Long Canyon is a sediment-hosted disseminated gold deposit.

The gold mineralization at Long Canyon is best described as sediment-hosted, Carlin-type gold mineralization.

The mineralization identified at Long Canyon shares many of the characteristics of Carlin-type gold mineralization, including:

• Stratigraphic control on mineralization - mineralization is hosted primarily in limestone, particularly in silty, thin-bedded units;

• Structural control on mineralization - mineralization occurs in karstic cavities, collapse breccias, and anticlinal fold hinges;

• Geochemical association - elevated arsenic, mercury, antimony, and thallium accompany the gold mineralization, while silver and base-metal concentrations are low; and

• Alteration - mineralization is associated with decalcification, silicification/jasperoid, oxidized variants of pyrite and arsenical pyrite or arsenopyrite, and clay alteration.

The Long Canyon project also displays some characteristics that are unlike typical Carlin-type gold deposits. The prevalent association of hematite with gold mineralization at Long Canyon is not a common characteristic among all Carlin-type deposits, although this phenomenon is associated with weathered/oxidized portions of some of the deposits.

The Long Canyon available mining fleet consists of two shovels and twelve 240-ton haul trucks.

Commercial production at Long Canyon was achieved in November 2016.

Oxide ore with suitable cyanide solubility is treated on a heap leach pad.

Long Canyon is permitted to process up to 5 million tons of ore annually, with developments that consist of:
* an open pit;
* a heap leach facility (HLF);
* a carbon-in-column (CIC) plant;
* a waste rock storage facility (WRSF); and
* support facilities including a truck shop and administration building.

A dilute sodium cyanide solution is applied to the stacked ore on the high-density polyethylene (HDPE) lined leach pads. Pregnant solution from the leach pads is collected in perforated piping under the leach pad, and reports to main collection headers that lie in a HDPE-lined Solution Collection Channel along the edge of the heap leach pad. The collection headers report to a Pregnant Solution Tank (PST), and a Process Solution Pond (PSP) is available for solution in case of upset plant operating conditions. The PSP has a total capacity of 17.4 million gallons, and is comprised of two connected internal cells of 4.9 million gallons capacity each, surrounded by a higher perimeter berm. The PSP is constructed with a double-lined HDPE membrane with interstitial leak detection, placed on compacted soil. The PST is an 8,000 gallon tank located on a shelf within the freeboard area of the PSP.

From the Pregnant Solution Tank, the pregnant solution is pumped to the CIC circuit where the gold is adsorbed onto carbon. Solution from the pond can be pumped to either the PST or the Barren Solution Tank inside the CIC building. The CIC circuit is located entirely within one building, adjacent to the PSP. The CIC consists of six carbon columns in series. The pregnant solution cascades from Column 1 to Column 6, while the carbon is advanced from Column 6 to Column 1. From Column 1, the loaded carbon is transferred into the Loaded Carbon Holding Tank then, loaded into transporters and taken to an existing refinery located at Newmont’s Gold Quarry / James Creek Project near Carlin, Nevada. The carbon is stripped and regenerated while the gold is processed into dore. Regenerated carbon is returned to Long Canyon for reuse. No refining is conducted at Long Canyon.

At the exit of Column 6 in the CIC, the barren solution is discharged to a Barren Solution Tank where sodium cyanide is added from two 10,000 gallon storage tanks, before being returned to the HLF. The heap leaching circuit is a closed-loop system with no process water discharge; fresh make-up water is added as required.

Gold recovered from the leach pad is transferred as gold-bearing carbon to Carlin for refining and shipment.