A possible denehole opened up beside Cold Harbour Road. It was approximately 5m deep and appeared to consist of a large main chamber with possibly a couple of smaller chambers off of this.

Reported by Kent Highways Service.

The site was visited on 1st February 2010 by KURG when a near circular hole approx 1.3m across was found adjacent to the 2.8m wide local road. Two small diameter service pipes running parallel to the road were noted crossing the void at a depth of 0.65m. Below ground the narrow opening gave access to a roughly ovoid shaped cavity around 3.0m in diameter and 4.5m deep to the top of a sloping debris cone consisting of fallen clay and flint. The void appeared to have been the result of the collapse of a man made chamber. The lowest attainable point was found to be 5.8m below the surface at the end of a vestigial chamber in the chalk lying to the south-south-west and filled to within 0.5m of the roof with clay debris. Tool marks were observed in the end wall of this chamber which indicates that it was excavated with a short-headed iron pick, the usual tool used to dig the small agricultural chalk mines known as deneholes which are numerous in this area. This structure was almost certainly a chalkwell type of denehole which has suffered a number of collapses in its history, the latest being the failure of the roof of a chamber. This may have occurred several years in the past as it often takes some time for the collapse to migrate up to the surface. It was not possible, with any certainty, to identify the position of the original access shaft or any other chambers. The eastern edge of the short fragment of a chamber had a vertical demarcation between the chalk wall and the clay infill which could conceivably have been the edge of a shaft or could equally have been a junction with another, now totally filled, chamber.
The junction between the Chalk and Clay-with-Flint was visible in the south of the cavity but was not discernable in the rest of the structure. Either it was obscured by the clay infill or the original miners had encountered a large ‘pipe’ or clay intrusion which may explain some of the instability of the excavation.

With so little of the original structure intact it is impossible to envisage the original form and shape. The local geology of Clay-with-Flint would suggest a date of excavation from the 17th century onwards. It was from this age that the technology of ploughs improved so that the heavy clay soils could be brought into cultivation. A date of 18th century could be suggested based on the dating of similar chalkwells in the local area (1).

<1> Kent Underground Research Group, 2010, Email to KCC from Rod LeGear regarding KURG recent discoveries and recording (Verbal communication). SKE16011.