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Water quality of the upper and lower coals have levels of iron and lead in <br />excess of drinking water standards. The sodium absorption ratios (SAR) are <br />high in four of the six wells. Total dissolved solids concentrations show a <br />range of 864 mg/1 to 2610 mg/1. Copper and sodium levels have increased since <br />the initiation of monitoring. The water quality of spring 4 has deteriorated <br />substantially with significant increases in ammonia, sodium, sulfate, <br />bicarbonate, TDS and magnesium. Nitrate and iron concentrations have <br />decreased. Ammonia, lead and sulfate are present in high concentrations. <br />Spring 4 originally discharged from the upper coal seam and currently is <br />representative of the backfilled spoils aquifer. <br />The operation will probably affect the quality of water in the water-bearing <br />strata within the mine area. Once the pit is backfilled, the applicant <br />predicts that 82.5 acre-feet/year of water will leach through the spoil and <br />will pick up additional concentrations of constituents from the overburden. <br />This water will eventually find its way into water-bearing strata in the mine <br />area. Although the operations will potentially degrade the quality of this <br />ground water, the net effect would be insignificant. The water within these <br />strata are naturally of such poor quality and low availability that they are <br />not useful for many purposes. <br />The Twentymile Sandstone aquifer is separated from the lower coals by two to <br />three hundred feet of l~w permeability interbedded sandstones and shales (K = <br />0.012 - 0,12 gal/day/ft ). The thickness and low permeability of the <br />interburden materials suggest that this aquifer will not be impacted by mining <br />at Hayden Gulch Mine. <br />The Dry Creek alluvial wells at the loadout appear to monitor the poor quality <br />waters produced by Lewis Shale alluvium rather than any impacts from the <br />loadout. Excessively high EC levels of 22.4-76 mmhos/cm and high SARs (27-49) <br />mask any impacts from the loadout facility. <br />No alluvial deposits were documented between the mine and the East Fork of the <br />Williams Fork along Hayden Gulch. Consequently, there should be limited <br />impacts from spoils water contribution to the surface water regime. <br />The applicant examined ground water use within a four mile radius of the <br />permit area. Nine registered water wells were found along strike or up dip of <br />the mine and water was used for stock watering and domestic use. In many <br />cases these wells are hydrologically isolated from the mine zone. There were <br />no registered wells downdip of the permit area. Therefore, adjacent water <br />users are not predicted to be impacted. <br />2. Surface Water <br />The Hayden Gulch Mine lies in the upper reaches of the Hayden Gulch watershed, <br />which is tributary to the East Fork of the William Fork. The Hayden Gulch <br />loadout is located in the Dry Creek basin. Surface water flow within the <br />drainages is sporadic and occurs primarily in response to periods of snowmelt <br />or individual rainfall events. <br />-19- <br />i .. <br />