are: sandstone, claystone, siltstone and coal unit. The observed geological structure is thrust fault with direction of N80oE. Based on rock mass classification, research area is divided into four rock mass type, which are: rock mass type 1 consists of slightly weathered sandstone with RMR value of 69 (good rock), rock mass type 2 consists of moderately weathered sandstone with RMR value of 59 (fair rock), rock mass type 3 consists of highly weathered claystone and siltstone with RMR value of 30 (poor rock), and rock mass type 4 which is fault zone with RMR value of 20 (very poor rock). From field observation result, research area is geologically divided into four lithology unit which are: sandstone, claystone, siltstone and coal unit. The observed geological structure is thrust fault with direction of N80oE. Based on rock mass classification, research area is divided into four rock mass type, which are: rock mass type 1 consists of slightly weathered sandstone with RMR value of 69 (good rock), rock mass type 2 consists of moderately weathered sandstone with RMR value of 59 (fair rock), rock mass type 3 consists of highly weathered claystone and siltstone with RMR value of 30 (poor rock), and rock mass type 4 which is fault zone with RMR value of 20 (very poor rock). Long term shear strength of claystone is 46% from its peak strength. The observation result also shows that long term shear strength, which is the result of creep test, relatively close to residual shear strength from laboratory test.