2019-06-28_REVISION - M1977004 (9)

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Homestake Mining Company May 10,2019 Regular(112d)Operation Reclamation Permit Application Package 5.0 RECLAMATION PLAN The topography of disturbed land and the degrees of disturbance vary greatly over the permit area, and therefore, the type of reclamation to be implemented may vary by area. The reclamation tasks to be performed across the Mine will require many years to accomplish. Certain tasks may be required to follow others in sequence and other ones may simply require a long time to implement or complete. Additional factors influencing the need for scheduling reclamation over multiple years, include budget limitations for each activity, as well as the prioritization of important tasks and within specific OUs. 5.1. Operable Unit 1: North Pit The current topography for the North Pit is shown on Exhibit F Map F-01A. 5.1.1. Previous Reclamation The majority of the rock dump in the North Pit has been regraded to its final slopes, terraced, and reseeded. 5.1.2. Proposed Reclamation The following reclamation activities are proposed within the East Diversion Ditch area: • The East Diversion Ditch will be re-established to convey runoff into the existing diversion ditch further south. The ditch will be graded and lined with a Geosynthetic Clay Liner(GCL) to minimize infiltration and seepage along its alignment. The following reclamation activities are proposed within the Landslide Toe Mitigation Area (defined as including the Northwest Pit Wall Layback, Partial Pit Backfill, French Drain and Southeast Pit Wall Buttress): • The outlet control structure associated with the North Pit Dam will be lowered approximately 8 ft below the current crest, to an elevation coinciding with the Partial Pit Backfilling of the in-pit lake. The North Pit Dam may need to be removed, depending on the construction requirements of the French Drain System to be installed within the current pit lake. • The Partial Pit Backfilling will be performed with borrow material generated from the Northwest Pit Wall Layback. The Partial Pit Backfill will be to an elevation approximately 4 ft below the current North Pit Dam. The preliminary design of this buttress is anticipated to require approximately 120,000 cubic yards(cy)of fill, as shown on Exhibit F Map F-01 B. A soil cover will be designed for the partial backfill to minimize infiltration of surface (non- contact) water and separate contact and non-contact flows. This cover will be planted to grass and shrubs in the manner implemented for the rock dumps. • A French Drain system will be installed to collect ground (contact) to capture water emanating from the underground mine workings,which currently expresses at the Chester Fault springs and within the North Pit Lake. Depending on the extent of uranium load reduction achieved with the phosphate injection system in the underground mine workings, the water captured with the French Drain may exhibit residual elevated uranium. EXHIBIT E-RULE 6.4.5(AMENDED RECLAMATION PLAN) Page 67 HOMESTAKE MINING COMPANY