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PREDICTIVE CAPABILITIES OF BATCH‐EXTRACT EXPERIMENTS USING WATER FROM A COAL MINE 1
Author(s) -
Naftz David L.
Publication year - 1988
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1988.tb00939.x
Subject(s) - orthoclase , extraction (chemistry) , groundwater , dissolution , aquifer , gypsum , water quality , calcite , coal , kaolinite , environmental science , feldspar , mineralogy , chemistry , geology , chromatography , geotechnical engineering , paleontology , ecology , quartz , organic chemistry , biology
The ability of batch‐extraction experiments to predict postmining ground water quality was evaluated. As a basis for evaluation, mineralogical and water quality data were used to identify the geochemical reactions that controlled the major‐ion chemistry in batch‐extraction experiments. The experiments used water and spoil material collected from a surface‐coal mine in the Powder River basin of northeast Wyoming. The batch‐extraction experiments consisted of a 2:1 solid:liquid ratio of ground water and spoil material (by weight). The chemical composition of the resulting batch‐extracts was determined after a contact time of 24 hours. Thermodynamically‐favorable reactions included calcite precipitation, gypsum dissolution, and formation of kaolinite as a result of orthoclase feldspar hydrolysis. Three reaction models were consistent with the therinodynanuc and mineralogic data. In general, the extracts had smaller major‐ion concentrations than did the water samples collected from the spoil aquifer. Correction ratios were calculated from these experiments and could be used in combination with additional batch‐extractions at existing or future lease areas to predict the quality of the ground water after mining.