2024-01-10_GENERAL DOCUMENTS - C1980007 (2)

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A = RxKxLSxCxP Where: A = predicted soil loss (tons/acre/year) R = erosivity index of local rain f all K = soil erodibility f actor LS = length/slope f actor C = vegetative corer f actor P = management practice factor It was assumed that factors R and P were unchanged between the two areas. A value for K was derived at every sample location,but the same value was used for the reclaimed area and the adjacent undisturbed area; no consideration of soil compaction was made, however given the time since reclamation took place(5-6 years)natural settlement and compaction will have occurred, so the assumption is acceptable. No consideration was given to management practices in P. Based on the assumptions made, the difference in the calculated value of predicted soil loss, A, was due to differences in the vegetative cover factor, C, and the length/slope factor, LS. Values for C and LS were determined from table values in"Rainfall erosion losses - a guide to conservation planning",by Wishmeier, W.H. and D.D. Smith, (Agricultural Handbook No. 537, USDA, Washington, D.C., 1978), based on field observations, sampling data and measurements made by Savage and Savage Environmental. The results of the RUSLE calculations indicate that significantly less sediment will be lost from the reclaimed areas (0.173 tons/acre/year)than the adjacent undisturbed area(4.938 tons/acre/year). Summary and Conclusions Based upon a review of the mine permit,the applicant's bond release application, and site inspections, the Division finds that Mountain Coal Company,LLC has replaced topsoil in accordance with the approved reclamation plan. Mountain Coal Company, LLC has established vegetation which supports the approved post mine land use and meets the approved success standard for vegetative cover. The Division finds that the reclaimed area subject to this bond release is not contributing suspended solids to streamflow or runoff outside the permit area in excess of premining levels or in excess of adjacent nonmined areas. IV. PROPOSED DECISION Based on the observations above,the Division proposes to approve Mountain Coal Company, LLC's request for a Partial Phase 11 bond release for the West Elk Mine. This proposed decision will release the applicant from liability for Topsoil redistribution and establishment of vegetation on the parcels described in Table 1. An accounting of the West Elk Mine's bond release history is provided in Table 2 below. C-1980-007 Page 8 of 10