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inflows to the mine resembles that of the spoil water. Mine inflow studies have shown the seeps generally have a conductivity of 3,000 µmhos /cm and are dominated by calcium, magnesium, and sulfate ions. A sample from the major inflow in the 6 -Right Entry (Exhibit 49, Table E49 -1) has a similar mixed cation/anion water type, with elevated sodium and chloride levels, and a conductivity of 4,660 Amhos /cm. The increased sodium and chloride levels are probably due to some seepage from marine shales overlying the Wadge Overburden, and from ion exchange of calcium and magnesium for sodium (see Exhibit 38). While the spoil water is typically a calcium /magnesium — sulfate water (see annual Hydrologic Reports, the 1998 Site 115 water is a sodium — sulfate water, Exhibit 49, Table E49 -1)_ This change in water type is probably due to ion exchange mechanisms and leaching from the overlying marine shales. Overall, flooding of rubblized areas of the mine under oxidizing conditions will tend to result in a water quality with higher sodium concentrations than present backfill water quality, but with a conductivity of 4,000 to 7,500 µmhos /cm. The water quality resulting from continued solute dissolution or changes in existing water chemistry under reduced conditions is difficult to predict using standard techniques such as leaching tests. Geochemical modeling was originally used to provide a better understanding of the mineral /water relationships that control the equilibrium chemistry of water in the flooded mine workings. The model used is a code developed by the U.S. Geological Survey referred to as WATEQF (Plummer, L.N., B.F. Jones and H.H. Truesdell, 1975, Water Resources Investigations 76 -13). The x -ray analysis reports and the Emerson Spectrograph analysis provided in Exhibit 36, Geochemical Analysis, indicate that for both roof and floor materials, quartz is the dominant mineral, with significant concentrations of iron, aluminum, silicate hydroxides, saponite and clays. The WATEQF model of mine water equilibrium, with respect to the water analysis from the flooded mine section provided in Exhibit 37, Water Test of Flooded Mine Working, indicates that the water is nearly at equilibrium with respect to quartz and calcite, and super - saturated with respect to Fe(OH)3 (Aq). An attempt to assess the mineral equilibrium of the water analysis in a condition of zero free - oxygen failed because the model would not converge_ Thus, the chemical composition of the sample would not be expected to remain the same under reducing conditions. We would expect that pH and Eh conditions would revert to premining conditions because of buffering due to calcite. Elements such as iron, manganese and other trace metals whose soluble concentrations are controlled by pH and Eli conditions, would also revert to premining concentrations. Sulfate reduction would not be expected because of limited organic matter to drive the reaction. Therefore, we expect that the water quality of the flooded workings under reduced conditions is largely controlled by the quality of the water, which exists prior to the onset of reducing conditions. Over most of the proposed mining area this will tend to be represented by the predicted water quality for areas where caving will occur before flooding. This applies for the materials tested. Based upon the water quality that has developed in actual flooded areas it appears that overlying marine shales are contributing sodium sulfate and some iron and manganese. However, the other conclusions of the water quality modeling appear to be correct. In order to quantify how solute leaching of the caved overburden material might change over time, the results of a leaching study performed by CYCC on overburden material collected from the adjacent Eckman Park Mine, was examined. The study was performed by H.R. Gardner of the USDA, and is included as Exhibit 38, Estimation of Salt Load from Spoil Material Based on Drill Samples. Seventeen Wadge overburden samples were collected from four holes approximately one mile apart. These holes were drilled into the same overburden strata as that found in the Foidel Creek Mine Pen-nit Area. Various size fractions were screened from the overburden samples and leached separately. Composite samples were also leach tested. The results of the study indicated that the <0.5mm size fraction represents 90 percent of all spoil fragments and contributes virtually all of the salts. Each of the 17 samples was placed in a sealed leach cylinder 9 em high and 10.5 cm in diameter. Samples were packed to a bulk density of 1.45 gm /cc. A water source was connected to the top of each cylinder such that a constant head was maintained and the flow regulated to about 50mm per day. The pH of the water was maintained at a constant value of 7.1. When the leachate began to flow from the bottom of each cylinder, the instantaneous electrical conductivity (EC} and the cumulative weight of leachate were measured and recorded on about 20 m] fractions. When the volume of the leachate from the sample exceeded the volume of the sample, the water source was turned off and the measurements stopped. TR13 -83 2.05 -143 11/03/14