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• Hydrologic Data Intapmarion and Impact A,mr ent for Pamir Area and Adjacenr Arran <br /> MINE WATER MANAGEMENT AND sanitary waste water. Or, it can be withdrawn for <br /> IMPACT ASSESSMENT dust suppression in the mine, in which case it then <br /> becomes mine water. <br /> The discussion of the mine water system and <br /> hydrologic impact assessment is organized by the WECC's Mt. Gunnison pipeline water rights were <br /> four sources of water: out of priority during a portion of water year 1989 <br /> (from approximately 15 June through 30 Septem- <br /> • North Fork water ber). Average daily low flow in the North Fork <br /> • sanitary wastewater during water year 1989 was 54 cfs. The maximum <br /> • mine water, and withdrawal at the intake is 450 gpm with both <br /> • runoff from disturbed areas. pumps operating.This is less than 0.017 percent of <br /> the observed average daily low flow in the river <br /> Use and discharge of water from these sources is during the water year. <br /> studied for its potential to affect the North Fork. <br /> North Fork Water Sanitary Waste Water <br /> During water year 1982, the conditional right to The sanitary waste water treatment plant has been <br /> withdraw water from the North Fork was deemed operating since the fall of 1982. During water year <br /> absolute. When this water right is in priority,water 1989,discharge from the plant averaged 3208 gpd. <br /> can be pumped from the intake point to the This discharge is approximately 0.0092 percent of <br /> freshwater storage pond(s) within the surface the average daily low flow of 54 cfs observed in the <br /> facilities area. In average years, this water right is North Fork during the year. <br /> • expected to be out of priority from July to Septem- <br /> ber. In 1977, it would have been out of priority Discharge monitoring results from the waste water <br /> from April to September. In water year 1986, treatment plant, conducted under NPDES Permit <br /> WECC's Mt. Gunnison Pipeline water right met No. CO-0038776,are included in Appendix J. The <br /> quadrennial diligence for the conditional portion. results of the analyses suggest the waste water <br /> Accordingly, an additional portion was deemed discharge has no measurable effect on water <br /> absolute by the Division 4 Water Court. That quality in the North Fork Gunnison River. <br /> decision brought the absolute portion to 0.88 cis. <br /> Mine Water <br /> The 10-acre-foot capacity pond provides for water <br /> storage during the term of permit; two ponds are <br /> anticipated forsubsequent permit terms.Watercan Mine inflows during water year 1989 were small. <br /> a The total mine water inflow was 9.3 acre feet <br /> also be stored in Sediment Ponds MB-I, MB-2, <br /> and MB-3 under a separate decree. Storage is during the year.The total water exiting the mine is <br /> usually limited to the maximum sediment level estimated to have been 13.2 acre feet. <br /> elevation. Transfer to FW-1 is possible as outlined <br /> in the M & R Plan. Average withdrawals are not The quality of mine water is considered good and <br /> expected to exceed 50,000 gpd during the term of offers no problem for treatment and discharge. <br /> permit and are likely to be on the order of 45,000 Mine water was primarily discharged from the <br /> gpd, depending on production levels and require- No. 2 Portal. No discharges occurred from Syl- <br /> ments. During 1989 average withdrawal was venter Gulch. <br /> 82.1 gpd for 250 working days. <br /> Mine water inflow for water year 1990 is expected <br /> Water from the freshwater pond(s) is used in two to be similar to that experienced during water year <br /> ways. It can be treated to meet potable and sani- 1989. Mine water is expected to have water quality <br /> tary water requirements, used, and then treated as characteristics similar to that reported in Table 5. <br /> • <br /> 13 <br />