PERMFILE49399

• Permit No: m2004044
• IBM Index Class Name: Permit File
• Doc Date: 8/4/2004
• Doc Name: Groundwater Model
• From: Tetra Tech RMC
• To: DMG
• Media Type: D
• Archive: No

- The Tucson South- southwest cell will be filled with fines
- The Challenger Pit will have a slope liner installed around it
- The Baseline Mine will be reclaimed as a lake and wetlands
- The Tucson South- west cell will be surrounded by a slurry wall
To simulate the calibration conditions and above activities, eight scenarios and two sub scenarios were
devised. They are summarized in Table 3.
Scenario 1: Calibration -This is the situation encountered at the site during the investigation for this
project (late 2003- early 2004). The old (existing) Seltzer Well in the proposed Tucson South -west
cells is running and the southern part of the Rogers pit is being dewatered and mined. Water levels were
measured and used for calibrating the model.
Scenario la: Calibration -This is the situation during the middle of 2004. The southern portion of the
Rogers Pit is not being mined and has filled with water. No other activities have started. This scenario
was run for 90 days to allow comparison of the simulated rise of water levels with those measured in the
monitoring wells. The comparison showed general agreement.
Scenario 2: No Mining -This scenario is idenfical to la, except that it was allowed to run long enough
to achieve aestablish aquasi-equilibrium condition for each season. This scenario simulates hydrologic
conditions in the area while no activities are taking place.
Scenario 3: New Seltzer Well and Existing Conditions Base -This scenario serves as the comparison
base for all subsequent scenarios. The only difference between this scenario and scenario 2 is that the
old Seltzer well has been abandoned and replaced by the new well between the east cell and the South
Platte River. This scenario simulates the situation just prior to mining activities.
Scenario 4: Early Mining -This scenario simulates the first new mining activities in the area. The
southern portion of the Rogers Pit is being dewatered and mined, as is the Challenger Pit.
Scenario 5: East Cell Mining -This scenario simulates the installation of the east cell slurry wall and
dredge mining of the southwest cell. The southern portion of the Rogers Pit has been filled with fines
while the Challenger Pit and Baseline Mine are dewatering and mining.
Scenario 6: West Cell Mining and Post Mining -This scenario simulates the final mining activities in
the area. The slurry wall has been extended around the west cell, separating it from the alluvial aquifer.
Mining in the Challenger Pit is complete and the slope liner has been installed. The Baseline Mine and
southwest cell have been backfilled with fines and a part of the Baseline Mine has been turned into an
unlined lake.
Scenario 6max: West Cell Mining and Post Mining -This scenario is identical to Scenario 6, but the
number and output of the new Seltzer Wells has been increased to the maximum decreed output.
Scenario 7: East Cell Mining (Isolated) -This scenario simulates the mining of the east cell and
southwest cell without the influence of the Challenger Pit and Baseline Mine. The purpose of this
scenario is to determine the effects of only the east cell.
- 8 - August 2004
I: V919_U19\TS GW Model\TS Report\TUaon SwN_Rpt Raft doc