Asphalt Emulsion Sealing of Uranium Mill Tailings
The use of asphalt emulsion to contain radon and radium in uranium tailings is being investigated at the Pacific Northwest Laboratory. Results of these studies indicate that a radon flux reduction of greater than 99% can be obtained using either a poured-on/sprayed-on seal (3.0 to 7.0 mm thick) or an admix seal (2.5 to 15.2 cm thick) containing about 18 wt % residual asphalt. A field test was carried out at the Grand Junction tailings pile in order to demonstrate the sealing process. A reduction in radon flux ranging from 4.5 to greater than 99% (76% average) was achieved using a 15.2 cm (6 in.) admix seal with a sprayed-on top coat. A hydrostatic stabilizer was used to apply the admix. This was followed by compaction to form the radon seal. Overburden was applied to provide a protective soil layer over the seal. Included in part of the overburden was a herbicide to prevent root penetration.
KeywordsRadon Emanation Radon Diffusion Asphalt Emulsion Pacific Northwest Laboratory Radon Flux
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