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2.04.7 Hydrology Description <br />6) Prior to commencing mining activities on lease COC -75916 that could <br />cause subsidence, an appropriate augmentation plan for replacement <br />water will be decreed. The augmentation plan will consider drought <br />conditions and the limitations of local water supplies. <br />MINE WATER INFLOW <br />The Bowie No. 2 Mine was basically dry from when the mine opened in 1997 <br />until the fourth quarter of 2002 when the mine began discharging water at a <br />rate of approximately 5 gpm. The inflow continued to increase with the <br />estimated mine inflow rate of 30 gpm. as of May 2003. This water was <br />directed from the portal areas to Sedimentation Pond C. At times the water <br />was directed to other sediment ponds if insufficient capacity was available in <br />Pond C. However, the mine water was only discharged from Pond C. <br />Water inflow into the mine is associated with sandstone channels or <br />fractures in the roof or flow from fractures in the floor. The pattern of water <br />inflow is one of steadily decreasing flow as the face mines through an area <br />and advances away from it. <br />Most areas dried up completely within several weeks of being mined. Where <br />areas didn't dry up completely, water inflow subsides to less than 1 gpm per <br />30 feet of entry to a few areas with 1 -3 gpm per 30 feet of entry. These <br />represent "damp" to "light drippers" as defined by NIOSH in their Coal Mine <br />Roof Rating System. The Bowie No. 2 Mine, D -Seam and B -Seam may also <br />encountered mine inflows from faults, fractures (if present) and perched <br />water bearing zones within the coal, the overburden, and the floor rock. <br />Faults are expected to yield more flow than either roof seeps or floor rock in <br />underground mining due to the secondary permeability created by the <br />fractures within the shear zones. Storativity within shear zones is usually <br />high which results in a higher initial inflow when the fault is first encountered <br />by underground mining and eventually slows to a rate dictated by the <br />permeability of the shear zone rock or slower up gradient medium. However, <br />the West Mains were mined though a fault which did not yield appreciable <br />inflows. <br />PR -14 2.04-63- 03/14 <br />