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Analyses at the Madrid station indicate a low-yield watershed with the mean annual runoff <br />• volume measured at 28,980 acre feet. <br />In terms of local water quality of the Purgatoire River and associated alluvium, mine discharge <br />and leachate from refuse contribute to higher ionization of the water and increased amounts of <br />trace elements. The main parameters of interest are sodium and other dissolved salts which may <br />affect downstream use of the water for irrigation. In the worst case, during low flow conditions, <br />effects of ionization caused by mining are insignificant when compared to the natural <br />deterioration of water quality as the river flows to the east. Figure 3.2-1 presents stiff diagrams of <br />water quality at stations PRS-I and PRS-4 on the Purgatoire River for November 1997 through <br />2001. As shown, water duality above the mine is similar to water quality below the mine. <br />Discharge from the site passes through treatment facilities or sediment impoundments. Copies of <br />the NPDES Discharge Monitoring Reports submitted to the Colorado Department of Public <br />Health and Environment are sent to CDMG as they are filed quarterly. No discharges were noted <br />at any of the ponds in 2008. <br />3.2.3 Alluvial Groundwater <br />Wells in the Purgatoire River alluvium, (stations PAW -1 through PAW -9) were monitored <br />during the year. Stiff diagrams of wells PAW-I, PA W-2, PA W-8 and PA W-9 in the alluvium <br />• at New Elk are shown in Figure 3.2-2. This shows slight decreases over the _past six years in <br />salinity in alluvial ground water quality in response to decreased mining activity. <br />Historic Allen Mine waste materials appear to be the major contributors to saline alluvial ground <br />water quality in the vicinity of the New Elk Mine (PA W-3 and PA W-4) (Figure 3.2-3). Saline <br />conditions were anticipated in the PHC, and conductivities and TDS concentrations have been <br />far lower than expected. During March and April of 1985, 500 feet of the Middle Fork of the <br />Purgatoire River was diverted to the north to create additional room for the coal stockpile at the <br />New Elk Preparation Plant. The original channel was backfilled with mine waste, and two <br />alluvial wells, PA W-3 and PA W-4, were established to monitor water elevation and chemical <br />parameters. Water quality does not appear to deteriorate significantly due to the presence of <br />refuse in the backfill between PAW -3 and PAW -4 and measures of salinity, sodium, and sulfate <br />are far lower than predicted by the PHC. A threefold increase over historic values in iron <br />quantities in PAW -3 and PA W-4 may be due to the steel casing of the wells. No further <br />monitoring is required for PAW-3 and PAW-4. Data on PAW-8 (Table B-5) and the Stiff <br />Diagram indicate that seepage from the current refuse disposal area contains similar <br />concentrations of sodium, potassium and calcium to the pre-law mine waste (PAW-4). Leaching <br />may be a cause for lower values from the old materials. Data from PAW-9 down stream of <br />the New Elk facilities indicated dilution having an effect on concentrations. <br />• <br />16