Andrew Bluett was joined by Colin & Ingrid Twissell, Nick Christian, Simon Glover and Councillor Andrew Gardiner for the third visit to the Cinderford Northern Quarter development area.
Andrew Gardiner was able to show us LiDAR (Light Detection & Ranging) aerial photographic images of the area which depict details of the ground contours and irregularities across the site. The significance of these images amongst other things is that they show depressions in the ground indicating the positions of some of the numerous shafts and holes resulting from past mining activity.
Simon Glover had previously made some exploratory visits to parts of the site seeking these depressions and evidence of “sink-holes” or collapse where some subsidence is in progress.
As a result of both the LiDAR images and Simon’s findings the party was able to locate and examine a number of the surface depressions, some of which showed recent evidence of movement, no doubt aggravated by the heavy rainfall and flooding that had affected Gloucestershire and many other areas in the late winter.
The CNQ site has been the subject of a detailed mining & excavation investigation by expert Paul Morgan, and whilst there is some disagreement regarding his findings, there is no doubt that historically the site has been extensively mined both with shafts and by opencast extraction and has been the site of opencast clay extraction for the local brickworks. It is believed that there is a significant aquifer under the area which could aggravate the deterioration of the ground in some areas. Estimates vary but the belief is that there are over 130 uncapped shafts on the site and could be more than twice that number.
The weather was bright but cloudy and chilly so no reptiles were evident; bird life was much the same as on previous visits but with the addition of some of the first of this spring’s Willow Warblers, newly returned from their southern winter quarters. Siskin & Crossbill were seen and heard overhead and a new addition to the species list was Pheasant. Ingrid Twissel had identified another species of fungus, the toxic and scarce (in southern areas) Gyromitra esculenta.
Staring into the abyss – Andrew Gardiner looking down into a former pit shaft that shows evidence of very recent subsidence.