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Geochemistry of batch-extract waters derived from spoil material collected at the Cordero coal mine, Powder River basin, Wyoming

Water-Resources Investigations Report 87-4200

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Abstract

Batch-mixing experiments to evaluate postmining water quality at the Cordero Mine were conducted by the U.S. Geological Survey during 1984 to 1985. Contact of groundwater from the spoil aquifer with fresh spoil material caused only small changes in major-element concentrations and in pH, unless sulfide oxidation or contact with soluble salts, such as epsomite, occurred. In contrast, large changes in major-element concentration resulted when water from the coal aquifer contacted the spoil material. Only three of seven reaction models considered to explain the water quality changes during the batch-mixing experiments were consistent with the thermodynamic and mineralogical data. The three models used to account for the observed water quality changes derived potassium from potassium feldspar; magnesium from chlorite or epsomite or both; sodium from cation exchange and halite; chloride from halite; silica from potassium feldspar and chlorite; sulfate from gypsum, or epsomite or both, and carbon from carbon dioxide. In general, water quality samples obtained from the batch-mixing experiments using water from the coal aquifer had smaller major-ion concentrations than the actual water quality in the spoil aquifer. These differences can be explained by the limited amount of efflorescent salt dissolution and volume of water used in the experiments. Correction ratios calculated for these experiments may be applied to batch-mixing experiments at other mines in the area, to predict postmining water quality. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geochemistry of batch-extract waters derived from spoil material collected at the Cordero coal mine, Powder River basin, Wyoming
Series title:
Water-Resources Investigations Report
Series number:
87-4200
Edition:
-
Year Published:
1990
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; U.S. Geological Survey, Books and Open-File Reports Section [distributor],
Description:
vi, 58 p. :ill., maps ;28 cm.