As part of a large scale depollution project of a former oil refinery site in Valloy Norway ADEDE was contracted to detect and clear UXO at the site.
The site was target of a heavy bombing attack in the final days of the war to deny the Germans their last hope of producing fossil fuels and lubricants. On April 25 1945, only a few days before the German surrender, Valloy was attacked by 119 heavy bombers delivering 1000lb bombs causing enormous damage. As a rule at least one in ten did not explode and the postwar clearance reports suggested that UXO is still present this day. Before we started field work we conducted a historical desktop research and work specific risk assessment for the project area in Valloy.
The geological characteristics of the site made this a very challanging job. Whereas we normally do a ferrous detection and then select targets for identification, in Valloy we had only limited areas in which we could discern big anomalies from boulders and metallic pollution in the subsoil. Boulders have a natural ferrous content, the signature of which can be mistaken for UXO. The top soil was contaminated with metal resulting from years and years of industrial use, signatures of which could easily mask a bomb lying underneath. The safest way to keep the work going was to clear the subsoil layer by layer by means of a manual UXO detection. During the project we found evidence of military presence in the shape of personal attire, bomb fragments and an unexploded 1000lb bomb.