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The decline in piezometric levels in bedrock zones 'upper sandstone facies', 'siltstone/coal facies', <br />' and 'lower sandstone facies' was anticipated as probable impacts as the result of underground <br />mining activities. As projected these impacts are localized and will most probably continue in the <br />proximity of the mined area. <br />' As projected, subsidence in Red Wash initially resulted in water ponding in the stream bottom. <br />The high content of silt and clay carried by Red Wash rapidly fills the ponds. The silt and clay <br />layers have sealed any cracks that formed in the alluvium as the result of subsidence. Water <br />continues to flow in the surface channel at Red Wash indicating that the basal alluvium is not <br />recharged by surface flow infilVation. <br />' 3.3 Slgnlflcance of Impacts to Use of Water <br />The current rate of withdrawal of water from the lagoon in the White River alluvium is far below <br />' that projected at full production. Based on the current level of production and the current rate of <br />withdrawal, BME is not likely to exceed the projected withdrawal rates even at higher production <br />levels. <br />t During this reporting period, no significant changes in piezometric levels were noted except for the <br />' °middle sandstone/coal facies' at 30-8M. <br />Water ponding in Red Wash as the result of subsidence over longwall panels No. 1, No. 2, No. <br />3, No. 4, No. 5, 6 and No. 7 acted as stilling basins for deposition of clays and silts being carried <br />down Red Wash. The significance of this impact is beneficial as the sediment load to the White <br />' River was reduced. The same impact is expected as a result of subsidence over subsequent <br />longwall panels. <br />' 3.4 Effectiveness of Mltlgatlon Measures <br />' Mitigation measures at the Deserado Mine primarily include impoundment structures to control <br />runoff from surface sites and coal refuse piles. These structures have worked well as no <br />discharges of 10-year runoff event and possibly contaminated water from these impoundments <br />' have occurred. Reclamation of areas disturbed during construction and operation is effective in <br />controlling both erosion and suspended solids during runoff events. Sediment control structures <br />such as berms, ponds and sediment fences are used to control run off from disturbed areas until <br />' vegetation and the natural contours are reestablished. <br /> <br /> <br />1 <br />19 <br />