UXO abbreviates Unexploded Ordinance, a term used to describe unexploded grenades, bullets, artillery shells and mortars. A UXB is an Unexploded Bomb, and many UXOs and UXBs remain today on ex military training areas or areas targeted by air raids in World War II.
UXOs and UXBs are obviously a threat to health and safety; and they can also create unnecessary environmental damage and cost implications. A UXO survey will assess whether there are any UXO causes for concern, which may be more common than you first think. It has been reported that over 15,000 UXOs were found between 2006 and 2009, in the UK alone. A 1,000kg bomb was found in East London in 2008 which had the potential to cause considerable damage, thus highlighting the importance of a UXB or UXO survey.
A Geophysical UXO survey will typically detect large UXBs up to 5 metres, and smaller items which are buried up to 2 metres deep. London and Portsmouth areas are where the most World War II UXBs are found in the UK.
The identification and location of harmful artillery is often essential at the design stage of construction projects, and an
UXO Survey may be of particular relevance to the redevelopment of brownfield sites. There are many types of UXO surveys, and to choose the best option surveyors will assess a number of factors. They will look at the ground type, its proposed use, the likely type of UXO and its likely depth. The survey may be used to ensure health and safety, or for use in archaeological exploration. There are three main types of UXO survey. Non-intrusive surveys involve the sensing of items from the surface, intrusive surveys involve data collection from sensors inside the ground, and marine surveys detect UXOs and other metallic objects under the sea.
Magnetometry is one of the more common techniques used in non-intrusive surveys, which uses Electro Magnetic Systems. Intelligent software manages the findings of
UXO Survey into a comprehensive set of data, filtering out any ambient magnetics. The data will then be considered and presented in a way which is clear to the client.
Buried fuel tanks and air raid shelters are another reason why a geophysical survey may need to be carried out, as they can create construction problems. Geophysical surveys also show buried mineshafts, air voids and cavities such as vaults, crypts, sewers and heating ducts, and subsidence is a good indicator of such air voids. The prominence of badger sets also show up in these surveys, and as they are a protected species, they must be considered during construction works. Geophysical surveys can also be used to show the characterisation of land forms, which can be done on a big scale. Other uses for these surveys are reinforced concrete mapping, used for locating foundations and such, when more foundations or a borehole are required; and high frequency structural radar, used for showing features within a building, such as hidden flues and chimneys, historic features and voiding.
If an UXO is discovered in a geophysical UXO site survey, the surveyors will stop all works, evacuate the area and contact specialist disposal experts. Once the area is declared safe it will be possible to continue development. It is important to carry out UXO surveys to ensure work is carried out in a safe manner under general health and safety guidelines.
