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