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<br /> <br />Requirement <br />Require-ment <br />citation Require- <br />ment <br />complied <br />with ? <br />eslno <br /> <br />Comment <br /> QR coal sequence - As shown in the spreadsheet attached to <br /> DRMS's review memo for the 2004 AHR, spoil leachate <br /> plumes aze capable of developing on the Trapper Mine only <br /> in aquifers in the QR coal sequence in D, F, G and Z pits. <br /> The QR sequence is monitored downgradient from the F pit <br /> in well GP-5. The QR is not monitored downgradient from <br /> i G and Z pits. (D pit has undergone final bond release.) <br /> Hydraulic conductivity of the QR of 0.03 ft/day indicates it <br /> would take 20 yeazs for a leachate plume to extend 548 ft. <br /> ' downgradient from the G, F, and Z pits (assuming 5% <br /> effective porosity and a hydraulic gradient of O.125ft/ft). A <br /> ' ground water point of compliance is not warranted for the <br /> QR due to the limited areal extent of a plume (it would not <br /> extend offsite) and the dilution of the plume that would <br /> result from dispersion. A dilute plume that does not extend <br /> outside the permit boundary indicates there is no potential for <br /> negatively impacting the QR sequence. <br /> 3'd White sandstone in Flume Gulch -The 3rd White <br /> Sandstone is the only stratigraphic unit having significant <br /> permeable that is in the ground water flow path of any coal <br /> ~ spoil leachate; therefore, the 3`d White is the only <br /> ' stratigraphic unit whose ground water quality may be <br /> <br />R <br />Basic Standards <br />CWQCC negatively impacted by mining at Trapper. Well GP-9 <br />d <br />. <br />for Ground regulations yes , <br />monitors the 3 White immediately downgradient from <br />' <br />Water 41 <br />4 and 41 <br />5 Trapper <br />s pits at a location where a leachate plume can be <br /> . <br />. expected to fore, as explained in the PHC (Section 3.8.3 of <br /> ' the permit). Well GP-9 is Trapper's ground water point of <br /> ~ compliance for the 3`d White sandstone as explained on <br /> permit page 2-242. Data from well GP-9 in 2006 indicates <br /> Trapper is in compliance with the Basic Standards for <br /> Ground Water for a domestic use classification for the 3`d <br /> ' White in a Specified Area that extends outward from <br /> Trapper's northern permit boundary on the east half of the <br /> mine to the axis of the Big Bottom Syncline, a distance <br /> ranging between I/2 and 3/4 mile from the boundary. <br /> Trapper is not expected to negatively impact water quality in <br /> ' the 3`d White outside Flume Gulch, as documented in the <br /> ~ spreadsheet attached to DRMS's review memo for the 2004 <br /> AHR. <br /> 3`d White sandstone and HI aquifer outside Flume <br /> Gulch. Artesian conditions are well-documented in the 3`d <br /> White sandstone throughout the Trapper mine site. Nigh <br /> head in the 3rd White sandstone and HI coal sequence will <br /> ' prevent invasion of these formations with spoil leachate <br /> outside Flume Gulch (see spreadsheet attached to DRMS's <br /> review memo for the 2004 AHR). High head appears to <br /> have prevented subsurface leachate invasion at well GF-5 in <br /> No Name Gulch. Seepage of coal spoil leachate from near <br />Page 3 <br />