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clock Created with Sketch. 30/11/15
11:20
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Originally posted by eshmun
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I don't think the ground would be soft where they are drilling at depth or they would have been chewing through these holes in no time. Not sure what he would mean by "caving in"? The drill string is probably about 4.5 inches in diameter and the hammer at the end might be about 5 inches, so rock would need to be filling up the small volume between the drill string and the edges of the hole. The drill rods are also turning with a lot of torque so I'm not sure if this is a very likely problem if the rock has reasonable competency. Also most RC rigs have blow down valves that can redirect air down the inner sample tube through the bit ports to clear blockages in the ports and inner tube and blow air back up the hole to clean it. My guess is that the rig doesn't have a very big air compressor and that water might be a problem for them. Something is stopping these RC holes going deeper and I'm not sure exactly what. A better drill rig would be answering the questions a lot faster in my opinion.
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Thanks very much Eshman.
