John Pit was dug by John Taylor in 1836 and closed in 1954 meaning it was operated by the NCB as a nationalised colliery for about 5 years.
There are literally hundreds of redundant pit shafts all over Wigan. Since Victorian times remarkably accurate plans have been kept of the position of shafts and details are retained by Wigan Council and by the Coal Authority. The plans can be seen by landowners and developers on request.
In the interests of safety shafts are normally marked in some way.
A brick or stone structure may be built round an open shaft – there are examples of this at Chisnell Hall Colliery at Coppull Moor (N53 36.342 W 002 40.977). Alternatively a concrete cap may be put on the top of the shaft – this is often marked by a small concrete structure rather like an OS trig point - there is an example of this at Prospect Pit at Standish (N53 34.683 W 002 39.417).
The third option is to fill the shaft. Companies closing pits often demolished the pithead-gear and simply pushed it down the shaft. The problem with this method is that material falling down the shaft could bridge across at some upper level leaving a void below. At a later date the bridging material could fail and collapse causing a dangerous hole to open at the surface. There have been several examples of holes opening in the Wigan area over the years and no doubt some of them were due to incorrect filling of shafts.
Where structures are to be built near redundant shafts a proper investigation by mining engineers is necessary and a remedial plan needs to be put in place. One system is to drill into the waste in the shaft until the bottom of the shaft is reached. Pea gravel is then dropped down the hollow drill as it is gradually withdrawn. This is done several times, to a predetermined pattern, until all voids are filled. The procedure is then repeated using cement slurry to fill spaces between the individual stones. This is considered one of the best ways to ensure that the redundant shaft will never be a danger in the future.
To complete and claim this earth cache;
- Look for evidence of the redundant shafts at John Pit near the coordinates given.
- If you wish you could post a photograph of the current evidence of the two shafts.
- Email me the answer to the following:-
- How are people kept away from the shafts? A photograph or a description would be fine.
- Do you think the shafts have been finally and completely rendered safe? Why do you think this?
- What is the different between the background of the 1950's photograph and the current view?
When you have emailed me the answers you may claim the cache and I will only inform you if there is a problem with your answers.