Otford Chalk Pit has reopened following investigations and actions to ensure the site is safe.
In recent years, sink holes have appeared at the Chalk Pit and in September 2023, we partially closed the area as a precaution. In June 2024 a survey indicated there may have been underground cavities throughout the site, posing a danger to life. The site was closed until it could be further investigated and made safe.
We subsequently commissioned further ground-penetrating radar surveys of the entire site to establish the causes and the extent of the subsidence.
The surveys found there were a number of small sink holes, but confirmed the majority of the site is safe.
Most of the Chalk Pit has now reopened with some restrictions:
- Walking access has been reinstated at the railway/scout hut entrance and at Pilgrims Way East
- Permanent fencing has been put up around the areas with sink holes
- For your own safety, you should not attempt to get into the fenced off areas and you are advised to keep to the main pathways.
The former Chalk Pit has an extensive industrial history having been mined for chalk during the Victorian period then used as a landfill site.
For many years, it was used as a public open space and was managed by Otford Parish Council until 2021. The Parish Council ended its long-term lease due to the mounting health and safety and maintenance costs from both sink holes and Ash Dieback. We then took responsibility for the site.
Survey results
Download and view the survey reports
Timeline
|
Phase |
Activity |
Location |
Date |
|---|---|---|---|
|
1 |
Ground Penetrating Radar Survey |
Chalk Pit |
10 June 2024 |
|
1 |
Ground Penetrating Radar Survey |
Scout Hut site |
19 June 2024 |
| 1 |
Geologist and KCC Engineers Site Survey |
Chalk Pit | 26 June 2024 |
| 2 |
Dimitrios Kalianidis BSc (Hons) CGeol FGS commissioned (Independent Chartered Geologist of the Geological Society, London) |
Chalk Pit | 26 June 2024 |
|
3 |
Commissioned a Geologist/Hydrologist to view all results |
Chalk Pit & Scout Hut sites |
Appointed 21 June 2024 |
| 2 |
Intrusive Ground Testing, such as boreholes, trenches and electronic survey |
Chalk Pit | From 8 October 2024 |
| 3 | Commissioned final Geologist report for re-opening of the Chalk Pit solutions (following testing) | Chalk Pit | February 2025 |
| 4 | Commissioned fencing off of sink hole locations (following testing) | Chalk Pit | April 2025 |
| Final | Reopening of the Chalk Pit | May 2025 |
Intrusive Ground testing
We commissioned the following three phases of works, which will began from 8 October 2024.
Phase 1
Geophysical data collection (resistivity; non-destructive survey). These included the data collection, interpretation and reporting of the underlying terrain to determine the resistivity characteristics of the ground, which can be attributed to the state of compaction/density of the wider underlying terrain.
Phase 2
Ground investigations - probing 10 metres below ground.
Phase 3
Reporting - The collation of the findings from the previous two phases and recommendations to repoen the site.