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.

Porphyry-hosted Copper-Gold Mineralization
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.

Crushing and Crushed Material Stockpile
Run-of-mine (ROM) material will be transported by haul trucks from the mine to the primary crusher, and fed to the crusher via a dump pocket with a two-truckload capacity. The primary crusher will be a 60 inch x 110 inch gyratory crusher, with an open side setting of 180 mm (7 inches) and a feed opening of 1,524 mm (60 inches). It will be powered by a 1,000 kW motor. The crushed material will drop into a discharge bin equipped with an apron feeder.

The apron feeder will meter material onto a stacking conveyor, which will feed to a coarse material stockpile. The coarse material stockpiles will have equivalent total capacity of about 240,000 tonnes and live capacity of 80,000 tonnes. This is equivalent to about 24 hours of SAG mill feed. Four belt feeders (two operating and two standby) will reclaim crushed material from the stockpile and transfer it onto the SAG mill feed conveyor.

Grinding
The grinding circuit for the La Arena II Project will be a conventional semi-autogenous grinding (SAG) mill-ball millpebble crusher (SABC) system. The SAG mill will be in a closed circuit with a pebble screen and a pebble crusher.

The ball mills will be in a closed circuit with hydrocyclone clusters. The SAG feed conveyor will feed ore to the SAG mill, 12.19 m diameter by 7.62 m long, flange-to-flange (40 ft diameter by 25 ft long, flange-to-flange) driven by a 24 MW gearless drive. The SAG mill product will discharge to a trommel and then to a pebble wash screen. The undersize of the trommel and pebble wash screen drops into the cyclone feed pump box. This will constitute fresh feed to two ball mills. It will mix with the discharge from the ball mills and be pumped to four primary cyclone clusters. Pumping will be by four centrifugal pumps with 895 kW variable frequency drives (VFD), with a fifth pump as operating spare.

The cyclone underflows will be fed to two ball mills. Each ball mill measures 7.92 m in diameter by 13.6 m effective grinding length (26 ft diameter x 44.5 ft EGL), powered by a fixed-speed dual- pinion synchronous drive, with each motor rated at 8.2 MW. The cyclone overflows will constitute the product of the grinding circuit and will be fed to the flotation circuit. The target size distribution is 80 percent finer than 106 microns.

The pebbles separated by the pebble wash screen will be collected on the pebble crusher feed conveyor, transported to two pebble crusher feed bins, and crushed by two MP1250 type cone crushers, 1000 kW, at a 13 mm closed-side setting. The crushed pebbles are returned to the SAG mill via the SAG feed conveyor. The pebbles may also bypass the pebble crusher onto a pebble stockpile for further handling, as deemed appropriate.

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 th ........