2010-06-24_REVISION - M2000158 (7)

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Mr. Jared Ebert June 22, 2010 Page 5 7 CIVIL RES'DURCES 19) Will the revegetation plan remain the same as currently approved in terms of fertilization, seedbed preparation, and vegetation establishment? The seed mix below will be used in the revegetation plan. The seed mixture will be sowed at a rate of 22.0 pounds of pure live seed per acre. In areas where mix is to be broadcast, the seeding rate will be double. SEED MIX Common Name (Variety) Scientific Name Growth Season Growth Form Seeds/Lb Lbs PLS/Acre Blue grama (Hachita) Chondrosum gracile Warm Sod/bunch 825,000 2.1 Little bluestem (Camper) Schizachyrium scopadum Warm Bunch 260,000 3.0 Prairie sandreed Calemovilfa longifolia Warm Sod 274,000 3.0 Sand dropseed Sporobolus cryptandrus Warm Bunch 5,298,000 0.3 Sideoats grama (Vaughn) Bouteloua curtipendula Warm Sod/bunch 191,000 5.6 Western wheatgrass (Arriba) Pascopyrum smithii Cool Sod 110,000 8.0 TOTAL LBS PER ACRE: 22.0 Areas to be seeded will be cleared so they are free of debris and rocks larger than 1/2" which may hinder tilling, seeding, finish grading or subsequent operations. The operator will evenly distribute and place topsoil to 6" (minimum) depth over the areas to be revegetated. Fine grading will be performed to maintain drainage into swales, away from structures, etc. as required to provide smooth well-contoured surface prior to proceeding. Finished seeded areas will have a positive drainage to prevent the ponding of storm and irrigation waters. The operator will drill mechanically with a native grass drill with depth bands on slopes less than 3:1. He will drill in manner that after surface is raked and rolled seed will have 1/4" to 1/2" of cover. Broadcast seeding will only be used on small areas not accessible to machine methods. 20) Slurry Wall: a) The applicant states the bentonite will meet the API 13a standards. Please provide the bentonite manufacture(s certificate of compliance. If these are unavailable, please commit to providing them with the final construction report and certification. We commit to provide this certificate with the final construction report and certification. b) The plan indicates the slurry wall trench will be keyed into base layer at least one foot or as directed by the owner/engineer. The dam cross-sections enclosed in the Exhibit C map indicates the slurry wall will be keyed into the base layer at a three foot minimum. Please clarify this discrepancy. If the base layer is weathered, fractured, or contains sand lenses, it may be necessary to provide a deeper key trench. A more detailed design of the slung walls has been completed, with a minimum key depth of four (4) feet and increased wall width (minimum of 42-inch wide). 21) Will reclamation be done in phases and concurrently with mining? The slurry wall plan indicates the slurry wall will be installed in the following order Ponds D1, D2, C1, C2, B, and A respectively. Will the embankment be constructed for each pond after the slurry wall has been installed for each cell, or will it be concurrent with slurry wall construction? Will the Operator install the slurry wall and construct the embankment for a particular pond prior to moving to the next pond? It may be helpful to conduct this plan in phases in order to keep the financial warranty amount to a minimum. For example, the Operator may want to finish construction of pond D1 and