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SECTION 2.0 Annual Hydrology Reportfor Trapper Mine (2001) <br />2.1 Climatological Data <br />The 2001 National Weather Service Cooperative monthly summaries and the historical precipitation <br />summary (1978-2001) are included in Section 2.5. 2001 precipitation totaling 13.14", provided 97 percent <br />of the established historical pre-mining (44-YR) annual precipitation mean but only 79% of the project-to- <br />date annual precipitation mean (Figure 2-1). The highest monthly precipitation amount was recorded in <br />May (1.92") with the second and third highest totals occurring in October and November (1.34" and 1.29" <br />respectively). Precipitation amounts were well below normal for the months of March, April, June, July, <br />September through December. For the second year in a row, the temporal distribution of precipitation <br />resulted in a much drier than usual growing season. <br />2.2 Pit Dewatering and Consumptive Water Use for 2001 <br />During 2001, Trapper dewatered approximately 29 acre-feet of water from three active pits. (Table 1-1 of <br />Section 2.5 shows the pumping volumes for each pit). No additional dewatering from wells in Ashmore, <br />Derringer or Flintlock pit occurred during 2001. The dewatering wells in the Derringer and Flintlock pits <br />were rendered inoperable during 1998 as mining operations progressed beyond their areas of influence. <br />No new dewatering wells were established in 1999, 2000 or 2001. All pit water was routed into the <br />NPDES drainage system with resulting discharges monitored accordingly. Pit dewatering volumes were <br />markedly lower in 2001 as compared to 2000 partly owing to a lighter snowpack runoff occurring in the <br />spring. <br />Approximately 83 acre-feet of water were used for dust suppression on haul roads and topsoil handling <br />operations in 2001. This quantity is approximately 25°h higher than the 2000 total. As previously noted, <br />the summer months of 2001 were drier than usual. Though dust suppression water demands were <br />• somewhat offset by the successful application of dust suppression chemical treatments on haulroads <br />during 2001, the longer hauls and drier than normal conditions combined to result in higher volumes of <br />water being used for dust control. Total water volume used by Trapper Mine in 2001 was approximately <br />112 acre-feet, slightly higher than the 2000 total. <br />2.3 Mining Advancement and Ash Disposal Sites <br />The 2001 Annual Hydrology Report maps depict the following mining activities through year-end: <br />a) Project to date utility waste disposal sites. <br />b) Project to date pit advancement (Toe of pit). <br />c) Project to date monitoring and dewatering wells; and natural and spoil springs and seeps. In the <br />2001 report, all spring and seep sites within the permit area are depicted to provide location <br />information for future reference. Sites that exhibited flows exceeding 5 gpm during the reporting <br />year are distinguished from sites exhibiting flows less than 5 gpm. <br />Three maps (Annual Hydrologic Report Map 2, Sheets 1, 2, 8 3) are provided to present this information. <br />These maps include the locations of monitoring wells that are proximal to active mining and that could be <br />affected in this permit term. <br />2.4 Monitoring Points <br />Rather than submitting an additional map series, please refer to current Permit No. C-81-010, Map M52, <br />for locations of all the operational hydrologic monitoring points. No new ground water monitoring wells <br />were installed during 2001. <br />No additional NPDES discharge points were constructed during 2001. <br />No new pit dewatering wells were installed during 2001. <br />