The long term outcome for both Welwyn Hatfield Borough Council and Hertfordshire County Council is to remove the risk of chalk mines in the areas and protect the future growth and prosperity of Hatfield.
Reviewing areas over a phased basis
Our review of eight areas commenced with the two Chantry Lane sites where mine workings were indicated by the investigations carried out in 2010.
To view the area, see the latest map of possible chalk mines in Hatfield.
In March 2011 we submitted an application for funding to the Homes and Communities Agency's Land Stabilisation Programme to carry out further ground investigations in Chantry Lane.
Funding was awarded in December 2011 and Mace were appointed to act as Project Manager for the scheme in early 2012 while Hyder were appointed to act as Geotechnical Engineer for the project in April 2012.
A microgravity survey was undertaken at the site in June and July 2012 to establish the boundaries of the probable mine indicated by the initial microgravity survey undertaken in 2010.
Subsequently, a targeted intrusive ground investigation was carried out between October 2012 and January 2013 and the data is currently being interpreted to determine the extent and condition of the mine to enable the design of the remediation works.
Remediation works at Chantry Lane were completed in 2015. Further information and a treatment report are available here.
We will look at each of the remaining six areas in turn to determine what needs to be done for those.
As more information is gathered it is expected that the areas affected will further reduce in size. Since 2007 the number of areas has reduced from 25 to 8.
Investigations and remediation that have already occurred in Hatfield
Investigations in Briars Lane, Hatfield proved that chalk mining had occurred. Remediation work has removed any risk of subsidence. This was completed in 2008.
What if you live or work within one of the areas identified?
There is nothing that you need to do at this present time. The councils intend to further investigate areas over a phased basis starting with the areas of highest probability. When an area is to be considered, all property owners in that area will be contacted.
We would like to know however, if your house has ever been underpinned or your land ever suffered from an actual subsidence incident. This will help us update our records. It may be used to also reprioritise areas.
If you are thinking of applying for planning permission please view the planning and building related issues planning and building related issues page.