Advanced Geophysical Classification – Fort Ord, California

KEMRON, under a five year, $85M task order under the Huntsville WERS contract is conducting multiple studies of Advanced Geophysical Classification system application at Fort Ord, California under a task order with the USACE Sacramento. The following information is a brief update on the findings and conclusions of recent and ongoing activities.

• The Munitions with Sensitive Fuzes Field Study conducted at Range 48 at Fort Ord was designed to compare the performance of the Geonics EM61 and the White River Technologies OPTEMA Advanced Geophysical Classification (AGC) system for locating 40mm HE projectiles in the near subsurface (0-12 inches bgs). DGM detection surveys were conducted with both the OPTEMA and EM61, and all detection targets were intrusively investigated to provide ground truth for the field study. The OPTEMA sensor was used in dynamic mode with dynamic data being used for anomaly detection. The detected target locations were then analyzed to classify the anomaly sources as targets of interest (TOI), which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. Detection targets not selected by the OPTEMA sensor but located by the EM61 were added to the OPTEMA target list to compile the final detection target list. Although a total of 11 acres were geophysically surveyed, because the anomaly density was found to be extremely high (2499 anomalies per acre) the area of investigation was subdivided into three (3) 25’x25’ grids that were used for the field study. A total of 412 DGM anomalies were selected as initial detection targets in these 3 grids. The dynamic OPTEMA AGC sensor data was then used to reduce the number of detection targets from 412 to 129 TOI. This is a 68.7% reduction in the number of targets that would need to be excavated in a production (non-field study) investigation. Of these 129 anomalies classified as potential TOI, a total of 44 MEC or MEC-like (inert) items were located.
• The Munitions with Sensitive Fuzes Field Study conducted at Unit 23 at Fort Ord was designed to compare the performance of the Geonics EM61 and the Geometrics MetalMapper 2×2 (MM2x2) AGC system for locating 40mm HE projectiles in the near subsurface (0-12 inches bgs). DGM detection surveys were conducted with both the MM2x2 and EM61, and all detection targets were intrusively investigated to provide ground truth for the field study. The MM2x2 was used in both dynamic and cued mode, with dynamic data being used for initial anomaly detection. Cued MM2x2 measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. Detection targets not selected by the MM2x2 sensor but located by the EM61 were added to the MM2x2 target list to compile the final detection target list. A total of 1.1 acres were geophysically surveyed. A total of 1814 DGM anomalies were selected as initial detection targets. The MM2x2 classification analysis reduced the number of detection targets from 1814 to 375 TOI. This is a 79.3% reduction in the number of targets that would need to be excavated in a production (non-field study) investigation. Of these 375 anomalies classified as potential TOI, a total of 3 MEC and 6 MEC-like (inert) items were located.
• The Risk Reduction in Units 11 and 12 conducted at Fort Ord was designed to remove large ordnance items (155mm and 8” projectiles) from the near subsurface (0-1 ft bgs and 0-2 ft bgs (area dependent)) prior to a controlled burn. This Risk Reduction used both the Geonics EM61 and the Geometrics Metal Mapper (MM) AGC system. The EM61 was used for initial anomaly detection over 468 acres that comprised Units 11 and 12. A total of 4625 anomalies were identified with the EM61 that were indicative of potential large MEC items (155mm and 8” projectiles) in the near subsurface. Cued MM measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. The MM classification analysis reduced the number of targets to be intrusively investigated from 4625 to 589. This is an 87.3% reduction in the number of targets requiring excavation. Of these 589 anomalies classified as potential TOI, a total of 237 MEC and MEC-like (inert) TOI were located. In addition to the recovered TOI, 437 non-TOI munitions items smaller than the risk reduction TOI were recovered from the intrusive investigation locations.
• The Risk Reduction in Unit 23 conducted at Fort Ord was designed to remove large ordnance items (155mm and 8” projectiles) from the near subsurface (0-1 ft bgs and 0-2 ft bgs (area dependent)) prior to a controlled burn. This Risk Reduction used both the Geonics EM61 and the Geometrics MM2x2 AGC system. The EM61 was used for initial anomaly detection over 368 acres that comprised Unit 23. A total of 1217 anomalies were identified with the EM61 that were indicative of potential large MEC items (155mm and 8” projectiles) in the near subsurface. Cued MM2x2 measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. The MM2x2 classification analysis reduced the number of targets to be intrusively investigated from 1217 to 242. This is an 80.1% reduction in the number of targets requiring excavation. Intrusive investigation of the 242 anomalies classified as potential TOI is currently scheduled.
• The Remedial Action at the area known as Broadway Bypass at Fort Ord was designed to locate and remove all MEC items to depth. This Remedial Action used the TEMTADS AGC sensor in both dynamic and cued mode over a 2 acre area. A total of 5021 detection anomalies were initially identified with the TEMTADS. Cued TEMTADS measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. The TEMTADS classification analysis reduced the number of targets to be intrusively investigated from 5021 to 2175. This is a 56.7% reduction in the number of targets requiring excavation. Of these 2175 anomalies classified as potential TOI a total of 50 MEC and MEC like (inert) items were located.
• The Remedial Action at Unit B-2A at Fort Ord was designed to locate and remove 4.2-inch mortars to a depth of 18 inches bgs. This Remedial Action used the Geonics EM61 and the Geometrics MM2x2. The EM61 was used for initial anomaly detection over 73.5 acres that comprise Unit B-2A. A total of 749 anomalies were identified with the EM61 that were indicative of potential 4.2-inch mortars in the near subsurface. Cued MM2x2 measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. The MM2x2 classification analysis reduced the number of targets to be intrusively investigated from 749 to 69. This is a 90.8% reduction in the number of targets requiring excavation. Intrusive investigation of the 69 anomalies classified as potential TOI is in progress.
• The Remedial Action at the Vernal Ponds at Fort Ord was designed to locate and remove all MEC items to depth. This Remedial Action used the Geonics EM61 and the Geometrics MM2x2. The EM61 was used for initial anomaly detection over 11 acres that comprised the Vernal Ponds. A total of 1007 anomalies were identified with the EM61 that were indicative of potential subsurface MEC. Cued MM2x2 measurements were then acquired at the detected target locations, and the cued data were analyzed to classify the anomaly sources as TOI, which would require intrusive investigation and removal, or non-TOI, which could be safely left in place. The MM2x2 classification analysis reduced the number of targets to be intrusively investigated from 1007 to 436. This is a 56.6% reduction in the number of targets requiring excavation. Intrusive investigation of the 436 anomalies classified as potential TOI is currently scheduled.