Two types of mineralized deposits are recognized at the La Arena property – high sulfidation epithermal gold deposits (La Arena mine) and porphyry-hosted copper-gold deposits (La Arena II project).

In porphyry deposits, the sulfide ore minerals are dominantly structurally-controlled, with most mineralization occurring as close-spaced and cross-cutting vein stockwork, vein arrays, fractures, breccias and disseminations. In the hypogene portions of copper porphyry deposits, the copper occurs predominantly as chalcopyrite; other important copper ore minerals may include bornite and enargite. Supergene copper mineralization is generally dominated by chalcocite and lesser covellite.

Copper-gold mineralization is associated with phyllic (quartz-sericite) and potassic (secondary biotite + magnetite + potassium feldspar) alterations, which is dominated principally by pyrite and chalcopyrite with lesser amounts of bornite, covellite, chalcocite and molybdenite. Mineral zoning from surface downwards below the oxidized cap is typically about 40 to 50 meters for the zone of secondary enrichment (chalcocite + covellite ± copper oxides) and ten to 40 meters for the mixed oxide-sulfide transitional zone (chalcocite + chalcopyrite ± covellite). The top of the primary sulfide mineralized zone (chalcopyrite ± bornite) which predominates at La Arena is typically located at depths in excess of 100 meters from the surface.

The copper-gold porphyry at La Arena II comprises an elongated mineralized body approximately 1,400 meters in length (oriented northwest-southeast) and 200 to 400 meters wide. Mineralization occurs as disseminations along hairline fractures as well as within larger veins. Mineralization has been identified by drilling to depths of 1,000 meters below the surface which shows the porphyry to be narrowing, but with no decrease in copper and gold grades.

Sulfide mineralization consists of pyrite, chalcopyrite and molybdenite, with accessory pyrrhotite, sphalerite, galena, arsenopyrite, marcasite and rutile. Very fine (~25 microns) particles of native gold have been observed. The FPA-2 intrusion has the most abundant copper and gold mineralization that is associated with phyllic (quartz-sericite) and potassic (secondary biotite, magnetite, K feldspar) alteration with copper grades ranging from nil to locally greater than one percent; gold grades range from nil to locally greater than one gram per tonne. Lower grade copper gold mineralization is related to the intra mineral FPA-3 intrusion, which locally contains copper grades up to 0.5 percent and gold grades up to 0.5 grams per tonne.

the La Arena II Project open pit to be mined by conventional drill, blast, truck and shovel methods. The mining fleet will consist of 320 tonne class haul trucks, 55 m3 electric cable shovels and 20 m3 wheel loaders. Blasthole drilling will be performed by diesel powered rotary single pass track drills. Rubber tired dozers will take care of cleanup near the shovels. Haul road and dump maintenance will be performed by a fleet of motor graders, track dozers and water trucks.

The design bench height is 16 meters. Double benching will be applied with a catch bench 10.5 meters wide in sediment rock type and 9.5 meters in the porphyry rock type. Inter-ramp wall angles will be 47.8° in sediments and 48.8° in porphyry.

Ramps are designed to be 34 meters wide including berms and ditches with a driving width of 27 meters. The crusher and mill facility will be located between the pit and the leach/tailings facility at the 3495 m elevation.

The crest of the pit ranges from 3578 m elevation on the west side to 3274 m elevation on the east side. The pit bottom elevation is 2476 m. The overall final pit dimensions are 2440 m in length by 2120 m wide.

The La Arena II Project open pit will be developed in three stages. The first stage was designed to deliver the majority of the oxide material to the leach pad earlier in the mine life and at the same time deliver 80,000 tonnes per day to the mill.

The mine plan was developed to deliver 80,000 tonnes per day of sulfide resources to the flotation process plant. Oxide resources extracted would be hauled directly to the new oxide leach pad. Over the 21 year mine life (excluding preproduction), the mine will deliver 587.4 million tonnes of sulfide resources containing 4.98 billion pounds of copper and 4.54 million ounces of gold to the flotation plant, with an additional 46.6 million tonnes of oxide resources containing 501 thousand ounces delivered to the leach pad. The average mining rate, including waste, is 132 million tonnes per year over the first 19 years of mining with a peak of 168 million tonnes per year.

