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Cripple Creek & Victor Gold Mining Company Squaw Gulch Valley Leach Facility Design <br />2.5 Seismicity <br />structural fill to the final SLF subgrade elevation. Refer to Detail 13 on Drawing <br />A270. <br />• For shallow mine adits and tunnels: Collapse the crown pillar by drilling and <br />blasting, excavate collapsed crown pillar, backfill with coarse shaft backfill, then <br />install a geogrid cap. Refer to Details 14, 15 and 16 on Drawing A270, as <br />appropriate. Geogrid design calculations are provided in Appendix C.1. <br />The areas requiring remediation have been initially identified from the available <br />information. Remediation activities will involve further investigations during <br />construction to provide more detail on the type and extent of mine workings that may <br />need to be remediated, including verification drilling and /or geophysics in areas of <br />heightened concern. Each feature observed on the surface, and identified <br />underground as potentially requiring remediation, will be re- assessed thoroughly again <br />as part of the remediation process; and the final remediation requirements will be <br />based on these re- assessments. <br />Based on the seismic evaluation submitted as part of Amendment No. 9, a Peak <br />Ground Acceleration (PGA) of 0.14g was selected for the VLF during operations, and a <br />PGA of 0.08g was selected for the VLF at closure. No change to these values was <br />warranted for the VLF design. <br />Project No.: 74201125G0 Page 12 <br />1 September 2011 <br />amec0 <br />