‘Ground detectives’ visit Pinner Wood School


‘Ground detectives’ visit Pinner Wood School

2 February 2018

LONDON - Representatives from Peter Brett Associates visited Pinner Wood School on Tuesday 16 January to help children and staff understand more about the chalk mines that lie beneath the school and how they have been made safe.

The mines were discovered after a hole opened in the staff car park in 2015. Harrow Council commissioned specialist engineers from PBA to conduct further analysis which showed the school buildings and playgrounds were sitting on top of a disused chalk mine. The analysis also showed that some of the tunnels had partially collapsed, leading to a risk of further holes opening on the surface. The findings led the council, the school governors and the Pinner Wood leadership team to close the school on 23 March 2017.

Since then PBA, and geospatial engineering consultancy, Geoterra, have been conducting in depth surveys of the site to determine the extent of the mines and ensure they are made safe.

The school is now open to all pupils and Dr. Clive Edmonds, PBA Project Director, and Stuart Chandler, PBA Project Manager, together with site engineers Natasha Withers and Harry Gordon, were welcomed to the school by the headteacher, Sarah Marriott, to help every child understand what had happened.

Commenting on the visit, Clive said:

“This was a such positive experience and the perfect way to bring our work on the Pinner Wood site to an end. All the children were very interested and asked plenty of questions about how the chalk mine got there and how we fixed the problem.”

Clive explained that the mine likely dates from at least the early 1800s. As is common for chalk mines of this age there are no mine abandonment plans so PBA had to discover the extent and state of the mine workings. This was confirmed by 3D-laser surveys, above and below ground, using the most up-to-date technology available.

As an engineering and infrastructure consultancy, PBA has a great deal of experience in purpose-designing ground investigations and determining possible solutions. In this case, it took just six months to fix a problem that was created over 200 years ago.

“We’re all thrilled to be back at our school; our exceptional staff, governors, children and their parents have really risen to the challenge of the last 12 months. It has been difficult for the children to understand why their school has been closed for so long when all the work took place underground. It looks like nothing has changed so this has really helped them see what happened and how their school has been made safe,” commented headteacher Sarah Marriott.

In a final comment, Clive said:

“It’s been fantastic to show everyone at Pinner Wood what we do. Sharing stories about how we are detectives of the ground, finding clues by drilling holes, has helped bring our work to life for the children, and I hope it has also inspired some future ground detectives.”