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Annand Draw Following the occurrence of spoil springs at the Yoast Mine, the total dissolved solid (TDS) content of surface water in Annand Draw is projected to increase from 950 to 3938 mg/l. These values, and all TDS values discussed below are mean TDS values during the irrigation season, which was considered to last from June l through September 30. No use is presently made of this water before it flows into Grassy Creek. Due to the minimal flows in Annand Draw, it is reasonable to assume that no future use of this water will be made, other than livestock watering. Therefore, this increase in salinity will not result in material damage. Grassy Creek An evaluation of the water quality impacts of the Yoast Mine on Grassy Creek in the permit application projects no increase in TDS in Grassy Creek downstream from the mine. This conclusion is drawn by estimating the quality of Grassy Creek water after salt loading from Yoast Mine spoil springs, and comparing that projected water quality to current water quality in Grassy Creek downstream from the Yoast permit area. Water in lower Grassy Creek currently has an average TDS of 2584 mil, partially due to the influence of spoil spring discharges from the Seneca II Mine. Seneca Coal Company predicts that lower Grassy Creek TDS will be 2177 mg/l after addition of Yoast spoil springs. Thus, Seneca Coal Company concludes that TDS in Grassy Creek will not increase as a result of Yoast Mine operations. Using Seneca Coa] Company's assumptions about spoil spring development at the Yoast mine, and the existing baseline water quality data for lower Grassy Creek, the Division estimated the TDS of lower Grassy Creek after establishment of Yoast spoil springs will increase by approximately five percent. Because the quantity and quality of Grassy Creek water is marginal or unsuitable for use as domestic or imgation water, this projected increase in salinity will not affect any uses of Grassy Creek water. The only current use of Grassy Creek water (livestock watering) will not be impaired by the projected increase in salinity. Sage Creek Life-of-mine plans for the Yoast Mine anticipate coal extraction within the Sage Creek watershed during the second and third permit terms. Preliminary estimates by Seneca Coal Company indicate that TDS concentrations in Sage Creek downstream from Yoast spoil springs may increase from 641 to 2l 18 mg/I. Yoost Mme 78 Much 6, 2001