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• available for that specific date), other sources of flow constituting 19.38 <br />of the total flow measured at TR-b was required containing TDS levels of <br />approximately 3,690 mg/1. The sources of flow for the unaccounted volume <br />came from two sources: springs or seeps and surface runoff. Several <br />springs and seeps which discharge from pre-law spoils at the mine are <br />monitored and contain TDS values greater than 9,000 mg/1. It is <br />interesting to note that the largest increase in TDS concentrations in <br />Trout Creek over the period of record occurred on that date between water <br />quality monitoring sites TR-A and TR-B with a difference of 789 mg/1. TR-B <br />is located approximately half-way between discharge points 007 and 009. <br />This occurrence suggests that springs or seeps provided a substantial <br />portion of the unaccounted for volume at TR-b. However, in April 1996, <br />after an above average year for snowfall, above average temperatures <br />occurred for an extended period of time which resulted in a quicker than <br />normal snowmelt giving rise to heavy runoff from areas in the vicinity of <br />the mine. This is substantiated by a review of the amount of total flow at <br />TR-b contributed by the discharge points. The average percentage of flow <br />to Trout Creek contributed during April by the discharge points is 13.3$. <br />On April 16, 1996, the discharge points contributed 218 of the flow or <br />approximately 160$ of their normal April contribution. Most notably was <br />• the increase in contribution from discharge point 009 (Moffat pond). The <br />average contribution from discharge point 009 constitutes 1. 9$ of Trout <br />Creek flow, but on April 16, its contribution was 9.88 of Trout Creek flow <br />or 250$ its average contribution for April. The above normal contribution <br />from this discharge point provides some insight into the 1990 mg/1 observed <br />at TR-D. <br />The final pit in the Moffat area had only been partially backfilled <br />by April 1996. As such, the final designed drainage had not been <br />constructed nor had the area been topsoiled or contour furrowed. The <br />runoff which occurred was presumably heavily laden with TDS from contact <br />with the exposed overburden. The presumption is substantiated when <br />reviewing the increase in TDS levels between monitoring station TR-H and <br />TR-C (TR-C is located immediately downstream of discharge point 009). <br />Trout Creek flow at TR-C had a TDS level of 1970 mg/1 which equates to an <br />additional increase of 5'13 mg/1 in TDS to Trout Creek flow when compared to <br />flow measured at TR-B. This represents a 2778 increase over the normal <br />April increase between these two monitoring stations. From tF.ese TDS <br />observations, it is not unreasonable to conclude that although about 208 of <br />the flow volume is unaccounted for using the mass balance equation, usage <br />• of the average April TDS concentrations for the CDPS 009 in the equation <br />probably resulted in an over estimation of the TDS concentration contained <br />Renewal 3 2.SA-8 Sune 13,1997 <br />