Location: Nekoma, North Dakota
We were commissioned by Midwest Environmental Consultants to perform a frequency-domain electromagnetic (FDEM) or electromagnetic survey and map areas of buried debris at a former anti-ballistic missile facility in North Dakota.
During environmental drilling and monitoring well installation, construction-related debris such as wood, metal and PVC were discovered at the site. The client wanted our help in mapping the areas where buried debris was located so additional ground water monitoring wells could be installed without issue.
We conducted an EM31 survey by mounting the transmitter and receiver unit on a non-conductive trailer and towed it in a zigzag pattern across approximately 20 acres. This method allowed the unit to collect real-time differentially corrected global positioning system (DGPS) data. EM data was downloaded into the DGPS file and quickly reduced and contoured to reveal eight high-conductivity zones consistent with the presence of buried debris. Subsequent test pits in the anomalous areas revealed buried debris in all eight locations. The testing and debris location mapping were completed in approximately two days.