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~ EFFLUENT MONITORING <br />The direct mine inflow, and discharges are discussed in the preceding section. In <br />addition to the direct discharges there are other effluent sites associated with the <br />operation. The underground discharge mixes with water from the adjacent surface mine <br />and then discharges through a point permitted by CYCC. The two sites associated with <br />the underground operations on Foidel Creek are: 1) Site 7, the discharge point from the <br />Waste Rock disposal pond, and 2) Site 84 (NPDES Site 005, Permit No. CO-0027154), <br />the discharge point for Pond D which receives the discharge from the waste rock pond <br />and the underground mine. During 1993 Site 7 discharged in response to spring runoff. <br />The outflow from the Fish Creek Tipple Sediment Pond (Pond E) is also monitored at <br />Site 62 (Site 001, NPDES Permit CO-0036684). Lastly, the Wastewater Treatment <br />Facility (WWTF) is monitored in accordance with NPDES Permit CO-0042161 (Outfall <br />002) <br />Flows <br />The historic discharge data for Pond D are presented on Figures 43 and 44. Discharges <br />from this site are effected by the mining activities and by seasonal variation. Prior to the <br />construction of the underground mine Pond D did not discharge continuously. Since the <br />opening of the underground mine the Pond has discharged almost continuously. This is <br />because of discharges of water from the underground mine and because of past discharges <br />of water from the waste rock site (Area 2 Pit). The level of the waste rock pond was <br />~• pumped down in early 1986 and the pond has discharged only once (May, 1988) between <br />January, 1986 and water year 1992. The discharge from Pond D was almost wholly <br />from discharge from the underground mine in 1992 and 1993. <br />The historic dischazge from FCT Pond E is plotted on Figure 49. It exhibits the same <br />seasonal pattern as the streams. The magnitude of the discharge was less than 5% of the <br />stream flow during the 1993 irrigation season. <br />Water Quality <br />Summaries of the water quality data for Sites 109 and 84 are presented on Tables 55 and <br />57 and on Figures 46 and 47. The data shows some typical seasonal variation: the water <br />quality improves during spring runoff. The discharge from Pond D closely follows the <br />water quality trends in the underground mine discharge, except during spring runoff when <br />the Pond D discharge has been diluted by surface runoff. However, the Pond D <br />discharge has a significantly lower iron level. <br />Summaries of the water quality data for Pond E (Station 62) are presented on Tables 59 <br />and 60 and on Figures 50 and 51. Figures 50 and 51 also include data from Springs 303- <br />0 and 303-1. No significant changes in the water quality were noted in the 1992 data. <br />C• -13- 6/10/94 1:23 pm <br />