Experience in mining plutonium for soil cleanup

Plutonium contamination from nuclear tests in 1962 is present at Johnston Atoll in soil throughout a 10-ha site. Since the middle 1980s, the Defense Nuclear Agency has been developing a mining operation to cleanup the contaminated soil. A plant now routinely mines plutonium from soil to make most of the soil clean and suitable for beneficial use. Before this initiative, the mining paradigm was to concentrate a valuable substance and leave waste tailings. Mining for cleanup represents a paradigm shift as it concentrates the radioactive substance for waste disposal and leaves the valuable substance, clean soil. The cleanup plant combines conventional mining and milling technology, radiation detection equipment, and microprocessor computer controls. A variety of technologies have been evaluated since the plant was first started in 1990. Success has come from soil sorters and classifiers. To May 1993, there were 37 weeks with some soil cleanup. The plant processed 17,000 tons of soil and made 98% clean. Production at 1,000 tons/week is routine. The plant concentrate will be further processed to reduce waste below 2%