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• years. The TDS should begin to drop before this time. Once the pyrite is fully oxidized and other salts are flushed out, the spoil water quality should approach the irrigation water quality, possibly dropping to 300 ppm TDS. Impacts To Receiving Waters Since these spoil springs were never present in the pre-mine landscape, their impact to the quality .of the receiving waters must be addressed. As described earlier, a spoil spring will develop on fhe northwestern part of the New Horizon #2 mine area where the single lowest point occurs along the lowwall crest, which is expected to be coordinate N = 602,530, E = 1,112,350 @ elevation 5580'. The sample point Spoil Spring 1 represents the spoil water discharge from the New Horizon #1 Mine and has has been monitored since 1987. Its location is shown on Ma3p 2.04.7-1-A. Spoil Spring 1 discharges into Tuttle Draw a short distance downstream. The predicted Spoil Spring 2 from the New Horizon #2 Mine will discharge into the minor tributary to Tuttle Draw, located immediately south of the western edge of the mine area. This tributary enters Tuttle Draw less than 1 mile downstream. Tuttle Draw enters the San Miguel River approxim~3tely 2 miles to the southwest. Sample site SW-N108 is located in Calamity Draw immediately upstream of any influence from the mine. Sample site Sw-N1 is located in Tuttle Draw immediately upstream of any influence from the • mine. Sample data over the past 12 years from these sites has shown that the TDS of the waters drops significantly when irrigation is active in the area. Therefore, the impacts to the receiving waters will be studied for both cases, with and without irrigation. The irrigation case corresponds to the September/October time period when flows are fairly low in the San Miguel River. The non- irrigation period corresponds to March/April when flows in the San Miguel are usually at peak. This is shown on Table 2.05.6(3)-4. • REVISED MARCH 2006 2.05.6(3)-37