PERMFILE138169

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: TAB 17 PROBABLE HYDROLOGIC CONSEQUENCE
• Media Type: D
• Archive: No

• using the following equations.
~
r = ( wet aree)
(Equation 1) Calculates radius of circle (cell) equal to maximum
R
wet pit are a.
w(u) = 4 Ts (Equation 2) Calculates a u value for Equation 3. o set equal
0
to average daily pit inflow rate.
S = 4Tut (Equation 3) Calculates a value for storage coefficient that will
z
r result in t he maximum drawdown (saturated thickness
at distance r) in the number of days in water for a
given year
w(u) = 4T(TS (Equation 4) Calculates w(u) and u for 1 and 5-foot draudouns.
0
~
r = LTtu
(Equation 5) Calculates the distance to the 1 and 5-foot
( S )
• draudouns.
where:
2
T = Transmissivity in ft /day;
3
0 = Net inflow in ft /day;
s = Dra wdown in ft;
w(u) = The well function of u;
S = Storage coefficient (dimensionless);
t = Time since discharge began in days;
r = Radius to drawdoun in fi.
All calculations for one and five-foot dra wdown contour distances using the above
equations are presented in Attachment 17-3. The summarized results of the drawdown
calculations are shown in Table 17-6. The largest estimated radial distance will occur in
the cadge overburden aquifer where a one-foot drawdown is predicted to occur 564 feet from
the mined area after 13 years of pi[ inflows. One-foot drawdown radial distances are
shown on Exhibit 17-1. Since the wedge and wolf Creek overburden and wedge and wolf Creek
coal units crop out towards the center of the anticline end to the south, there will be no
• draudouns as a result of pit inflows in this direction.
11 Revised 03/24/95