2012-08-03_PERMIT FILE - C1981012 (4)

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April 16, 2012 Page 17 2. The material removed as part of the foundation preparation should be stockpiled in the area designated for topsoil and used later for reclamation purposes. If additional soil materials are needed for reclamation, excavation of the proposed West Portal DWDA foundation can be extended to the depths necessary to achieve required quantities. 3. Any underground openings encountered during surface preparation must be dismantled to the extent practical. Portals and tunnels that cannot be excavated in their entirety should be properly sealed and backfilled prior to coal mine waste placement. The rope slope should be sealed, according to MSHA standards, prior to placement of the mine development waste rock. 4. Upgradient surface water should be routed away from or around the waste pile by adequately sized diversion channels. 5. The coal waste pile should be designed and graded to shed surface water and precipitation off all portions of the pile both during and after coal waste placement. 6. Coal waste should be placed near its optimum moisture content as indicated in Table 7. Waste material placed significantly above or below the optimum moisture content likely will not achieve adequate compaction or shear strength. Once a suitable moisture content is achieved, coal waste should be sealed (by compaction) to minimize infiltration from precipitation and should be graded to shed water per the drainage plan. 7. Ongoing strength testing and in -situ moisture /density testing of the compacted coal waste material may be warranted to ensure that the assumptions made in this evaluation are valid. If coal waste composition, moisture content, or placement techniques change, AAI must be immediately notified to evaluate the impacts of the change on the stability of the waste pile. 8. AAI must be notified if a waste pile geometry different than the one evaluated and discussed in this report is considered. Also, if coal waste composition, moisture content, or placement techniques change, or any other assumption presented in this report is not valid, AAI must be notified to evaluate the impact on the stability of the coal waste pile. AAI remains available for consulting during final design and construction, and can assist with field monitoring of ground conditions, as needed. It is recommended that NECC have procedures for field implementation of the report's recommendations. Recommendations provided in this report do not constitute a final design. The recommendations provided herein are based on accepted practice and referenced sources have been cited where appropriate. Agapito Associates, Inc.