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Requirement Regulation Comment <br /> The 2019 and 2020 data from groundwater wells fell within <br /> historical ranges. All PAW monitoring stations showed a <br /> CWQCC decrease of TSS in 2019. TSS decreased in 2020 with the <br /> Q. Basic Standards regulations exception of PAW2,where an increase was noted. PAW 8 <br /> for Ground Water 41.4 and 41.5 showed a dramatic decrease in TSS between 2019 and 2020 <br /> while Paw 8 was similar to previous years and also while <br /> decreasing TSS between Q2 and Q4 monitoring. <br /> Requirement Regulation Comment <br /> Based on the information provided by the operator in the probably <br /> R. Restoration of hydrologic consequences,PHC, section of the permit,2.05,there <br /> ground water CDRMS is not a confined aquifer in the monitoring area. The geologic <br /> recharge to regulation layers consist of interbedded sandstone and coal layers with <br /> approximate pre- 4.05.12(3) permeability highest along the coal layers and lower between the <br /> mining rate bedding planes. Subsidence will increase permeability between <br /> layers at and above mined areas. There does not appear to be a <br /> confined aquifer within the area of mining or monitoring. <br /> Probable Hydrologic Consequences(PHC),predictions in <br /> section 2.05 and Exhibit 8 of the New Elk permit appear <br /> accurate. <br /> The impact of backfilling a reach of the Middle Fork of the <br /> Purgatoire River with mine waste predicts increases of calcium, <br /> sodium, sulfate and TDS(Exhibit 8,pg 29). 2019 and 2020 <br /> sampleing at PAW 2,downstream of the backfill, show lower <br /> contributions with the exception of Calcium in 2019. In 2020 all <br /> S. Minimization of contributions were lower than predicted values. <br /> disturbance to the CDRMS Subsidence is expected and no surface water flow or water <br /> hydrologic regulation quality impacts are expected. Mining related subsidence will <br /> balance within increase vertical permeability and wells above the zone of <br /> and adjacent to 4.05.1(1) increased permeability are not likely to be impacted by mining <br /> the permit area (Section 2.05). <br /> PAW 9 is a shallow alluvial well, situated more than 400 feet <br /> above the planned mining horizon. NE 1-10 is designed to <br /> monitor impacts to groundwater in the mining horizon. <br /> Monitoring began in this well in 2019. <br /> Probable Hydrologic Consequences(PHC),predictions in <br /> section 4.8.3 of the permit appear accurate. Significant changes <br /> in surface water quality or quantity have not been observed for <br /> 2019 or 2020. <br /> Page 3 <br />