Preliminary UXO survey - Phase 1

T&A's preliminary UXO investigation is a desk study to establish whether there is an increased risk of the presence of UXO from the Second World War in a specific area.

Why preliminary UXO investigation?

Reasons for conducting a preliminary UXO survey may be that ground works are planned in an area that hasn't been touched  since the war or that there are indications of fighting and bombing in or near the research area.

Historical archive

T&A has already conducted many preliminary investigations throughout the Netherlands. In addition, T&A has mapped the entire Dutch railway system, cable and gas pipeline traces, rivers and dikes over a few tens to hundreds of kilometers. This resulted in an extensive archive of historical data.


The preliminary UXO investigation consists of two phases, in which several activities are carried out:

I - Inventory of source material

  • Literature study
  • Archival research
  • Interviews with local inhabitants and eye witnesses
  • Aerial photography interpretation

II - Assessment of the source material

This phase will only be carried out if the problem inventory gives rise to it:

  • Assessment of the inventory
  • Horizontal and vertical delimitation of the suspect area
  • Determination of the explosives types

The end result of the research is a report and an inventory map in GIS. This indicates where and at what depth there may be explosives and of what type.


In a UXO risk analysis,  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 risk analysis is not a mandatory step between the historical preliminary research and the field research (detection and approach of UXO). In some cases, however, the risk analysis can be of added value to reduce time and costs:

  • During the historical preliminary research 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.


T&A specializes in Community-wide Preliminary UXO Investigation. We perform a desk study of the entire territory of ​​a municipality, water board or province, to determine which locations are suspected of possible presence of UXO. In carrying out the historical preliminary research, T&A takes into account the wishes and procedures of the client. This allows individual adjustments to be made quickly. These are the possibilities for a tailor-made UXO investigation for each municipality, province or water board:

Preliminary UXO investigation at specific locations

In this option, T&A conducts a historical preliminary investigation for a limited number of locations within the territory. This may be because there are plans for construction or infrastructure adjustments at these locations in the near future. It may also include areas where fighting has taken place during WWII and where specific locations are known to have an increased UXO risk.

UXO quick scan

A quick scan provides a low-cost insight into the areas within the territory that require further investigationa. Based on a selection of sources, T&A maps of the acts of war in the area. The result is an overview map of the territory. For the low-risk areas, further research is not strictly necessary. However, if work is planned in a high-risk area, further investigation or demarcation should be performed.

Preliminary research per project

For organizations that like to work per project, it is possible to have all preliminary UXO investigations carried out by T&A at a favorable, fixed price. As a result, over time you will have an increasingly extensive, unambiguous database of the acts of war in your territory. T&A can easily process changes in guidelines and regulations by updating existing investigations.

VEO Bomb Map

Would you like to know whether preliminary investigations and/or investigations into UXO have already been carried out within your management area? Consult the VEO Bomb Map. In this application, T&A Survey and other specialized and WSCS-OCE certified companies share  information about completed Preliminary Investigations and Investigation Projects.

With T&A's Omni soil scan, the risk of high additional costs can be considerably reduced at a limited, fixed rate.

What is the Omni soil scan?

The Omni soil scan is a desk study that provides insight into the possible risks in the field of archeology, geotechnical or hydrological soil composition, pollution, foundation remains, UXO, cables and pipes. Archive material and aerial photos from different periods are used for this.

Omni Soil scan plus

The Omni soil scan plus complements this desk survey with several drillings, CPT and a geophysical field survey to immediately identify potential risks.

Advantages of the Omniscan:    
  • More information about the soil reduces failure costs during implementation.    
  • T&A has all specialists under one roof, which gives the client a single point of reference.   
  • The client receives a single report containing the conclusions of several disciplines.