2023-03-09_PERMIT FILE - M2022013 (6)

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Page 19 6.4.12 EXHIBIT L - Reclamation Costs Typical Liner and Regrade for Extraction Limit Wall — Final Reclamation _ _ _ _ _ _ _______________- Original ground surface Sequence Topsoil 1. In cycles • Install liner in 6"lifts Static Water Level Backfill to 3H•1V Liner 2. Replacetopsoil Regraded slope at 3H:1V g p Backfill material Unexcavated Perimeter Wall (slope 1.25H:1V ) Keyway Bedrock Typical Liner and Regrade for Extraction Limit Wall Raptor conservatively estimates for Financial Warranty purposes an approximately 4,020- foot wall excavated at 21-1:1V, a 2,180-foot wall at 1.25:1V slopes, and a 4,610-foot wall at 3H:1V. Perimeter liner at 21-1:IV, 4,020 lin.ft. x 78 sq.ft./ft x 4 ft. / 27 = 46,610 CY of liner placed at an estimated cost of $2.20/CY = $ 102,541.11. Perimeter liner at 1.251-1:1V, 2,180 lin.ft. x 56 sq.ft./ft x 4 ft. / 27 = 18,095 CY of liner placed at an estimated cost of $2.20/CY = $ 39,808.46. Perimeter liner at 3H:1V, 4,610 lin.ft. x 111 sq.ft./ft x 4 ft. / 27 = 75,590 CY of liner placed at an estimated cost of $2.20/CY = $ 166,298.33. Keyway at the base of the 3:1 slope is estimated at 9,500 lin.ft. x 16 sq.ft. / 27 = 5,630 CY of liner placed an estimated cost of $2.20/CY = $12,385.19. $ 321,033.08 Total Liner Installation Cost NOTE: This is a conservative approach to the estimation of reclamation cost for financial warrant at the projected 5-year disturbance. The distance of 2H:1V wall is maximized which has a higher lining cost than wall at 1.25H:1 V. Also, if sufficient backfill material were available or accessible on site from either topsoil or overburden material in temporary stockpiles, or readily accessible from bedrock exposed, backfilling all the VARRA COMPANIES, INC. TWO RIVERS SAND GRAVEL AND RESERVOIR PROJECT MARCH 2O22 A REGULAR IMPACT[112]CONSTRUCTION PE RMIT APPLICATION—COLORADO DIVISION OF RECLAMATION MINING&SAFETY OFFICE OF MINED LAND RECLAMATION