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Letter to Ryan J. McHale 3 :February 16, 2010 <br />Permit Application Adequacy Review File No. M-2009-076 <br />must be provided. <br />d. In order for the perforated pipe drains at the base of the tailing to be effective, they must be bedded in high <br />permeability fill to form a blanket drain. The proposal to install drain pipes at each twenty foot level will <br />create numerous penetrations through the impoundment shell, which are detrimental to long term stability. <br />DRMS suggests that a plan to use chimney drains to tie sequentially installed drainage into the basal blanket <br />drain be developed. <br />e. The tailing impoundment proposal contained in the application is for a dam that will be raised using the <br />upstream method. These types of dams are particularly susceptible to failure during seismic shaking, and <br />although the Hukill Gulch site is not in a highly active seismic zone, the area is prone to earthquakes. In <br />order for DRMS to approve dam raising by the upstream method, there must be absolute certainty that each <br />sequential raise is founded on previously emplaced tailing that are unsaturated. A test plan and schedule for <br />detection of saturated tailing must be provided. The stability analysis required under item 8b above must <br />consider stability during the maximum credible earthquake for the location. <br />9. Exhibit D states that geotextile or jute netting will be applied after seeding areas of the tailing impoundment <br />under reclamation. If geotextile is used, it must be a biodegradable product specifically designed for use in <br />revegetation projects. <br />10. Exhibit D states that Arkansas Valley Seed Co. Mountain Mix at 40-50 pounds PLS per acre broadcast, or <br />others that are compatible shall be used. Seed mix and application rate must be specified in the permit <br />application and once approved, can only be varied through permit modification approval by DRMS. The <br />Mountain Mix includes species that would not be effective on south facing slopes. A seed mix tailored to the <br />site must be developed; the NRCS can assist with this. Species that are growing at the site now and species <br />that are known to establish in the soil type present at the site should be included in the mix. The proposal to <br />double the recommended broadcast seeding rate is not acceptable; over application of seed is detrimental to <br />plant establishment. For the seed mix that is approved, the broadcast seeding rate should be designed to result <br />in application of 80 seeds per square foot. <br />11. Exhibit D states that any infrastructure development or structures, equipment, and trailers brought into the <br />site will remain following reclamation. Venture Resources has provided a plan for their orderly <br />decommissioning and storage. The DRMS has identified the following issues with this proposal. <br />a. Venture Resources states that the water holding pond will remain to use for fire protection in the post <br />mining setting. The permit application states that the pond will be filled using Idaho Spring's municipal <br />water trucked to the site during mining and milling operations. Details for diversion or other effective <br />controls to prevent capture of runoff from rain or snowmelt by the pond both during operations and after <br />reclamation must be provided. <br />b. Venture Resources states that the leachate collection facility including the sediment collection pond, <br />diversion ditches, concrete collection barrier, pumps, electric control panels will remain in place for <br />"Tailings Impoundment short-term post-closure maintenance." The DRMS will not release the bond until <br />after leachate generation ceases, so these facilities will be removed under the permit; provide a plan and <br />estimated costs for removal and disposal. <br />c. Venture Resources states that mobile millsite equipment may remain on-site in an inactive state for storage. <br />Clear Creek County Planning Department informs DRMS that storage of equipment following release of a <br />mined land reclamation permit is not acceptable in the M1 and M2 zones. Therefore, the reclamation plan <br />must be changed to provide for complete removal of structures, equipment, fuel, lubricants, and chemicals,