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County, approximately 14 miles east of the Trapper Mine (U.S. Geological Survey <br /> Water Resources Investigations Report 92-4187). The model is described in the <br /> probable hydrologic consequences of the permit application (Section 4.8). <br /> Permit section 4.8.2.2 discusses potential drawdown impacts to adjacent wells. A <br /> groundwater monitoring program is discussed in section 4.8.3.2 of the permit. Point <br /> of compliance wells are in place. No drawdowns have been detected in aquifer <br /> wells within one mile from the permit boundary. Observed drawdowns have been <br /> temporary and are limited to the immediate vicinity of the pits. The operator <br /> expects such limited drawdowns to continue with future mining. <br /> The proposed mining operation will have little if any effects on the post-mining <br /> recharge capacity. The applicant's studies concluded that the recharge capacity of <br /> the reclaimed spoils will actually be slightly higher than the pre-mine condition. <br /> The mine activities should not impact any regional aquifers except the Third White <br /> Sandstone. Mined strata dip far beneath the Yampa River alluvial aquifer and <br /> communication between these strata and the alluvial aquifer is negligible. <br /> Surface Water Impacts <br /> Surface water flow and quality are monitored in the Flume System, Johnson Gulch, <br /> No Name Gulch,Ute Gulch, Pyeatt System, Oak, Gulch, Horse Gulch and Deal <br /> Gulch. Generally, Johnson,No Name East Pyeatt and Middle Flume gulches <br /> exhibit flow over the course of the year. The most noticeable change in surface <br /> water quality resulting from mining activities constitutes increased levels of total <br /> dissolved solids (TDS). TMI expects higher TDS in some surface water runoff <br /> for a few years after reclamation in an area. Increased TDS levels occur <br /> periodically when the contribution from precipitation and snowmelt is at a <br /> minimum(base flow conditions). <br /> Conductivity, TDS and major constituents tend to increase as the ground water <br /> contribution comprises a larger portion of flow. For a detailed analysis of surface <br /> water impacts,the 2019 Annual Hydrology Report, Section 2.5 of the permit <br /> presents the most current information. <br /> Leachate that may discharge from the toe of the Horse Gulch Fill probably will <br /> cause an increase in the dissolved solids content of natural stream flows in <br /> Horse Gulch. Rain or snowmelt provides most natural surface water flows in <br /> Horse Gulch. Although loading of Horse Gulch surface flows with dissolved <br /> solids from the fill would be a local impact, it does not rise to the level of <br /> material damage because use or potential use is not likely to be impaired.An <br /> exceedance of an instream standard in Horse Gulch is unlikely because leachate <br /> from the fill will probably be alkaline (like all other Trapper leachates) and is not <br /> likely to contain high concentrations of the inorganic or metals constituents for <br /> which there are numeric standards in Horse Gulch. <br /> Ground Water Impacts <br /> The 2019 Annual Hydrology Report AHR), Section 2.5 of the permit presents the <br /> most current information regarding springs and seeps at TMI. Table B-2 Appendix <br /> 18 <br />