A new online map reveals the location of dozens of war-time unexploded mines and bombs around the UK coastline, enabling developers of offshore energy projects to work out how to safely carry out operations.
Projects such as wind farm and cable laying require detailed information about areas mined by British and German forces during World War One and World War Two, when thousands of explosive devices were deployed in the waters around the UK coastline.
The interactive risk map also shares vital data about unexploded ordnance (UXO) from military armament training and munitions dumping. It also reveals previous UXO finds.
The map combines a range of data sources, including information from the UK National Archives, the Hydrographic Office and archives in Europe. Ordtek has also liaised with military sources.
The Mine Map been produced by UK firm Ordtek, which has offices in Eye, Suffolk, and at OrbisEnergy, Lowestoft and has taken three years to develop.
The company is currently doing risk assessment work on the world’s biggest wind farm site at Hornsea, off Hull, for DONG Energy and ongoing safety support at the Race Bank site off the North Norfolk coast, where last year they found 41 unexploded items ranging from small rockets to 1,000lb high-explosive bombs.
Thirty-six items were still live and had to be blown up offshore. The other five were inert and brought back to shore for disposal.
The company has also helped identify and recover 70 items from the Solent ahead of channel dredging for new Royal Navy aircraft carriers. These ranged from modern-day projectiles to 18th century cannon balls.
Ordtek director Lee Gooderham, said: “Geophysical seabed surveys, including looking for potential UXO, are a routine part of assessing sites ahead of construction work.
“It’s not the complete database, although finer detail will be available at a later date.
“However, it is helping developers to understand UXO hazards while making their initial tender bids for wind farm sites and it’s allowing vessel operators to begin risk assessments.
“It helps them to see how much potential unexploded ordnance there is in an area, and work out how much it might cost to dispose of it.”
The sea off East Anglia saw heavy military wartime activity and was a prime area for dumping unused munitions. Mr Gooderham said post-war dumping records were sketchy as navigation was less sophisticated and, instead of heading to a chartered disposal spot, a ship’s crew sometimes simply threw it overboard on a corridor stretching back to harbour.
While it was possible to map known mining and dumping areas it was not feasible to chart every unexploded torpedo and bomb whose positions were not recorded. However, they would be located during the more detailed surveys, as happened with the Race Bank finds, which were potentially the most explosive batch Ordtek had found so far.
Once UXO is confirmed – often using remotely operated vehicles (ROVs) and divers – the details are passed to military and civilian bomb disposal experts who carry out clearance ahead of onsite work starting.
Mr Gooderham said the process from desktop risk assessment to final clearance could take over three years on large projects.
Ordtek plans to produce maps for European waters.