Chalk

Introducing: The Ground Report

Terrafirma, an expert provider of environmental information and data intelligence, today launched the Ground Report, a risk and liabilities report designed to enable property professionals to better identify, manage and resolve ground and environmental hazards…

Sinkholes: Explained

Delve behind the scenes of the Channel 5 documentary on Sinkholes.

The word sinkhole has become a term broadly used term to describe any hole in the ground created by erosional processes and the drainage of water. Ground hazards in the UK are often synonymous with the word sinkhole which can span from just a few feet in diameter to gigantic chasms large enough to swallow whole buildings.

They can have devastating consequences as can be seen on the new three-part Sinkhole documentary which began on Monday 20 November on Channel 5 and features extensive commentary from sinkhole expert and Terrafirma CEO and founder, Tom Backhouse.

Chalk Mine Collapse at Field Road, Reading, Berkshire

The collapse of a chalk mine in west Reading forced the immediate evacuation of dozens of residents. These residents then suffered for years due to the extensive and drawn out remediation of the affected area, but eventually had their patience rewarded after the works finished and the area declared safe once again.

Sinkhole caused by collapsed Chalk Mine at Pinner Wood School, Harrow, Greater London

A large sinkhole opened in the car park of Pinner Wood School, Harrow, forcing its immediate temporary closure. Geotechnical surveys and site investigations have been commissioned to determine the cause of the collapse and assess the stability of the land.

Sinkhole at New Build Development, Plumstead, London

On the 2nd May 2016 a sinkhole believed to be 60ft deep and 16ft wide opened up on the doorstep of one of Skillcrown Homes new developments within Brickfield Cottages, Plumstead. The result of which led to the establishment of a 25m hazard zone and evacuation of 50 residents by the combined effort of the emergency services and Hexagon Housing, all of which were provided with assistance at a council run rest centre and overnight accommodation by the housing association. Following this, on the 3rd May evacuated residents were reportedly staying with families or in hotels whilst structural engineers looked to secure the site. The result of which, 30 households were returned to normality, whilst 10 awaited contact by Hexagon Housing. The remediation efforts, whether planned, completed or on-going are unknown.  

Sinkhole in Plantation Gardens, Norwich

On 9th April 2016, a 20-foot-deep sinkhole appeared at Norwich’s Plantation Garden, causing subsidence cracks to the neighbouring hotel on Earlham Road. This is a stone’s throw away from the 1988 sinkhole which swallowed a double-decker bus. The Plantation Garden is itself an old chalk quarry, with multiple mining tunnels leading off it. It is the collapse of a mining tunnel that is thought to have caused this sinkhole.

Sinkhole in Lawrence Square, Gravesend, Kent

In early 2015 at Lawrance Square, Northfleet, Gravesend, Kent – an extended period of subsidence culminating with the appearance of a sinkhole has forced several shops to close and evacuation of 7 sets of council tenants for fears of further subsidence.
 

Sinkhole makes global news in St Albans, Hertfordshire

On 1st October, 2015, a giant sinkhole opened up in Fontmell Close, St Albans forcing families to evacuate their homes and cutting off utilities to over 50 properties.