Preferably, hydrogen is introduced into the coal bed in an amount within {HEAD ~ the range} of 0.2–1.0 standard cubic feet of hydrogen for each standard cubic foot of {TAIL ~ methane} recovered from the coal bed formation 
Preferably , hydrogen is introduced into the coal bed in an amount within { HEAD ~ the range } of 0.2–1.0 standard cubic feet of hydrogen for each standard cubic foot of { TAIL ~ methane } recovered from the coal bed formation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH