The Goldstrike deposits are all Carlin type deposits, with fine to very finely disseminated gold and arsenic bearing pyrite. The host rocks are generally sedimentary, mostly calcareous formations, frequently altered and decalcified. There is hydrothermal alteration and there are collapse structures which generated the breccias that host the deposits. The alteration and folding and faulting have led to poor rock quality in the deposits in generally and locally very poor ground conditions in the vicinity of the major faults.

The Rodeo deposit is located approximately 4,500 ft south of the Meikle underground mine and 3,600 ft north of the Betze-Post open pit.

Economic grade mineralization occurs in two zones in the Rodeo area, the Upper and Lower zones. The combined dimensions of the two zones have a strike length of 2,300 ft. The zones extend from the elevation of 3,500 ft to 4,700 ft, with a true thickness of 100 ft to 200 ft.

The Upper Zone consists of four subzones: The Upper North, Middle, Upper South, and West subzones. The Upper Zone lies within a stratigraphic and structural antiform that has a shallow plunge to the north-northeast. Mineralization is hosted in the Upper Mud, Soft Sediment Deformation, and Planar units of the Popovich Formation as well as Jurassic lamprophyre dikes. The morphology of the mineralized zone is dictated, in order of significance, by the proximity to favorable feeder structures, receptive lithologies, and struc ........

Goldstrike underground operations use two mining methods for extraction: long hole open stoping and underhand drift & fill, both of which rely on cemented backfill for support.

In relatively good to fair ground conditions, where longhole stoping methods are used, the wall and back instability is reduced by mining smaller, longhole sections and filling before mining the next section. In poor ground, the underhand drift and fill method provides a backfill roof for subsequent lifts in the mining cycle.

Rodeo is a trackless operation, using two different underground mining methods: long-hole open stoping and drift-and-fill.

The paste fill plant was commissioned at Rodeo in 2013. The method utilizes tailings from the Roaster facility mixed with cement. This method replaced backfill from the Rodeo cemented rock fill plant in 2013 when the open pit mined through the plant’s aggregate delivery raise. Paste fill is cheaper and more efficient than the cemented rock fill and offers another way to dispose of Roaster tailings.

The underhand drift and fill method is utilized in areas of fair to poor ground conditions regardless of the width of the zone. The underhand drifts are nominally designed as 4.6 metres (15 ft) wide by 4.6 metres (15 ft) high. The minimum width is 4.6 metres (15 ft) (one drift). The primary drift is driven with increased ground support to hold the ground open, then backfilled with a high strength cemented rock fill at th ........

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