SITE INVESTIGATION started last week into the cause of a major land subsidence in south Edinburgh. Fifteen houses were seriously damaged last month when the ground at Ferniehill Terrace sank by up to 1m.
The subsidence occurred on 9-10 November in two movements, each lasting six hours and producing a 70m wide settlement trough.
The 1960's-built local authority houses will now be demolished and Arup Scotland has been called in by Edinburgh City Council to investigate the risk of further movement.
The subsidence is believed to have been caused by the collapse of 300 year old mine workings in hard limestone 30m below the surface.
But so far no voids have been found underground. 'It's not a traditional crown hole settlement, its more like a large block failure, ' Arup Associate Alan Richmond told NCE.
Contractor Raeburn is drilling boreholes on the site to try and find the mine workings, which are believed to emanate from an adjacent quarry. This is expected to be followed by sonar and video camera inspections once the workings are located.