GENERAL49579 - Laserfiche WebLink

Home Browse Search

The effects on water quantity are expected to be minimal. An increase in imperviousness due to the construction or roads and buildings can be expected to cause an increase in runoff amounts. The rate of runoff will increase over natural conditions because of the increased efficiency of conveyance channels. However, these effects are moderated by the detention of runoff in the pond and subsequent evaporation of pond water. In general, only slight changes m the hydrologic balance of surface water are expected due to the underground mining operations proposed at the King Coal Mine. Changes in water quality can be expected to occur as a result of mining. An increase in erosion rates are expected from the disturbance of soils and vegetation, however, these are compensated by deposition of sediment in the sediment pond. An increase in total dissolved solids (TDS) may occur from well water pumped and used for dust suppression and other operational use. Evaporation of water standing in the pond may also cause an increase in TDS, although the increase above background concentrations (1500-2000 mg/1) is not expected to be large. The Division has determined that probable hydrologic effects on surface water identified above will not preclude use of the water below the point of discharge from the mine. This conclusion is based on the small and infrequent flows relative to the lazge amount of dilution available in receiving waters. The quality of surface water is limited on site and the treatment systems should act to mitigate any adverse effects on surface water. Ground Water Effects There are two potentially impacted ground water systems within and adjacent to the King Coal operation: the Menefee Formation and the Hay Gulch alluvial system. The probable hydrologic consequences of mining to the Menefee Formation are negligible. The Menefee is essentially dry at the King Coal Mine. This has been historically documented during past operations. Additionally, a drilling program initiated in 1980 for the proposed Shalako Mine (about 1 mile northeast of the King Coal Mine in Hay Gulch) confirmed [hat the coal and overburden aze essentially free of water. Perched aquifers, which may be located above the mined seam, will be dewatered during the course of mining operations . The perched aquifers above the mine are probably limited both in number and in areal extent. There is no documented use of any of these aquifers, nor is there any evidence to suggest that these aquifers supply base flow to any local steams or springs. Therefore, impacts to perched aquifers, and the Menefee Formation as a whole, will be minimal. The second ground water system identified near the permit area is the Hay Gulch alluvial aquifer. This aquifer system may be potentially affected by surface runoff from the mine bench or discharge from the sediment pond infiltrating into the alluvial body. This infiltration could cause localized increases in total dissolved 16