PIT AND BERM COAL STORAGE
Walter E. Lowthian, Senior Chemical and Solar Engineer
Heery and Heery, Architects and Engineers
Atlanta, Georgia 30345
INTRODUCTION
Strategies which have been developed over the last decade to cope with coal pile
drainage have focused on collecting and treating the runoff.   Typically, the runoff is
directed to an ash pond or a separate catch basin and subsequently treated.   Treatment
usually includes pH adjustment and removal of suspended solids, but often requires the
addition of polymers, etc., followed by clarification in  order to remove the suspended
or newly precipitated solids.
An alternate or complementary strategy    is to work with the coal pile design to reduce the pollutant concentration or to reduce or eliminate the runoff.   This paper is
directed toward developing a design strategy to accomplish these goals.
In order to develop the design rationale behind the specific case history discussed
toward the end of the paper,   several topics relating to the behavior of coal in storage
are first reviewed.   The review is not exhaustive, but should provide the reader with the
fundamentals of coal and its oxidation as they pertain to three important storage parameters:    pollution potential, spontaneous combustion, and coal quality degradation.
The specific case history is a design developed for an industrial facility using about
100 tons/day of coal and storing about 3000 tons in a 10,000 ft2 pile.   This is small
compared to utilities and many industrial facilities, but it is believed the fundamental
design approach can be applied with success to much larger installations.   The design
is for a reserve storage pile, but the principles of design will be beneficial for live
storage piles also.
Stanley Consultants has had wide spread experience with coal handling and storage
as engineers for power plants and industrial boilers for the past 35 years.   Although we
believe the pit and berm method to be a versatile and attractive method of storing
coal, we caution the designer to treat each case anew until additional experience in
many types of applications confirms the general applicaton of the design strategy.
POLLUTION POTENTIAL OF COAL
Coal Classification
Coal is a heterogeneous material which varies widely in its properties from region to
region, mine to mine, and seam to seam.   It even varies according to the coal operator
and weather conditions during mining and transport.   This variation in properties affects
the methods and equipment design for storing, handling, preparing, and burning.   This
paper briefly reviews properties which affect storage and pollution impact [1,2,3].
Because the chemical, thermal, and mechanical properties vary so widely, methods
of classifying coal have been developed.   These methods have concentrated on burning
and coking properties.   A "pollution index" or some method of characterizing the relative pollution potential of coal has not been developed, but traditional classification
methods provide helpful indications of pollution potential.
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