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Site 109 are estimated to be a maximum of 9.8 using the analysis from 6 -Right as a worst case (Exhibit 51, <br />Table E51 -1). The TDS concentration, using the analyses from 6 -Right would be approximately 4,000 mg/L <br />and would be dominated by sodium and sulfate. <br />• As discussed in Rule 2.04.7, Ground Water Information, the most plausible explanation of increased calcium, <br />magnesium, sulfate, iron and TDS in mine discharge as compared to baseline formation water or leach test <br />results for coal, roof or floor materials, is that formation water in the vicinity of the portals has been impacted by <br />water emanating from upgradient mine spoils. Observations of mine inflows near the portals along with <br />elevated TDS, sulfate, calcium, magnesium and iron observed in the Wadge overburden well TW -1 down <br />gradient of surface mine spoils support this conclusion. The salinity of mine inflow water described in the May, <br />1985 Mine Inflow Survey, shows a conductivity plume downgradient from the surface mine spoils. As mining <br />operations progress further from this plume we can expect to see reductions in TDS levels and changes in ionic <br />composition with dilution of spoil water inflows. However, these decreases may be offset somewhat by the use <br />of water from Sites 114 and 109 in the underground system. <br />As of June 1999, some inflows to the underground mine have shown higher conductivities. The large inflow tc <br />the EMD at 6 Right has a conductivity of 4,660 µmhos /cm (Exhibit 51, Table E51 -1). Pumping of the Fish <br />Creek Borehole ceased in July 1996. At that time, the conductivity was approximately 4,420 µmhos /cm. When <br />pumping restarted in August 1999, the average conductivity had increased to 7,300 µmhos /cm (Exhibit 51, <br />Table E51 -5). However, inflows to the EMD (excluding 6- Right) measured during the 1997 and 1998 Mine <br />Inflow Surveys averaged 2,800 to 2,900 µmhos /cm. In addition, water from Pond A is the source of make -up <br />water for the underground mine equipment. It has a conductivity of 2,900 µmhos /cm. The ability to discharge <br />from the pit south of Pond D directly into Foidel Creek will provide greater control over the water quality in the <br />creek. The current system, Site 109 into Pond D via the pit, has a lag time associated with the discharge. After <br />both the pit and pond are full, it takes time for them to dewater after discharge from Site 109 is stopped. Once <br />the direct line to Foidel Creek is established, the discharge can be stopped instantaneously, thus assuring the <br />• discharge minimizes downstream impacts. The impacts from this discharge have been discussed previously, as <br />the water quality should not change due to this alternate system. <br />The 6RT water and the Fish Creek Dewatering Well discharge water are strongly sodium sulfate waters. The <br />Pond A water is calcium - magnesium sulfate water, with a conductivity averaging 2,900 µmhos /cm. Use of the <br />Pond A water helps balance the salt loading levels and sulfate of the ground water inflows to the mine, and <br />reduces SAR. <br />The TORT mine water can be classified as an alkaline sodium sulfate water, with elevated hardness and .Total <br />Dissolved Solids. Conductivity averages 3,400 µmhos /cm, pH ranges from 8.4 to 8.6, and TDS averages 3,300 <br />mg/L. Other parameters are generally in compliance with State water quality standards. SAR values in the <br />range of 6 to 7, coupled with elevated conductivities, do not pose a sodicity risk for the dominant soil types in <br />the area, based on the US Salinity Laboratory's Hanson diagram. <br />The potential impact of past mine discharge to Foidel Creek is addressed in WATBALP, a water quantity and <br />quality model of the Trout Creek drainage (Exhibit 32, Quantity and Quality Modeling Analyses of Surface - <br />Water Resources of the Trout Creek Basin). The modeling analysis was based on mine discharge projections in <br />Table D of Exhibit 33, Mine Water Control Plan. The comparison on Figure 4 -g, Ground Water Quality Data, <br />of this sample with average mine discharge characteristics in 1984, shows that the sample is more representative <br />of spoil discharges than actual mine discharges and thus constitutes a worse case estimate of mine discharge <br />quality. The assumed water quality characteristics of mine discharge were based upon a single sample that was <br />assumed to be representative of mine outflows (Exhibit 33, Mine Water Control Plan). Mine inflow projections <br />have changed since the original modeling. The streamflow numbers and baseline water quality numbers from <br />the model combined with new (April 1999) projected mine inflow and discharge projections (Exhibit 51, Tables <br />• E51 -12 to E51 -14) were used to project future impacts on the local drainages. <br />RN08 -05 2.05 -153 03/12/10 <br />