In-depth assessment of potentially threatening cavities below ground

Underground cavities may exist below a site due to either mining operations or as natural occurrences. Both man-made and natural cavities exist in a wide range of areas across the UK and can pose risks to planned infrastructure.

Natural cavities are commonly formed by the dissolution of soluble rocks such as chalk and limestone. Over long periods of time, the dissolution cavities ultimately form subterranean cave systems and may result in sinkholes. Underground cavities, therefore, pose a potential threat to the structural integrity of existing and proposed developments.

All known sinkholes in the UK are registered on the Natural Cavity Database. This provides a good indication of high-risk areas where others are likely to form. The highest occurrences of natural chalk cavities are in Kent, Essex, Berkshire, Buckinghamshire, and Hertfordshire, while limestone cavities are found in South Wales and the Peak District.

All recorded non-coal mining activities related to the extraction of other minerals such as flint, chalk, clay, sandstone, limestone, gypsum, salt, ironstone, etc., are also available on database records. Many of these are open pit workings, but some involve underground excavations and shaft access. Many of the disused and closed shafts pose a risk of collapse and land instability.

We rely on a combination of the Natural Cavity Database, the Non-Coal Mining Cavity Database, and our extensive experience to review and analyse all available information to conduct a comprehensive assessment of the potential risk of underground cavities on sites where this may be an issue.

Underground Cavities
Underground Cavities
Underground Cavities