Laserfiche WebLink
never seen that stream-bed overtopped, nor evidence thereof. Accordingly, by deduction <br /> the 5-year and possibly higher storm discharges must have been contained in the 3-5 <br /> foot wide triangular channel. The SCS Curve numbers were adjusted until the discharge <br /> of Structure 4 was about 6-8 cfs and then applied to the 10 yr and 100 yr jlows. <br /> 59. Appendix 10, Drawing CCVSAI I-9. This drawing has two section callouts (X and Y)on <br /> each of the three plan views (1, 2 and 3). The profile labeled"4" is assumed to be the "X" <br /> section, but it does not show the cut and/or fill for EMP21 b. There is no corresponding"Y" <br /> section shown on the drawing. <br /> • Why is the cut/fill for section X not shown in the profile? Please resubmit the drawing <br /> showing the cut/fill for EMP21 b. <br /> RESPONSE. Drawing CCVSAII-9 has been revised to include Section Y; to show the <br /> profiles of EMP 21 a and EMP21 b; and to show the existing terrain, the terrain after <br /> mining, and the terrain after backfilling the Schist Island area of the North Cresson <br /> Mine. See Attachment 13. <br /> • Where is the corresponding Y section/profile for EMP21A? <br /> RESPONSE. See response above. <br /> APPENDIX 10 - Design Report for Storm Water Management at the Chicago Tunnel Site <br /> 60. Narrative Description of Mining Activities,p. 1 <br /> • The last sentence of the first paragraph states "CC&V has delegated responsibility for <br /> the management of the stormwater to that contractor". The Division has a regulatory <br /> relationship with the permittee, not the operator(when different than the permittee). <br /> Please acknowledge CC&V is responsible for stormwater management. <br /> RESPONSE: Newmont acknowledges it is responsible for managing stormwater at the <br /> site. The statement referred to the expectation by the Newmont that the contractor <br /> on site at the time would comply with regulatory requirements, including <br /> stormwater. <br /> 61. Narrative Description of Mining Activities,p. 2 <br /> • The top of page 2 states "no measurable or reported discharge has occurred from the <br /> [Chicago] tunnel". This was written just prior to the Division's December 2014 <br /> approval of TR-03, allowing CC&V to reopen the tunnel, which was plugged at the <br /> time this 2014 report was written. Please clarify whether any measurable or reported <br /> discharge has occurred from the Chicago Tunnel since it was reopened. <br /> RESPONSE: There has been no measurable or reported discharge of water from the <br /> Chicago Tunnel since it was opened in 2015. <br /> 62. Methodology and Basin Descriptions, p. 4 <br /> • The bulleted summary of the various basins states exceedingly large times of <br /> concentration. A review of the Sedcad model report(see p. 10, "Subwatershed Time of <br /> Concentration Details") explains why. The time of concentration estimates include <br /> overland/sheet flow segments significantly greater than 300 feet(e.g.,p. 10 of <br /> SEDCAD report Stru#1, SWS #1 is 6,063.94 horizontal feet). TR-55 Upland method <br /> for time of concentration calculations limits overland flow segments to less than 300 <br /> feet(see top of page 15) and based on experience should be shorter as slopes increase. <br /> Please review all times of concentration estimates to ensure proper methodology and <br /> Page 28 of 30 <br />