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Requirement Regulation Reviewed Comment <br /> Q. Parameters to be Table 4.8-13 <br /> of CDRMS <br /> analyzed in <br /> mining Yes <br /> groundwater <br /> samples permit C-81- <br /> 010 <br /> Well GP-9 monitors the Third White Sandstone immediately <br /> downgradient from Trapper's pits at a location where a <br /> leachate plume can be expected to form,as explained in the <br /> PHC(Section 4.8.3 of the permit). Well GP-9 is Trapper's <br /> groundwater point of compliance for the Third White <br /> Sandstone as per permit page 4-242. The 2019 data from <br /> well GP-9 does not reflect any new exceedances of the Basic <br /> Standards for Ground Water for a domestic use <br /> classification based on the parameters analyzed. (This <br /> classification is for the Third White Sandstone in a Specified <br /> Area that extends outward from Trapper's northern permit <br /> boundary on the east half of the mine to the axis of the Big <br /> Bottom Syncline,a distance ranging between 1/2 and 3/4 <br /> mile from the boundary.) There continue to be exceedances <br /> of the drinking water standards for Fe and Mn; however,Fe <br /> and Mn exceedances also occurred in well GP-9 prior to <br /> mining in the area upgradient of this well. Other <br /> groundwater quality factors(e.g.,concentrations of TDS and <br /> sulfate),continue to remain within historical sampling <br /> CWQCC ranges and indicate that coal spoil leachate has not reached <br /> R. Basic Standards regulations Comment GP-9. <br /> for Ground Water 41.4 and 41.5 <br /> Flume Gulch alluvium could also be contaminated by coal <br /> spoil leachate. The Coy well is the groundwater point of <br /> compliance for the Flume Gulch alluvium,as per permit <br /> page 4-242. Sampling data from 2019 indicates no <br /> exceedances of the Basic Standards for Ground Water for <br /> the classification of agricultural use at the Coy well. <br /> However,it should be noted that Fe and Mn results were the <br /> highest concentrations during sampling. <br /> Iron(Fe)results were highest ever recorded in wells GF-I I <br /> and P-8 at 1.40 and 0.40 mg/L respectively. Well GD-2 also <br /> saw 31d highest concentration recorded at 0.60 mg/L. These <br /> concentrations are not well explained in the text if at all. <br /> Additional explanation of the exceedances are warranted. <br /> Manganese (Mn)concentrations were highest recorded in <br /> wells P-8 at 0.3 mg/L and Coy well mentioned above. <br /> Lead(Pb)concentration in GP-8 was the second highest <br /> ever recorded at 0.001 mg/L and well below the standard of <br /> 0.05 mg/L. <br /> Page 3 <br />