A technique was developed for collecting cores for radiometric analysis from beneath a low-level radioactive-waste landfill to determine the rates of downward radionuclide migration below the trenches. A closed pipe was driven through the buried waste, and a removable point withdrawn. The hole was then advanced by alternately pushing a coring device, then driving an inner casing to the depth reached by the coring device and cleaning out cuttings from within the casing. The effectiveness of the technique was limited by inability to predict the location of impenetrable objects within the waste in some parts of the burial ground and difficulty in detecting when the end of the pipe first penetrated undisturbed material beneath the trench floor. Geophysical logs of the completed hole were used to help determine the trench-floor depth. (USGS).