Analysis of disposal of uranium mill tailings in a mined out open pit
Mined out open pits are presently under consideration as disposal sites for uranium mill tailings. In this method of tailings management, the escape of contaminated liquid into an adjacent aquifer is the principal environmental concern. The modified Bishop Method was used to analyze the structural stability of a clay liner along the highwall and fluid flow models were used to analyze the effect of tailings solutions on groundwater under several operating conditions. The slope stability of a clay liner was analyzed at three stages of operation: (1) near the beginning of construction, (2) when the pit is partially filled with tailings, and (3) at the end of construction. Both clay lined and unlined pits were considered in the fluid flow modeling. Finally, the seepage of tailings solutions through the clay liner was analyzed. Results of the slope stability analysis showed that it would be necessary to construct the clay liner as a modified form of engineered embankment. This embankment would be similar in construction to that of an earthfill dam. It could be constructed on a 1 : 1 slope provided the tailings slurry were managed properly. It would be necessary to maintain the freeboard height between the embankment and tailings at less than 4 m. A partially dewatered sand beach would have to be located adjacent to the embankment. Potential leakage and aquifer contamination was modeled for lined and unlined pits of various designs. Sulfate, and possibly U and Th, are the most likely contaminants. Results from the model showed the clay and soil cement lined pit to be most effective in containing the pollutants.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6596210
- Report Number(s):
- CONF-780740-3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CLAYS
CONTAMINATION
EMBANKMENTS
ENVIRONMENTAL TRANSPORT
FEED MATERIALS PLANTS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROLOGY
INDUSTRIAL PLANTS
LINERS
MANAGEMENT
MASS TRANSFER
MILL TAILINGS
MINERALS
NUCLEAR FACILITIES
OXYGEN COMPOUNDS
RADIOACTIVE WASTE DISPOSAL
RADIONUCLIDE MIGRATION
SOLID WASTES
TAILINGS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER