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• <br /> <br />E. M evaluation of the effects of mining on ground <br />and surface water quality during and after mining. <br />During site inspections, Jim Herron has noted that <br />monitoring wells at the mine site are improperly <br />installed. Perforated casing extends above ground. <br />Perforations above ground will allow surface waters <br />to enter the well and bias both water levels and ground <br />crater quality. This situation can be remedied by <br />digging dawn around the casing to a depth of three <br />feet, cutting of the perforated casing, gluing on a <br />section of solid casing, and filling the hole around <br />the well to the surface caith cement. These monitoring <br />wells should be fixed immediately. <br />Grand Pfesa Coal Company should provide to the Division <br />completion diagrams for each monitoring we 11. This <br />diagram should include the perforated or slotted, <br />casing interval,the solid casing interval, the location <br />and type of formation packer or seal, gravel packed <br />interval, open hole interval, back filled interval, <br />and the geologic units into which the well is completed. <br />Grand'Mesa Coal Company is diverting surface runoff <br />into the mine work from 0.096 acres at the E belt <br />Portal, 0.331 acres at the E intake Portal, and <br />proposes to divert surface runoff from 2.468 acres <br />into the D seam mine. This water is then pumped out <br />of mines into sediment ponds for treatment. Such <br />discharges into underground working is forbidden under <br />Rule 4.04.16 unless the applicant can demonstrate <br />that such practices will not degrade water quality. <br />The sediment pond at Che load out site at the old <br />Holly Sugar Factory in Delta is designed as a no <br />discharge structure. The dewatering of this pond <br />is to be through evaporation. Figure 2.05.3(7)-1 <br />contains a letter from Thomas A. Kelly, Assistant <br />Division of Water Resources Engineer in Montrose. <br />In this letter, 4ir. Kelly approved a small evaporation <br />(sediment) pond with a total capacity of 0.8 acre foot <br />of storage from a 100 year flood event. The calcualtions <br />within the permit application are for the 10 year <br />24 Hour event and the capacity of the pond is 2.9 <br />acre feet (e.g. surface area of 0.725 feet times <br />4 feet of depth). The pond is also excavated into <br />alluvial materials and therefore will loose a great <br />deal of the water through deep percolation through <br />the pond bottom. This may pollute the ground water <br />