Date of Award

1981

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geography, Geology, and Anthropology

Abstract

Acid drainage is a naturally occurring process that often results from weathering and oxidation of impurities in coal. When coal is exposed through mining, the problem is magnified and it is estimated that some 11,000 miles of streams in the United States are affected by acid mine drainage. As a contribution toward a better understanding of the nature of acid mine drainage, this study evaluates changes in acidity of a small stream that drains areas in which both surface and underground coal mining have occurred. Thirty-three sample days of field measurements, spread over a period of eight months, at twelve sites on the stream were utilized to measure drainage from two potential acid sources within its drainage basin. These sources were surface runoff from a gob and slurry area associated with a surface coal mine and the constant flow of water from an open air shaft constructed for a now abandoned underground mine. The data collected included stream discharge, stream water pH and related areal measurements. These data were used to evaluate the total amount of pH activity, the amount of pH depression, stream discharge and pH recovery for each sample day. Data analysis indicated that during the observation period no distinctive seasonal differences occured in pH or discharge levels during the observation period. Similarly, no systematic relationship was found between the stream pH and discharge. Despite the lack of meaningful correlations between pH and dischage, variations in acidity, as related to discharge, were assessed through the use of a derived Acid Drainage Index (ADI). The proposed ADI was an empirically derived equation which rated acid drainage conditions in terms of the amount and kind of pH activity and the amount of water in the stream. It utilized the variables pH and discharge to determine how distinct acid drainage conditions could be identified. In this study three types were delineated. These are (1) baseflow period of low flow when the acid load was diluted by available water in the stream and categorized by ADI values between 0 and 19, (2) transition period reflecting moderate ADI values ranging from 20 to 94, and (3) flushout period of highest flow when the amount of acid entering the stream exceeded the ability of the stream to dilute it, and ADI values were above 95. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI

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