2015-03-16_REPORT - C1981010 - Laserfiche WebLink

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RECEIVED MAR 1 6 [015 2014 Annual Hydrology Report for Trapper Mine _ __ -, RPrlamation, Mmmg & Safety 2.1 Climatological Data The 2014 National Weather Service Cooperative monthly summaries and the historical precipitation summary (1978 -2014) are included in Section 2.5. For the year of 2014 precipitation totaled 17.91 ", providing 132 percent of the established historical pre- mining (44 -YR) annual precipitation mean and 108 percent of the project -to -date annual precipitation mean (Figure 2 -1). The highest monthly precipitation amount was recorded in August (3.95 ") with the second and third highest totals occurring in September and May (2.04" and 2.02 ", respectively). 2.2 Pit Dewatering and Consumptive Water Use for 2014 During 2014, Trapper dewatered approximately 31.16 acre -feet of water from four active pits and 99.15 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 2014. All pit water was routed into the NPDES drainage system with resulting discharges monitored accordingly when pumped off site. The majority of pumped water was utilized on haulroads for dust suppression. Approximately 171.85 acre -feet of water was used for dust suppression on haul roads and topsoil handling operations in 2014. This value declined this year compared to rising consumption during the past few years. The majority of this water was utilized from A -Pit where water has been stored in the inactive pit. Dust suppression water demands continue to be offset by the successful application of dust suppression chemical treatments on haulroads. Haul routes were similar in 2014 to 2013 routes. Life -of- mine Haulroad is still the primary route for coal delivery to the Craig Station. Continued activity in the eastern portion of the mine accounts for the majority of dust suppression water usage. Reduction in temporary haul routes through the slide, and an extremely wet August may account for the reduced water usage after several years of increased consumption. Total water volume used by Trapper Mine in 2014 was approximately 302 acre -feet, a slight increase over 2013 consumption at 245 acre feet. 2.3 Mining Advancement and Ash Disposal Sites The 2014 Annual Reclamation maps (see Trapper's 2014 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 2014 report, all applicable 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 2014.