The differences between the coal drawing face and non-coal drawing face are low stowing factor in the goaf, vigorous movement of roof, and high stress peak abutment pressure along the strike.

It is one of an estimated 11 new coal schemes planned in Poland, while 28 more are on the drawing board in Germany, according to the WWF.

All told, there are some 150 plants on drawing boards around America, which derives 56% of its power from coal.