HR: 1340h
AN: H23F-1503    [Abstracts]
TI: Use of Strontium Isotopes to Quantify Interaction of Water With Coal Combustion Byproducts in an Abandoned, Partially Grouted Coal Mine, West Virginia, U.S.A.
AU: Hamel, B L
EM: blhamel@geo-image.com
AF: University of Pittsburgh, Department of Geology & Planetary Science, Pittsburgh, PA 15260 United States
AU: * Stewart, B W
EM: bstewart@pitt.edu
AF: University of Pittsburgh, Department of Geology & Planetary Science, Pittsburgh, PA 15260 United States
AU: Kim, A
EM: ann.kim@netl.doe.gov
AF: U.S. Department of Energy, National Energy Technology Lab, Pittsburgh, PA 15236 United States
AB: The Omega Coal Mine, West Virginia, was actively mined until the late 1980s. Subsequently, water filled the mine void and acid discharges developed along the mine perimeter. The mine was partially grouted in 1998 by injecting coal combustion byproducts (CCB) mixed with cement in an attempt to reduce the acid discharge and stabilize the ground surface. Discharge continued after grouting, including from the grouted portions of the mine. In this study, discharge chemistry and strontium (Sr) isotope ratios were determined to identify and quantify the extent of interaction between mine waters and the CCB material used to grout the abandoned mine. Eight sampling sites were monitored around the downdip perimeter of the mine. In general, the major and trace element chemistry of the discharges was not sufficient to distinguish between discharges that interacted with grout and those that did not. Elements that showed the most separation include potassium and arsenic, both of which were elevated in the waters that interacted with CCB grout. In contrast, strontium isotope ratios were capable of delineating discharges that were clearly from grouted portions of the mine vs. those that were derived from non-grouted areas. Discharges that bypassed the grouted portions had ⁸⁷Sr/⁸⁶Sr ratios ranging from 0.7151 to 0.7159, while two discharges that interacted with grout had ratios in the range of 0.7140 to 0.7146. The water treatment system inlet, which receives both grouted and ungrouted discharges, yielded intermediate isotope ratios. Leaching experiments on CCB grout, coal, and surrounding floor and roof rocks are consistent with the isotopic trends observed in the discharges. Based on these results, waters that interacted with grout received 30-40% of their strontium from the CCB grout material, suggesting that leaching of CCB is a significant contributor to discharge chemistry.
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: Fall Meeting 2005