The Goldstrike deposits are Carlin style deposits. Carlin deposits comprise stratabound disseminated gold mineralization hosted by Silurian-Devonian carbonate rocks that have been metamorphosed to varying extents. The deposits are hydrothermal in origin and are usually structurally controlled. The carbonate host rocks are part of an autochthonous miogeoclinal carbonate sequence exposed as tectonic windows beneath the Roberts Mountains allochthon.

Gold mineralization in the underground mine is subdivided into East Banshee, West Banshee, Meikle, South Meikle, (East) Griffin, Extension, West Griffin, Rodeo, Barrel, West Rodeo, and North Post deposits and sub-deposits. The sulphide mineralization is associated with silicification and argillization, and there is little or no oxide mineralization. In sulphide mineralization, the gold is intimately associated with very fine-grained pyrite and marcasite. Associated sulphide minerals include arsenopyrite, realgar, orpiment, and stibnite. Gangue minerals include quartz, calcite, and barite. Realgar and orpiment are generally low in abundance; however, these minerals are locally common in stockwork veinlets, fracture fillings, and breccia matrices.

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. [2019, Technical Report, p.161]

The Goldstrike property has two processing facilities: an autoclave installation, which was originally designed to treat the property’s non-carbonaceous sulfide (refractory) ore; and the roaster, which is currently used to treat the property’s carbonaceous ore (whose active carbon content responds poorly to autoclaving). The original combined installed capacity of these two facilities was approximately 27,000 to 30,000 tonnes per day. After the implementation of the thiosulfate modifications described below, the combined installed capacity of the two facilities is expected to be approximately 26,000 to 27,000 tonnes per day. These process facilities treat the ore from Goldstrike’s open pit and underground mines, as well as ore from other Barrick properties. Gold recovered from the ore is processed into doré on-site and shipped to outside refineries for processing into gold bullion.

The TCM technology uses calcium thiosulfate to leach the gold after pressure oxidation rather ........