Phoenix is a skarn-hosted polymetallic massive sulfide replacement deposit.

Au-Cu-Ag-Pb-Zn skarn mineralization at Phoenix is centered about the Eocene Copper Canyon granodiorite porphyry stock. Paleozoic sedimentary rocks within two miles of the stock have undergone strong thermal metamorphism (hornfels) and metasomatism (skarn). Metal zonation is manifest by a CuMo core close to the stock grading outward into proximal Cu-Au-Ag, Au-Ag and distal Pb-Zn-Ag mineralization.

The Phoenix surface mine’s available mining fleet consists of three shovels and sixteen 240 ton haul trucks.

The Phoenix mill produces a gravity gold concentrate and a copper/gold flotation concentrate and recovers additional gold from cyanide leaching of the flotation tails.

Process facilities include a flotation mill which processed approximately 11 million tons of ore in 2015, a carbon-in-leach plant, a copper leach pad and solvent extraction electrowinning (“SX/EW”) plant. The copper leach and SX/EW plant was constructed in 2013, which allows for the production of copper cathode.

At Phoenix, ore containing copper and gold is crushed to a coarse size at the mine and then transported via conveyor to a process plant, where it is further crushed and then finely ground as a slurry. The ore is initially treated by successive stages of flotation resulting in a copper/gold concentrate containing approximately 15% to 20% copper. Flotation concentrates are also processed via a gravity circuit to recover fine liberated gold and then dewatered and stored for loading onto ships or rail for transport to smelters. The flotation tailings have a residual gold content that is recovered in a carbon-in-leach circuit.

In addition, at Phoenix, copper heap leaching is performed on copper oxide ore and enriched copper sulfide ore to produce copper cathodes. Heap leaching is accomplished by stacking uncrushed ore onto impermeable, synthetically lined pads where it is contacted with a dilute sulfuric acid solution thus leaching the acid soluble minerals into a copper sulfate solution. The copper sulfate solution is then collected and pumped to the solvent extraction (“SX”) plant. The SX process consists of two steps. During the first step, the copper is extracted into an organic solvent solution. The loaded organic solution is then pumped to the second step where copper is stripped with a strong acid solution before being sent through the electrowinning (“EW”) process. Cathodes produced in electrowinning are 99.99% copper.