Laserfiche WebLink
+vaer discharges typically contain elevated concentrations of dissolved solids. Generally, the volume of runoff <br />acid potential for significant leaching are at maximum levels during peak-flow periods. However, it is during these <br />• same periods that increased streamflow volumes result in the greatest dilution. <br />Increased concentrations of dissolved solids are commonly observed immediately adjacent to the discharge point. <br />Decreases in dissolved solids concentrations occur downstream from the mine as the discharge mixes with natural <br />drainage and dilution and dispersion occur. Four primary locations on Foidel Creek are monitored in the vicinity <br />of Eckman Park and Mine No. I. Station 14 is upgradient of mining activity; USGS Station 09243800 (Station <br />800) is a short distance downstream from Station 14 and is also downstream from the discharge point of Pond A, <br />.alticlt captures drainage from a large number of spoil springs; Station 8, which is downstream from Mine No. I <br />and the Foidel Creek Mine; and USGS Station 09243900 (Station 900), which is located farther downstream but <br />above the confluence of Foidel and Middle Creeks. <br />Dissolved solid coitcen[rations for background conditions at Station 14 have averaged 614 mg/I for the period from <br />1979 to 1996. Station 800, downstream from the discharge of Pond A, has averaged 2,465 mg/I for the period <br />from 1986 to 1496. Station 8, located farther downstream, has an average of 1,808 mg/1 for the period from 1979 <br />to 1996. Station 900, on Foidel Creek downstream of Station 8, has averaged 2,342 mg/I for the period from 1486 <br />• to 1996 (AHR 1996). The difference in dissolved solids concentrations from the upstream to downstream stations <br />is attributable primarily to spoil spring discharges related to surface mining. <br />Tlie greatest increases in dissolved solids concentrations in receiving streams is during the low-flow periods of the <br />year. Foidel Creek has several months of very low to zero natural flow. During tftese periods, discharge of spoils <br />+vater to the creek will result in water quality in the creek which will approach that of the spoils water. The quality <br />of typical spoil water is characterized by TDS values in the order of 4,000 mg/I and is dominated by calcium, <br />magnesium, and sulfate ions. An independent evaluation of hydrologic conditions in backfilled areas of the <br />Eckman Park operation was submitted to the CMLRD on April 30, 1986 in the form of a report titled, Backfil( <br />Hydrologic Eva(unrion, Eckman Park Mines. Calculations performed as part of this study indicated that <br />discharges from spoils during low-flow periods were expected to be on the order of 0.0435 gpm per acre of spoil. <br />The Eckman Park operation was projected to eventually have about 4,000 acres of disturbed area. Consequently, <br />the discharges from the backfill after final reclamation were expected to be on the order of 180 gpm, with <br />maximum values of up to 300 gpm during these periods. Higher discharges of 3,000-4,5000 gpm were expected <br />• <br />1996 Permit Ren. Permit Renewal 780-144-25 Revised 3/18(97 <br />