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• COhih1ENT: <br />c. The Division requested a discussion of low flow conditions in the <br />worst case analysis. Instead, mean monthly flows and TDS <br />concentrations were used for each month of the year for each year <br />during the previous permit term. A reasonable estimate of expected <br />minimum flow at SW-S2-1 should be used in the worst case analysis. <br />RESPONSE: <br />Refer to the response to the first PHC comment immediately following <br />Comment 10 regarding the assumptions which have been incorporated into <br />the PHC analysis. In these assumptions, the criteria by which flow <br />conditions and TDS concentrations which are used in the impact analysis <br />are established. <br />CCNMENT: <br />d. SJadge impoundment effluent TDS concentrations were used in the <br />+:~orst case analysis. A conservative estimate cf ~,~orst case <br />conditions would be to use maximum values of TDS from ground water <br />monitoring of spoils in the Grassy Creek basin. <br />RESPOt1SE: <br />Refer io the response to the first FHC comment regarding the assumptions <br />which have been incorporated into the PHC analysis. <br />COMMENT: <br />e. The unit-area contribution of spoils aquifer inflow developed from <br />the Fish Creek basin (Spoils Spring ^;o. I) tray be useful in <br />determining the quantity of spoils inflow to Grassy Creek. A value <br />of cfs/acre could be estimated based on ~neasured flow and area of <br />disturbance contributing to the spring flow. <br />RESPOPISE: <br />Based on discussion between PCC and MLRD hydrologists on September 30, <br />I°E6 of the data presented in Figure i-31, the approach presented in <br />• this comment is not considered to be applicable to the Seneca II Mine <br />and, as a result, has not been used in the PHC analysis. <br />~3 <br />