Aquifer restoration at in-situ leach uranium mines: evidence for natural restoration processes

Technical Report · Fri Apr 01 04:00:00 EST 1983

DOI:https://doi.org/10.2172/6192987· OSTI ID:6192987

Deutsch, W J; Serne, R J; Bell, N E; Martin, W J

Pacific Northwest Laboratory conducted experiments with aquifer sediments and leaching solution (lixiviant) from an in-situ leach uranium mine. The data from these laboratory experiments and information on the normal distribution of elements associated with roll-front uranium deposits provide evidence that natural processes can enhance restoration of aquifers affected by leach mining. Our experiments show that the concentration of uranium (U) in solution can decrease at least an order of magnitude (from 50 to less than 5 ppM U) due to reactions between the lixiviant and sediment, and that a uranium solid, possibly amorphous uranium dioxide, (UO/sub 2/), can limit the concentration of uranium in a solution in contact with reduced sediment. The concentrations of As, Se, and Mo in an oxidizing lixiviant should also decrease as a result of redox and precipitation reactions between the solution and sediment. The lixiviant concentrations of major anions (chloride and sulfate) other than carbonate were not affected by short-term (less than one week) contact with the aquifer sediments. This is also true of the total dissolved solids level of the solution. Consequently, we recommend that these solution parameters be used as indicators of an excursion of leaching solution from the leach field. Our experiments have shown that natural aquifer processes can affect the solution concentration of certain constituents. This effect should be considered when guidelines for aquifer restoration are established.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6192987
• Report Number(s): NUREG/CR-3136; PNL-4604; ON: DE83012477
• Country of Publication: United States
• Language: English

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11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
520301* -- Environment
Aquatic-- Radioactive Materials Monitoring & Transport-- Water-- (1987)
54 ENVIRONMENTAL SCIENCES
ACTINIDES
AQUIFERS
CHEMICAL REACTIONS
DISPERSIONS
DISSOLUTION
ELEMENTS
ENVIRONMENTAL QUALITY
GROUND WATER
HYDROGEN COMPOUNDS
LEACHATES
LEACHING
METALS
MINING
MIXTURES
ORES
OXYGEN COMPOUNDS
SEDIMENTS
SEPARATION PROCESSES
SOLUTION MINING
SOLUTIONS
URANIUM
URANIUM ORES
WATER
WATER QUALITY