The mineral deposits along the Carlin Trend form a suite of deposits known as Carlin-type. 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 Pete Bajo Complex is made up of three deposits: Pete Bajo, Fence, and Full House. Pete Bajo is the down-dip extension of the mineralization mined in the Pete open pit. The Fence deposit is located to the north, about 366 m down-dip of the Pete Bajo deposit. Full House is a down-dip extension of the Carlin East deposit and is offset by the Bullmoose Fault.

Lithologic units recognized in the Pete Bajo Complex include the upper portion of the Hanson Creek Formation (Ohc), Roberts Mountains Formation (SDrm), Popovich Formation (Dp), Rodeo Creek Formation (RC), and the upper plate Vinini Formation (Ohc).

The majority of the gold mineralization in the Pete Bajo Complex is hosted within the lower unit of the Popovich Formation (DpW). Localized, thin intercepts are also present within the Roberts Mountains Formation (SDrm) unit. Low angle faulting along the Popovich Formation (Dp/SDrm) contact thins or removes the upper units of the DpW within various zones of Pete Bajo resulting in discontinuous mineralized strata. These units are subsequently offset by a series of northwest striking apparent normal faults that dip to the northeast. An East-West striking, sub-vertical dike swarm has also been observed across the Pete Bajo and Fence deposits.

The Carlin Complex has three major operating underground mines including Goldstrike underground, Leeville and the Portal Mines (including Pete Bajo and Exodus/Northwest Exodus). All mines utilize drift and fill and/or long-hole stoping and are accessed by shaft or portals.

The mining methods used at Pete Bajo are primarily longhole open stoping with some overhand drift and fill. Mining sizes and orientations are defined by orebody geometry, geotechnical parameters and minimum mining sizes based on the equipment fleet.

Typical heading dimensions are 4.6 metres (15 ft) high and wide, and stopes are 4.6 metres (15 ft) wide for primary, and 9.1 metres (30 ft) for secondary stopes. Mining height is defined by orebody thickness. Where there is sufficient vertical extent, sub-levels for stopes are established at 13.7 m (45 ft) intervals.

The Mill 5 facility uses a combination of flotation and cyanide leaching to recover gold. The basic steps are as follows:

• Crushing and grinding where ore is ground to the appropriate particle size, usually about 65% -200 mesh;
• Conditioning with a mixture of chemicals to provide for air bubble attachment to pyrite, arsenian pyrite, and arsenopyrite particles while minimizing bubble attachment to gangue minerals such as silica or calcite;
• Froth flotation where the pyrite, arsenian pyrite, and arsenopyrite are floated into a concentrate by sparging air into the conditioned slurry;
• Concentrate is thickened and filtered so that it can be further processed through a separate oxidizing facility such as the Mill 6 roaster or the Sage autoclave;
• Residual gangue or flotation tailings contain sufficient residual gold to warrant CIL processing;
• CIL processing involves leaching of the slurry with cyanide to dissolve the gold and then adsorb the gold o ........