2024-03-28_REVISION - M2015030 (2)

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Chavers Mining Resource DRMS Permit No.M-2015-030 Amendment No.2(AM-02) March 2024 Page 19 6.4.12 EXHIBIT L - RECLAMATION COSTS 6.4.12(1) COST ESTIMATE The reclamation plan for the Chavers Mining Resource is to backfill the Site at least to the minimum requirement of one (1) foot above the historic high measured water table elevation as a worst-case reclamation scenario.The pre-mining surface topography of the Site gently sloped from the south to the north. The historic high groundwater elevation is 4,910.33 ft amsl in monitoring well MW-3 which is located near the midpoint of the Site. This indicates that a midpoint baseline backfill elevation of 4,912 ft amsl will provide sufficient coverage (i.e., 1.67 feet). In February 2024, photogrammetry was conducted to document current topography of the Site. ASCI utilized Propeller software to map site contours and perform the earthwork cut/fill volume calculations to balance the affected area to the midpoint backfill elevation of 4,912 ft amsl (actual backfill will smoothly transition from south to the north). The contour map generated by Propeller is presented in Exhibit L-1. The material volumes generated by Propeller are presented in the following table. Earthwork Volumes to Balance the Site to 4,912 ft amsl Fill Material Required(Total) 764,398 CYs Cut Material On-site 680,718 CYs Required Fill Material to be Imported from Off-site 83,680 CYs Based on the photogrammetry conducted, 83,680 CYs of material is required to be imported from off-site to balance the Site. To determine the cost to import this material, ASCI obtained three(3) quotes,each valid for 12-months, from area operators to purchase,load, and haul (includes freight and fuel charge) the backfill material to the Site (Exhibit L-2). A conversion factor of 1.5 was used to convert tons to CYs. The average cost of the three (3) quotes was used when calculating the reclamation bond required for the Site. The average push distance for a dozer to push material dumped at the pit crest is approximately 150 feet. Exhibit L-3 presents the costs that would be incurred by the state, broken down into the various major phases of reclamation, to complete reclamation of the Site as geotechnically stable, non- erosive, properly draining, and weed-free. To ensure the reclamation bond remains sufficient, ASCI commits to re-evaluating earthwork volumes to determine the amount of backfill material required to be imported from off-site annually. In addition, if a permitted mine site operated by ASCI is not specified as the source for off-site backfill material, ASCI will obtain revised cost estimates to purchase, load, and haul the required volume of backfill material to be imported from area operators. This information will be submitted to DRMS as part of the Annual Report each