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0.92 to 6.0 ft'/day, based on hydraulic conductivity values of 0.04 to 0.34 ft/day (average <br /> 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 <br /> water has TDS levels varying from 1050-4444 mg/l, averaging 2822 mg/1 at New Horizon <br /> Mine 2, and TDS levels varying from 5438-7100 mg/1 and averaging 6701 mg/1 at New <br /> Horizon Mine 1. The three wells at New Horizon Mine 2 exhibit two distinct geochemical <br /> characteristics. Two wells have calcium/magnesium sulfate water with the pH averaging 5.4. <br /> One well, 17-P1, is an alkaline sodium sulfate water with the pH averaging 9.2. Iron, <br /> manganese, aluminum, fluoride and pH levels exceed recommended water quality criteria for <br /> agricultural use, and concentrations of aluminum and fluoride exceed recommended water <br /> 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 <br /> representative of water within the lower Dakota Sandstone. This confined aquifer is <br /> recharged along the Uncompahgre Plateau to the northeast and discharges towards the <br /> southwest. Transmissivity was measured at six sites and varies from 3.0 to 88 W/day, <br /> averaging 38 W/day. Hydraulic conductivity values varied from 0.07 to 4.5 ft/day, <br /> averaging 1.6 ft/day. This aquifer is not used locally to any great extent. <br /> The water in the underburden is characterized as a hard, moderately alkaline saline water <br /> with high sulfate concentrations (average sulfate concentrations of 695 mg/1). Two wells <br /> show a calcium/magnesium sulfate type water while one well shows an alkaline sodium <br /> bicarbonate type water. The TDS varies from 960-2648 mg/1, averaging 1619 mg/l. <br /> Dissolved iron levels vary from 0.02 to 2.51 mg/l and average 0.63 mg/l. The sodium <br /> bicarbonate well occasionally exhibits pH levels which exceed the recommended agricultural <br /> standard. Another well shows manganese levels which exceed the agricultural standards. <br /> All wells meet the recommended water quality standards for livestock watering. The <br /> underburden aquifer does not produce acceptable water for domestic purposes; TDS, sulfate <br /> and ammonia standards are exceeded. <br /> Ground water within 150 feet of the ground surface has been only minimally developed for <br /> use in the Nucla area. High salinities and occasionally high sodium or sulfate concentrations <br /> preclude its use as domestic, agricultural or stock water. In addition, moderate hydraulic <br /> conductivities are coupled with low sustained well yields (less than 1.5 gpm), discouraging <br /> sustained dependence on wells completed within these aquifers. <br /> Soils <br /> There are two primary soil series present on undisturbed sites within the present New <br /> Horizon Mine 1 permit area. The major soil is the Shavano series. It is a fine, loamy, <br /> mixed, frigid (ustic) Camborthid. Topsoil quality is good to an average depth of 18 inches <br /> on the gentler slopes and 12 inches on the steeper slopes. <br /> The Persayo series is found in conjunction with the Shavano soils on isolated ridges and <br /> steeper slopes in the permit area. The surface soils may range in texture from sandy clay <br /> 8 <br />