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.

Tri-Star (Silverstar and Goldstar)
The gold deposits at the Tri-Star complex (formerly Genesis) are developed along the Tuscarora, Turquoise, and Ridge anticlines within the Lynn Window. They occur over an area of about 3.2 kilometres long by 1.9 kilometres wide. The Silverstar deposit occurs in the hinge of the Tuscarora anticline whereas the Bluestar Point, Bobstar, Goldstar, and Payraise deposits occur on the more western anticlines. The anticlines are intruded in the north by the 158 Ma Goldstrike intrusion, a thick composite diorite–granodiorite sill complex.

Five major lithologic units are recognized in the Tri-Star deposit from surface mapping and drill hole logging: Tertiary Carlin, Devonian Rodeo Creek, Devonian Popovich, Silurian Roberts Mountains, and Ordovician Hanson Creek Formations.

Mineralization is preferentially developed in laminated silty limestone and bioclastic debris flows of the Popovich and Roberts Mountains Formations, but locally can also occur in contact metamorphosed calc-silicate hornfels, Rodeo Creek Formation siliceous mudstone, siltstone and calcarenite, Vinini Formation mudstone/quartz hornfels, and fractured Goldstrike intrusive margins. Gold deposits generally occur where mineralizing fluids exploited thrust faults, conjugate northwestand northeast-striking normal faults, and anticline hinge zones. The deposits have dimensions that range from about 183 to 457 metres by 61 to 183 metres. Mineralization can be stratabound locally but is typically discordant to the formations along faults with thicknesses ranging from 15 metres to 91 metres.

The Carlin Complex has three major open pit operations including Goldstrike, Gold Quarry and Goldstar (Part of Tri-Star (Genesis)). All three are truck and shovel operations.

Similar to Goldstrike, the Gold Quarry and North Area Carlin (Goldstar) open pit mines are mined by conventional drill and blast followed by truck and shovel load and haul. Rock material in mill ore zones are drilled, blasted and mined in 6.1 metres (20 feet) passes to ensure minimal dilution. Material in leach and waste zones are drilled, blasted and mined in 12.2 metres (40 feet) passes.

North Area Carlin and Gold Quarry pits have haul road effective widths for two-way travel of 100 ft (30 m) for cut-to-fill roads and 120 ft (37 m) for external fill roads with a maximum grade of 10%. Minimum pit-bottom width is designed at 150 ft (45 m). Bench heights vary from 20 ft (6 m) to 40 ft (12 m).

Goldstar pit slopes have been designed using a 40º to 45º double bench configuration for all walls. The slope angles used in the reserve pit design are based on the performance of the 42º to 45º slope angles in similar rock types in the historical Genesis pit. In the design pit, the maximum slope height will be nearly 1,040 ft (317 metres) along the south wall of the pit. Previous geotechnical work has identified local areas of intense clay alteration associated with faults in the pit. Geotechnical risk associated with these zones have been evaluated and remedial measures have been designed, as required.

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 ........