Context and Event:
A sinkhole reported on 02/04/18 has appeared in Merthyr Tydfil within a new build site, Cwrt Aneurin Bevan, developed by Taylor Wimpey. The sinkhole which is reportedly 20 ft (6m) deep with a 2 ft diameter has exposed underlying utility pipes and resulted in local residents losing access to their new homes [1,2].
According to the Merthyr Tydfil Council, the sinkhole is showing signs of increasing in size posing a higher threat to residents from further collapse and subsidence. Heavy rainfall is expected to exacerbate damage caused by the sinkhole and although attempts have been made at redirecting the surface water using sand bags, subterranean water is likely to continue to erode the void beneath the development.
Merthyr Tydfil councillor Andrew Barry said gas engineers have been called to the estate along with the housing developers Taylor Wimpey, with remediation efforts to fill the void, undertaken to prevent further collapse.
Merthyr Tydfil is an area with a rich history of coal mining activity. The land formerly occupied by the Mardy Hospital site has been extensively mined for coal via underground and surface methods. Several mining features, such as underground tunnels known as ‘adits’, have been identified by Terrafirma within a 100m radius of the sinkhole as well as numerous mine shafts and other extraction features.
Sinkholes are synonymous with areas of historic mining activity, particularly in the vicinity of mine entries. These features often pose a greater risk of collapse when they are unrecorded and untreated – an increasingly common situation on new build developments in heavily mined areas.
Failure to appropriately consider the mining history of prospective new build sites is often a gamble and can cause detrimental impact to both financial position and reputation of housing developers.
Terrafirma’s unique SinkholeAlert continues our ambition to better educate and alert prospective homeowners to the many and varied hazards & liabilities the ground poses. TerraSearch Assess identifies all reported sinkholes and ground collapse within 50 metres of a property and accesses a weekly updated ‘live’ database of 9000 sinkholes and ground collapses from across the UK.
To keep up to date with our blog ‘What Lies Beneath’ – please visit: https://www.terrafirmasearch.co.uk/understand-the-ground/