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Colony Reclamation Cost Estimate, Update to Exhibit L Rev. Sept. 2023 All of the alphanumeric area designations for these are the same as those assigned in summer 1982, and are depicted as such on Figure L-1, Reclamation Bond Areas, included herewith. With the approval of Middle Fork Dam as a permanent post-mining fixture in the 2007 Area Reduction, a few of the above areas might also be considered in their final condition. For example, roadway maintenance requirements and access to the dam and the upper plateau areas would seem to justify leaving the shop and office buildings as permanent fixtures in Areas 4 and 5 (lower valley) of the affected area. Similarly, the small "Summit Ridge" flat area 8B has been used as a marshalling yard and laydown area for equipment for Middle Fork Dam inspections and maintenance since 1985. However at this time reclamation costs for these areas are still included within the current reclamation liability estimate. Colony may apply for a second area reduction in the future to designate these and a few others as in their final form, but that is not proposed at this time. . The location and numerical identification of the remaining affected acres are shown on reclamation Figure L-1. The acreage associated with each area is listed in Table L-2, along with direct cost portion of the overall reclamation cost attributable to each area. Overview of Exhibit E Reclamation Standards Assumed for this Cost Estimate The reclamation standards described in Exhibit E of the original 1980 permit application have been used as the basis for this reclamation cost estimate. Except for Area 9, Davis Gulch dam site, and Area 6, Mine Bench, all of the remaining affected acreage falls into the category of "Process Plant and Mine Support Facilities". The relevant portions of Exhibit E are those that address these limited categories of disturbance, essentially pages E-48 through E-52 of the permit application. Although there have been no changes to the reclamation plans or performance standards for the spent shale piles, which constitute the majority of Exhibit E of the original permit application, those sections dealing with reclamation of spent shale areas are not relevant at this time simply because these areas have not yet received any spent shale. Further, reclamation standards for roads that were included in Exhibit E are no longer relevant to this review because all of Colony's access roads, including their cut and fill side slopes and roadway surfaces are now classified as permanent post-mining features and are therefore now in their post-mining condition. Accordingly, the steps described in the reclamation timetable, seeding and mulching techniques and seed mixes applicable to the "Process Plant and Ancillary Facilities", specifically the seed mix in Table E-3 of the 1980 permit application, are the basis for the revegetation components of these cost estimates. It should be noted that the earthwork components of the reclamation cost in the 2017 surety reduction and in this surety update are by far the largest components in the total reclamation cost estimate. Exhibit E calls for a minimum of 6 to 12 inches of topsoil to be spread on the process plant and ancillary facilities. Therefore, this reclamation plan will use an average of 9 inches to cover these areas, so that the actual thickness in place will vary from about 6 inches to 12 inches as per the 1980 permit application. However, the topsoil salvaged from these areas and stockpiled in the two large topsoil stockpiles about one mile northwest of the plant site contains more material than is required to place an average of 9 inches over the ancillary areas still classifies as disturbed areas. These include Plant Site Area 18, Coarse Ore Valley Area 17, La Sal Laydown Area 16, and the Upper Davis Gulch Dam Materials Stockpile Area 10B. After sufficient topsoil to reclaim the ancillary areas to an average depth of 9 inches has been extracted from the stockpiles, the remaining materials in the stockpiles will be re-graded down to Page 3