Laserfiche WebLink
<br /> <br /> <br /> <br /> <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br /> <br /> <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us <br />John W. Hickenlooper, Governor | Mike King, Executive Director | Virginia Brannon, Director <br />July 18, 2016 <br />George Robinson <br />Wildcat Mining Corporation <br />3926 North State Hwy 67 <br />Sedalia, CO 80135 <br /> <br />RE: May Day Idaho Mine Complex, Permit # M-1981-185, TR-5 As-built Deficiencies <br />Mr. Robinson: <br />On March 3, 2016 the Mined Land Reclamation Board issued an order requiring Wildcat Mining <br />Corporation (WMC) to complete repair and stabilization work at the Chief Portal, as approved <br />through the Technical Revision (TR-5), by July 1, 2016. On June 29, 2016 the Division of <br />Reclamation, Mining and Safety (Division) received your “as-built” report for the stabilization work <br />conducted at the Chief Portal. Division review of the report and an on-site inspection of June 30, <br />2016 (report attached) found that some of the stabilization work was not completed in accordance <br />with the approved plan as required by the Board. <br />The March 16, 2013 Geotechnical Stability Report completed by J. Erich Rauber made specific <br />recommendations for stabilizing the Chief Portal. These recommendations were incorporated into <br />the work plan approved through TR-5. Mr. Rauber recommended that fill materials used to <br />construct the 1.5H: 1V slope be free of organic materials with the largest particle sizes less than six <br />inches, and that the fill should be placed in layers of eight inches or less, moisture conditioned and <br />compacted to within 3 percent of the optimum moisture content, and be compacted to at least 90 <br />percent relative compaction. Mr. Rauber’s report noted that onsite material would be suitable as fill <br />once oversized rocks were removed. Mr. Rauber also recommended that sub drainage be installed, <br />and the finished slopes revegetated. TR-5 required that all disturbed slopes be revegetated and that <br />all slopes steeper than 3H:1V have erosion control blankets installed. <br />The December 2011 Board Order requires Division approval of the as-built certification. The TR-5 <br />as-built report does not contain the required documentation to show that the recommended fill <br />material was utilized, or the moisture treatment or compaction requirements adhered to during <br />construction of the Chief Portal slope. The report also does not address sub drain installation or the <br />revegetation requirements. <br />On June 29, 2016, representatives from the Division inspected the site and noted that some of the <br />work completed at the Chief Portal was not consistent with specifications approved through TR-5. <br />WMC has conveyed that modifications were made during construction in order to address field <br />conditions encountered. These modifications were not submitted to the Division for review and <br />approval prior to the construction. Accordingly, the Division has concerns regarding the long-term <br />stability of the Chief Portal slope. <br />On July 8, 2016, the Division received a technical revision request (titled TR-5.1 by WMC, but to be <br />processed as TR-7 by the Division) from WMC. TR-7 requests to remove the revegetation <br />requirement for the slope immediately above the Chief Portal. Instead of vegetation, scree has been <br />placed on the slope in order to stabilize it. However, the coverage is not complete and the Division <br />does not believe this will be adequate for erosion control or long term stability. Therefore, WMC