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the upper portion of the reservoir in 2008, the native materials under the sediments consisted of topsoil, <br />peat and clean sub-soils that allowed for the reclamation of over 125 acres of acid generating capped <br />tailing facilities. Climax will salvage the topsoil and clean native materials to continue reclamation of 1 <br />Dam, capping exposed tailing and covering of the sediment disposal area at 2 Dam for dust control. <br />Dam Safety <br />The primary intent of this year's cleanout effort is to remove the lime sediments. In order to remove <br />these sediment materials with earthmoving equipment, soft topsoil, peat, and subsoil will have to be <br />removed to allow access. It is anticipated that the toe area of the dam was stripped of topsoil and that <br />the construction effort will only be removing lime sediment from the toe area and leaving the native <br />materials in place. <br />The State of Colorado Rules and Regulations for Dam Safety and Dam Construction, 5.10.1.2 states: <br />"Borrow areas shall be located at least 200 feet from either toe of the dam. The dimension of this limit <br />may be reduced using engineering analyses indicating that the reduced dimension will not negatively <br />impact dam stability and/or foundation seepage." Climax has developed the following approach to <br />ensure that this year's efforts will not negatively impact dam stability and/or foundation seepage: <br />1. Performed a review of historical drawings. The review indicates that the construction area for <br />the dam was stripped down to a competent foundation prior to construction. The bedrock in this <br />area is a very competent Elk Mountain porphyry. <br />2. Climax has surveyed and staked the toe of the dam and placed stakes at 50' intervals out to <br />300' from the toe as shown on the attached drawing "2010 Robinson Lake Project, Robinson <br />Lake Toe Projection." In order to protect the integrity of the dam during and after the removal <br />effort, the State Engineer's Office will be contacted when sediment removal operations are <br />within 300' of the toe. This will allow time to schedule a site visit and project review prior to <br />removal efforts approaching the 200' limit. Any required changes to construction approach or <br />method can be implemented prior to advancing beyond the 200' limit. <br />3. A geotechnical engineer has been retained for analysis of the dam stability and any additional <br />analysis required as construction progresses toward the toe of the dam. Any analysis or <br />recommendations by the geotechnical engineer will be forwarded to the State Engineer's Office <br />for review and approval. <br />4. The fill plan submitted April 23, 2008 will be reviewed and amended as necessary to ensure <br />safe refill of the reservoir. <br />Climax will work closely with the State Engineer's Office to ensure that dam integrity and safety is <br />maintained. Please contact me with any issues or concerns that you may have regarding our planned <br />approach. <br />Thank you, <br />a? <br />Tavis D. Rogers, PE <br />Senior Engineer - Climax <br />Encl: 2010 Robinson Lake Project, Robinson Lake Toe Project