Coal mine spoil, a mixture of black shale parent rock and other lithologies, continue to impact water quality across Appalachia as a legacy of historic coal mining operations. Spoil material is chemically similar to the ore they once contained and have historically been deposited at the point of removal without any environmental considerations for potential impacts. Coal-bearing black shales are known to contain significant concentrations of the metal(loid)s  such as Mn, Fe, Ni, Cu, Zn, As and Se as well as high sulfur concentrations. The release of trace metals from the shale during weathering is directly related to textural and morphological properties of the metal-host phase. The main hypothesis for this study is that the metal(loid)s from the pyrite are being incorporated into the secondary minerals forming in the soil with only small losses as dissolved species. This investigation will combine: (1) a synchrotron-based x-ray microprobe analysis of the soils forming on coal mine spoil to describe the speciation and distribution of contaminants at the micron scale and mineralogical abundance and distribution, and (2) batch reactor experiments to simulate the weathering of the parent rock by simulated rain water and quantify fluxes of metal(loid)s released from the parent shale. Microprobe analyses indicate that the metal(loid)s are remaining in the soil and are primarily associated with Fe. Preliminary analyses of metal(loid) leaching, measured by ICP-OES, indicates that there is an initial pulse of As, Se, Cr, Cu, and Zn release but Fe concentrations are increasing with time. These patterns persist across the range of particle size being weathered.<br/>

Metal(loid) release from coal mine spoil during simulated weathering

253rd National Meeting (2017)

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