Projects

The U.S. Army Corps of Engineers (USACE) Los Angeles District, awarded Bristol this Remedial Action (RA) of the of the Former Fort Huachuca MRS03 – Artillery/Mortar Range, Target Area A, a 548-acre munitions response site in Cochise County, Arizona. In 1999, USACE determined that the area was eligible for the Formerly Used Defense Sites Program.  Bristol performed a Remedial Investigation/Feasibility Study under a previous USACE contract and supported USACE’s determination of the Selected Remedy, which included digital geophysical mapping (DGM) and surface/subsurface removal of munitions and explosives of concern (MEC).  

Leveraging recently innovated geophysical investigation technology, USACE and Bristol deployed multiple APEX units, which utilize sensors capable of one-pass advanced geophysical classification (AGC) to detect, classify, and select subsurface targets of interest that most resemble MEC. This reduces the effort and cost to the government for the subsurface removal phase of the RA by minimizing non munitions-related debris as targets.  Bristol investigated areas that were not accessible to APEX but were accessible to traditional DGM methods with EM61. 

Site preparation prior to geophysical investigation required extensive effort, starting with biological and cultural resources surveys, coordination with federal and state agencies, and development of technical memoranda defining how the RA would be executed while being protective of these resources. Bristol then deployed surface sweep teams of unexploded ordnance (UXO) technicians to remove MEC and munitions debris (MD) from the surface to prepare the site for vegetation clearance to meet the ground clearance requirements of the APEX and EM61 units.  

All UXO encountered during surface preparation were successfully disposed of by detonation from October to December 2021. The MD was certified as material documented as safe and transported to a smelting facility for recycling. 

At the conclusion of the project, Bristol supported USACE in developing Data Usability Assessments and a Remedial Design Completion Report, which provided the information necessary to gain stakeholder concurrence and to scope the subsurface removal portion of the RA based on high quality, defensible site data.