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1.0 INTRODUCTION <br />This report presents the ground -water and surface -water monitoring results for Trapper <br />Mine for 2017. Mining activities during 2017 include continued expansion of the L pit. All other <br />pits were not mined during 2017. Pit dewatering was conducted in the L pit in 2017. Well <br />dewatering was used in 2017 in the G pit area and these volumes of water and pit dewatering <br />volumes are presented in Table 1-1. <br />Ground -water monitoring of the aquifers associated with Trapper Mine started in 1974 <br />and well data for the monitoring wells is presented in Table 1-2. The ground -water flow regime has <br />been divided into the major sandstones and coal/adjacent sandstone aquifers. This division of the <br />aquifer systems was selected at clay and shale units, which have the potential to retard vertical <br />movement. Figure 1-1 presents the schematic of the aquifer units at Trapper and is useful with the <br />basic well data table in Table 1-2. The monitoring data tabulations presented in Appendices A, B <br />and C give only the last ten years of data. Appendix D is a CD of this report with all of the historical <br />monitoring data in its Appendices A, B and C. Aquifer properties are presented in Table 2-1 of the <br />1990 Annual Hydrologic Report. <br />The Twenty Mile Sandstone is the first major sandstone below the mined coal seam at <br />Trapper Mine. The U coal seam and adjacent sandstones is a minor aquifer between the mined coal <br />seams and the Twenty Mile Sandstone. The Q and R coal seams and sandstone between these two <br />coal seams have been labeled the QR aquifer. This is one of the major aquifers of interest because <br />C, D, E, F, G, K, L and Z pits have mined the Q and/or R coal seams, currently the L pit mines the Q <br />seams. The K, L, and M coal seams and the sandstones, which are stratigraphically in this interval, <br />are called the KLM aquifer. In 2017, the L pit mined the H, H1, H2, I1, I2, K, MK, LK, ML, M, <br />MM, LM, Q, UQ and MQ seams. The KLM aquifer is above the QR aquifer, but below the HI <br />Trapper Mining Company 1-1 <br />2017 Annual Report <br />