The present invention provides a cutter for {HEAD ~ an earth boring system} that has a rotary unit which bores into {TAIL ~ earth formations} to form a hole therein 
The present invention provides a cutter for { HEAD ~ an earth boring system } that has a rotary unit which bores into { TAIL ~ earth formations } to form a hole therein
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH