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inflow sources for the workings. If the King I Mine or King II Mine workings were <br />to eventually fill with water, it seems unlikely the water could be transmitted from <br />the workings to the Cliff House Sandstone through intergranular porosity in roof <br />rock of the workings because the roof rock is composed of shale, which probably is <br />impermeable to water. (Drill hole sample logs in Appendix 4 of the permit show the <br />Upper 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, however, <br />could provide a conduit of flow for water from the workings to the overlying Cliff <br />House. Therefore, if the workings fill with water, and subsidence fractures convey <br />that water to the Cliff House Sandstone, then impacts could possibly occur to the <br />water quality in the Cliff House Sandstone aquifer down -dip from the workings, if <br />mine water is lower quality than ambient ground water. Significant flow from the <br />workings to the Cliff House through subsidence fractures is unlikely, however, <br />because head in the overlying (higher elevation) Cliff House would be greater than <br />the head 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 King I <br />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 area <br />at the mine site will be routed through sediment ponds. Effects of mining on this <br />water will involve changes in the magnitude and duration of runoff and changes in <br />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 cause <br />an increase in runoff amounts. The rate of runoff will increase over natural <br />conditions because of the increased efficiency of conveyance channels. However, <br />these effects are moderated by the detention of runoff in the pond and subsequent <br />evaporation of pond water. In general, only slight changes in the hydrologic balance <br />of surface water are expected due to the underground mining operations proposed at <br />the King I and II Mines. <br />Changes in water quality can be expected to occur as a result of mining. Increases in <br />erosion rates are expected from the disturbance of soils and vegetation; however, <br />these are compensated by deposition of sediment in the sediment ponds. An increase <br />in total dissolved solids (TDS) may occur from well water pumped and used for dust <br />suppression and other operational use. Evaporation of water standing in the ponds <br />may also cause an increase in TDS, although the increase above background <br />concentrations (1500-2000 mg/1) is not expected to be large. <br />The Division has determined that probable hydrologic effects on surface water <br />identified above will not preclude use of the water below the point of discharge from <br />19 <br />