... type DTH drilling rig 1,Driving type:pneumatic and hydraulic 2,Crawler 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 ... Machinery Co.,Ltd. is professional manufacturer of DTH drilling rigZhengzhou Dayu Machinery Co.,Ltd web: 2012 New type DTH drilling rig