2019-06-28_REVISION - M1977004 (12)

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Homestake Mining Company June 17,2019 Regular(112d)Operation Reclamation Permit Application Package 3.0 RECLAMATION COST ESTIMATE 3.1. Basis of Cost Estimation The 2019 cost estimation model was prepared using the SRCE spreadsheet, Version 1.4.1, Build 016c. This version allows for flexibility in using either User-defined or Nevada-approved Cost Data Files, as discussed in the following section. This spreadsheet was developed by the State of Nevada and is available for download at http://www.nvbond.org. SRCE is a tool that was originally developed for mining projects in the State of Nevada as a cooperative effort between the Nevada Division of Environmental Protection, Bureau of Mining Regulation and Reclamation, the U.S. Department of Interior, Bureau of Land Management, and the Nevada Mining Association. The model was developed to facilitate accuracy, completeness and consistency in the calculation of costs for mine site closure and reclamation. Although originally developed for use in Nevada, it is now used extensively by public and private property mining projects in several states and jurisdictions. As a standard practice, Barrick has applied the SRCE model for calculating reclamation and closure costs at projects company-wide. The model includes built-in worksheets for the calculation of reclamation activities that are specific to a mining project. Where the capabilities of SRCE did not provide adequate estimation tools applicable to the Mine, the reclamation costs were estimated in "User Sheets" provided at the end of the model. The reclamation costs are based on the reclamation plan presented in Exhibit E (Amended Reclamation Plan), the Maps presented in Exhibit F (Reclamation Plan Maps) and the assumptions presented in Section 3 3.2. Reclamation Costs The SRCE model was coupled with input costs in the Cost Data File, which can either be user- defined or based on the Nevada-approved file. For the purpose of this model, the user defined cost data file was used, using cost data from the Nevada-approved Cost Data File and RSMeans (2018), as a method of reasonably estimating labor, material, and equipment costs from pre- approved costs data sources. Printouts of this Cost Data File are provided in Appendix B for reference.The SRCE model built up costs from first principals for each activity,and were generally based on the following: • Reclamation costs are estimated assuming that SRCE-defined crews and fleets are used to perform the reclamation activities. • Heavy equipment used in the SRCE model is standardized with Caterpillar, because the company manufactures an extensive line of equipment and offers comprehensive technical specifications and productivities. Caterpillar's equipment productivities used in the SRCE are derived from the Caterpillar Performance Handbook, Edition 35 (Caterpillar, 2004). • Productivities were calculated assuming that all equipment pieces will be operated by operators with average skill levels and equipment have a job efficiency ranging from 30-50 minutes per hour, depending on the type. Productivities for other equipment were EXHIBIT L-RULE 6 4 12 (RECLAMATION COSTS)(Revised June 17,2019) Page 3 HOMESTAKE MINING COMPANY