| http://www.w3.org/ns/prov#value | - In apparatus as defined in claim 8; said means for enabling a sharpening action to be effected including a plurality of circumferentially spaced passages for directing fluent material upwardly against the lower end of said core bit to sharpen the same; said releasing means projecting below said sharpening device and being engageable with the bottom of the bore hole to release said device and allow
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