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...Predrainage methods for tunnel dewatering robert g lenz moretrench american corporation state of the art in most applications choice de watering systems comes down to ejector well point or as it is practiced united states deep installed from surface effect partial day partly and science although removal complete water free a heading unlined stretches tun tool revolves around quantities be pumped nel has always been necessary chore tunneling work im necessity closely spaced pickup points proved equipment techniques today have wells an application which large made soils relatively can removed few locations with common occurrence operations purpose reasonably predictable dependable result between program may any one fol ejectors are used where communication lowing device another limited lower level so that static compressed constrained aquifers rather thin hori air pressure required conduct mining within zontal flows would occur over top impervious layers acceptable contractual physical l...