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53 ftI/day, averaging 13.3 ft-'/day. The McWhorter analysis of pit inflow conservatively estimated <br /> that the hydraulic conductivity of the overburden was 0.61 ft/day. Hydraulic conductivity <br /> calculations from field tests of the overburden showed a range of 0.39 to 1.05 ft/day, indicating <br /> moderate permeability. <br /> The water found in the overburden is characterized as very hard, saline, calcium/magnesium sulfate <br /> water with neutral pH. TDS levels vary from 1 494-1 0074 mg/l and average 4613 mg/l. Sulfate <br /> concentrations are very high, varying from 875 mg/1 to 6872 mg/l and averaging 3176 mg/l. In some <br /> of the overburden wells, sulfate, TDS, manganese and fluoride exceed recommended standards for <br /> livestock drinking water. In addition, concentrations of manganese and fluoride exceed the <br /> agricultural use standards in some wells. <br /> The Dakota coal has been described as an aquifer. Wells completed in the Dakota show water level <br /> fluctuations of 1.3 to 14.6 feet. The water table exhibits seasonal fluctuations with high water levels <br /> in late fall. The aquifer is recharged from the east north-east and discharges to the west and along <br /> Calamity Draw. The transmissivity varies from 0.92 to 6.0 ft2/day,based on hydraulic conductivity <br /> values of 0.04 to 0.34 ft/day (average values of 0.19 ft/day), reflecting moderate flow capabilities. <br /> The water quality of the Dakota coal is unacceptable for most uses. The saline, sulfate-based water <br /> has TDS levels varying from 1050-4444 mg/l, averaging 2822 mg/1 at New Horizon Mine. Three <br /> wells at the New Horizon Mine 2 exhibit two distinct geochemical characteristics. Two wells have <br /> calcium/magnesium sulfate water with the pH averaging 5.4. One well, 17-P1, is an alkaline sodium <br /> sulfate water with the pH averaging 9.2. Iron, manganese, aluminum, fluoride and pH levels exceed <br /> recommended water quality criteria for agricultural use, and concentrations of aluminum and fluoride <br /> exceed recommended water quality criteria for livestock. <br /> The aquifer underlying the coal is identified as the underburden aquifer. The wells in the <br /> underburden have been completed 17 to 64 feet below the coal, and samples are representative of <br /> water within the lower Dakota Sandstone. This confined aquifer is recharged along the <br /> Uncompahgre Plateau to the northeast and discharges towards the southwest. Transmissivity was <br /> measured at six sites and varies from 3.0 to 88 ft''/day, averaging 38 ft'/day. Hydraulic conductivity <br /> values varied from 0.07 to 4.5 ft/day, averaging 1.6 ft/day. This aquifer is not used locally to any <br /> great extent. <br /> The water in the underburden is characterized as a hard, moderately alkaline saline water with high <br /> sulfate concentrations (average sulfate concentrations of 695 mg/1). Two wells show a <br /> calcium/magnesium sulfate type water while one well shows an alkaline sodium bicarbonate type <br /> water. The TDS varies from 960 2648 mg/l, averaging 1619 mg/1. Dissolved iron levels vary from <br /> 0.02 to 2.51 mg/l and average 0.63 mg/l. The sodium bicarbonate well occasionally exhibits pH <br /> levels which exceed the recommended agricultural standard. Another well shows manganese levels <br /> which exceed the agricultural standards. All wells meet the recommended water quality standards <br /> for livestock watering. The underburden aquifer does not produce acceptable water for domestic <br /> purposes; TDS, sulfate and ammonia standards are exceeded. Measurable trace element <br /> concentrations in the underburden aquifer include aluminum, arsenic, boron, cadmium, copper, <br /> fluoride, iron, lithium, manganese, mercury, nitrate, vanadium and zinc. The highest concentrations <br /> of arsenic, mercury and copper were measured in the underburden aquifer at the New Horizon <br /> mining area. <br /> 8 <br />