St. Albans Sinkhole - Update

According to the BBC's web site today, the void which opened up at Fontmell Close at the beginning of the month has now been backfilled, but that geophysical surveys (gravity) below the surrounding roads and footpaths suggest that there is at least one other void in the same area.  A copy of the image showing the survey reuslts (corutesy Hertfordshire County Council via the BBC News Web Site) is shown at the bottom of this post.

It does also appear that the site is a former clay pit on which housing was later built.  It is suspected, as was the case in Reading (e.g. Field Road), that there has been mining of the Chalk below the clay pit and it is these mine workings that have collapsed leading to the formation of the void.

The next step is expected to be intrusive investigations to search for voids and back up the geophysical surveys. 

Backfilling the existing void apparently required 48 lorry loads of foamed concrete.  Sadly the residents closest to the now backfilled void have still not been able to return home due to ongoing safety concerns.