Gold Mine Process

1- Location Drilling
The active mining process begins with the drilling of blast holes, approximately 40 feet deep and 16 to 22 feet apart. The drill holes are located by Global Positioning System (GPS) mapping technology. The drill cuttings are sampled to confirm gold content.

2- Blasting
Controlled blasts of the drill holes break the rock and minimize movement. Controlled blasts help limit ground vibrations that are carefully monitored to ensure the vibrations are within strict permit limits.

3- Mining
The broken rock, called "muck," is surveyed and marked with flags to indicate gold-bearing ore and non-gold bearing rock referred to as "overburden."

4- Hauling
Large dump trucks are then used to move the ore to the primary crusher for processing. The overburden is backfilled to previously mined areas or is moved to engineered storage areas.

5- Crushing
Ore is processed at the two-stage crushing and screening facility and hauled to the Valley Leach Facility (VLF).

6- Leaching
The VLF is a double-lined, and in some areas triple-lined, zero-discharge area where the gold is recovered. A dilute solution of sodium cyanide is applied using agricultural-type drip irrigation tubes, which are buried under the crushed rock surface to dissolve the gold. The gold-bearing solution is captured at the bottom of the lined area. The solution containing the gold is called "pregnant solution."

7- Processing
The gold is recovered from the pregnant solution with a carbon absorption process. The gold laden carbon is processed to create a gold-rich mud. After the gold is recovered, the solution with no gold, called "barren solution," is reconstituted and then re-circulated to the VLF to repeat the gold recovery process.

8- Pouring
The gold-rich mud is sent to the refinery furnace and heated to separate the gold and silver from any non-metal substances. The resulting 98% gold-silver mixture is called "doré" (daw-rey). The doré is shipped to a specialized refinery to be processed into 99.999% pure gold or 24 karat.