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C- 1981 -019 PR -03 <br />Eng/Geotech PAR No. 2 <br />22 -Jun -2011 <br />Page 5 of 5 <br />1. The S &W Study is thorough in its analysis of site conditions, material properties, and <br />analysis of stability. The study is dated July 2009, and was developed using the obsolete <br />plan for mining of Little Collom X Pit. Please update the S &W Study to address any <br />revised ground or spoil pile configurations that may arise as a result of the anticipated <br />changes in mine plan for X Pit. <br />Colowyo responded that there will be no changes to the spoil pile configuration <br />resulting from changes made to the mining plan. Item resolved. <br />2. Exhibit 7 Item 26, Fig. 2 illustrates a proposed "Collom Sump ". It appears that this sump <br />pond may be located near the toe of the proposed excess spoil pile. Please ensure that <br />S &W are informed of the presence of the sump, and its position in the mining sequence, <br />so that any potential effects it may have on the pile itself or the foundation materials may <br />be considered in the stability evaluation. <br />Colowyo states in the March response letter that it will obtain confirmation from S& W <br />or, if necessary, re -run the stability analyses. Please provide the Division with <br />correspondence from S& W addressing any effects the Sump may or may not have on <br />the temporary excess spoil pile. <br />3. The 2 paragraph on S &W Page 11 states that, "Prior to publication of our report, <br />Colowyo informed us the spoil slope will be decreased from the 3H:1 V slope used in our <br />models to a slope of 3.5H:1V..." On Map 29C, Section A -A' does show a slope of <br />3.4H:1V on the southern slope of the pile, but the northern (and most critical, for <br />stability) slope continues to be labeled as 3H:1 V. <br />a. Please provide clarification of the actual slope proposed for construction of the <br />northern face of the temporary excess spoil pile. <br />Colowyo confirmed that Map 29C does represent the planned configuration <br />(3H:1 V on the northern slope). Item resolved. <br />b. The paragraph quoted in part, above, ends with an incomplete sentence. Please <br />review and revise, as appropriate. <br />Colowyo explained that the "to" is extraneous. Item resolved. <br />4. The S &W Study (Section 8.0, page 12) provides specific conclusions and <br />recommendations regarding construction of the excess spoil pile. Section 9.0 addresses <br />S &W's Monitoring recommendations. Language found in Rule 4 (pp. 22 -23) does not <br />clearly commit Colowyo to following the S &W conclusions and recommendations. <br />Please revise Rule 4 Section 4.09 to clearly communicate Colowyo's intent. <br />Colowyo has revised the text in 4.09 to include a direct reference to the S& W report. <br />Item resolved. <br />This concludes my second adequacy review of the Collom application. Please do not hesitate to <br />contact me if you have any additional questions. <br />cc: Sandy Brown, DRMS <br />