Stratigraphic Relations to Acid Mine
Water Production
GEORGE P. HANNA, JR., Director,
Water Resources Center
The Ohio State University
and
RUSSELL A. BRANT, Asst. Chief,
Ohio Division of Geological Survey
Columbus, Ohio
A very general statement can be applied to acid mine drainage in asserting that wherever oxidizable pyritic materials are exposed, the problem ensues. The problem, however, assumes varying degrees of importance from
one geographic location to another, and with variation in depth as successive
beds in the stratigraphic column are exposed. Thus the loci of acid mine
waters cover a large area, and the acid source in normal terms is quite diffuse.
For some years the Ohio State University and the Ohio Division of Geological Survey have maintained a cooperative effort in the field of acid mine
drainage research (1,2). The current presentation is a joint attempt to describe some of the stratigraphic relations and point out their influence on acid
mine drainage. Because of more familiarity with the Ohio problem, we will
set the stage with a general geologic description of the Eastern Ohio coal
fields and then utilize this geologic column in a more specific description of
the coal-to-coal interval. The comments in general will be restricted to the
Pennsylvania (on age terms) coal bearing rocks of Ohio, and their implication
with respect to acid production.
Laboratory studies relating to the oxidation of selected material from the
column are also presented in an attempt to associate quantitatively the acid
producing potential with generalized classes of materials.
Lastly, since the stratigraphic and geologic relations of oxidizable materials suggest that certain handling and disposal methods can be effective in
the alleviation of at least a portion of the problem, some of the more obvious
partial solutions are reiterated. A plea is also advanced for more quantitative
analysis and correlation of the oxidation potential of various materials, in
order to provide a more complete understanding of the overall problem.
The Ohio bed rocks that outcrop in the Eastern third ofthe state belong to
two major systems, the Pennsylvania and Permian. These systems are a part
of a large geologic structure known as the Appalachian Basin; and since the
structure resembles a basin, as the name implies, the rocks are exposed from
the outer edge toward the axis in a successive series of outcrops, (Figure 1).
The Permian rocks form the central area of the basin. Most of the coal beds
and hence most ofthe coal mining in Ohio occurs in the Pennsylvania system.
The Northern and Western outermost band of outcrop in Ohio, called the
Pottsville Group, is characterized by containing coal beds which are rather
discontinuous and thin and associated with marine limestone. The lower
portion of this formation consists of sedimentary fill of deep valleys in the
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