... drilling rig 3,CE,ISO9001 4,Warranty 2Ys 2012 New type DTH drilling rig:Zhengzhou Dayu Machinery Co.,Ltd. have ... whole equipment have small vibration and working stable. 3,New type boom of Dayu DTH drilling rigThe scope adjustable sysytem ... DY100 DC140 DC120Rock Hardness f=6~20 f=6~20 f=6~20 f=6~20 f=6~20 f=6~20Diameter of Hole ... rigZhengzhou Dayu Machinery Co.,Ltd web: 2012 New type DTH drilling rig