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to 23. 0 cfs (Table 3) . The Animas River was monitored only in the <br /> fa' l due to changes in personnel and equipment failures . Sampling <br /> could not be conducted before the annual snowmelt began. Only low <br /> flow data are sought from the Animas River in order to identify <br /> tailings pond impacts on stream water quality. A discharge of 75 . 0 <br /> cfs upstream (AR-3 . 5 ) , and 81 . 0 cfs downstream (A:.-4) were recorded <br /> during sampling in September 1987 , indicating a net gain of six cfs <br /> through the tailings pond reach. Lateral inputs include Boulder <br /> Creek and several small channels which are predominately dry during <br /> Sep tember. <br /> An opportunistic sample was obtained from Eureka Gulch above the <br /> :eery Tunnel in October 1987 at a flow rate of . 06 cfs . Eureka Gulch <br /> is an intermittent stream, freezing over in winter. This sample was <br /> ob-ained from the future routine monitoring site ciscussed in <br /> Amendment No. 3 . <br /> Quality Cement Creek waters are a calcium sulfate type above <br /> and below the mine discharge point (sites CC-1 and CC--2, Table 3 ) . <br /> These waters carry some carbonate (not illustrated in Table 3 ) as <br /> would be suspected by the dominate calcium cation. Dissolution of <br /> calcite vein mineralization is buffering the portal discharge waters <br /> and natural ground water discharge to Cement Creek. <br /> Mine discharges are adjusting the pH of Cement Creek upwards to <br /> near neutrality. Though upstream Cement Creek waters (CC-1 ) are acid <br /> (pH = 3 . 5 to 4 . 5 ) the acidity is very low and the pH is easily <br /> adjusted upwards . Suspended sediment transport is very low during <br /> most of the year; and it is generally an order of magnitude below the <br /> -11- <br />