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Title: Methods of minimizing ground-water contamination from in situ leach uranium mining. Final report

Technical Report ·
OSTI ID:5833637

This is the final report of a research project designed to study methods of minimizing ground-water contamination from in situ leach uranium mining. Fieldwork and laboratory experiments were conducted to identify excursion indicators for monitoring purposes during mining, and to evaluate effective aquifer restoration techniques following mining. Many of the solution constituents were found to be too reactive with the aquifer sediments to reliably indicate excursion of leaching solution from the ore zone; however, in many cases, the concentrations of chloride and sulfate and the total dissolved solids level of the solution were found to be good excursion indicators. Aquifer restoration by ground-water sweeping consumed large quantities of ground water and was not effective for the redox-sensitive contaminants often present in the ore zone. Surface treatment methods such as reverse osmosis and electrodialysis were effective in reducing the amount of water used, but also had the potential for creating conditions in the aquifer under which the redox-sensitive contaminants would be mobile. In situ restoration by chemical reduction, in which a reducing agent is added to the solution recirculated through the ore zone during restoration, can restore the ore-zone sediment as well as the ground water. This method could lead to a stable chemical condition in the aquifer similar to conditions before mining. 41 figures.

Research Organization:
Pacific Northwest Labs., Richland, WA (USA)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
5833637
Report Number(s):
NUREG/CR-3709; PNL-5319; ON: TI85010011
Country of Publication:
United States
Language:
English