AbstractThis paper describes the new percussion‐reverse circulation system, designed and developed in Italy for water‐well drilling. In a special reverse circulation rig, the percussion bit, consisting of a tube with external welded blades, slides up and down on the outside of the hollow drill pipes, while the hollow drill pipes remain still. The field of application of the reverse circulation method is thus enormously enlarged; either hard, cemented formations or soft, unconsolidated deposits, as well as big boulders of any size are bored much faster and more efficiently than with any other method of drilling, provided that a sufficient source of water is availa
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