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-5- <br />• waste. All of these piezometers were installed subsequent to placement <br />of waste on the site; therefore, they cannot be directly correlated <br />to pre-existent conditions. The water level in these piezometers was <br />highest during mid-winter, but had little variation overall. All of <br />the piezometers monitored for field information showed a slightly <br />acidic pN. This is in sharp contrast to the normal mine water, which <br />has a pH around 8.4. The pH of these refuse piezometers is similar <br />to the old mine water, and may have a similar source in roof rock not <br />ordinarily exposed to water. The conductivity varies differently with <br />each well. R-1 remained constant (with the exception of surface water <br />leakage). R-3 and R-6 increased during the year, and R-4 decreased <br />during the year. The conductivity again shows similarities to the <br />old mine water in that it is higher than E-seam aquifer water. <br />The sediment pond piezometers consist of three on the outer toe <br />of the sediment pond and one north of the pond. The three toe piezo- <br />meters were installed to monitor the stability of the dam. The P-4 <br />was a nearby drill hole for the D-seam portal investigation. The toe <br />piezometers appear to exhibit a seasonal variation with their high <br />levels in May and their low levels in February, but these variations <br />are more likely to be affected by the mine dewatering. The average <br />water elevation in these piezometers is approximately the elevation of <br />the bottom of the cutoff trench for the dam. P-4 remained relatively <br />constant at a level below the average water level in the pond. <br /> <br />