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<br />1.0 INTRODUCTION <br />This report presents the ground-water and surface-water monitoring results for <br />Trapper Mine for 1997. Significant mine activities during 1997 include continued expansion <br />of the Ashmore (A), Derringer (D) and Hawken (H) pits. Mining started in the Flintlock (F) <br />pit in 1997. Dewatering was conducted in the A, D, F and H pits in 1997. Construction of <br />an additional NPDES site, 019 (Oak Gulch), was completed in the Fall of 1997. <br />Ground-water monitoring of the aquifers associated with Trapper Mine started in <br />• <br />1974. The ground-water flow regime has been divided into the major sandstones and <br />coal/adjacent sandstone aquifers. This division of the aquifer systems was selected at clay <br />and shale units which have the potential to retard vertical movement. A tan pull-out index <br />presents the schematic of the aquifer units at Trapper on one side and the basic well data <br />table on the other. It is suggested moving this index sheet to the section of the report being <br />reviewed. Aquifer properties are presented in Table 2-1 of the 1990 Annual Hydrologic <br />Report. <br />The Twenty Mile Sandstone is the lower-most aquifer monitored at Trapper Mine. <br />~J <br />The U coal seam and adjacent sandstones are the second aquifer monitored. The Q and <br />R coal seams and sandstone between these two coal seams have been labeled the QR <br />aquifer. This is one of the major aquifers of interest because D, E, and C pits have mined <br />the Q and R coal seams, currently only the D pit mines these seams. The K, L, and M coal <br />seams and the sandstones which are stratigraphically in this interval are called the KLM <br />aquifer. D pit also mines the L seam. The F it mines the Q and M seams. The KLM aquifer <br />is above the QR aquifer, but below the HI aquifer. The H and I coal seams and <br />1-1 <br />