... air pressure DTH drill.Drill the hole at the speed of 8-16m/h with the rock rigidity f=6-20 ... small mining areas in the productivities of 200,000m3 annually, or serves as the auxiliary equipment of the large or medium mining to ... tool)Drill toolsXHH90 ,XHH110, DHD90, XHHG110 down-hole drilling rig of KQ90Y