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Twentymile Coal, LLC. <br />Page 5 <br />November 16th 2018 <br />Rule 2.05.6 <br />19. Proposed revised page 2.05-131 cuts off the "Probable Hydrologic Consequences" section <br />heading and the first sentence of this section that is currently on page 2.05-131. Please revise this <br />page to include this information. Addressed with 11/13/2018 submission <br />20. Proposed revised page 2.05-145 does not include a portion of the paragraph from the preceding <br />page. Please review these pages and insure the text follows from the preceding and subsequent <br />pages. Addressed with 11/13/2018 submission <br />21. Proposed revised pages 2.05-145 to 146.1 appears to be missing information pertaining to the <br />Wolf Creek Reserve that was added with TR83. Please review the currently approved pages and <br />make the appropriate revisions to the most recent application pages. Addressed with 11/13/2018 <br />submission <br />22. Proposed revised page 2.05-153 indicates that with the system, iron reduction at a maximum <br />design flow rate is estimated at 59%. However, based on the C2HM Hill design submitted with <br />Exhibit 49EE indicates the iron reduction at the maximum designed flow of 357 gpm will be <br />57%. Please revise the page to address this discrepancy. Addressed with 11/13/2018 <br />submission <br />23. The proposed passive water treatment system design submitted to be included in Exhibit 49EE <br />indicates that the target TDS removal goal is not achievable with a constructed wetland system <br />that includes the 6MN Reservoir as a final polishing pond even with the maximum and minimum <br />expected flows of 375 and 75 gpm. Proposed revised page 2.05-153 indicates that the passive <br />water treatment system will reduce TDS with associated reductions in EC and that discharge from <br />the 6MN reservoir will be managed to keep EC levels below downstream material damage <br />thresholds. Please explain in detail how the discharge will be managed to keep EC levels below <br />the material damage threshold as the design appears to indicate that this will not be possible? <br />Text relative to EC is still present without explanation, even though this system is not <br />proposing to discharge please explain in detail how EC will be managed. This paragraph <br />also quotes the reduction of iron as 21% but the design report states 20%. Please verify the <br />accuracy of this data. <br />24. The flow rate and water quality of Trout Creek below Fish Creek can be affected by discharges at <br />site 109, 115 and proposed future discharges from the 6MN Reservoir. TC proposes to revise <br />page 2.05-155 to indicate that Site 109 has not discharged in some time; however this site has not <br />been decommissioned to the Division's knowledge and could potentially be utilized. Pages 2.05- <br />154 through 156 discusses detailed plan to adjust the flows at either site 109 and 115 in order to <br />meet the applicable Sulfate standard on Trout Creek. Based on a review of Exhibit 51 and the <br />passive water design, the sulfate level discharged from the 6MN Reservoir after treatment could <br />potentially have sulfate levels that could exceed the sulfate level discharged at Site 115. There is <br />