This page details why the chalk mine review of Hatfield took place, the result of the study and what it may mean to if you are a homeowner or business in Hatfield.

Nine areas of possible risk from chalk mining have been identified in Hatfield. Of these, only two areas have been identified as highly likely to have chalk mines.

Please see Icon for pdf the map to view the areas of possible chalk mines.


Summary of the chalk mine review of Hatfield

Following the discovery of chalk mines in Briars Lane, Hatfield, it was agreed by Welwyn Hatfield Borough Council and Hertfordshire County Council to undertake a study to review the possibility of chalk mining elsewhere in Hatfield.

Working with project managers Mace Ltd and with specialist consultants Hyder, the study looked at historical information and geotechnical data such as the composition of the ground and the natural landscape.

The study systematically pulled together data, often some of it indirect, to indicate the relative likelihood of chalk mining activity. The result was a map that showed areas of evidence and a risk assessment model for council services to use.  This was published in 2007.

The result of the study allowed us to proactively investigate areas, either to rule out the risk of any subsidence or to put in place measures to minimise any risk.

Following further investigation, completed in 2009, it was concluded that the initial areas identified were significantly smaller than originally thought. Some of the areas that do remain  are also smaller in size.

We then commissioned the next phase of our investigation to gain further information. This was completed in August 2011.  

We then commissioned the next phase of our investigation to gain further information. Of the 14 areas, six were identified as 'no significant risk' and were removed from the list. Four were reduced in size but not eliminated and two were inconclusive.

Evidence from two combined sites in the vicinity of Chantry Lane indicated that mine workings were present at this site.  See below for further information on the remediation work carried out at Chantry Lane, including the treatment report published on completion of the work in September 2015.


Chantry Lane Chalk Mines Remediation Newsletters

These newsletters are produced by the council's appointed contractors: Mace, BAM Ritchies, and Hyder


Treatment Report September 2015

The Chalk Mines Treatment Report can be viewed below. Further appendices relating to individual properties are available to view upon request. Please contact us to arrange a viewing.

Public Meeting Presentations

Both Welwyn Hatfield Borough Council and Hertfordshire County Council will continue working on establishing more authoritative information on the possibilities of chalk mines in the Hatfield area. If you are interested to know what's going to happen next, view the project plan page.

Map of possible chalk mining locations

In total 9 areas have been identified as possible historical chalk mining locations.

Key to the map

  • The marked red areas are where evidence has been found to suggest that chalk mining may have occurred.
  • The blue circled areas around the red areas are 100 metre buffer zones. From previous records of chalk mining, tunnels leading away from shafts tend not to extend further than 100 metres. These boundaries give a rough guide of the areas to be looked at further.

Previous maps