JK930 Crawler DTH Rig for Hard Rock and Deep Hole Work Granite, basalt, hard sandstone — the JK930 is the rig we send when the ground fights back and the holes run deep. It carries a 6-inch DTH hammer on 30 bar air and will chase a 138-210mm hole down to about 40 metres before you need to step up to a heavier class. Why the deep holes hold The feed system gives you 40 kN down and 65 kN pullback. That reserve is the part most buyers overlook: 35 metres down in fractured rock
