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STATE OF COLORADO <br />DMSM OF UC""Ti^ MINMIG MID SAFETY <br />0"Vft" of Na"pl0unyes <br />1313 Shannrn St, Roam 31 S <br />oww 'Cowwpaow COLO vxt O <br />Mf0"" 00 M-3567 a <br />RE y =CLAMATION <br />FAX- t3= 83MI06 MINING <br /> SAE?TY <br />DATE: June 7, 2010 <br /> ,k <br />ea.?. <br />TO. Wally Erickson w?+•? 8. knit <br />eweWN o?laonr <br />FROM: Allen Sorenson <br />RE: Access Road Review, Wildcat Mining Corporation, Idaho Mine, File No. M-2010-003 <br />The Division of Reclamation, Mining, and Safety (DBMS) engineering staff have reviewed those <br />portions of the permit application submittals received from Wildcat Mining on June 1 and June 7, 2010 <br />related to the access road tram La Plata County Road 124 to the La Plata River. The Geotechnical <br />Reconnaissance Report provided presents the conclusion that if construction is completed and repairs <br />are made, the mad can be put to restricted use as access to the mines. The DRMS concurs. The <br />Geotechnical Reconnaissance Report recommends that a Work Plan be prepared by an experienced <br />geotechnical engineer and presents the minimum elements to be addressed in the Work Plan relative to <br />roadway fill, retaining walls, and monitoring. The Geotechnical Reconnaissance Report further <br />recommends that implementation of the Work Plan be oversm by an experienced geotechnical <br />engineer. Exhibit 7 to the June 7, 2010 submittal is a Work Plan for the road; the Work Plan provided <br />does not include minimum elements recommended in the Geotechnical Reconnaissance Report, for fill, <br />sloping, retaining walls, and monitoring. Until a Work Plan that addresses these minimum elements is <br />provided, reviewed, and accepted, DRMS cannot approve a permit application to include the road. <br />Moreover, DRMS requires the following issues be addressed in a Work Plan, <br />1. The Geotechnical Recormaisu=e Report states that that the upper 30 inches of the road must be <br />compacted to at least 90 percent relative compaction perAST'M D1557-02 and that in areas where <br />less than 30 inches of fill will be placed to complete construction of the road, to over excavate. <br />scarify, and compact to 95 percent. DRMS would require compaction to 95 percent throughout the <br />upper 30 inches of road, and notes that ASTM D1557-02 has been superseded by ASTM D 1557.09. <br />The Work Plan must also include a specification for maximum lift thickness for fill to be placed, <br />and must call out a frequency for testing of fill and test methods to. be employed. <br />2. The Geoteelmical Reconnaissance Report states that the cut slopes in the cut through section at the <br />top of the hill are performing well. However, DBMS will require that these slopes be laid back to <br />1.25:1 (H:V) as recommended in the Tmutner Geotech report to La Plata County that is included in <br />the Idaho Mine permit application. A description of how these slopes will be laid back must be <br />included in the Work Plan. <br />3. All other recommendations for fill, sloping, retaining walls, and monitoring contained in the <br />Geotechnical Reconnaissance Report are acceptable to the DRMS, and must be incorporated into <br />the detailed Work Plan. The Work Plan must include design details and specifications for all <br />ele =w of road construction and repair, and must specify a monitoring frequency for mad <br />performance monitoring systems to be installed, and specify maximum allowable movement <br />ewam or oohs or <br />h9aW Land RneWmition nenMer . Crand JLRC4?op . Duranan Adive and Ined v* Minas