EM61Mk2 for Unexploded Ordinance/ Munitions and Explosives of Concern (UXO/MEC)

Recently, we were asked to conduct an EM61Mk2 survey to map the location of unexploded ordnance or munitions and explosives of concern (UXO and MEC). Reports indicated that the study area may have been used as an Explosive Ordnance Disposal (EOD) Area. EM61Mk2 data were collected in conjunction with a Trimble R8 RTK GPS unit over the site to determine the lateral limits of debris. The new standard of practice for quality control in UXO/MEC surveying, dictates that an Instrument Verification Strip (IVS) be surveyed in the morning before data collection and in the evening after data collection for quality control. The IVS was approximately 60 by 15 foot area was conducted as a background and then resurveyed after surrogate munitions or seeds were planted. The IVS data was processed on site and the seeds were picked with Oasis Montage UX Detect by Geosoft. After the IVS was completed the site was surveyed for UXO/MEC and the GPS was used to delineate surface cultural features (i.e. fence posts, metal debris, and a metal cattle feeder).

The Trimble Base Station Unit was set at a known bench mark and set to communicate with the rover unit.

The Instrument Verification Strip surveyed with surrogate munitions or seeds in place.

A berm feature in the study area was reportedly used to block blast waves from going down canyon during demolition of faulty or expired munitions.

The Trimble Rover Unit was affixed to the top of the EM61 MK2 and the study area was surveyed on a 2.5 foot line spacing.

The EM61Mk2 Data was processed and detected features with the right criterion were picked and were placed on a dig list for excavation and disposal or demolition if necessary.

Some benefits to consider:

  • This survey work is not intrusive and can be conducted in endangered habitat sensitive areas.
  • Information provided can help to focus sampling plans on target rich areas.

We have used EM61 Surveys to:

  • Map UXO/MEC
  • Map landfill limits
  • Map utilities
  • Map underground storage tanks
  • Delineate reinforced concrete foundations and footings.