UXO Survey - What Is It And Why Do I Need One?

uxo survey - unexploded ordnance

UXO, which is the common abbreviation for unexploded ordnance, are explosive weapons such as bombs, bullets, mines and artillery shells that are unspent. These items are often hazardous, potentially at risk of detonation even though they may have been dormant for decades. There are large quantities of these items remaining in the UK, particularly in areas used for past military activity or hit by air raids during the Second World War, such as London and Coventry.

These unexploded objects pose an obvious risk to health, safety and the environment, especially during construction work in affected areas, and can cause significant damage if not dealt with in a safe manner.

What Is A UXO Survey?

It is the process of scanning and probing the terrain or marine environments to assess if there is any unexploded material embedded in the ground of the site, ensuring any planned construction works can be carried out as scheduled with the minimum amount of risk to those involved.

When deciding on the level of survey required a number of factors need to be considered; the type of ground, proposed use, risk of UXO contamination in that area, and if the risk is present then the likely penetration depth all need to be taken into account.

Do I Need A UXO Survey?

ww2 uxo

Although it has been over 70 years since World War II ended, unexploded ordnance still poses a significant risk in many areas across the UK. In London alone it is estimated that as many as 10 percent of bombs dropped did not detonate on impact, and as a result could potentially be dangerous if unearthed.

The Construction Industry Research and Information Association (CIRIA) reported that over 15,000 items of ordnance were found in UK construction sites over a period from 2006 to 2009 alone, which averages at over 5000 a year.

Establishing the potential risk and location of UXO contamination is vital, and evidence of UXO clearance is often required at critical stages of construction projects, especially for the redevelopment of brownfield sites.

Geophysical Survey Methods

There are two main types of geophysical survey used for the detection of unexploded ordnance, each one having their advantages and factors to consider before implementing;

Non-Intrusive Survey

uxo non intrusive survey

A non-intrusive UXO survey involves scanning the surface of designated target areas using magnetometry equipment. This sophisticated equipment can detect ferrous anomalies in the ground that are similar in size and dimensions as ordnance materials. A magnetometer survey can detect a 50kg bomb at a depth of up to 4 metres, depending on the condition of the ground and site in general.

Generally Non-Intrusive surveys are used on Greenfield sites as they can be ineffective on Brownfield sites.

Intrusive Survey

intrusive uxo survey probe

An intrusive UXO survey involves using probes and sensors inserted into specially drilled holes to detect whether there is unexploded ordnance present.

This is recommended in situations where it is likely that the penetration depth of any suspected ordnance is beyond the detection capabilities of a non-intrusive survey, or in unsuitable conditions such as areas of made ground and gross ferro-contamination.

Marine UXO Survey

The British coast has been contaminated over a period of centuries by unexploded ordnance, an underwater or offshore UXO survey will identify and minimise the risk to health and safety. There are a number of methods used to carry out marine surveys including specially trained divers and mechanical means.

Typical projects which may require Marine UXO surveys include windfarms, subsea cables, pipe laying projects, oil, gas and mineral exploration and capital dredging projects.

Desktop Survey

Also known as a threat or risk assessment, this refers to a non technical survey using historical evidence and research to determine the likelihood of UXO contamination. During WWII extensive records were kept detailing bombing activity, as a result there are a wide range of comprehensive source materials available to use in determining the risk of unexploded bombs and ordnance.

Some of the resources used to compile a desktop survey include;

  • Public archive resources
  • Bomb census maps
  • Historical aerial photography
  • History of the area regarding military activity
  • Military records

Need a UXO Survey?
Request a call back to discuss your requirements.

Request Call Download Brochure