History of Wigan   (Help with ancient and recent history.)

OS maps are not reliable as sources of Roman remains. It is well known that they recorded such if locals described it as such. (With first edition, it is what you need for it to serve artillery targeting, ie an ordnance survey) There was no Archaeologist input to First Series. A lot of such errors have been logged.

For a long time, the argument was made that Romans were not using coal, as wood was still in widely available, and more easily got than coal. It is also much more difficult to engineer the grate and flue to suit coal: even at the Rainhill trials, all the locomotives were burning coke. Rocket was later converted: it took them a while to get the technology right for coal burn.

But Romans were making glass around Wilderspool, and firing clay rooftiles around Holt, so maybe they had industry that performed better with coal.

Somewhere, there is an account of when building required temporary diversion of the Duggie, and in the then exposed river bed they found something which, when cleared of river silt, appears to be remains of a Roman Mine. It consisted of linked polygonal chambers, which is similar to known Roman metal mines in Spain.

Sadly, it is the form of mine in which slaves could be employed, as they do not have the opportunity to destroy supports and bring down the roof on themselves and/or their captors.