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mine areas are not under perennial stream valleys, but under steep hillslopes. <br />There is a potential for the formation of acidic and toxic mine waters. The applicant has <br />submitted analyses of the coals, roof, and floor strata. The analyses of the roof and floor <br />materials performed by the Soils Laboratory of Colorado State University (Appendix 3-I <br />of the PAP) indicate that these units contain insufficient carbonate minerals to buffer the <br />iron sulfide (e.g., pyrite) contained in these strata. These analyses indicate that these <br />strata are acid-forming and potentially toxic. Ground water quality in overlying and <br />underlying aquifers may be degrading through vertical communication of strata caused <br />by faults and fractures. Degradation of water quality would result from prolonged <br />exposure of water to, host formations, fractured roof strata, and the exposed coal strata <br />(roof, floor, face, ribs, gob, etc). <br />The depletion of ground water from aquifers may affect the discharge of over and <br />underlying aquifers to springs and seeps, and to the hydrologic regime of the aquifer(s). <br />The applicant has identified (PAP) only two springs, SP-1 and SP-2, in the permit and <br />adjacent areas. Any groundwater denied these springs would be released from the mine <br />portals. Recharge of deep aquifers into the Piceance Creek structural basin might be <br />diminished (due to loss of hydraulic head above the mines), but pooled mine water <br />becomes a source of recharge to all hydraulically-connected seams of lower piezeometric <br />levels. Such is not likely at the North Thompson Creek Mines. Piezeometric surfaces of <br />ground water about the mined areas are higher than the mine portals. There is likely little, <br />if any, recharge into these aquifers from the flooded mines. If there is any, such water <br />would be carried to great depths and undoubtedly becomes quite high in dissolved solids. <br />This water would probably be unfit for most domestic and agricultural uses. Drilling of <br />wells to these depths would be uneconomical. There are no known registered (State <br />Engineer's Office) wells in the mine permit area. Owing to these factors, the mines are <br />not materially damaging the ground water of any water user through vertical migration of <br />degraded mine waters, or diminished recharge. <br />The coal processing wastes from the wash plant are combustible, acid-forming, and <br />potentially toxic. These processing wastes, along with coal mine waste, were placed in a <br />coal refuse pile. This pile was constructed to minimize exposure of wastes to air, surface <br />water, and ground water through (1) compaction of the waste in two-foot lifts, <br />(2) coverage of the refuse pile with non-toxic cover, (3) provision of permanent surface <br />diversion of surface runoff from undisturbed areas around the pile, and (4) benching and <br />sloping the pile such that erosion and infiltration of the final pile is minimized. It was <br />constructed over the relatively impermeable Mancos Shale Formation and not over any <br />aquifer or ground water flow path. With the above construction procedures, the effects of <br />the refuse pile on the quality of ground water should be minimized and should not cause <br />material damage to any ground water currently in use. A sedimentation pond was <br />constructed at the toe of the mine waste pile. The intention of this pond was to perform as <br />a sedimentation pond for surface runoff from the waste pile area, and to collect any spoil <br />spring discharge that might develop. This pond is now permitted for retention as a stock <br />pond, and may collect runoff from the watershed above or be filled by discharge from the <br />mine water treatment system upstream. The refuse pile pond was constructed on top of <br />North Thompson Creek C-1981-025 <br />Permit Renewal 05 <br />12 May 2009 <br />t8