| http://www.w3.org/ns/prov#value | - of and interiorly of said jacket, a core bit secured to the forward end of said bit body, a plurality of longitudinally spaced sealing devices for forming between said jacket and work drilling means `a pair of longitudinally'extending front and rear chambers sealed one from the other during the drilling operation, conduit means including a ilexible hose for introducing liquid coolant under pressu
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