24 Mining Constru C tion 1 2013 Our success is based on drilling with the right equipment to provide mines with the most effcient drilling option Jerry Murthi Owner of Niriki Minex Sejati drilling company The drill crew of Nariki Minex S ajati pose for the camera during drilling at the P rima S arana Gemilang coal mine on the Indonesian island of K alimantran Prima Sarana Gemilang mine i n the coal o F i ndonesi A t he majority of b lasthole drill rigs in Indonesia are used in the coal indus tr y and the Prima Sarana Gemilang mine is a typical e xample Located on the island of Kalimantan the mine has Atlas Copco DML and DM45 drills on site and the upg raded DM30 II w as recentl y added to the feet According to drilling contractor Nariki Mine x Sejati the ne w addition has increased fe xibility b y pro viding more choices in the 171 mm 200 mm 6578 in hole range J e r r y M u r t h i s e c o n d g e n e r a t i o n o w n e r of Nariki sa ys The g round on Kalimantan isn t too dense and doesn t need much more than a good b ump to break it up He sa ys the 200 mm capability of the ne w DM30 II allo ws his compan y to drill lar ger holes and suffcientl y sized patter ns y et smaller holes w hen necessar y Nariki operates at about 15 mine proper ties in the countr y and Mur thi sa ys the com pan y s success is based on drilling with the right equipment in order to pro vide a mine with the most effcient drilling option The compan y has lar ger drills b ut sa ys it almost ne v er needs to drill a 228 mm 8 in hole or lar ger W e drill mostl y with a b urden of 78 m and 89 m spacing The maneuv erability of the DM30 II is g reat Ha ving the drill rig that of fers more options because of its size is a beneft to the mine and also helps with mine planning F or rotar y drilling the DM30 II has a more p o w e r f u l c o m p r e s s o r d e l i v e r i n g 2 9 7 m 3 m i n at 75 bar compared to the 254 m 3 m i n at 76 bar of the DM30 The mine has tw o pits and before drill ing be g an ripping w as used to break up the cla ystone and sandstone for mation The rock is just hard enough that b lasting results in more producti v e e xca v ation