Carlin is a sediment-hosted disseminated gold deposit.

A portal within the Gold Quarry pit provides access to workings. Gold mineralization is hosted in decalcified, silty limestone units of the Siluro- Devonian Roberts Mountains Formation, which are folded into a northeast-trending anticline. Northeast-striking faults allowed gold mineralization to deposit along the hinge and limbs of the anticline. Unique to Chukar is the occurrence of visible gold along fractures.

Gold grains range from <0.1 to 10.0 microns in size and usually occur associated with microfractures or disseminated in microcrystalline cherty matrix. Au:Ag ratio ranges from about 2:1 in mill grade ores to 1:3 in leach grade ores.

Gangue Materials: silica, iron oxides, kaolinite, barite, alunite, pyrite.

The Chukar Footwall Underground mine workings are collared in the southwest corner of the Gold Quarry Pit; three portals are being driven into the walls of the open pit mine. Ore is mined using longhole-stope and cut-and-fill methods.

The majority of the underground ore as well as higher-grade surface refractory ores are processed through the roaster (Mill 6), which consists of a grinding circuit, roasting circuit and a conventional carbon-in leach circuit. Mill 6 processed approximately 3.4 million tons of ore in 2016. Higher-grade surface oxide ores are processed by conventional milling and cyanide leaching at Mill 5. Additionally, Mill 5 operates as a flotation mill treating lower grade, non-carbonaceous, sulfidic refractory ore to produce a gold/pyrite concentrate. Mill 5 processed approximately 5 million tons of ore in 2016.

Mill 5 is a pyrite floatation plant that processes sulfide and oxide ores that are ground in a sag mill and ball mills. The material is then sent to the floatation circuit where the sulfides are floated and dried for later processing in the autoclave or roaster. The oxide material remaining after floatation is sent to a set of carbon-in-leach (CIL) tanks for gold recovery. Mill 6 consists of a double rotating mill and a roaster; sulfide material is fed to the roaster where the sulfides are volatilized. Material leaving the roaster is sent to a set of CIL tanks at Mill 5 for processing. Tailings from both CIL circuits is combined and sent through a Caro’s Acid cyanide destruction circuit before disposal in the Mill 5/6 TSF.