May 31 2017

Pinner Wood School – Progress Report, May 24, 2017

Dear resident,

This is the fourth of our regular updates on the work that our project team are undertaking at the site of Pinner Wood School. The site is currently closed after the discovery of previously unmapped chalk mine tunnels under the school building, some of which had collapsed roofs.

We are pleased to report that our drilling continues to progress at a fast pace. We have now almost completed our grid pattern of boreholes across the site and the good news is that we have discovered no evidence of voids or broken ground to the west of the school.

The next stage in the process is to deploy the laser scanner, provided by a company called Geoterra. It is scheduled to arrive and begin work tomorrow, Thursday 25th May and continue operating until Friday 2nd June. We are preparing 26 boreholes for laser scanning (largely corresponding to the red circles on the maps overleaf), with the intention of creating a thorough 3-D picture of the condition of the ground at depth. In addition, we will be sending high definition cameras and lights down those same boreholes, to help us gain more information.

Our first rig will continue completing installations suitable for the laser scanner.

Our second and thirdrigs will be finishing the planned boreholes on the southern side of the school and around the boundary of the site near the known mine-workings at the south east.

The courtyard mini-rig has made good progress in the past fortnight and will continue its work around the courtyard. It has not found any evidence of voids or significant broken ground.

Findings west of the school as at 24 May 2017.


Findings east of the school as at 24 May 2017.


  • Green Circle: Borehole with no evidence of voids
  • Yellow Circle: Borehole with evidence of soft ground
  • Red Circle: Borehole with evidence of void or significant broken ground
  • Blue Dot: Planned future Borehole
  • Red Hash: Tunnels discovered by March laser surveys
  • Grey Area: School buildings

By the time of our next bulletin, due a day earlier than usual on Tuesday 6th June, we expect all of the exploratory drilling work to be complete. We may also have some information to relay from the laser scanning and CCTV work. Lastly, we will be making an announcement regarding the temporary location for the Pinner Wood pupils’ schooling from September 2017.

Thank you for your understanding and your continuing support.

If you know any resident who would like to receive this bulletin or have any other questions, please contact us at regeneration@harrow.gov.uk or by post to Regeneration, Harrow Civic Centre, Station Road HA1 2XY.

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1 comment

  1. Sunny

    Another 2 week wait for parents, pupils and staff to find out details for the temporary location. I wonder why Harrow Council were unable to meet their target date of last week?

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