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The Probable Hydrologic Consequences(PHC)section of <br /> Trapper's mining and reclamation permit(Section 4.8.3), <br /> discusses the possibility of a high-TDS plume of coal spoil <br /> leachate forming in the Third White Sandstone downgradient from <br /> the Trapper Mine in Section 29-T6N-90W. Such a plume would <br /> not be expected to form until several years,possibly decades, after <br /> the pit is reclaimed in the adjoining Section 32. Compared to pre- <br /> mining ground water conditions, such a plume would have <br /> elevated dissolved solids,which could possibly impair the use of <br /> ground water in the Third White Sandstone. <br /> Spoil leachate could also invade the alluvium in Flume Gulch by <br /> seeping down into the subsurface from spoil springs flowing on <br /> T. Prevention of the land surface in the gulch. <br /> adverse impacts CDRMS The Third White Sandstone is monitored in the area of the <br /> to ground water regulation possible plume in well GP-9, and the alluvium is monitored with <br /> systems outside 4.05.11 the Coy well. Monitoring data from both wells indicate that a <br /> the permit area plume has not reached these wells. Well GC-2 completed in the <br /> 3,d White Sandstone up-gradient of well GP-9 has shown evidence <br /> of the predicted plume with elevated TDS levels and sulfate levels <br /> that initially increased over time but have since stabilized and <br /> appear to be decreasing. Other wells down-gradient of spoil <br /> backfill such as well P-8 completed in the Third White Sandstone <br /> and well GD-2 completed in the R aquifer are also showing signs <br /> of elevated TDS/Sulfate likely leaching from backfilled spoils <br /> (OK). TDS Levels in well P-8 appear to have stabilized after a <br /> large increase in 1995 but are remaining above baseline levels. <br /> TDS/Sulfate levels in the alluvial wells have fluctuated <br /> significantly over the years but appear to be within natural levels <br /> according to the report. <br /> Page 5 <br />