Gold mineralization at Fort Knox Mine is hosted entirely within the Late Cretaceous (~92 Ma), Fort Knox granite pluton. The contact with the Fairbanks Schist is abrupt. Drilling indicates that the pluton contacts plunge steeply to the north and south and moderately to the east and west. The surface exposure of the pluton is approximately 1,100 m (3,609 ft) in the east-west direction and 600 m (1,969 ft) northsouth.

The Fort Knox Pluton has been subdivided into three phases based on grain-size and textural differences. Intrusion of a biotite-rich fine-grained granodiorite was followed by medium- grained porphyritic granite. The youngest intrusive phase is coarse-grained, porphyritic granite (Bakke, 1995). The texture is dominantly porphyritic, with megacrysts of quartz and k- feldspar, which become more sporadic in the fine- grained phase. The pluton is granite-granodiorite in composition, and the mineralogy of all phases is generally sub-equal amounts of quartz (30%), plagioclase (30-40%), and k-feldspar (20 to 30%) (Bakke, 1995; Blum, 1983).

The major structural trends controlling shear vein orientation and mineralization at the deposit- scale are defined by NW-trending, moderately to shallowly SW-dipping fault zones. The fault zones are typically filled with granulated white quartz, and range in thickness from 0.3 to 1.5 m. The zones have mixed groundmass alteration, with a range of phyllic and argillic alteration assemblages. In the vicinity of the ........

The Fort Knox Gilmore expansion will be an extension of current operations from 2021 to 2027. The existing operation is a conventional hard-rock open pit using drilling, blasting, loading, hauling and support functions.

Two new pushbacks have been designed and scheduled for the Gilmore expansion area: Phase 9 and Phase 10. Phase 9 contains approximately 156 million tonnes of ore and waste, while Phase 10 contains approximately 230 million tonnes of ore and waste, for a total 386 million tonnes of additional mining.

Initial mining of Gilmore is planned for 2019 as surplus mining equipment capacity is released from the Phase 8 East mining areas. Mining rates increase significantly in 2021 and 2022 as tonnages mined from Phase 8 East decrease. The mining of ore from Phase 9 roughly corresponds to the commissioning of the new Barnes Creek heap leach facility, which is the planned processing destination for the majority of the ore mined from both Phase 9 and 10. Phase 9 contains significant quantities of ore at shallow depths. Some ore mined from Phase 9 in 2019 through 2021 will be processed at the Walter Creek heap leach facility as sufficient capacity would not yet be available at Barnes Creek. Mining of Phase 9 is planned for completion in 2024.

Phase 10 mining is planned to start in 2022 when space and vertical advance constraints restrict the development of the Phase 9 pushback. Phase 10 contains little ore in its higher elevations and ........

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