Surface geophysics at the UMTRA project site in Lakeview, Oregon

Prior to initiating an expensive drilling and testing program to determine the hydrogeologic features underlying an abandoned uranium mill tailings pile and raffinate ponds, reconnaissance level electromagnetic induction and surface electrical resistivity profiling were conducted to map apparent ground conductivity at and around the Lakeview site. Three hundred sixteen (316) electromagnetic induction measurements and twenty-eight (28) electrical resistivity measurements were obtained to prepare a conductivity map for an area of approximately 500 acres. Contouring of these geophysical measurements indicated the intensity and extent of contaminant plumes. The plume characteristics were subsequently confirmed by measurements of total dissolved solids from ground-water samples. The design of the ground-water monitoring and hydrogeologic testing programs were based upon the results of the geophysical surveys