Preliminary UXO investigation
Unexploded Ordnance (UXO) from the Second World War is sometimes encountered during excavation and dredging work. This can lead to dangerous situations. With a preliminary UXO investigation, T&A can determine whether there is an increased risk of explosives. Reasons for conducting a pre-examination CE may be:
- Planned earth-moving activities in post-war undisturbed soil.
- Indications of combat and bombing in or near the research area.
T&A has already carried out many preliminary UXO surveyss throughout the Netherlands. In addition, T&A has mapped out the entire Dutch railway, cable and gas pipeline routes, rivers and dikes over a tens to hundreds of kilometers. As a result, we have an extensive archive with historical data.
UXO investigation in 3 phases
T&A Survey conducts explosives research in 3 phases:
- Phase 1: Preliminary UXO investigation (desk research)
- Phase 2: UXO Detection (field research)
- Phase 3: UXO Approach (field research)
The preliminary UXO investigation consists of two phases, in which several activities are carried out.
- Literature study
- Archival research
- Interviews with local inhabitants and eye witnesses
- Aerial photography interpretation
- Assessment of the inventory
- Horizontal and vertical delimitation of the suspect area
- Determination of the explosives types
In a project specific risk analysis (PRA) the risk of UXO presence in the subsurface is mapped in order to deterimine how the planned activities can take place in a safe way.
The PRA is not a mandatory step between the historical preliminary research and te field research (UXO detection and UXO approach). In some cases however the PRA can be of added value to reduce time and costs:
- During the preliminary UXO investigation the suspect areas have not yet been been vertically defined and the post-war groundworks have not yet been mapped.
- The planned activities are very diverse and extensive and the UXO research is likely to be expensive and has to take place in a restricted timespan.
Municipalities often carry out preliminary UXO investigations per project, which means that the costs in municipalities with growth potential can become considerably high over time. These separate investigations within a municipality are often carried out by different parties, which means there is a high risk that work will be carried out double and valuable analyses will be lost. T&A Survey therefore has created two options for municipalities to map the risk of explosives more efficiently and cost-effectively:
| OPTION 1 || OPTION 2 |
| One-off municipality wide || Customized per project |
| || |
T&A has already carried out many preliminary UXO investigarions throughout the Netherlands for, among others, the municipalities of Deventer, Haarlemmermeer, Tiel and Voorst and various waterships. In addition, T&A has mapped out the entire Dutch railway, cable and gas pipeline routes and rivers and dikes over tens to hundreds of kilometers. As a result, T&A has an extensive archive with historical data from almost all Dutch municipalities.
- High quality historical research which reduces the area to be surveyed in the detection phase.
- Use of innovative detection techniques gives a 3D image of the objects detected and reduced the amount of objects to be removed.
- T&A is independent has no interest in extensive, superfluous digging activities.
- UXO investigation can be combined with geophysical of environmental research.