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House Sandstone through intergranular porosity in roof rock of the workings <br />because the roof rock is composed of shale, which probably is impermeable to <br />water. (Drill hole sample logs in Appendix 4 of the permit show the Upper <br />Coal Seam of the Menefee formation, the seam mined at the King I Mine, is <br />bounded above and below by shale.) Subsidence fractures in the roof rock, <br />however, could provide a conduit of flow for water from the workings to the <br />overlying Cliff House. Therefore, if the workings fill with water, and <br />subsidence fractures convey that water to the Cliff House Sandstone, then <br />impacts could possibly occur to the water quality in the Cliff House Sandstone <br />aquifer down -dip from the workings, if mine water is lower quality than <br />ambient ground water. Significant flow from the workings to the Cliff House <br />through subsidence fractures is unlikely, however, because head in the <br />overlying (higher elevation) Cliff House would be greater than the head <br />exerted by the mine water. <br />Menefee Formation- Like the Cliff House Sandstone, mining impacts to the <br />Menefee formation are improbable because it is unlikely the workings of the <br />King I and II Mines will fill with water. <br />Surface Water Effects <br />With the exception of two small area exemptions, all runoff from the disturbed <br />area at the mine site will be routed through sediment ponds. Effects of mining <br />on this water will involve changes in the magnitude and duration of runoff and <br />changes in water quality. <br />The effects on water quantity are expected to be minimal. A decrease in <br />permeability due to the construction or roads and buildings can be expected to <br />cause an increase in runoff amounts. The rate of runoff will increase over <br />natural conditions because of the increased efficiency of conveyance channels. <br />However, these effects are moderated by the detention of runoff in the pond <br />and subsequent evaporation of pond water. In general, only slight changes in <br />the hydrologic balance of surface water are expected due to the underground <br />mining operations proposed at the King I and 11 Mines. <br />Changes in water quality can be expected to occur as a result of mining. <br />Increases in erosion rates are expected from the disturbance of soils and <br />vegetation; however, these are compensated by deposition of sediment in the <br />sediment ponds. An increase in total dissolved solids (TDS) may occur from <br />well water pumped and used for dust suppression and other operational use. <br />Evaporation of water standing in the ponds may also cause an increase in TDS, <br />although the increase above background concentrations (1500-2000 mg/1) is <br />14 <br />