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TexAmericas Center LSAAP High Explosive Burning Grounds Remedial Action Phase II

When the former Lone Star Army Ammunition Plant (LSAAP) was closed under the 2005 Base Realignment and Closure (BRAC) Act, the U.S. Army entered into an Environmental Services Cooperative Agreement with the local redevelopment agency, TexAmericas Center (TAC), to investigate and remediate Army-retained contaminated sites that could be transferred to TAC under a memorandum of agreement following cleanup. Matrix was retained by TAC to perform a Military Munitions Response Program (MMRP) remedial action on the High Explosive Burning Ground (HEBG) where fuses, small munitions items, and explosive-contaminated items from the LSAAP munition loading lines were thermally treated for destruction.

Matrix cleared 51 acres of surface munitions and explosives of concern (MEC), munitions debris (MD), and scrap metal, then completed digital geophysical mapping (DGM) of the site that identified five saturated response areas (SRAs) comprising 24 acres with high metallic signatures. Our UXO team investigated and sampled the soil and debris in the SRAs using armored equipment to define the lateral and vertical extent of the contamination. The investigation identified burnt debris, ash, MEC, and MD to a depth of eight feet. As part of the Phase I efforts, the team destroyed all MEC found during the surface sweep and in the trenches using binary high-energy liquid explosive (HELIX) that penetrates and encapsulates small fuses and grenades. All work was summarized in a draft Affected Property Assessment Report (APAR) which emphasized that remediation of the SRAs would be required to protect human health and the environment.

During Phase II, Matrix conducted single-point anomaly clearance of approximately 27 acres outside the SRAs identified during initial remediation, using DGM to relocate, investigate, and remove over 5,000 metallic anomalies. The Army also funded remediation of four smaller SRAs that Matrix excavated using armored equipment to advance through burnt debris to native soils. The bottoms of excavated areas were inspected with handheld magnetometers to verify all metallic debris had been removed, and both the bottoms and the sides were sampled for munitions constituents. Metal was separated from other debris using over-belt magnets and eddy current magnets to remove ferrous and nonferrous materials. Our UXO technicians inspected over 3 million pounds of metallic debris that was removed from the soil and ash, recovered 10,000 MEC items that required demolition, and demilitarized metallic debris prior to recycling. Matrix characterized the soil/ash that had been separated from the metal, with approximately 2,500 cubic yards transported, treated, and disposed of as characteristic hazardous waste and an additional 2,000 cubic yards transported and disposed of as industrial waste.