2007-03-16_REPORT - C1981010 (8)

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higher precipitation in 2006. These responses indicate that the mining from the QR seams, which is nearest in the F pit mining that began in 1997, has not significantly affected water levels in GP -5 and GP -6. Figure A -13 presents the change in water -level elevation for alluvial well P -1, located in the Pyeatt drainage north of the PA. This data demonstrates classic seasonal responses, highs in winter /spring and lows in late summer /fall. Overall the water levels were similar in 2006. Well P- 3 is completed in the Lewis Shale outcrop, which is in contact with the Pyeatt alluvium. It had demonstrated the same seasonal variations (Figure A -13) as the alluvial P -1 well but has recently been dry. Water -level elevations for the Johnson Gulch alluvial well J -1 are also presented in Figure A -13. The J -1 water levels remained steady in 2006. 2.2 GROUND WATER - LEVEL ELEVATION (PIEZOMETRIC MAP SUMMARY) Hydro- Engineering developed three piezometric maps to show the water level flow patterns for the QR, HI and 3rd White Sandstone aquifers at Trapper Mine Water levels from the Fall of 2006 were used to develop these maps. Map No. 2 -1 presents the water -level elevations for the QR aquifer. The water -level elevation is presented for the QR wells: GD -2, GE -1, GF -6, GP -5, and GP-6 and backfill wells GD- 3 and GF -11. The ground -water flow in the QR aquifer is mainly to the north. Mining has only affected the QR aquifer close to the D, E, F, G and Z pits by causing drawdowns very near the pit edges. The installation of backfill wells GD -3 and GF -11 has defined the depressed elevations in the backfill areas. The wells in this area experienced fairly steady levels during 2006. The water level increases in 2006 are likely due to more recharge this last year. The backfill water levels will likely stabilize lower than the pre-mine levels due to the increased permeability of the backfill Trapper Mining Company 2-8 2006 Annual Report