Unexploded ordnance is one of the most common and dangerous forms of industrial contamination. Mainly it's the legacy of military training and has contaminated large areas of valuable land on the urban fringes of cities across the world. This land now requires remediation to meet housing and other social and environmental needs.
Gap Geophysics Australia, in collaboration with our partners, provides a full range of services for UXO detection and Explosive Ordnance Disposal (EOD), including:
- Historic research;
- Assessment of the nature and levels of UXO contamination;
- High definition surveys to identify and precisely locate UXO and other military waste;
- Validation of detected items to establish whether they are UXO;
- Remediation of UXO contaminated areas;
- Quality control of the detection and remediation processes; and
- Quality assurance of de-contaminated areas.
Historical Research
Gap staff and associates have extensive experience in historic research, as well as the ability to access historic records from a number of sources related to military activity over the past 100 years.
Historic research can establish the probable usage and potential existence of UXO or other explosive ordnance waste (EOW) on the site.
Assessment
To determine the extent and possible levels of contamination, Gap uses a number of techniques, including:
- Ground geophysical surveys (digital and analogue) to gain either precise or statistically valid information about the type and density of contamination;
- Visual reconnaissance of sites to precisely identify the nature and types of contamination.
Site assessment can accurately predict the level and type of contamination, as well as the likely cost of survey and remediation.
Survey
Gap uses its own high precision geophysical equipment and methodologies, developed over more than 15 years of working with UXO.
Gap's TM-6 Magnetometers and TM-5EMU Electromagnetic Detectors are among the most sensitive, efficient and ergonomic digital instruments for sub-surface detection - three vital components in achieving the best UXO detection. Gap's advanced data processing and geological noise rejection technologies, highly skilled geophysicists, experienced project managers and over 15 years experience in UXO detection consistently achieve extremely high detection and low false alarm rates
TMI
TFEMI
Comparison of Total Magnetic Intensity (TMI) and Total Field Electromagnetic Induction (TFEMI).
UXO seeded field site, Newholme, Armidale.
TFEMI relatively insensitve to geology - can detect larger items at greater depth than TMI.
Validation
Once the survey results have been processed and interpreted, a physical excavation and examination is carried out to safely identify UXO and other contamination.
Gap's highly qualified staff identify, mark and record UXO, or suspected UXO, removing and disposing of inert items of EOW and related material.
Quality Control
Gap employs extensive quality control procedures to ensure that:
- 100% of the survey area is covered, using accurate satellite positioning;
- The instruments are functioning properly and recording in accordance with their specification;
- The maximum possible level of UXO is detected by using “blind” seeding of a site with UXO representative of the items likely to be found and the depths they might penetrate;
- Professional interpretation of the collected data meets the highest possible quality standards;and
- Assessment and investigation includes systematic internal quality checks and supervisory practices.
Quality Assurance
Where required, Gap's digital imaging systems and staff also conduct QA surveys of previously remediated areas. In many cases it is not necessary to remove all metal from the site - so this process delivers an accurate representation of what objects remain in the sub-surface and provides a final digital audit trail of the remediation process.