2010-07-21_PERMIT FILE - C1982056A ‎(4)‎

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 7/21/2010
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

Water quality data from the 001 -83 -106 well indicates that the Trout Creek sandstone baseline water quality is a
sodium bicarbonate type with moderate sulfate concentrations and very low concentrations of calcium and
• magnesium as depicted graphically in Figure 4 -a, Ground Water Quality Data. Total dissolved solids concentrations
are in the order of 900 mg/l. Period of record date for well 001 -83 -106 shows a total dissolved solids concentration
of 330 mg/1 to 960 mg/, well 95M001 shows a range of 450 mg/1 to 1010 mg/l, and well FBR 2 -E shows a range of
760 mg/l to 1010 mg/l, well 97012TC shows a range of 810 mg/l to 1030 mg/l, and well 97013TC shows a ranes of
703 mg/1 to 810 mg/l.
Wadge Overburden
The Wadge Overburden consists of a sequence of siltstones, shales, coal and fine- grained sandstones. The sequence
varies in thickness from 50 to 100 feet, averaging approximately 75 feet. The Wadge Overburden is characterized by
low permeability, limited continuity, low yield and relatively poor water quality. These factors preclude utilization of
the ground water contained in this sequence for all practical purposes, except small stock watering installations. The
Wadge Overburden is directly affected by the mining operation.
Field data from ground water monitoring wells shown on the Twentymile Park Hydrology Map (Map 13) were used
to construct a potentiometric contour map for the Wadge Overburden sequence in this area for August- September
1983 prior to the start of underground mining. The potentiometric map for the Wadge Overburden was constructed
using only water level date which were deemed to be reliable. Previous potentiometric maps had used water level
data from wells that were not fully completed in the Wadge Overburden sequence. The following criteria were used
to select data for construction of the map.
1. Water level data must be from wells that have reliable completion information to confirm that the well is
completed in the Wadge Overburden.
• 2. Overburden wells in the center of the Twentymile Park Basin, where flowing artesian head conditions
exist, must be adequately "shut -in" to obtain a reliable pressure reading.
3. Water level data must be taken with the period of August to September, 1982.
Water level elevation data from Wadge Overburden wells which met all the above criteria area shown in parentheses
below the well on Map 13, Twentymile Park Hydrology. The Wadge Overburden wells that could not be used for
construction of the potentiometric map are listed with the criteria that were not met:
Well
Criteria Not Meet
Comments
001 -SW -7
3
001 -L-1
3
001 -D -5
3
006 -W -16
1
No completion data
006 -W -17
1
No completion data
006 -W -18
1,2
No completion data
006 -80 -2
1,3
No completion data
006 -82 -38
1
Suspect completion data
06 -81 -31
2
06 -82 -62
3
21 -81 -16
2
All other wells listed on Table 7, Ground Water Monitoring Well Inventory or located on Map 13, Twentymile park
Hydrology, are completed in units other than the Wadge Overburden.
• Seasonal water level variations in ground water monitoring wells are graphically depicted in Figure 3, Well
Hydrographs, and data are listed in Table 8, Ground Water Data. The hydrograph for well 006 -82 -48 (Figure 3 -b),
completed in the Wadge Overburden shows some seasonal variation in the order of 10 to 15 feet, but does not show
any trend of drawdown that might indicate effects from underground mining. This is the closest Wadge Overburden
PR 03 -06 2.04 -21 05/07/03