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,, <br />areas, which will likely alter the backfill hydraulic characteristics quite <br />• radically from that found in a dragline operation. We cannot at this time <br />make a more accurate prediction as to the resulting discharge from the <br />backfilled areas until we begin to collect field data. We .expect that the <br />compacted zones would dela the to eak flow after s_ r~in~s_no~wme'rt <br />p ~ extend the period of high flows. The total flow volume shouted <br />rPm3in ~. <br />Prediction of Consequences of Spoils Water Discharge to Downstream Water Quality <br />A salt load analysis is applicable to the East Fork of the <br />Williams Fork River. The groundwater discharge enters Hayden Gulch, which <br />ultimately flows south and enters the East Fork of the Williams Fork River. <br />Table 6, "Condensed Summary of Surface Water Quality Information <br />For East Fork of Williams Fork Near Pagoda, Colorado at USFS Gage <br />092400," found in Section 2.04.7, Hydrology Description of the HG Coal <br />Company Permit, contains the following information: <br />~ "1'~e~ Parameters i 1~~ <br />7D41o l7 c{3 Stream FTw (inst. CFS) 93.82 <br />Conductivity (micromhos) 210.0 <br />~~:~r, ri,n Z4.1 C'FS PH 8.38 <br />„`~~ ~ ~~ Z3v Total Dissolved Solids (Mg/L.) 117.0 <br />,ias(br~) 04 -ism Utilizing the following equation,. the concentration of additional <br />. salt loading entering the Williams Fork is estimated. The projected <br />increase in salt concentration in the Williams Fork are for average flaw <br />conditions based on the worst case assumption that all of the flow in <br />Hayden Gulch is from the mine related discharge. <br />Cwfd = (Fhg)(Chg) +(Fwfu)(Cwfu) <br />Fhg + Fwfu <br />WHERE: Cwfd = Concentration of East Fork of Williams Fork <br />Fhg = Flow rate of Hayden Gulch from mine discharge <br />Fwfu = Flow rate of the East Fork of Williams Fork upstream <br />Chg = Concentration of Hayden Gulch mine discharges <br />Cwfu = Concentration of East Fork of Williams Fork upstream <br />THEREFORE: <br />Cwfd = (•114 CFS)(2800 mg/1) + (93.82 CFS)(117 mq/1) <br />. CFS + 93.83 <br />woi;r Case- ~~1 C FC of u~~na F/L <br />~~ 5 <br />~~.~~~ <br />~ ~~~.~ <br />Cwfd = 120.26 mg/1 <br />~13i~~ <br />Revised November, 1986 <br />n-''. <br />n~ <br />