... DTH drilling rig 3,CE,ISO9001 4,Warranty 2Ys 2012 New type DTH drilling rig:Zhengzhou Dayu Machinery Co.,Ltd. have ... produced DTH drilling rig and air compressors for mining project over 20years.Product range:1,All Pneumatic DTH drilling rig2 ... the whole equipment have small vibration and working stable. 3,New type boom of Dayu DTH drilling rigThe scope adjustable sysytem ...