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TAB 16 <br />PROTECTION OF THE HYDROLOGIC BALANCE <br />Introduction <br />The surface mining and reclamation activities that are to be carried out at the Seneca II-W Mine have <br />been designed to minimize disturbance of the hydrologic balance within the permit boundaries and <br />areas adjacent to the mine. Activities of the mining operation that assure protection of ground water, <br />surface water, stream buffer zones, water rights and alternative water supplies, and alluvial valley <br />floors are addressed in this part of the permit. Mining and reclamation activities, as well as monitoring <br />and data reporting, have been planned in accordance with the Probable Hydrologic Consequences (PHC) <br />determination (Tab 17) and the analysis of baseline hydrologic, geologic, and other pertinent <br />information required in the permit application. Reference to additional tabs regarding complete details <br />of mining and reclamation operations that address aspects of the protection of the hydrologic balance <br />are documented in the following sections when and where they are appropriate. <br />Ground Water Protection <br />Ground water protection is addressed in three parts: 1) ground water quality; 2) ground water <br />quantity; and 3) ground water monitoring. <br />Ground Water Quality. Mining activities involving replacement of spoil material into the mine pits are <br />described in Tab 20, Backfilling and Grading. Handling procedures for topsoil and overburden are <br />described in Tab 21, Minesoil Reconstruction. Procedures for handling topsoil and overburden were <br />developed after analysis of the chemical and physical properties of these materials in the mining <br />complex (see Tab 6, Geology; Tab 9, Soil Baseline Study; and Tab 17, PHC "Impacts of Spoil Water <br />Quality on Ground and Surface Water Quality"). Geochemical analysis of the spoil indicated that the <br />material is slightly acidic to neutral in pH (range = 6.1 to 7.3). However, the analysis of the <br />overburden indicates the material has an excess neutralization potential on the order of 60 tons per <br />1,000 tons of overburden material (see Tab 6, Table 6-6). The only acidic layer identified in the Wadge <br />mining area overburden is the Lennox Coal seam that comprises approximately three to five percent of <br />the unit in the northwestern part of the mine area. For Seneca II-W South, paste pH ranges from 6.4 <br />to 8.3 and mean weighted acid potentials were 26 to 103 TCaC03/1000T. <br />Additional information provided from the analysis of lithologic quality and ground water monitoring, in <br />combination with the neutralization potential of the overburden, indicate that replaced spoil material <br />should have only minimal or no impact on the ground water quality (also see Tab 17, PHC). SCC has <br />also planned to sample the replaced topsoil and upper three feet of final graded spoil material to <br />determine the suitability for plant growth (see Tab 21, Minesoil Reconstruction). <br />1 Revision 01/02