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inspection in March 1986 documented inflows of 200 gallons 'per <br />day. This inflow gradually slowed once this perched aquifer was <br />completely dewatered. Inflows during 1991 failed to produce over <br />3 gpm for any significant period of time. Currently, mine inflows <br />remain less than 1,000,000 gallons annually. <br />COVCC has established an extensive monitoring system to monitor <br />water levels in colluvial/alluvial. deposits in the permit area and <br />in the alluvium of streams overlying mine entries. Permeability <br />tests on colluvium in the East.Roatcap Creek drainage averaged <br />1.2x102ft/day. No significant water level fluctuations have <br />been noted in conjunction with mine inflows. Mine inflows in the <br />mains underlying East Roatcap Creek averaged less than 1 gpm from <br />1987 to 1993. <br />The permeability of the coal aquifer was measured in 1986 at <br />1.4x102ft/day. This insignificant aquifer has yet to make a <br />visible contribution to mine inflows. COVCC imports water for <br />dust suppression from their wells in Steven's Gulch. In 1983, for <br />example, the operator estimated that approximately 6.24 million <br />gallons of water is consumed as moisture on the coal, 0.5 million <br />gallons is consumed through increased humidity in the ventilation <br />air, and less than 0.5 mfllton gallons is lost through seepage <br />into the floor of the mine. <br />Surface Water - <br />The Orchard Valley Mine area will not significantly affect the <br />local. surface water hydrology or the regional hydrology. Sediment <br />control measures will ensure protection to•stream quality. No <br />mine water will discharge from the portals and no water will be <br />withdraxn from the creek. An overland ditch will divert water <br />into West Roatcap Creek thus bypassing the OVWM site. Clean water <br />diversions above the main facilities minimize surface water runoff <br />through the site. Mine inflows under and adjacent to the creek <br />are predicted to be insignificant. A brief discussion of sediment <br />control measures, subsidence impact mitigation, surface water <br />inflow predictions and water augmentation plans follow. <br />The Orchard Valley mine plan is designed to minimize the impacts <br />of the project on the surface water hydrology of the region. <br />Disturbed area drainage from the mine benches, parking area, west <br />portal fill, and loadout site is collected and treated on the <br />site. Four sediment ponds collect disturbed-area drainage from <br />the mine benches. Another pond controls sediment generated by the <br />underground development waste pile. One pond controls drainage <br />from the timber storage area., and two ponds collect drainage from <br />the disturbed areas of the loadout, truck scales, and coal <br />stockpile area. The west portal area drains to one sedimentation <br />pond except for exempted portions of the fill face which have a <br />small area exemption waiver. A system of lined and unlined <br />ditches convey waters from the disturbed areas to the ponds. The <br />mine operator has applied for and/or obtained the appropriate <br />-29- <br />