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Mr. Dave Canning Page S ix April 15, 1982 Bonding Calculations (cont'd) More detail should be provided as documentation for estimating portal sealing, backfilling, tospsoiling, soil preparation and re vegetation costs. A detailed work sheet should be provided, including relevant operating assumptions such as: A. Mass balance calculations, B. Haulage distances, C. Equipment type (make and model) D. Location, job efficiency, and production adjustment factors, E. Labor rate used, and, F. Reference from which hourly equipment costs and production figures were obtained. The estimated costs for portal sealing should include costs of materials, delivery, labor, and the number of entries to be sealed. Due to the fact that the Apex No. 1 portals are utilized for ventilation for the Apex No. 2 Mine, these portals must also be reclaimed. In order to backfill the portal area and to fill the sediment pond as proposed, fill material of a non-toxic non-polluting nature must be imported. These volumetric and cost calculations must be provided. Soil preparation costs should be broken down into ripping, disking and topsoil haulage and distribution. Revegetation costs should include the seed mix costs, seedling costs, costs for drill seeding, hydro-seeding, mulching fertilization and labor. 2.05.4(2)c Backfilling and Grading The applicant has requested a variance from approximate original contdur, based upon steep slope mining conditions. The original slope within the portal bench area, as the applicant observes, exceeded 80$. Further, a county public right-of-way exists immediately below the portal bench. See the Land Use section and the Steep Slope mining sections of this document for further discussion. The applicant proposes to partially backfill the portal bench cut. The 30-foot high portal bench cut will be backfilled to approximately 15 feet in depth, resulting in 10 foot of cover being placed above the 5-foot thick coal seam outcrop. The portal fill will be graded to approximately 45o in slope, resulting in a 5-8 foot wide toe bench at the foot of the back- filled slope. This bench will assist in catching any debris which might fall from the bench cut or the overlying natural slopes. This configuration should assist, therefore, in prevent- ing injury or damage to users of the county public right-of-way.