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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/I 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. Transmissiviry was measured at six sites and varies from 3.0 to 88 ftz/day, <br />averaging 38 ft2/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 acalcium/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 mgll. <br />Dissolved iron levels vary from 0.02 to 2.51 mg/1 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 t.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) Camborihid. 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 />