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<br /> <br />Requirement <br />Requirement <br /> <br />citation Require- <br />ment <br />complied <br />With ? (yes <br />/no <br /> <br />Comment <br />F. Antidegradation CWCC <br /> <br />Rule for Surface regulations The Edna Mine is not subject to the Antidegradation Rule because the receiving waters, <br /> <br />Water 3.1.9(2) and yes Segment 13c in Region 12 of the Yampa River basin, are designated "Use-Protected". <br /> 3.3.0. <br /> Ground water in the Trout Creek alluvium is the only ground water that could be adversely <br /> affected by the Edna Mine. (Bedrock aquifers that abut spoil backfil] probably are too <br /> impermeable to transmit leachate.) Edna monitors alluvial water quality in two <br /> downstream alluvial wells, TR-3 and TR-4. Data from both wells indicate mining has not <br /> caused adverse impacts to the quality of ground water at these locations. The mine is in <br /> compliance with the Basic Standards for Ground Water at these two locations, should a <br /> point of compliance be established at either location. <br /> Hydrogeology of West Ridge area inferred from cross-sections and density logs in <br /> Section 1.1 ofthe permit: <br />G. Basic Standards Geometry ojsaturated Zone in spoil that feeds Spoil Spring 1 -Cross-section G-G' <br />(Interim C WQCC shows the maximum thickness of the saturated zone in the spoil aquifer occurs near <br />Narrative regulation yes well PM-7 where it is about 50 ft. thick (assuming: the base of the spoil aquifer is at <br />Standard) for 41.S.C.6 the base of the Wadge coal, former well PM-7 is the lowest elevation of the Wadge <br />Ground Water where it was mined, and the top the saturated zone is the elevation of Spoil Spring 1 <br /> (7137ft.). The minimum thickness is near fonner hole B.H. 24-S-73 (in cross-section <br /> F-F') where it is about 25 ft. thick. G-G' and F-F' indicate the saturated zone feeding <br /> Spoil Spring Icovers about 400 acres in Sections 13 and 14, 4N-86W. <br /> Bedrock in low-wall of pit may be a permeability barrier to subsurface discharge of <br /> leachate where leachate has maximum head -Cross-section G-G' shows that spoil <br /> probably abuts only shale in the low-wall of the pit at former well PM-7, thus <br /> preventing leachate discharge into bedrock at this location where head at the base of <br /> the saturated zone is at its maximum of 50 ft. <br />Page 2 <br />