UNEXPLODED ORDNANCE
FEATURE SPONSOR
SEABED SAFETY REDUCING RISK
Ensuring the seabed is safe for development is an essential part of the site assessment process. In addition to avoiding hazards such as wrecks, boulders and shallow gas accumulations, the presence of unexploded ordnance (UXO) is another significant threat to consider. The process of reducing risks to development on the site involves a number of stages undertaken by specialists in their fields, including desk studies, site surveys and if items are discovered, the clearance of ordnance from the seabed using methods including ROV removal.
UXO SURVEY EXPERIENCE
Osiris Projects are experienced in UXO surveys utilising towed magnetometer arrays, which typically comprise of a number of caesium vapour magnetometers towed in an array with very small offsets between sensors of only a few metres.
These multiple magnetometer towing arrangements allow for very dense coverage of the seabed and sub-seabed in the endeavour to detect ferrous metals that are often present in UXO’s. One or more side scan sonar systems also form part of the array to allow for the detection of objects on the seabed.
ACCURATE CONTROL
Accurate control of the towed magnetometer’s position and altitude above the bed are key to maintaining the highest possible detectability of UXO’s. For this reason, in addition to the accurate subsea positioning of the towed sensors via USBL positioning, the altitude of the sensors is also maintained at a minimal height above the seabed by exploiting the magnetometers on-board altimeter. The position and altitude of each of the individual sensors is constantly monitored and adjusted by the on-board survey crew.
COLLABORATION
Osiris Projects have worked closely with both developers and specialist UXO consultants to ensure that the highest possible tolerances of detectability are achieved and the company is currently developing a 4 magnetometer array to be towed from the latest addition to the survey fleet, Bibby Athena.
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