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Groundwater contamination from an inactive uranium mill tailings pile: 1. Application of a chemical mixing model
Author(s) -
White A. F.,
Delany J. M.,
Narasimhan T. N.,
Smith A.
Publication year - 1984
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr020i011p01743
Subject(s) - tailings , groundwater , uranium , gypsum , environmental science , contamination , trace metal , dissolution , geology , aquifer , geochemical modeling , environmental chemistry , mining engineering , metal , chemistry , geotechnical engineering , metallurgy , materials science , ecology , biology , paleontology
Low‐ p H process waters contained in a number of inactive and abandoned uranium mill tailings in the United States represent potential sources of radionuclide and trace metal contamination of groundwater. Detailed investigations at a typical site at Riverton, Wyoming, indicate that chemical transport occurs from initial dewatering of the tailings, downward infiltration due to precipitation, and groundwater intrusion into the base of the tailings pile. Except for elevated uranium and molybdenum concentrations, current radionuclide and trace metal transport is limited by the near‐neutral p H conditions of the groundwater. Significant reactions include the dissolution of calcite, production of CO 2 , and precipitation of gypsum and the hydroxides of iron and aluminum. A geochemical mixing model employing the PHREEQE computer code is used to estimate current rates of the groundwater contamination by tailings water. A maximum mixing of 1.7% of pore water is a factor of 2 less than steady state estimates based on hydraulic parameters.