This informal CPD article, ‘What is a UXO investigation?’, was provided by Brimstone Site Investigation, who are Explosive Ordnance Disposal (EOD) experts dedicated to the safe removal and disposal of Unexploded Ordnance (UXO) across the United Kingdom and around the globe.
If you work in a profession that involves ground-intrusive work, it is essential to consider the potential risk of encountering unexploded ordnance (UXO) on your site. There are a range of services available to mitigate the risk of UXO, including UXO assessments, surveys and investigations.
The importance of UXO investigations
UXO investigations play a vital role in assessing and managing the risks associated with UXO on construction sites. These investigations are often conducted as follow-up activities to intrusive or non-intrusive surveys, aiming to validate and further investigate modelled targets. In some cases, they can also serve as standalone services to rule out any unexpected UXO discoveries.
UXO Watching Briefs
A UXO Watching Brief is an excavation supervised by a UXO engineer. It uses a tried and tested methodology which is flexible enough to promote rather than hinder your on-site excavations. This service mitigates the likelihood of any unplanned UXO encounters and is ideal when other methodologies are not suitable for your project. A UXO watching brief supports reduced digs, excavations, trial pits and archaeology.
UXO Search and Clear
Another UXO investigation service that might be suitable for your site is a Search and Clear. This is where on-site UXO engineers will establish picketed areas in the pre-determined ‘at risk’ zone, before systematically clearing lanes using search equipment. They will mark, excavate, and log any targets as they present themselves.
This UXO investigation method is most effective on greenfield sites, but it can also be used on areas of made ground depending on the degree of metal contamination. One benefit of this service is that it can look for both ferrous and non-ferrous objects, including aluminium detonators and brass fuses.
UXO Borehole Support
Finally, UXO engineers can support your borehole and drilling projects to ensure all operatives are kept safe throughout the process. This service can support the use of cable-percussive, rotary, window and windowless samplers and other drilling methods by progressively clearing the position as the borehole deepens. The engineer will assess the local ground conditions as the drilling progresses to calculate the theoretical maximum bomb penetration dept. The hole will then be tested for magnetic signatures at intervals of 1m, beginning from the surface, by lowering a magnetometer probe on a cable extension to the bottom of the borehole.
What happens next?
Upon completion of the investigations, if no items of unexploded ordnance are found, you will be provided with an As Low As Reasonably Practicable (ALARP) certificate. This certificate demonstrates that the risk of UXO has been mitigated to the lowest reasonable level, ensuring the safety of your operatives. With the ALARP certificate in hand, you can proceed with your project confidently.
In the event that UXO is encountered during the investigation or construction process, immediate action is necessary. This typically involves contacting the police and Explosive Ordnance Disposal (EOD) teams, who will identify the item and safely remove or dispose of it. While this may result in a slight delay to your project, prioritising safety is paramount.
UXO investigations are essential for managing the risks associated with unexploded ordnance on construction sites. By engaging in services such as UXO Watching Briefs, Search and Clear operations, and UXO Borehole Support, you can ensure the safety of your workforce and proceed with your project confidently.
We hope you found this article helpful. For more information from Brimstone Site Investigation, please visit their CPD Member Directory page. Alternatively, you can go to the CPD Industry Hubs for more articles, courses and events relevant to your Continuing Professional Development requirements.