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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 2016 Annual Hydrology Report, Section 2.5 of the permit, presents the most <br />current information regarding springs and seeps at TMI. Table B-2 Appendix B <br />presents the 2007 -2016 water quality data for springs and seeps at Trapper Mine. <br />Flow from the springs and seeps is shown on Table B-2. The table indicates that <br />only the East Pyeatt and East Pyeatt South springs discharged during 2016 at rates <br />that exceeded 5 gallons per minute, the minimum for collecting a sample. <br />The NPDES permit #CO -0032115 issued by the Colorado Department of Public <br />Health and Environment describes water quality monitoring requirements. For mine <br />water discharges, the permit lists six outfalls for monitoring. Currently some of the <br />listed outfalls encompass Phase III bond released areas and therefore are no longer <br />subject to DRMS monitoring requirements. <br />IV. Topsoil <br />Soil information can be found in Section 2.6, Volume II and Section 4.9, Vol. IV. <br />The Division previously granted a variance from topsoil removal in accordance with <br />Rule 4.06.2(2)(a). Specific areas which the operator will not strip topsoil are limited to <br />rocky areas which occur over limited areas throughout the mine area. Each area <br />approved is handled separately as a minor revision to the permit and no general variance <br />is currently approved. <br />V. Sealing of Drilled Holes and Underground Openings <br />Sealing of wells, holes, and other openings is discussed in permit Section 3.3, Vol. III. <br />The Division requires each hole, well, or other underground opening be capped, sealed, <br />backfilledor otherwise managed as per Rule 4.07.3. <br />VI. Use of Explosives <br />The blasting plan, as well as other items related to blasting, are discussed in permit <br />Section 3.4, Vol. III. <br />The Division approved blasting at times other than those described in the blasting <br />19 <br />