A sonar survey was carried out in March 2017.
This showed, amongst other things, that the lower, narrower shaft is not centrally placed but is to one side of the upper, wider shaft.
The upper shaft appears to be in good condition but the lower shaft has had a fall of material from the north-east side which has filled the lower portion of the shaft and is probably the reason why some of the pump risers appear to have fallen down the shaft.
The Trust is now in the process of organising a camera survey of the shaft to determine the work that will be needed in phase 2 of the restoration, if any, to stablise the shaft.
For the history and details of the shaft please see here.