Are there regular holes above each other in two opposite faces of the shaft all the way down? As that would help in identifyig where the guide rails for the cage would have been if there was a cage.
If the shaft had a beam engine with a fairly long stroke i.e. 10ft there may have been resting platforms each 10ft for the men to step of the pump rod onto the platform.
If stuff was brought in and out by bucket I would have expected the shaft to be circular like most of the early shafts here in Pembrokeshire.
Photograph:
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Pembrokeshire, The Forgotten Coalfield!