ANALYSIS OF THE EFFECT OF ROCK MASS STRENGTH ON THE STRENGTH OF ROCK BOLT AT PT ANEKA TAMBANG UBPE PONGKOR

• Main Author: Setiawan Anwar, Andy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40003
• Institution: Institut Teknologi Bandung

PT Aneka Tambang UBPE Pongkor is an underground mining company that manages gold ore. Ore in the form of quartz veins with geological conditions in the form of mountains dominated by tufa breccia. One of the reinforcement systems used is rock bolt. In determining the right type of rock bolt, it is necessary to know the ability of each type of rock bolt to the type of structure and quality of rock mass. Based on face mapping, rock mass rating was obtained at Cross Cut 474 Kubang Cicau KKRB I with massive rock structure is 53 (class III above), at South Vein B Gudang Handak with blocky rock structure is 45 (class III below), and at Workshop Vein Ciguha with a very blocky rock structure is 40 (class IV above). Based on the pull out test, at rock mass with class III above obtained minimum strength of friction bolt is 6 tons, stiff bolt is 16 tons and mechanical anchor is 18 tons. At rock mass with class III below, minimum strength of friction bolt is 5 tons, stiff bolt is 13 tons and mechanical anchor is 9 tons. At rock mass with class IV above, minimum strength of friction bolt is 3 tons, stiff bolt is 11 tons and mechanical anchor is 8 tons. The strength of rock bolt increases in proportion to the rock mass rating. Mechanical anchor are more effective in massive rock structures, while stiff bolt and friction bolt are more effective in blocky rock structures.