I am not sure (need to check, but probably someone here knows already), but I seem to recall that CH4 has a worse greenhouse profile than even CO2?
EDIT Hasty posting. Sorry. @xhomerx10 does indeed know and promptly explained.
So it seems the issue is incomplete combustion which could presumably be solved by appropriate flame technology at the place of combustion.
Again, good that the gas is being used for something useful but it's not using it for mining that makes any impact on CO2 or so-called "CO2 equivalent" emissions.