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Permit M-1977-493—Climax Mine Of additional importance to reclamation is the control of erosion and sediment runoff. Climax has obtained coverage under the Colorado Discharge Permit System (CDPS)—Stormwater Discharges Associated with Metal Mining Operations and Mine-Waste Remediation program (Certification No. COR-040178) and maintains a current Storm Water Management Plan (Climax Molybdenum Company 2022); Climax conducts regular inspections as directed by this plan. Best management practices (BMPs)to control erosion and sediment (e.g., silt fence and straw wattles) are regularly installed, inspected, and maintained as needed throughout the mine site. BMPs will continue to be used routinely during production and reclamation activities as needed to comply with regulations. Discharges included in the stormwater program are located outside of the active mining and industrial areas and include areas such as reclaimed sites, access roads, etc. Water discharges occurring from within the active mining and industrial areas are managed under Climax's CDPS No. CO0000248; this permit contains effluent limitations, monitoring requirements and other conditions regulating water quality. E-5 Grading As stated in previous approved plans, disturbances with slopes that need regrading will, whenever possible, be graded to no steeper than 2H:1 V and 3H:1 V slopes for OSFs and TSFs, respectively. TSF outslopes have been constructed at slopes of 3H:1 V or flatter and do not require any regrading during reclamation activities. The design of the OSFs will incorporate stability evaluations based on this maximum overall composite slope of 2AH:1 V. All OSF outslopes, currently at the angle of repose, will similarly be regraded to a maximum interbench slope of 2H:1 V. Final OSF slopes are anticipated to be regraded and may achieve slopes flatter than 2H:1 V to promote long-term stability (Exhibit D, Section 3.3). Ultimately, grading will be implemented to maintain drainage control and stability. When possible, shallower slopes will be graded to promote revegetation. Exceptions to this general standard include the open pit. The majority of the open pit will not be graded. E-6 Growth Media The use of on-site soils to provide nutrients and organic matter and enhance their water-holding capacity has historically been successful as growth media at Climax. This can be achieved with additions of a combination of seed and mulch. This section provides detail regarding the ongoing soil salvage and stockpile operations across the site as well as a discussion regarding various soil amendments historically used. E-6.1 Reclamation Cover Salvage Overburden soils (combined topsoil and subsoil) are being salvaged and stockpiled throughout the mine for future use as reclamation cover. Mobile equipment will be used to remove reclamation cover materials that will be either directly hauled from areas affected by mining activities to the reclamation site or placed in designated storage areas adjacent to each production area for easy reapplication to the disturbed area, as shown in Figure F-02. Reclamation cover has been salvaged and stockpiled at Climax since 1978. Current stockpiles located around the mine site include approximately 816,100 cubic yards for stockpiles west of State Highway 91 and 1,375,000 cubic yards east of the highway for future reclamation use (Figure F-02, Exhibit F). Additional soil will be salvaged from areas of planned disturbance prior to raising the dams on the Mayflower TSF and increasing the size of the McNulty OSF (Section 1-6 in Exhibit 1). Approximately 2,239,000 cubic yards and 4,899,800 cubic yards are planned to be salvaged from the McNulty OSF and Mayflower TSF expansion areas, respectively. If necessary, BMPs will be implemented to reduce erosion from the new stockpiles. Climax is proposing two reclamation cover removal options. The first option is used when reclamation cover materials are being directly hauled from the disturbance area to reclamation. The second option is used when reclamation cover materials are being stockpiled for later redistribution. Exhibit 1: Soil Information contains the baseline soil salvage depth and volume tables for the McNulty and North 40 OSFs (Table 1-1)and Mayflower TSF (Table 1-2) mining areas. The baseline soil volume summary contained in Table 1-4 (Exhibit 1), contains a listing of soil removal areas and total salvage volumes compared to reclamation cover replacement volumes. The salvage depths are based on a critical review of the USFS White River and Pike soil survey soil map unit descriptions. Soil salvage depths will be determined by in-place soil monitoring to be conducted ahead of soil removal operations. Deep soils for reclamation cover are usually located in draws and valley floors while ridge tops have generally very shallow topsoil with high coarse fragment contents. Shallow ridge soils usually covers rocky parent material Exhibit E E-4 May 2024