Mining starts approximately 2.5 years before mill start-up. Approximately 281 million tonnes of material will be mined before the mill is in operation, including an estimated 23 million tonnes of oxide material and 28 million tonnes of sulfide material containing 240 million pounds of copper and 215 thousand ounces of gold.

The process plant for the La Arena II Project has been designed with a nameplate capacity of 80,000 tpd. The annual ore tonnage milled is nominally 28.8 million tonnes with a life of mine average feed grade of 0.38% Cu and 0.24 g/t Au.

Two processing streams are envisioned for the La Arena II Project. Oxide leach material will be hauled to a ROM leach facility. Sulfide material will be hauled to a differential flotation processing facility (mill) where a copper-gold concentrate and a pyrite concentrate will be produced. Waste rock will be hauled from the pit to the dry stack tailings facility for use as a buttress or to the waste rock storage facility.

All oxide material encountered during the mining of La Arena II will be hauled directly to a new leach facility that would be built within the dry stack tailing facility. The current carbon adsorption columns will be relocated adjacent to this new facility. Loaded carbon will be transported from this facility to the current ADR plant for stripping. After stripping the carbon will be transported back to the new leach facility.

The La Arena II sulfide material would be hauled to the crusher. The material will be crushed and ground to liberate Cu and Au for flotation. Comminution begins with a gyratory crusher to crush ROM sulfide material in preparation for semi-autogenous grinding (SAG). The SAG mill discharges to a trommel-vibrating screen combination. The screen oversize is sent to a pebble crusher before being returned to the SAG mill. The SAG mill product is further ground by two ball mills, which are operated in closed circuit with hydrocyclone clusters. The hydrocyclone underflow reports back to the ball mill, while the overflow proceeds to the rougher flotation cells.

Flotation of copper in the La Arena II process plant will be accomplished using two banks of rougher flotation cells to achieve recovery, and two stages of cleaning to meet smelter grade requirements.

The cyclone overflow from the grinding circuit will report to the rougher bank feed tanks. Tailing from the rougher banks will report to the flotation tails thickeners.

Rougher concentrates will be sent to one of two 300 kW vertical regrind mills. Both will be in closed circuit with hydrocyclones. Concentrate from each rougher bank will be sent to the corresponding regrind pump box where it will combine with discharge from the regrind mill. From the pump box, the slurry will be pumped to the hydrocyclones for classification. The hydrocyclone underflow will be returned to the regrind mills, while the overflow will flow to the first cleaner flotation circuit. The target particle size distribution for the reground material is 100 percent finer than 25 microns. A circuit bypass will be included such that rougher concentrates can be pumped directly to the first cleaner cells without going through the regrind step.

Two stages of cleaning will upgrade the reground concentrate to meet smelter specifications. In addition, a first cleaner scavenger stage will be installed to produce tailing that can be forwarded to the final flotation tailing without significant loss of sulfide copper.

The concentrate of the first cleaner cells will be transferred to the second cleaner flotation circuit while the tails proceed by gravity to the cleaner scavenger flotation circuit. Concentrate from the cleaner scavenger flotation circuit will be sent to the regrind circuit feed. Tailing from the cleaner scavenger circuit will be pumped to the flotation tails thickener.

The concentrate from the second cleaner flotation circuit will be pumped to the concentrate thickener as final concentrate. The tailing from the second cleaner flotation circuit will be recycled to the first cleaner flotation circuit.

Concentrate from the second cleaner flotation circuit will be dewatered in the 30 m diameter concentrate thickener. The thickened concentrate will be pumped to two vertical filter presses, operating in parallel. The filtered concentrate will be conveyed to a concentrate stockpile, from where it will be loaded onto trucks by a front-end loader for shipment to the smelter. Representative samples of the concentrate will be taken prior to shipment for copper, gold, silver, and moisture analysis.

Pyrite will be floated from the copper flotation tailing to mitigate acid-generation from the tailing. Tailing from the copper flotation process may be conditioned with sulfuric acid to lower the pH depending on results of future tests. The conditioned slurry will then be processed in a bank of six 630 m3 rougher flotation cells in series. The concentrate will be thickened and piped to the filtration building near the tailing storage facility. There, the thickened pyrite tailing will be filtered with three horizontal filter presses with 2.5 m by 3.5 m plates. The filtered pyrite tails of about 18% moisture will be deposited by mobile conveyors to a separate lined pyrite storage facility.