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interceptor trench drain, as shown in detail 5 of Figure 5 of the Barr report. There is <br />another pipe that is flowing into the ditch from the same general direction so we are <br />unsure about what this ditch was on April 10, 2012. <br />6. Barr reports portions of the drainage chimney blankets were placed against near - vertical <br />rock faces. That is not how the details are shown in Figure 5 where the bedrock slope is <br />uniformly at about a 2:1. <br />Concerning the RPEE, A comment made by the mine excavation supervisor was that the <br />rock buttress was going to have to be deeper and higher quantities of sandstone boulders would be <br />needed. It is hard to discern on plan sheets but has the geotech report plans and drawings address <br />or acknowledge this change in the current technical revision? <br />Also, the content of the CGS review of TR -127 for the RPEE, dated September 26, 2011, <br />addressed to Tom Kaldenbach, remains applicable for this review. That review is attached to this <br />memo. <br />In closing, if the two location of slope failures were to reactivate, they would likely only affect <br />mine operations. Based on the stability analyses, the drainage of the slopes is critical, as is continual <br />monitoring for movement and measurement of water (pore pressures). The monitoring plan for the <br />HR -1 appears comprehensive and adequate except for one of the mirrors (prism ?), #2059, that <br />appears to be located on the road. <br />Thank you for the opportunity to comment on this Technical Revision. If you have any <br />questions about the content of this review, or if some of the assumptions made in this memo are <br />incorrect, please call Jon White at ext. 8332. <br />Cc: Karen Berry, CGS <br />Attachment: CGS memo to DRMS (West Elk TR -127) dated September 26, 2011. <br />