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• location of the well relative to the subsurface strike and dip of the wal seams in the Browning and Colt pits makes contact with any leachates virtually impossible. No Second or Third White Sandstone wells exist within one mile north of the permit boundary in the Pyeatt Gulch area. Significant drawdowns in the Third Whfte Sandstone to the north of the mine are not expected because drainage of groundwater to the north end of the mine, due to the increase in permeability in the backfill aquifer, will likely moderate water level changes in the Third White Sandstone aquifer north of the mine. Significant natural water-level changes have been observed in the Third White Sandstone aquifer at wells GC-2, GP-9 and P-8 due to wet and dry cycles. These natural changes are likely to mask any water-level changes due to mining. The DR (92425, 89740) and KLM (88592, W606) wells in the eastern portion of the permit should not be impacted due to their distance from mining. Wells 226553F, 226554E and 22100E are completed below the Twentymile Sandstone and should not be impacted by Trapper mining operations. Third White Sandstone wells which exist within one mile downgradient of the eastem portion of the Trapper Mine permit are permitted wells 80998 and WFi24-74. These iwo Third White Sandstone wells exist downstream of proposed mining operations in the Flume Gulch drainage. Mining is not expected to significantly affect the water levels in these wells. The closest Third White Sandstone well (80998) to the eastem mine pits is approximately 6000 feet north of the planned mine cuts in this area. Additional Second and Third White Sandstone wells exist further from the permit boundary. These wells are unlikely • to see water levels affected by the Trapper mining activity. Continued monitoring in Third White Sandstone wells GC-2 and GP-9 will be important in defining whether any water quality impacts develop in this aquifer due to mining activities. Second White Sandstone wells in this area are very unlikely to be affected because their outcrop is north of the northern limits of the Trapper pits. Some potential exists for water quality to be affected in Third White Sandstone wells in areas north of mining operations in the Flume Gulch drainage. Elevated TDS levels in groundwater could persist for a prolonged period of time following mining as previously discussed. As this groundwater moves downgradient into the Third White Sandstone, some ambient water quality constituent concentrations could see increases. The percent pyrite wncenVation in A East pit and the Flume drainage will be reflected in the temporal duration of elevated groundwater quality constituent concenVations observed in this area. TDS and sulfate concenVations from the backfill in this drainage can be expected to fall within ranges previously established in other backfill monitoring wells at Trapper. The overall quality of this water will be dependent upon the degree of dilution that occurs as a result of underburden inflows, however, some degradation in groundwater quality in the Third White Sandstone is possible. Pre-mining sulfate concentrations as defined at wells GC-2 and GP-9 range from approximately 600 to 800 mg/I with TDS values ranging from approximately 1300 to 1400 mgll. • Considering the range of permeability values likely to exist in the Third White Sandstone, calculations characterizing groundwater movement in this area suggest a plume of higher TDS water could migrate at a rate varying from tens to hundreds of feet per year. At a projected groundwater flow rate of 4-2389 R^v:5icn: Tip' 1Py