Stability of multilayer earthen barriers used to isolate mill tailings: geologic and geotechnological considerations
This report briefly discusses how seismic activity, erosion, climatic change, slope stability, differential settlement, and cover design could affect the long-term integrity of multilayer earthen cover systems. In addition, the report suggests ways to design and construct covers so that adverse impacts can be avoided or minimized. The stability of multilayer earthen barriers used to isolate uranium mill tailings depends on the morphology of the disposal site, the engineering of the barrier, the condition of the tailings, and the possible impacts of earthquakes, erosion, and climatic changes. When designing a cover for or siting a tailings pile, one must take into account both geologic and geotechnological variables. To alleviate the adverse effects of possible seismic activity, tailings piles should never be located on or near active or capable faults. Existing piles near faults should be moved to safer sites or engineered to withstand possible displacement and shaking. Liquefaction generally can be prevented if the tailings and their underlying material are compacted to a relative density of 60% or greater, or if they are kept dry. If the tailings are saturated, dewatering schemes may have to be used. Erosion may be caused by streams, glaciers, or wind, depending on the geomorphic and atmospheric conditions at the site. Fluvial erosion can be prevented by using dikes (and avoided by initially siting the pile a safe distance away from stream courses). In some cases, fluvial waters or rainfall may have to be rerouted over the pile via armored ditches. Eolian erosion can be minimized by vegetating the disposal site or covering it with gravel. Because of the wide geomorphic and geotechnological variations extant at most sites, a single cover design cannot be cost-effectively and efficiently used at all sites.
- Research Organization:
- Battelle Pacific Northwest Labs., Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6327063
- Report Number(s):
- PNL-3902; ON: DE81028403; TRN: 81-015884
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
COVERINGS
EROSION
SEISMIC EFFECTS
ENGINEERED SAFETY SYSTEMS
MILL TAILINGS
STABILIZATION
RADIOACTIVE WASTE DISPOSAL
CLIMATES
CONSTRUCTION
DESIGN
GEOLOGY
LIQUEFACTION
SEISMICITY
SITE SELECTION
SLOPE STABILITY
SOILS
MANAGEMENT
SOLID WASTES
STABILITY
TAILINGS
THERMOCHEMICAL PROCESSES
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052001* - Nuclear Fuels- Waste Processing
052002 - Nuclear Fuels- Waste Disposal & Storage
580201 - Geophysics- Seismology & Tectonics- (1980-1989)