In the event there is only minimal water in the medium and region prior to freeze front sweep, {TAIL ~ water} may be injected into {HEAD ~ the earth} 
In the event there is only minimal water in the medium and region prior to freeze front sweep , { TAIL ~ water } may be injected into { HEAD ~ the earth }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD