Year of Publication

2009

Degree Name

Master of Science (MS)

Document Type

Thesis

College

Arts and Sciences

Department

Geology

First Advisor

Dr. Christopher D. Barton

Second Advisor

Dr. Alan E. Fryar

Abstract

At the Bent Mountain surface mine, Pike County, Kentucky, a study has been ongoing since 2005 to assess the influence of various types of loose-graded mine spoils on water quality and forest establishment. Six research plots consist of two replicates of brown weathered sandstone, gray unweathered sandstone, and mixed brown sandstone, gray sandstone, and shale that were emplaced according to Forestry Reclamation Approach criteria. A series of analyses was initiated in 2007 to examine influence of spoil matrix composition on sulfate and carbonate geochemistry of infiltrated waters, as well as to investigate the occurrence of Phytophthora, a group of exotic forest pathogens that cause dieback and may affect success of founder species of hybrid American Chestnut (Castanea dentata Marsh.) Borkh.)), on the surface of mine spoils and in infiltrated waters.

To identify the constituent responsible for elevated sulfate concentrations, as well as determine the role of alkalinity in spoil waters, PHREEQC geochemical modeling was used to analyze aqueous speciation of sulfates and carbonates with respect to time and tailing media. Variance of δ34S values was analyzed to determine source of sulfate minerals. Oxidation of minor amounts of pyritic coal enriched the δ34S value in the brown plots. Overall, plots had acceptable water quality parameters, substantiating various types of mine spoils for the FRA, although brown proved best for tree establishment.

Methods were employed to determine whether Phytophthora were present in the surface of mine spoils and in infiltrated waters of 2005 plots as well as 2007 plots to determine if a chronosequential effect occurred. P. cryptogea was detected from surface spoil and from waters infiltrating brown sandstone plots. The brown spoil, relative to other spoil types, has greater soil moisture, greater nutrient availability, and lower pH, which may promote the occurrence and survival of the microorganism. The occurrence of the pathogen in the 2005 plots versus 2007 plots is notable; greater ground cover from colonizing species may be a precursor to Phytophthora detection on the plots. P. cryptogea is a possible threat to American chestnut, however, high infiltration rates in loose-dumped mine spoils should reduce damage by the pathogen.

Over time, the relation between water quality parameters (as influenced by spoil matrix composition), tree success, and presence of Phytophthora, is of interest as certain hydrogeochemical parameters may cause stress on trees that may increase susceptibility of plants to disease caused by Phytophthora. Alternatively, certain water geochemical parameters may directly affect Phytophthora by promoting or inhibiting survival and transport of the pathogen in spoil and infiltrated spoil waters; this too has consequences for tree establishment on loose-dumped mine spoils.

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