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~• Therefore, to ensure s stability Factor of Safety of at least 1.3 at the Portal Bench <br />Turnout, continued dewatering of the full cross section is required. To return this section <br />to its approximate original condition and contours, the downslope retaining walls must be <br />removed and the section should be backfilled in uniform lifts, with approved on site <br />material, to appro~mately 85% or more of maximum density by the Standard Proctor <br />Density test. The upslope retaining wall can be removed or left in place. Leaving it in <br />place does in fact improve the Stability Factor of Safety for this localized area. <br />Therefore, for this reason it is recommended that it be left in place and buried. The top <br />segment should be removed so that the topsoil depth is not intercepted by any binwall <br />metal material All in place piezometers should be protected so that the dewatering <br />system can be monitored alter all reclamation procedures have been completed. .Any <br />areas not being effectively dewatered should be delineated and the horizontal drains <br />should be redrilled in these areas. <br />Therefore, at the Portal Bench Turnout -Access Road Station 65+00, the following <br />procedure is recommended for reclamation in order to ensure a Stability Factor of Safety <br />of 1.3 or greater. <br />1. Inspect and ensure that the dewatering system is operating properly. Check <br /> and take measures to protect all in place piezometers. <br />2. Carefully remove and dispose of the concrete structures protecting the <br /> outlet oP the horizontal drains. <br />3. Remove and salvage the downslope retaining walls. <br />4. Remove the top portion of the upslope retaining wall so that the top of the <br />~~ wall is below the proposed top soil depth. <br />5. Backfill to the approximate original contours, minus topsoil depth, in <br /> uniform 8" lifts. Backfill shall be compacted to at least 85% of maximum <br /> Standard Proctor Density. <br />6. Spread topsoil to an even depth of 12" to 18" as called for by the Md~R plan. <br />7. Seed and mulch as called for by the MdcR plan. <br />8. Leave all areas tree draining end provide erosion protection for seed on <br /> steep slopes as required by the MckR plan. <br />F. Reclamation of Substation Pad: <br />The substation pad is within the area designated for potential activity. As such, a <br />dewatering system will be installed to stabilize the substation pad during the <br />construction and operational stages of the Mt. Gunnison Mine. <br />The substation pad, with its retained fill and cut slopes, is comparable to the case <br />of Access Road Station 65+00. The recommended reclamation procedures for <br />ensuring a Stability Factor oY Safety of 1.3 are the same as for that case. The <br />dewatering of this area must be continued after all reclamation activities have <br />been completed. Once all superstntetures have been removed, the downslope <br />retaining walls can be removed and the section can be backfilled in uniform ]ayers <br />to at least 85% of the maximum Standard Proctor Density. The upslope retaining <br />wall should be left in place and buried; the top segment of the wall, however, <br />should be removed below the proposed topsoil depth. <br />~• <br />