2012-01-23_REVISION - M1981021

• Permit No: M1981021
• IBM Index Class Name: REVISION
• Doc Date: 1/23/2012
• Doc Name: Final EPP wit Constr. Schedule.
• From: Denison Mines
• To: DRMS
• Type & Sequence: AM1
• Email Name: RCO
• Email Name: SSS
• Media Type: D
• Archive: No

Model Run
Annual
Potential
ET (in.)
Annual
Precipitation
(in.)
Annual
Actual
Evap.
(in.)
Annual
Runoff
(in.)
Annual
Infiltration
(in.)
Annual
Percolation
(in.)
West
Sunday -
Average
Precipitation
67.0
12.8
12.7
0.0527
12.7
0.0103
West
Sunday -
Wettest year
on Record
67.0
19.9
18.07
0.190
19.7
0.0106
Topaz-
Average
Precipitation
67.0
12.8
12.7
0.0185
12.7
0.00822
Topaz-
Wettest year
on Record
67.0
19.9
18.1
0.0619
19.8
0.00849
Exhibit 13 -3. Summaru of UNSAT -H modeling results.
Section 13
Geochemical Data and Analysis
Based on the UNSAT -H simulations, the estimated percolation through the rock piles
is estimated to range from 0.008 to 0.011 inches per year. The simulations show the
importance of evaluating upward movement of water from the rock piles caused by
evaporation because the majority of water that infiltrates the surface of the
development rock piles evaporates in the semi -arid environment present at the
Sunday Mines Group.
The UNSAT -H simulations suggest that significant percolation from the base of the
development rock piles is unlikely. However, a small amount of percolation is
estimated for all simulations. The simulations further suggest that infiltration of
precipitation followed by upward evaporative flux of water stored within the
development rock areas are dominant mechanisms controlling the volume of
percolation through the development rock areas. Minor differences in the physical
characteristics of the development rock from West Sunday and Topaz mines as well
as the magnitude of annual precipitation are less important controls on the expected
volume of percolation. Additional sensitivity analyses were also conducted and
indicate that the model is not particularly sensitive to modifications in convergence
parameters, node spacing or initial moisture conditions. Detailed sensitivity analysis
information is presented in Attachment 0.
Summary of Findings: The water balance estimates and the UNSAT -H simulations
indicate that significant percolation from the base of the development rock piles is
unlikely. These evaluations further indicate that infiltration of precipitation followed
by upward evaporative flux of water stored within the development rock areas are
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13 -9