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

conductivity of the alluvial portions of the aquifer was set at 400 feet per day and adjusted in areas of
higher bedrock as discussed in section 2.3.
Tabte 2: Comparison of Simulated vs. Measured Water Levels

Well 3/10/2004
Measured
Elev D Modeled

Elev Dry Mod-Meas

Difference X3/2004
Measured
Elev Wet Modeled

Elev Wet Mod-Meas

Difference
TSMW-1 4953.5 4953.8 0.3 4954.7 4959.6 4.9
TSMW-2 4954.4 4955.1 0.7 4955.6 4960.5 4.9
TSMW-3 4953.6 4953.7 0.1 4954.1 4957.0 2.9
TSMW-4 4951.8 4951.8 0.0 4952.5 4955.8 3.3
TSMW-5 4952.5 4953.3 0.9 4953.9 4960.0 6.1
TSMW-6 4951.3 4951.1 -0.2 4952.0 4955.5 3.5
TSMW-7 4951.4 4950.6 -0.8 4951.5 4953.7 2.2
TSMW-8 4951.3 4950.7 -0.6 4951.1 4953.0 1.9
TSMW-9 4948.6 4946.6 -1.9 4949.8 4949.0 -0.8
TSMW-10 4948.5 4946.9 -1.6 4949.4 4948.8 -0.6
TSMW-I1 4946.6 4944.2 -2.4 4947.6 4945.8 -1.8
TSMW-12 4948.0 4945.9 -2.1 4949.9 4950.1 0.2
TSMW-13 4944.3 4937.6 -6.7 4948.1 4941.0 -7.1
TSMW-14 4945.5 4942.9 -2.6 4948.6 4952.5 3.9
TSMW-IS 4947.2 4945.6 -1.6 4950.1 4957.4 7.3
TSMW-16 4954.5 4949.4 -5.1 4955.3 4957.2 1.9
TSMW-17 4951.5 4954.3 2.8 4953.9 4962.9 9.0
BBA-1 4946.93 4946 -0.9 4949.88 4947.8 -2.1
BBA-2 4946.40 4945.1 -1.3 4949.02 4946.8 -2.2
BBA-3 4947.97 4947.5 -0.5 4950.39 4949.5 -0.9
Average: -1.2 Average: 1.8
3.3 Mining and Post-MininE Simulation Results
The model was used to simulate both the water table effects during mining and the long-term changes in
water table conditions as a result of the mining activities and associated water storage facilities. The
potential effects on neighboring wells and surrounding areas were evaluated by comparing simulated
pre-mine wet (high) and dry (]ow) season levels with simulated during- and post-mine seasonal high and
low water levels.
The model area is very dynamic, with many hydrologically impacting activities planned for the near
future. Hence, numerous scenarios were run to show the individual effects of the various activities. At
the time of this report, our understanding ofplanned activities in the area is as follows:
- The Seltzer well will be moved from the west cell to a location near the South Platte River
- The southern portion of the Rogers Pit will be dewatered again and mined out
- The Challenger Pit will be dewatered and mined
- The Baseline Mine will be dewatered and mined
- The Tucson South- southwest cell will be dredge mined
- The Tucson South- east cell will be surrounded by a slurry wall
- 7 - August 2004
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