In a further embodiment of the invention, at least one common well is used for {TAIL ~ both the recovery} of methane from {HEAD ~ the coal bed formation} and the introduction of hydrogen into the coal bed formation 
In a further embodiment of the invention , at least one common well is used for { TAIL ~ both the recovery } of methane from { HEAD ~ the coal bed formation } and the introduction of hydrogen into the coal bed formation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH