The crusher replaces the drilling machine upon {HEAD ~ completion} of {TAIL ~ the drilling} of a guide hole by the drilling machine 
of
The crusher replaces the drilling machine upon { HEAD ~ completion } of { TAIL ~ the drilling } of a guide hole by the drilling machine
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH