2011-06-06_REVISION - M1981185 (61)

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Response to Preliminary and Secondary Issues April 28, 2011 1 ne report recommends stones should be laid back to 125.1 (H. 0; where slopes are greater than 10 feet high, benches should be constructed at 10 foot vertical intervals In our review of the report, we found no basis for the 125.1 slope recommendation, nor a basis for constructing benches at 10 foot vertical intervals In this section of road, slopes are near vertical, as noted in the Trautner report The R2 Geotechnical Reconnaissance report observed that the slopes are performing well; recent visits to the site confirm this conclusion The exposed bedrock is strong, fracturing is slight, and the bedding of the rock is favorable an relation to the existing access road cut slopes. On this basis, we recommend slopes be laid back to vield slopes no steeper than 1.1 Where, residual soil or colluvium as exposed at the top of the cut it should be laid back to no steeper than 151 The access road design was prepared and stamped by CLC Associates and the geotechnical data were collected by R Squared, Inc and the report stamped by a Colorado registered professional engineer: June 4 and June 7 2010 Memo from Mr. Allen Sorenson to Wally Erickson Re: Access Road Review, Wildcat Mining Corporation Idaho Mine File No M.2010-003. Question #1 June 4 and June 7, 2010 Allen Sorenson's Memos The Geotechnical Reconnaissance Report states that the upper 30 inches of the road must be compacted to at least 90 percent relative compaction per ASTMDI557 02 and that in areas where less than 30 inches offill will be placed to complete construction o the road to over excavate scarify, and compact to 95 ercent. DRMS would require compaction to 95 percent throughout the upper 30 inches of road and notes that ASTM D155 7-02 has been superseded by ASTMDI557-09 The Work Plan must also include a specs zcation or maximum lift thickness for all to be placed and must call out a frequency for testing offill and test methods to be employed Response #I- June 4 and June 7,2010-Allen Sorenson's Memos Mr. Sorenson's requirement is included in the Road Construction work plan See Attachment F-CLC Road Design- Third Adequacy Response Question #2 June 4 and June 7, 2010 The Geotechnical Reconnaissance Report states that the cut slopes in the cut through section at the top of the hill are performing well However DRMS will require that these slopes be laid back to 1.25:1 (H.- V) as recommerrda11 ;;1 th, Tv,,,,f- r__„t,._L . - - 11 Response-Second and Third Geotechnical Issues 8 5/27/2011