mine shafts

Depending which books you read it is estimated that there were 3/5 thousand mine shafts in and around Wigan .It is funny the town never collapsed with the amount of coal that was extracted from under it. Are there any shafts which are only covered with timbers not capped I remember years ago there was a shaft on the left going up to the motorway bridge at Windy Harbour which was only covered with railway sleepers.

From an ex-miner too? The mind boggles!

I read that there is estimated to be around a thousand shafts within a 5mile radius of the town centre.

Says Two thousand in Davies's book, but I do not know if anybody is counting them, or just pulling figures out of thin air!

I should imagine a good percentage of these shafts where bell pits

Probably. Maybe count is also including Day Eyes.

I have read that earliest mention of coal in the district was in 1300's, at Burnhill, which apparently is either in Bryn or Ashton, but I have never been able to ascertain precisely where. So it is possible we are considering a long period over which mines may have been sunk. Even longer, if the Romans mined coal in the district, as some findings indicate.

Peter,
The mining did result in subsidence/collapse... hence the 'Flashes' - large bodies of water where land had sunk. Even the railway track disappeared in Pennington, Leigh. Moving on, some canal locks have twisted due to mining subsidence.
Ena,
There is an old OS map that indicates Roman mining north of the town, but I guess it would be surface or bell pit rather than deep pits.

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.

PS An interesting example of the problem with OS maps.

You can find the assumed site of Coccium shown on OS maps.

It isn't Wigan!

Come to that, it isn't Coccium either!

And, guess what: it isn't Roman!

Ena... thank you for that very interesting and educational narrative. Greatly received.
Yes, Roman mining on OS (and other more relatively recent offerings) is rather speculative. All of your text is noted and agreeable.
The question of Roman activity in Wigan is still a work to be concluded... ancient writings offered a scenario. More relatively recent excavations have given us a better picture.
The earlier excavations at the Wiend revealed a Roman warehouse or perhaps factory/workhouse - in this area a store of mined coal was encountered. This can be regarded as perhaps 4 alternatives;
Coal was mined in Wigan
Coal was mined nearby
Coal was transported to Wigan for local use
Coal was temporally deposited in Wigan for use futrher on.
But, all is speculative... I hope future archaeology might give us a more accurate delineation of our town's history.
I expect every single person will have their own agenda, but I am always persuaded or given direction form actual facts.