Removal of overburden soils from buried waste sites

Transuranic (TRU) waste buried in pits and trenches is covered with a soil cap, or overburden, to shed water. During retrieval operations, the overburden (expected to be clean) must be removed carefully to avoid breaching the soil/waste matrix within a pit or trench and to confine any possible local spot contamination. This necessitates removal in precise (7.6- to 15.25-cm) increments with a high degree of accuracy. In addition, during overburden removal the overburden must be characterized to a depth that exceeds each cut of soil. A field demonstration was conducted to evaluate a technology for removing overburden soils a the Radioactive Waste Management Complex (RWMC), Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory (INEL). The demonstration evaluated equipment performance and techniques for removing overburden soil and controlling contamination and dust. To evaluate the performance of these techniques during removal operations, personnel took air particulate samples, physical measurements of the soil cuts, maneuverability measurements, and rate of soil removal data. The overburden was spiked at specific locations and depths with rare earth tracers to provide a medium for evaluating samples. Analysis to determine the precision and accuracy of the soil removal, amount of dust generated, and potential spread of contamination was performed