STUDY OVERBUDEN FRAGMENTATION BY BLASTING RESULT USING AIRDECK METHOD (COMBINATION MIDDLE AND BOTTOM AIRDECK) OF DIGGING TIME EXCAVATOR EX – 3600 AND PC – 4000 AT MINE COAL PT BUMA JOB SITE LATI, EAST BORNEO, INDONESIA

• Main Author: YOSNANDA (NIM : 12113029), JAYA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22678
• Institution: Institut Teknologi Bandung

Mining activities begins with overburden removal. Before overbuden excavated, the rocks must broken used the drill-blasting method. The drilling activity was carried out using Atlas Copco DM 45 drill kit, type of drill used was a 7 7/8 inchi with tricon roller bit. Pattern drilling used is staggered pattern with the direction of drilling straight, method of blasting is the method of non-electric (nonel) with a pattern of blasting streak between holes using a surface delay of 25 ms, 67 ms, 109 ms and in hole delay 400 ms, 500 ms. The explosives used were a Trojan Emulsion 4070. Digging time of EX 3600 and PC 4000 for each material blasting results are part of the target to be reached by PT. Buma Job Site Lati. Powder factor planned by the company is 0.227 Kg / BCM then when used that powder factor target is obtained predictive value of P80 by using a combination of bottom and middle air deck is 814 330 mm and obtained predictive value of digging time is 14.509 second. Air decking method is believed to produce good rock fragments but with low consumption of blasting explosive. That makes PT Bukit Makmur Mandiri Utama Tbk apply the method of air decking. This study was conducted to determine the performance of the method of air decking over affect to digging time loader EX 3600 and PC 4000 with fragmentation size limitations by 1/3 times the size of the bucket loader unit.