Look fascinating, I never realised the workings were so extensive, are they pillar and stall style diggings?
From what little I know of jet workings (which is next to nothing) are they always above ironstone and do they relate to the outcrops of coal at all? Is the statification that clear anyway?
Sorry, if you're busy please ignore the questions and keep exploring, your research has dragged me back to my transport geography project at university which was looking at the Grosmont-Pickering line, the ironstone workings and related blast furnaces at Goathland (and the horse-worked incline). Strange how the mind works added to which when I last worked in M'bro for BSC they employed some 200,000 people overall. Don't time change.