The ability to safely and efficiently locate, identify, and remove buried objects on practice and test ranges is critical to the U.S. Department of Defense’s mission and its goals of safe operation, sustainability, and environmental stewardship.

Although several robust, advanced sensor technologies have been developed for discriminating buried objects on ranges as targets of interest (TOIs), widespread acceptance of the technologies requires that they be demonstrated on live sites, where the impact of operating and data acquisition and analysis parameters can be fully evaluated. The potential benefit of the technology is to reduce the number of subsurface investigations that are required to remove hazardous munitions and explosives of concern (MEC) in areas where subsurface clearance is required.

CB&I Federal Services LLC (CB&I) geophysicists participated in the Environmental Security Technology Certification Program (ESTCP) Demonstration of Advanced Geophysics and Classification Technologies on Munitions Response Sites at the Former Fort Ord, California (Fort Ord), and Redstone Arsenal, Alabama (RSA).

The overall objective for both sites used in the project (Fort Ord and RSA) was to demonstrate and validate Advanced Classification (AC) techniques in challenging site conditions. At Fort Ord, the primary challenge was to detect and classify munitions in areas with high subsurface metallic clutter. The primary challenge at RSA was to collect high-quality advanced sensor data in highly wooded areas that could be used for classification. Each site also had additional unique objectives that were determined in concurrence with CB&I, the U.S. Army Corps of Engineers (USACE), and project stakeholders during the project planning phase.

At Fort Ord, CB&I collected approximately five acres of dynamic MetalMapper (MM) data, which included high, medium-high, medium, and low anomaly density areas. The resulting data was used to select targets for cued measurements. Cued measurements were then used to model each target source, which resulted in the creation of a prioritized dig list. All targets were investigated for evaluation of the classification effort.

At RSA, CBI collected approximately 8.21 acres of dynamic Time-domain Electromagnetic Multi-sensor Towed Array Detection System (TEMTADS) 2×2 data in various site conditions, including high-density anomaly areas, heavily wooded areas, and areas subject to site cultural noise. The resulting data were used to select targets for cued measurements. Cued measurements were then used to model each target source, which resulted in the creation of a prioritized dig. Of these cued measurements, 221 targets were selected for subsurface investigation.

Both the MM and TEMTADS 2×2 are time domain electromagnetic (TDEM) sensors, making use of three-dimensional receiver coils, with seven and four receiver cubes, respectively. In the larger MM sensor, transverse excitation of subsurface metallic objects is accomplished explicitly with three orthogonal transmitter coils. In the smaller TEMTADS sensor, transverse excitation is accomplished implicitly via the four vertical transmitter coils at offsets from the sensor center.

In general, the primary objectives for Fort Ord were met. CB&I successfully collected high-quality dynamic and cued data using the MM and were able to meet the performance objectives for data quality. All large munitions were correctly classified as TOI. However, one of the large munitions items recovered (155 millimeter projectile) was classified as a smaller munition as defined for this project. The objective for correctly classifying the smaller munitions was met but the final dig list for the smaller munitions included a high percentage of incorrectly classified non-TOI items.

CB&I successfully collected both dynamic and cued data within heavily wooded areas encountered at Redstone. Four of the blind quality control (QC) seeds were not classified as high confidence TOIs as per the performance objective but were included in the final dig list as “can’t decide” digs. Of the 26 additional TOI items recovered, 19 of these were classified as high confidence TOIs, while the remaining 7 were classified as “can’t decide” digs.

This work was done by Sandra Takata for the Environmental Security Technology Certification Program (ESTCP). For more information, download the Technical Support Package (free white paper) below. ESTCP-0003


This Brief includes a Technical Support Package (TSP).
Data Collection Using the MetalMapper in Dynamic Data Acquisition and Cued Modes

(reference ESTCP-0003) is currently available for download from the TSP library.

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This article first appeared in the October, 2020 issue of Aerospace & Defense Technology Magazine.

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