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<br />' As projected, subsidence in Red Wash initially resulted in water ponding in the stream bottom. <br />t The high content of silt and clay carried by Red Wash rapidly filled 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 in Red Wash. <br />' 3.3 Significance 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 />' During this reporting period, significant changes in piezometric levels were noted for the "middle <br />sandstone/coal facies" at TW2-17M (a decrease of 11.2 feet), the lower sandstone facies at 33- <br />' 8L (a decrease of 31.2 feet), and all 32-7 wells (decreases of 23.0, 36.9, and 61.6 feet for the <br />upper, middle and lower facies). <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 Mitigation 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 out of <br />compliance discharges of 10-year runoff event and possibly contaminated water from these <br />impoundments have occurred. Reclamation of areas disturbed during construction and <br />' operation is effective in controlling both erosion and suspended solids during runoff events. <br />Sediment control structures such as berms, ponds and sediment fences are used to control <br />' runoff from disturbed areas until they are revegetated and stabilized. <br />3.5 Changes Necessary to Minimize Impacts <br />' Based on the success of mitigation measures to date and the impacts so far observed, no <br />' changes in mining operations or procedures are warranted. <br /> <br />' 13 <br />