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Mr. Humphries <br />Page I3 <br />November 17, 2011 <br />addition, the Applicant has identified forestry as a post- mining land use. Please provide the <br />Division with a technical justification for omitting trees from the proposed seed mix. <br />13. The Applicant has provided a cost estimate for the permanent closure of the existing Cross <br />Mine Portal as well as the new Cross Mine Decline Portal. Please clarify if the Idaho Tunnel <br />Portal will require permanent closure as part of the Reclamation Plan. If the Idaho Tunnel <br />will require permanent closure, then the Applicant must include the associated costs in the <br />financial warranty estimate. <br />14. Please provide the Division with the dimensions of the snow roofs which cover the access <br />points to the Idaho Tunnel Portal and the existing Cross Mine Portal. In addition, please <br />describe the materials used to construct the snow roofs and provide the dimensions of any <br />foundations associated with these structures. This information is required to calculate the cost <br />to reclaim the site. If a snow roof will be constructed at the new Cross Mine Decline Portal, <br />then the above requested information will be required for this structure as well. <br />15 Please provide the Division with a description of the materials which were used to construct <br />the Caribou Mine office and dry room. In addition, please describe the type of building <br />materials which will be used to construct the new Cross Mine office and dry room and <br />specify the thickness of the foundations. This information is required to calculate the required <br />financial warranty. <br />16. Please specify the total number of acres which will require topsoil replacement and seeding. <br />17. The Applicant has stated the mine workings will be filled with dewatered tails and cement. <br />The Applicant must demonstrate the backfilling of the portals with tails will eliminate the <br />discharge of mine water. In the Division's experience, portals which discharge mine water <br />must be backfilled at least 20' from the entrance and the backfilled material must be <br />compacted to achieve a coefficient permeability of 1x1 -5 cm/sec. Alternately, the Applicant <br />may provide design details for the construction of hydraulic plugs. In order to evaluate the <br />plan to backfill the portals with cemented tails, the following information must be submitted <br />to the Division: <br />a) Cross sections of the portal entrances. <br />b) An estimate of the volume of tailings required to backfill the mine workings. <br />c) An estimate of the volume of cement to be mixed with the tailings. <br />d) A description of how the material will be backfilled and compacted. <br />e) Describe where the tailings material will come from and demonstrate that this <br />material will be available upon closure of the portals. <br />f) An estimate of the rate of water discharging from the portals. <br />g) The rate of slope of the portals. <br />