#TITLE_ALTERNATIVE#

• Main Author: AGUSTINUS RABUDIANTO (NIM 12104006), TYAS
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17477
• Institution: Institut Teknologi Bandung

South Ciurug, one of mine at Gold Mining Business Unit of Pongkor, PT. ANTAM, Tbk, will be developed to reach level under elevation of 500. Ramp-down have to develop as transportation media which connect levels on mine, to fulfill this porpose. Geotechnical investigation are needed to grasph rock mass condition and create supporting system rekomendation to ensuring stability around opening of tunnel. At early stage (before constraction of ramp-down) geotechnical investigation have been done. The results are rock mass condition and support system recommendation. The next investigation need to be held, when apart of ramp-down have been constract with the porpose to know the real condition of discontinuity and rock mass around opening. And then, verivication early support system recommendation are needed to ensuring validity of this recommendation for the next using.<p>This observation using empirical method of Geomechanical Classification System (RMR, Bieniawski 1989). The result of geological structure measurement are around the result of early investigation, about 050o until 061o on dip direction, 58o until 64o on dip. This orientation parallel to Ciurug vein orientation 70o/060o (Dip/Dip direction). Rock mass condition are fair to good rock, as the result of rock mass classification. The average of corrected RMR, show that ramp-down A has corrected RMR value 60.17 (fair rock), ramp-down B value 60.53 (fair rock), and ramp-down access value 65.61 (good rock). General rock mass condition as the result of observation activity have the same condition with the early stage geotechnical investigation (fair to good rock).<p>Early support recommendation give more rapid rockbolt spacing, so we need to arrange based on the result of modification support recommendation. The modification support are combination of rockbolt, wiremesh and steel support which are calculated with number of safety factor, 2. This safety number used because of vital function of ramp-down as connection media between level in mine. For very good rock, generally no support required. For good rock, installation rockbolt with 2.4 m in length, row spacing 1.33-2 m, between row spacing 2.46-4.53 m and additional wire mesh installation on the roof. For fair rock, installation rockbolt on roof and wall with 2.4 m in length, row spacing 1.33-2 m, between row spacing 2.46-4.53 m with additional wire mesh installation on the roof and wall. Poor rock, installation 2.4 m in length of rockbolt. Row spacing 1.33 m, between row spacing 2.46 m. Steel support are required with spacing 1.5 m and additional wire mesh on the wall and roof. <br />