reacting the oxidant and fuel in the oxidizers to produce heat to heat {HEAD ~ a portion} of {TAIL ~ the formation}; and 
of
reacting the oxidant and fuel in the oxidizers to produce heat to heat { HEAD ~ a portion } of { TAIL ~ the formation } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH