Three-dimensional inversion of induced rolarization data from simulated waste

The Idaho National Laboratory (INEL) Cold Test Pit (CTP) has been carefully constructed to simulate stored hazardous waste occurrences. In order to test various methods of non-invasive subsurface waste location techniques, a simulated waste pit has been constructed using safe materiaIs, and designed to resembie old waste pits as closely as possible. This Cold Test Pit (CTP) has been investigated by a number of workers using several different methods. The present work was carried out as part of the Electromagnetic Integrated Demonstration (EMID), which also inc1udes an assortment of electromagnetic techniques (pellerin and Alumbaugh, 1997). The CTP was constructed as a 13 x 70 m trench, segmented by transverse berms into cells. The southern-most cell investigated in the EMID project, contains stacked drums and boxes and a variety of randomly positioned barrels, pipes, a large metal tank, etc., this location is referred to as the Large Object Pit (LOP). The buried drums located in the center of the trench inc1ude both cardboard and metal drums containing scrap metal and nonmetallic materiais. The cell is described as being a three-meter waste seam with about 1.5 m of soil cap, thus the depth of the bottom of the waste is about 4.5 m. The cap is composed of c1ay-rich soil trucked in from other areas of the INEL complex. Host material is local soil overlying resistive Snake River basalt.