With regards to this:"To my recollection QPME is assisting coal...

With regards to this:

"To my recollection QPME is assisting coal mining industry to reduce their emissions. If they aren’t I’d be very interested to know why?"

The heat-trapping ability of a gas measured against carbon dioxide is its GWP (global warming potential).

For example, methane has a GWP of 28, meaning it is 28 times more potent than carbon dioxide. Emitting one tonne of methane into the atmosphere is equivalent to emitting 28 tonnes of carbon dioxide.

Coal mine emissions are primarily methane, so QPME just combusts that methane to convert it to carbon dioxide. It's still about the same amount of gas overall, it's just 'less' environmentally damaging (relatively).