West Weares "sinkholes"

[Graigwen]

I noticed by chance a report by Dorset Council in facebook about footpath collapses yesterday. This does not seem to be on their website yet. I know absolutely nothing about the location and report it in case others who know more wish to comment.

"
Our Erosion Risk Management Team have noticed these sinkholes on Footpath 6 by West Weares on Portland, which they suspect could be part of a future wider cliff failure in the area.

As a result, we’re moving the current footpath closure back towards Priory Corner, and will be diverting the Southwest Coastal Path along existing rights of way through Tout Quarry.

For your safety, please note on-site signage and do not use the footpath within the closed area. Thank you.


Dorset Council photo.

 

[tim.rose2]

It's possible there's a rift system beneath this, but most like just gaps in boulders. The area was extensively quarried (Tout Quarry) in the 18th & 19th Centuries. Back filling techniques involved stacking unwanted blocks (often very large) behind the active face, forming walls of spoil which moved forward with the quarry face. Over time these became the new 'surface'. Those area now have footpaths over them with little understanding what lies beneath. I dare say once the path has been diverted it'll get looked at! I'm not sure the exact location of this hole so the first question is whether this is untouched ground (i.e. below the quarried free stone, so would have been the quarry floor) or above back fill. It's pretty obvious to determine based on the relative heights. The cliff edge behind Tout is the old quarry floor level (i.e. the bottom of the freestone / top of the cherty series).