Only a theory butNofold is the name of one of the House coal seams from memory about 1'6" thick - ventilation of these narrow seams were often achieved by using a fire at one opening to draw air through the workings from another; although the extent of the chimney seems a bit elaborate. A good example is at the entrance of Addis Hill level driven through the rock to the Highdelf seam linking up with Heywood Pit - The fire grate is on the right of the level immediately inside the entrance.

Cheers

Vurrister