A second conduit means is provided within the housing for receiving a second flow of fluid from the plenum chamber and for directing the second fluid flow out of the housing in the reverse direction toward the first end of the housing, the second fluid flow being effective as a scavenger flow to convey the dust and cuttings removed from {TAIL ~ the vicinity} of the cutting cone by the first fluid flow away from the bit assembly and out of {HEAD ~ the drill hole} 
A second conduit means is provided within the housing for receiving a second flow of fluid from the plenum chamber and for directing the second fluid flow out of the housing in the reverse direction toward the first end of the housing , the second fluid flow being effective as a scavenger flow to convey the dust and cuttings removed from { TAIL ~ the vicinity } of the cutting cone by the first fluid flow away from the bit assembly and out of { HEAD ~ the drill hole }
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