UNEXPLODED ORDNANCE
FEATURE SPONSOR
UXO DETECTION
DEVELOPMENT: DEVISING SAFE AND EFFECTIVE SOLUTIONS
Unexploded ordnance (UXO) is widely found in both the North Sea and Baltic Sea as a result of past conflicts, particularly the First and Second World Wars
Between 1848 and 1946 approximately 150,000 mines and millions of aerial bombs were dropped into the Baltic Sea alone. There is also a high concentration of mine lines in the Gulf of Finland. The steel casing on these munitions remains largely intact at deeper water depths because the mines were not only constructed to endure high water pressure, but the Baltic Sea’s low salinity and oxygen levels also create conditions for slower corrosion.
CLEARING THE WATERS After WWII, the nations surrounding the Baltic Sea conducted mine- hunting campaigns to clear the waters from the UXO threat and much of it has been removed or destroyed. After the dissolution of the Soviet Union in the 1990s however there was a general arms reduction and mine hunting capacities in the Baltic Sea were significantly reduced. The remaining mines that were considered
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to be problematic were located mostly near Estonia, Latvia and Lithuania.
But in 2003 the attitude toward UXO shifted. During efforts to salvage a Swedish reconnaissance airplane lost in the central Baltic during the Cold War era, four German mine lines from 1916 were encountered. When the Swedish Navy inspected the mines they were found to be in excellent condition – even after 87 years on the seafloor. With this renewed awareness of the potential threat on the Baltic seafloor, mine-hunting capacity increased once again.
CONTINUED THREAT UXO continues to pose a threat to any seabed activity in the Baltic Sea, whether it is building windfarms, laying cable or installing pipelines. The biggest construction campaign in the Baltic Sea by far has been the laying of the Nord Stream Pipeline stretching from Russia all the way to
Germany at a length of approximately 1,220km. Prior to the laying of the twin pipeline, Nord Stream performed a meticulous UXO survey together with MMT. To safely install the pipelines, security corridors were defined to a width of 15m along the routes, with some extended areas, resulting in over 10,000km of UXO survey work between 2007 and 2010.
At the time, the existing systems for UXO detection were limited in coverage. In order for Nord Stream to safely cover the security corridors, innovative ideas were needed. Together MMT, Nord Stream and Innovatum improved the Smartsearch™ system to consist of a 6.5m wide frame pushed by a Remotely Operated Vehicle (ROV), resulting in the coverage of a 7.5m corridor per survey line. The system at this stage had a typical noise level of ±10 – 15 nT/ft, with local noise between 20 and 25 nT/ft. At
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