Briely stated, the present invention provides {HEAD ~ a bit assembley} for a rotary drill having, a source of {TAIL ~ fluid} under pressure 
Briely stated , the present invention provides { HEAD ~ a bit assembley } for a rotary drill having , a source of { TAIL ~ fluid } under pressure
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH