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<br /> <br />Requirement <br />Require- <br />ment <br />citation Require- <br />ment <br />complied <br />with ? (yes <br />/ no <br /> <br />Comment <br /> There is no known impairment of water use caused by the mine <br /> outside the permit area. <br /> North Fork Gunnison River. The West Elk Mine discharges <br /> surface water into the North Fork at two mine water discharge <br /> points (outfalls 017A and 018A) and at five sediment control <br /> ponds ( MB-3, MB-1, MB-2R, RPE,and SG-1). The West Elk <br /> Mine appeared to not significantly degrade water in the North <br /> Fork in 2004 based on a comparison of samples taken from the <br /> North Fork immediately upstream from the mine (page C-1 of <br /> 2004 AHR) and the North Fork immediately downstream from <br /> the mine (page C-2 of 2004 AHR). TDS in North Fork water <br /> increased where the stream passes the mine, rising in September <br /> from 170 mg/1 above the mine to 242 mg/l below the mine, but <br /> the TDS in the North Fork remained well below a 700 mg/l <br /> threshold that may be considered a level of concern for irrigation <br /> water use. <br /> Natural springs - Monitoring showed reduced flows from some <br /> springs compared to previous years. Spring hydrographs <br /> indicate seasonal precipitation fluctuations are a more likely <br /> cause of the reduced flows than mining. <br />U. Prevention of <br />material Bedrock ground water - Data from the down-gradient bedrock <br />damage to the CDMG monitoring wells (03-11-1 and 01-11-1) indicate there have been <br />hydrologic regulation yes no significant impacts to bedrock ground water outside the <br />balance 4.05.1(1) <br />permit area. High TDS in one monitoring well appears <br />outside the anomalous and warrants further discussion. TDS in B seam <br />permit area monitoring well SOM-129H increased from 2970 mg/1 to 8400 <br /> mg/l in 2002, and has remained around 8400 mg/l. This <br /> increase appears to indicate water has flowed from the Rollins <br /> Sandstone into the well, based on the chemistry similar to the <br /> Rollins (a sodium chlorideibicarbonate water type and the <br /> relatively high concentration). The Rollins likely is in hydraulic <br /> communication with the B seam where the intervening sequence <br /> is relatively thin. The change in water quality in the SOM-129H <br /> well does not threaten the water quality in bedrock units due to <br /> the low permeability of those units. (Discharge of this high <br /> TDS water to the alluvium or surface water of the North Fork <br /> through the B seam subcrop in the alluvium does not threaten <br /> alluvial water quality because such a discharge is not an increase <br /> above what would naturally discharge from the subcrop of the <br /> Rollins in the North Fork alluvium.) <br /> Alluvial ground water - A negative impact to North Fork <br /> alluvial water from mining is unlikely as explained in the <br /> preceding discussion of the Basic Standards for Ground Water. <br />Page 6