Large Scale, High Resolution Survey For Burial Pit And Trench Mapping

A large scale, high resolution geophysical survey was performed at the Idaho<br>National Engineering Laboratory, a Department of Energy facility. This facility<br>has served as a test site for the development of nuclear power production since<br>the early 1950's. Beginning in the early days of operation at the site, a<br>variety of waste products from industrial and nuclear processes have been<br>disposed of primarily at one approximately 88 acre site at the Subsurface<br>Disposal Area within the Radioactive Waste Management Complex.<br>In support of the CERCLA process, a chemical sampling program is being designed<br>to characterize the migration of hazardous products away from the burial pits and<br>trenches into the surrounding environment. In order to safely and effectively<br>remove soil samples for chemical analysis from the areas immediately surrounding<br>the burial sites without encountering the waste pits an integrated geophysical<br>survey was proposed. The purpose of this geophysical survey was to map the<br>location of the burial pits and trenches and identify unrecorded burial sites<br>within the survey area.<br>A geophysical survey consisting of over 50,000 magnetic field measurements and<br>nearly 50,000 induced electromagnetic readings was conducted over approximately<br>50 acres of the site. Within the area, 9 large pits and more than 25 closely<br>spaced narrow trenches were mapped. In addition several areas of potential<br>contamination were identified that can now be addressed in the chemical sampling<br>survey. This paper will discuss the design considerations and results of this<br>unusual survey.