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<br />' related to electrical conductivity by linear regression. Volume of leachate <br />' produced was related to time by computing the travel velocity of water through <br />the spoils. The results of these experiments are shown in Figure 17, Predicted <br />Leach ate Concentration, Energy Mine No. 1. Note that the predicted average TDS <br />' concentration over 100 years is 2483 mg/1. <br />' In 1983, similar column leach tests were performed on underground <br />development waste to demonstrate that ground water quality will not be degraded <br />' by leaching of waste rock. The test procedures and results are presented in <br />Exhibit 24, Column Leach Study of Mine Waste Material. The trend of leachate <br />' production from roof, floor and coal waste was very similar to that of mixed <br />overburden spoil described above. At the conclusion of the column leaching <br />' procedure, the leachate water was analysed for constituents listed for ground <br />water in "Guidelines for the Collection of Baseline Water quality and Overburden <br />Geochemistry Data" (CMLRD, 1982). <br />1 <br />The analyses of leachate water, shown in Exhibit 24, Column Leach Study of <br />' Mine Waste Material, were compared to existing pit water chemistry shown in <br />Table 54, Energy Mine No. 1 Pit Water Quality. The average concentrations of <br />' major cations and anions were converted to milli-equivalents per liter and <br />plotted on a piper diagram, shown in Figure 18, Leach ate Chemistry, Energy Mine <br />' No. 1. In addition, the average concentrations of major ions in ground water <br /> adjacent to the Energy Mine No. 1 pit were plotted. The piper diagram shows <br /> similar water chemistry for leachate from underground mine waste and mixed <br />' overburden spoil. The leachate water from both sources shows a change in water <br /> chemistry from that of ground water in the adjacent overburden aquifer; this <br />' change is from a predominately sodium-sulfate type in the overburden aquifer to <br /> a calcium-sulfate type in leachate water. The predicted level of leachate <br />' concentration, taken as an average over 100 years is approximately 2500 mg/1; <br />the average concentration of TDS in the adjacent overburden aquifer is <br />' approximately 650 mg/1. However, the change in water chemistry and the absolute <br />concentrations of individual ions in leachate water are compatible with the <br />' post-mining land use for Energy Mine No. 1 and the Foidel Creek Mine, which is <br />cropland and pastureland. <br />4 <br />