@Nyddfwch I am also finding in Northamptonshire, Bedfordshire & N Hertfordshire that almost every wood here today, is only present because earlier mining had left the land fit for agriculture. Here are ancient iron ore adits at Wakeley Woods in Northants for example. #historicalgeography #Industrialarchaeology #LandscapeHistory #Postindustrialwoodland

@demorgan Wow, that is great detail. My bell pits and workings are so much harder to identify. Here's an extract from a leaflet I did a while ago showing areas of heavt mining but had been heavily plugged and landscaped. Often, my first clue is bad drainage or orange water in the streams. This is from my local Lidar, which has been my best friend in looking at the land around Swansea.

@Nyddfwch If your friend knows anything about the Calland Coal mine in north Swansea starting in about 1807, I would love to hear from him. I believe it was at Fforest, & former colleagues from Swansea believe that the shafts and mine site are now the site of Tesco Superstore Car Park. They had other pits at Landore. My own knowledge of the geography of S Wales is limited, so I don't recognise the site covered by your map sadly.

@demorgan I'll see what I have. I do have this plan which is the geological mapping for the Lower Swansea Valley Project from 1965. I think this is an accurate plan because the Geological Survey sheet (247) was considered unreliable in parts. This is because it was mapped very early in the 1830s.

@Nyddfwch far further than anybody had expected, with the result that they had to spend much more to sink the shaft deeper, than they had expected. It came good in the end.

@demorgan Although I use the Record Office a lot but I've never looked at coal records as most of my areas had coal pits that shut before records began!