There are indeed vast quantities of coal remaining under the UK, all of which is gassy to a greater or lesser extent. To get the gas ("coalbed methane") out, you have to drill a number of wells and then pump. The gas, which is adsorbed onto the coal, moves out under depletion of pressure via cleats or natural fractures in the coal. As the coals are usually below the aquifer, you have to pump a great deal of potentially-contaminated water out before getting the gas to flow, and this can cause pollution if the water is dumped in nearby rivers. There are also a lot of planning restrictions in the UK that restrict where you can drill. To my knowledge, the technique has not yet proved commercial in the UK.

In the USA, where environmental and planning restrictions are less onerous, the technique has been very successful in the mid-West. I think that the geology is much more favourable there; in Europe the coals (Carboniferous ones) have been subject to several phases of tectonic uplift and degassification which makes the remaining gas more difficult to extract.

Of course, coals do de-gassify naturally in coal mines, as testified by gas explosions in the past. People have tried to extract the gas via pumping air in and out of mines, both used and disused, but I think the amounts of gas actually recovered are quites small. You have to then seperate the gas from the air, and also have to keep the mine pumped free of water , both of which make the technique generally sub-commercial, in the UK at any rate.

OK, you can also make gas artificially out of coal, by heating it in vats, which is the old-fashioned way of doing it before the discovery of natural North Sea gas. This would be potentially feasible should there be sufficient nearby mineable reserves. However, the gas is of a poorer quality than the North-Sea variety, and would necessitate the wholesale changeover of boilers, cookers and pipework at huge cost (they already had to do this once when they switched to North Sea gas in the early 1970s). Also the environmental impact (aside from the coal mining) is horrendous. The by products include cyanide, heavy metals (arsenic), sulphides and phenolic tars. Many former coal gasworks sites in the UK are still unuseable and derelict today due to this sort of contamination.
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Geologist, worked on coal-bed methane wells in Czech Republic and on contaminated former coal gasworks sites sites in UK.

In addition, the burnable gas from coal seams is almost pure methane, which requires different burners to gas from oil wells. While petroleum gas contains much methane, it also contains higher hydrocarbons which alter the burner requirements.
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Worked in the CQ coal industry 16 years, mostly on gas analysis, including analysis of seam gases.

The UK is currently extracting 1mill+ tonnes of Coal still from it’s mines. You should look at BP, and shell (partly british) and look at there profits, you’ll see we really don’t need to be looking elsewhere for resources.

People seem to think resources are scarce on this earth – god no. If the UK and Europe get geothermal energy worked out, there’s enough there to keep the entire world and it’s current consumption levels for 10,000 years!!! Also, ’scarcity’ is when things become expensive, aka expect the UK to start digging it’s coal when everybody else has none left (Then it’s a scarce, which means it becomes 10 fold more expensive to the buyer). We closed them in the first place due to the transition to Nuclear energy which makes way more sense – resource is never a question of human morality – always a question of business – which ultimately becomes a question of utter profit. You should be proud us Brits live up the "survival of the fittest theory", without such business acumen we would be a 3rd world country!
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