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1.0 INTRODUCTION <br />This report presents the ground-water and surface-water monitoring results for Trapper <br />Mine for 1995. Sienificant mine activities during 1995 include continued expansion of the Ashmore <br />(A), Derringer (D) and Hawken (H) pits and an increase in dewatering well pumpage in D pit. <br />Dewatering was conducted in both the A and H pits in 1995 as compared to last yeaz where no <br />dewatering occurred. Construction of an additional NPDES site, 017 (Oak Gulch), was begun in <br />the Fall of 1995. Construction is expected to be completed in 1996. <br />Ground-water monitoring of the aquifers associated with Trapper Mine started in 1974. <br />The ground-water flow regime has been divided into the major sandstones and coal/adjacent <br />sandstone aquifers. This division of the aquifer systems was selected at clay and shale units which <br />have the potential to retard vertical movement. A blue pull-out index presents the schematic of the <br />aquifer units at Trapper on one side and the basic well data table on the other. It is suggested <br />moving this index sheet to the section of the report being reviewed. Aquifer properties are presented <br />in Table 2-1 of the 1990 Armual Hydrologic Report. <br />The Twenty Mile Sandstone is the lower-most aquifer monitored at Trapper Mine. The <br />U coal seam and adjacent sandstones are the second aquifer monitored. The Q and R coal seams <br />and sandstone between these hvo coal seams have been labeled the QR aquifer. This is one of the <br />major aquifers of interest because D, E, and C pits have mined the Q and R coal seams, currently <br />only the D pit mines these seams. The K, L, and M coal seams and the sandstones which are <br />stratigraphically in this interval aze called the KLM aquifer. D pit also mines the L seam. The KLM <br />aquifer is above the QR aquifer, but below the HI aquifer. The H and I coal seams and sandstone <br />• between these two coals have been termed the HI aquifer and has been mined in the A, B, and C <br />1-1 <br />