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-30- <br />CWI has established an extensive monitoring system to monitor water levels in <br />colluvial-alluvial deposits in the permit area and in the alluvium of streams <br />overlying mine entries. Permeability tests on colluvium in the East Roatcap <br />Creek drainage averaged 7.2x102ft/day. No significant water level <br />fluctuations have been noted in conjunction with mine inflows. Mine inflows <br />in the mains underlying East Roatcap Creek averaged less than 1 gpm in 1987. <br />The permeability of the coal aquifer was measured in 1986 at 1.4x102ft/ddy. <br />This insignificant aquifer has yet to make a visible contribution to mine <br />inflows. CWI imports water for dust suppression from their wells in Steven's <br />Gulch. In 1983, for example, CWI estimated that approximately 6.24 million <br />gallons of water is consumed as moisture on the coal, 0.5 million gallons is <br />consumed through increased humidity in the ventilation air, and less than 0.5 <br />million gallons is lost through seepage into the floor of the mine. <br />Effects of the Orchard Valley Mine - Surface Water <br />The Orchard Valley Mine area will not significantly affect the local surface <br />water hydrology or the regional hydrology. Sediment control measures will <br />ensure protection to stream quality. No mine water will discharge from the <br />portals and no water will be withdrawn from the creek. An overland ditch will <br />divert water into West Roatcap Creek thus by-passing the OVWM site. Clean <br />water diversions above the main facilities minimize surface water runoff <br />through the site. Mine inflows under and adjacent to the creek are predicted <br />to be insignificant. A brief discussion of sediment control measures, <br />subsidence impact mitigation, surface water inflow predictions and water <br />augmentation plans follow. <br />The Orchard Valley mine plan is designed to minimize the impacts of the <br />project on the surface water hydrology of the region. Disturbed area drainage <br />from the mine benches, parking area, west portal fill, and loadout site is <br />collected and treated on the site. Four sediment ponds collect disturbed area <br />drainage from the mine benches. Another pond controls sediment generated by <br />the underground development waste pile. One pond controls drainage from the <br />timber storage area, and two ponds collect drainage from the disturbed areas <br />of the loadout, truck scales, and coal stockpile area. The west portal area <br />drains to one sedimentation pond except for exempted portions of the fill face <br />which have a small area exemption waiver. A system of lined and unlined <br />ditches convey waters from the disturbed areas to the ponds. The mine <br />operator has applied for and/or obtained the appropriate NPDES permits. <br />Effluent quality from the sedimentation ponds will be monitored to determine <br />permit compliance. <br />Subsidence effects have the potential to impact arty or all springs, seeps, and <br />ponds within the affected permit area. In order to protect water resources <br />but still allow mining, CWI has developed a subsidence damage preventative <br />mine plan, subsidence repair procedures, a water replacement plan, and an <br />intensive monitoring system. <br />The mine plan has been designed to preclude mining in certain critical area <br />where water rights exist. For example, the north extreme of East Roatcap <br />Creek will not be undermined to prevent impacts to certain water rights. Ih <br />areas where the overburden depth is less than 800 feet, CWI will conduct <br />limited coal extraction under streams to minimize the potential for any <br />