PERMFILE46234

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: TAB 07 HYDROLOGIC DESCRIPTION
• Media Type: D
• Archive: No

opposite ie true; the underburden i• under a higher confining pressure then is the
overlying coal unit in that area of the lease. Thie would imply the Wedge underburden is •
not in direct hydraulic communication with the overlying and underlying coal units, at
least across most of the Yoast lees ehold. In general, the Wedge underburden does not
contain sufficient water, nor ie it sufficiently connected hydraulitellY with the
overlying Wedge coal unit to warrant classification es en aquifer. The Wolf Creek
underburden may also be hydraulically isolated from its overlying tool unit.
Ground Voter Chemistry. The following section discusses the geochemicel reactions that
effect regional and local ground water chemistry end details site specific ground water
quality.
The general geochemicel processes that affect ground water quality in the Yoast area are
as follows. Water Containing carbon dioxide percolates below ground surface, dissolves
carbonate minerals end possibly gypsum, and exchanges calcium end magnesium ions for
sodium ions. The following reactions illustrate these processes more specifically. In a
near-surface environment, carbon dioxide gas (COZ) from the atmosphere and from organic
decay reacts with water (HZ0): •
COZ + HZ NzC03 (1)
The resulting carbonic acid (HZC03) dissociates:

X
C0 H * HC0 (2)
z
3 3
+ z
NC0 H
+ C0 (3)
3 3
The effect of Reactions 1, 2, and 3 is to produce a slightly acidic environment conducive
to the dissolution of calcite (CaC03) and dolomite CaNg(L03)2 .
2+ 2-
CaC03 Ce + CD3 (4)
CaM9(C03)z Caz+ + Mgz+ + 2C03z (5)
Reactions 4 end 5 result in en increase in the concentrations of calcium (Caz+) and •
+
magnesium (Mg ), and en increase in the concentration of Carbonate (C03z ), which forces
+
a decrease in hydrogen (N ) concentration end en increase in bicarbonate (HC03 )
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