NCS Survey, an Acteon company, completed a bathymetric survey of Rubislaw Quarry on 20–21 March to aid decision making for the redevelopment of the site. For 200 years, Rubislaw Quarry, which is in the west of the City of Aberdeen, supplied 6 million tonnes of granite to prestigious construction projects worldwide, including the footings for the Forth Rail Bridge and for Waterloo Bridge in London.
The quarry closed in 1971 and has since filled with water to a depth of 152 m.
The survey involved acquiring and processing multi-beam echo sounder data to produce a 3D digital terrain model of the flooded quarry to determine the water depth and identify any objects on the quarry bed for further investigation using a remotely operated vehicle (ROV). The data will also aid volumetric calculations to determine the amount of water involved if the owners decide to partially drain the quarry, as the rising water level is a potential threat to neighbouring homes and businesses.
The survey equipment was provided by NCS Survey and Seatronics, another member of the Acteon group of companies, which also provided the eyeball ROV used for investigating the sonar contacts on the second day of the survey.
A crane lifted the lightweight offshore support vessel used for the survey in and out of the quarry between nearby blocks of flats.
The survey was successful but the anticipated abandoned machinery was not found: the only submerged objects identified by the sonar survey were found to be trees when inspected using the ROV.
[mappress] Subsea World News Staff , April 12, 2012;