2009-03-17_REPORT - C1981010 (5)

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RECEIVED • 2008 Annual Hydrology Report for Trapper Mine i Anna 2.1 Climatological Data Division oK,,;,,[nation, Mining and Safety The 2008 National Weather Service Cooperative monthly summaries and the historical precipitation summary (1978-2008) are included in Section 2.5. 2008 precipitation totaled 16.39", providing 121 percent of the established historical pre-mining (44-YR) annual precipitation mean and 99 percent of the project-to-date annual precipitation mean (Figure 2-1). The highest monthly precipitation amount was recorded in May (3.12") with the second and third highest totals occurring in December and September (2.18" and 1.97", respectively). 2.2 Pit Dewatering and Consumptive Water Use for 2008 During 2008, Trapper dewatered approximately 25.45 acre-feet of water from four active pits and 52.25 acre-feet of water from G-Pit dewatering wells. (Table 1-1 of Section 2.5 sub-section 1.0 shows the pumping volumes for each activity). The dewatering wells are expected to produce at approximately the same rates for 2009. All pit water was routed into the NPDES drainage system with resulting discharges monitored accordingly. Pit dewatering volumes were comparable to previous years, excluding 2007 when intense storm events caused more pit-dewatering activities. Approximately 94 acre-feet of water were used for dust suppression on haul roads and topsoil handling operations in 2008. This value is higher than 2007 values at 89 acre feet, but well within the normal range of water usage on the site. Dust suppression water demands continue to be somewhat offset by the successful application of dust suppression chemical treatments on haulroads. Haul routes were similar in 2008 as 2007. However increased activity in the eastern portion of the mine may have accounted for increased water usage. Total water volume used by Trapper Mine in 2008 was approximately 171 acre-feet, slightly less than 2007 consumption at 168 acre feet. 2.3 Mining Advancement and Ash Disposal Sites The 2008 Annual Reclamation maps (see Trapper's 2008 annual report), the Water-Level Elevation maps 2-1, 2-2 and 2-3 (included in this report) , and permit Map M52 (see mine permit) 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 2007 report, all spring and seep sites within 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 2008. Well GP-6 was completely abandoned as planned in 2008 Well 81-03A will need further investigation for proper abandonment in the future as it is a flowing well. Well GF-3 is currently plugged and has not shown any signs of leakage or flow. Complete reclamation of this well will occur in the future.