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I • 3.1.3 Groundwater <br />As might be anticipated from no noticeable impact from dewatering activities conducted in the 1980's, <br />there has been no noticeable impact on groundwater hydrology from the gradual flooding of the New <br />Elk Mine. The appazent low vertical transmissivity and integrity of the surrounding rocks might inhibit <br />any effect of free water on the rechazge of the overburden. The depths to which recovery might be <br />taking place are probably too far removed from the ground surface to manifest any impacts at the <br />surface (seeps and springs) at this time. <br />3.1.4 Piezometers <br />Refuse Disposal Area piezometer readings are included in this report (Table B-10). TH-201, on the first <br />bench, and TH-202 and TH-203 on the second and third benches had minimal water throughout the <br />year. Embankment stability, the primary purpose of the piezometers, is discussed within the quarterly <br />waste pile certifications. <br />3.2 WATER QUALITY <br />• 3.2.1 Springs and Seeps <br />There is no evidence that mining activities have affected the water quality of springs or seeps, nor are <br />such changes anticipated. Additional discussion of springs and seeps is contained in Appendiz C. <br />3.2.2 Surface Water (Streams and Rivers, and Ponds and Direct Discharges) <br />Results of water monitoring by the USGS indicate a change in water quality between Stonewall, a <br />location above the New Elk Mine, and Madrid, a location below the Golden Eagle Mine. These changes <br />are probably a result of natural lowering of water purity due to geologic parameters, geography <br />(Stonewall is located on the Middle Fork of the Purgatoire River as is the New Elk Mine, the Golden <br />Eagle Mine is located below the confluence of the Middle Fork, and Madrid is located yet below the <br />confluence of the South Fork above Trinidad Reservoir), contributions from the New Elk and other land <br />uses (point and area sources water quality change) between the two stations. The Stonewall site <br />(07124050) acquires water from a 52.1 squaze mile area and the Madrid site (07124200) measures <br />water from a 505 square mile watershed. <br />There is a natural deterioration of water quality as the stream flows out of the igneous terrains, through <br />sodic sediments, and into mazine sediments. There is a relationship between Purgatoire River water <br />quality and flow quantities. From historic (USGS) infoanation the minimum flow of the Purgatoire <br />River at Stonewall, above the two mine sites, is 4 cubic feet per second (cfs). The conductivity was <br />. deduced to be 345 umhoslcm at a flow of 4 cfs~ The minimum flow of the Purgatoire River at Madrid, <br />below the mine site, is 10 cfs and the average conductivity is 125 umhos/cm. In general, conductivity <br />values are higher at lower levels of flow (suggesting dilution during periods of snow melt or rain). <br />15 <br />