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2004 Annual Hydrology Report for Trapper Mine Z.1 Climatological Data The 2004 National Weather Service Cooperative monthly summaries and the historical precipitation summary (1978-2004) are included in Section 2.5. 2004 precipitation totaling 13.56", provided 100 percent of the established historical pre-mining (44-YR) annual precipitation mean and 83 percent of the project-to-date annual precipitation mean (Figure 2-1). The highest monthly precipitation amount was recorded in September (2.43' with the second and third highest totals occurring in April and November (1.83' and 1.50° respectively). Precipitation amounts were well below normal for the months of January, March, August and December. 2.2 Pit Dewatering and Consumptive Water Use for 2004 During 2004, Trapper dewatered approximately 37.20 acre-feet of water from three active pits and 40.68 acre-feet of water from G-Pit dewatering wells. (Table 1-1 of Sedion 2,5 shows the pumping volumes for each activity). An increase in pumping from dewatering wells is expelled in 2005. All pit water was routed into the NPDES drainage system with resulting discharges monitored accordingly. Pit dewatering volumes were slightly higher in 2004 as compared to 2003. Approximately 66 acre-feet of water were used for dust suppression on haul roads and topsoil handling operations in 2004. This is lower than the 2003 total of 86 acre feet. Dust suppression water demands continue to be somewhat offset by the successful application of dust suppression chemical treatments on hautroads. Haul routes were similar in 2004 as 2003. Total water volume used by Trapper Mine in 2004 was approximately 144 acre-feet, almost equivalent to 2003 total of 140 acre feet. 2.3 Mining Advancement and Ash Disposal Sites The 2004 Annual Reclamation maps (see Trapper's 2004 annual report), the Water-Level Elevation maps 2-1, 2-2 and 2-3 (included in this report) ,and permit Map M52 (see mine penult) depict the following mining activities through year-end: a) Project to date utility waste disposal sites. b) Project to date pit advancement (toe of pit). c) Project to date monitoring wells, and natural and spoil springs and seeps. In the 2004 report, all spring and seep sites wlthin the permit area are depicted to provide location information for future reference. 2.4 Monitoring Points Refer to Map M52 in the mine permit for locations of all the operational hydrologic monitoring points. No new ground water monitoring wells were installed during 2004. West Horse #1, NPDES 024, was constructed in 2004 and Middle Flume #3, NPDES 020, was leaned in 2004. No changes occurred to other NPDES sites in 2004. Eight (8) new pit dewatering wells were installed during 2004. Monitoring wells GB 1, 2, and 5 and GF 1, 2, and 3 were partially abandoned in 2004. Abandonment will be completed in 2005.