A traverse mechanism may be provided to allow {HEAD ~ the coring bit} to be advanced into {TAIL ~ a pipe} being cored 
to be advanced into
A traverse mechanism may be provided to allow { HEAD ~ the coring bit } to be advanced into { TAIL ~ a pipe } being cored
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH