2014-02-27_REVISION - C1981010 - Laserfiche WebLink

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Trapper Mining, Inc. C- 1981 -010; PR7 Adequacy Review No. 2 Page 8 of 15 3.3.3 East Panel Landslide Geotechnical Evaluation 20. On page 3 -27b, Stations 5 to 8 have replaced Stations 1 to 4 that were listed previously. For the purposes of continuity, a new paragraph should be inserted at the top of page 3 -27b which gives a brief description of what happened to the original four stations, and when the current stations were placed in service. a. Trapper's Response: linfornnationn has been added to enclosed page 3 -27b addressing site installlationn dates, eqt ipment 6istalllled at each monitoring station, annd removal dates for unndIlVIlduall stations. 1n addition, Figure 3.3.3 -1 (enclosed page 3 -27c) has been updated to reflect current station locations and Table 3.3 4 (unclosed page 3 -27d) is updated to reflect current active locations. Enclosed page 3 -27a is revised to correct a typo. b. Division's Response: Please update the aerial photo snap on page 3 -27c to depict all eight monitoring stations. Also, please include a date on the map for the aerial photograph used. 4.08.1 Surface Water 21. The current page 4 -173; section 4.08.1.2, discusses haul road culvert sizing. This section references Tables 4.8 -1 and 4.8 -1a which are proposed to be replaced with Table 4.8 -2 and 4.8 -2a submitted with the revision. Please update the permit text on this page with the revised table numbers cited. a. Trapper's Response: Page 4 -173 has beenn revised «itln the requested cllnange to tine table ueferunces and is unclosed. b. Division's Response: This item is considered resolved. 22. Proposed Table 4.8 -2; Haul Road Culvert Sizing, lists the culverts that exist at the site. The following culverts were added to the table and depicted on the revised M51 maps; ASH -1, ASH -2, BH -1, EMF -1, MZ -1, MZ -2, MZ -3 and MZ -4. It appears these culverts have been installed but were not part of the current approved permit. Also, many culverts are depicted on the M51(Sheet 3) map for proposed culverts that appear to be for the future haul roads to be constructed in the next permit term. Rule 4.03.1(4)(e)(v) indicates that "culverts shall be installed to accommodate flow from the intersecting drainages, and from road surface drainage as necessary to control erosion. Designs for culverts shall be in accordance with 4.03.1(4)(e) except where alternative specifications are approved." Permit section 4.08.1.2 indicates culvert sizes are determined by running hydrologic models. For the culverts listed above and the future culverts to be installed, please submit the information/parameters used to determine the proper culvert sizing. Other Operators submit copies of the SEDCAD runs the\, use to design culverts. a. Trapper's Response: Table 4.82 llnas beenn updated to indicate the status of each culvert oun the site. Per perunit section 4.8.1.2 and the regulations, only culverts ki tmdisturbed areas req ire designs. Rule 4,03.1(4)(a)(6'i) states haul roads «ithki disturbed areas will be designed annd constructed using the best technology available. The footnote cohnnn of Table 4.82 indicates whether a particular culvert is placed under a certified haul road built through unndisturbed areas per rule 4,03.1(4)(a)(iv) or is present inn disturbed areas. Appendrt S contains the certified haul road infornnation. Trapper does indeed utillize hydrologic modeling to deterunine the sizing of it culverts, however these models are typically donne as needed at the time of construction and are not retaMed. For the above ueferunced culverts, per the regulations, designs are snot necessary annd «-ere constructed using piratical annallysis of the anticipated runoff. The exceptions is culvert EMF- 1 which was sized accoudinng to the cullvert just upstream that was designed maunv years pnor to EMF -1 installlationn. The table denonnstrates that the installed culverts are more tlnaun adequate to haundle auny flow to this structure.