Middle Zone and La Cantera constitute two of the four drill-tested mineralized porphyry intrusive and breccia bodies on the La Mina property. In both deposits, the intrusive centers are occupied by a series of porphyry stocks and related breccias that together make up porphyry copper gold deposits. In the case of La Cantera, the core of the deposit consists of a late, barren porphyritic stock resulting in a typical “doughnut” pattern (plan view) in its concentric relationship to the surrounding mineralized units. In the case of Middle Zone, the barren core is an amorphous feature that appears to have intruded preferentially along pre-existing planes of weakness. Various intrusive/breccias phases were involved in development of the porphyry deposits alongwith multi-phase alteration mineralization events, as most-often expressed by pronounced densities of veinlets cross-cutting the diamond drill core. Hydrothermal magnetite is an important gangue mineral associated with gold and copper, and potassic alteration is an important alteration type associated with higher gold and copper grades.

The La Cantera Deposit is slightly elliptical in plan view (long axis NW-SE), measuring approximately 200 m by 190 m in plan view on surface with a depth extent of 350-600 m based on the results from 24 drill holes. Average grades are close to 0.8g/t Au with 0.3% Cu. The Middle Zone Deposit lies approximately 400 m north of La Cantera, and consists of a more pronounced elliptical body in plan view (long axis NE-SW), which remains open at depths of over 600 m, based on the results of 39 drill holes for a total of 14,159 meters. Fault displacement appears to have offset the western and eastern lobes of mineralization, and faulting appears to bound the western edge. Mineralization here is of two types. The first is high copper-gold ratio, similar to what is seen at La Cantera. The second is high gold with relatively low copper. Overall, the grades are lower than La Cantera, close to 0.5g/t Au with 0.1-0.2% Cu, over true widths of up to 100 m.

MMC recommends that conventional truck and shovel open pit mining methods be used in order to best exploit the resources at the La Mina Project. This approach is well suited for these near surface, disseminated deposits. Mine schedules in Section 14 have been developed based on Inferred resources.

Open pit mining will take place two distinct areas: La Cantera and Middle Zone. La Cantera consists of a single pit mined in three phases. Middle zone consists of a single phase pit. The pit and phase outlines are shown in. Dilution was assumed to be included in the model blocks, given the size of the blocks relative to mineralized zones and loading equipment. Mining would take place on 10m benches using haul roads with maximum 10% grades for access.

A conventional jaw crusher facility will be designed to crush run-of-mine (ROM) material to reduce the incoming feed material from the open pit mine at a total average feed rate of 650 t/h.

The major equipment and facilities in this area includes:

-Stationary grizzly,
-ROM surge bin,
-Vibrating grizzly,
-Jaw crusher,
-Secondary feed stockpile,
-Belt feeders,
-Conveyor belts, metal detectors, self-cleaning magnets and belt tear detectors,
-Belt scale,
-Dust collection system.

Haul trucks from the mine will dump ROM material onto a ROM surge stockpile. Material will be fed by a front-end loader dumping feed material into the 60-tonne capacity ROM surge bin. The surge bin will be equipped with a stationary grizzly with 600 mm × 600 mm square apertures to prevent oversize rocks from entering the circuit. A rock breaker will be available to break up any rocks larger than 600 mm which cannot pass through the stationary grizzly. The capacity in the surge bin will provide a steady feed of ore to the jaw crusher.

The ore will feed a vibrating grizzly for sizing and minus 150 mm material will bypass the jaw crusher and report directly to the primary stockpile via the stockpile feed conveyor system. Oversize material will be reduced to 80% minus 150 mm in the jaw crusher and will be discharged onto the stockpile feed conveyor via the jaw crusher discharge conveyor.

The crushed ore will be conveyed to the top of the primary stockpile. The total live capacity of the stockpile will be approximately 12,500 live tonnes equivalent to the throughput rate for one day.

From the stockpile, a front-end-loader (FEL) will feed a conveyor, which will transfer the ore to the secondary crushing circuit.

The secondary and tertiary cone crushers will crush the coarse feed material to 80% passing 12.5 millimeters (mm) for the milling process. The crushing and screening will be conducted as a dry process. The main items of equipment in the secondary and tertiary crushing circuit will be the following:

-Crusher feed bins
-Conveyor belts
-Cone crushers
-Vibrating sizing screen
-Metal detector
-Belt magnet
-Belt feeders
-Mill feed bin
-Cone crusher area dust collection system

The material from the primary crushed stockpile will be reclaimed using feeders and a conveyor and discharged to the secondary crusher feed bin. Material in the secondary bin will be metered into the secondary cone crusher via a belt feeder. The secondary cone crusher will produce a product size P80 of 25 mm.

The crushed material from the secondary crusher will be discharged onto the screen feed conveyor, which will deliver the ore to vibrating sizing screens. The screens will be a doubledeck vibrating screen. The top-deck will have 30 mm square apertures and the bottom-deck will have 15 mm square apertures. The vibrating screen will be 2,000 mm wide and 5,000 mm long. Oversize from the vibrating screens will report to a conveyor that will deposit the material in a bin over two tertiary cone crushers.

The grinding circuit will reduce the size of the crushed material to the particle size required for the flotation process. The grinding process will be a single-stage operation with the ball mill in closed circuit with classifying cyclones. The grinding will be conducted as a wet process. The grinding circuit has the following main items of equipment:

-Conveyor belt feeders,
-Conveyor belt,
-Conveyor belt weigh scale,
-Ball mill, one unit 5,000 mm diameter × 9,000 mm long,
-Mill discharge pumpbox,
-Cyclone feed slurry pumps,
-Classification cyclone cluster,
-Vibrating trash screen,
-Sampler system.

The ball mill will have a classification circuit consisting of a mill discharge pumpbox, cyclone feed pumps and a classifying cyclone cluster. The discharge from the ball mill will be directed into a mill discharge pumpbox where dilution water will be added as required to adjust the slurry density for cyclone classification. The slurry in the mill discharge pumpbox will be pumped to a cyclone cluster for classification. The cut size for the cyclones will be at a particle size of P80 of 106 µm, and the circulating load will be 300%. The cyclone underflow will be returned to the ball mill as feed material.

The bulk rougher flotation circuit is shown in. Grinding cyclone overflow from all four ball mills will collect in a single vessel for distribution to one row of rougher flotation cells. The distributor dissipates the energy of the cyclone overflow and allows air trapped in the pipe to vent. It also decouples the bulk flotation from grinding. One row of 28.3 m3 tank cells will provide approximately 30 minutes of residence time.

The reground rougher concentrate will be cleaned in one stage of mechanical cells and one stage of flotation columns. Sodium cyanide solution is also added to depress pyrite; provision is made for adding frother and collector throughout the circuit. Regrind cyclone overflow will be pumped to a distributor that splits the flow between two banks of eight 100 m3 tank cells, which constitute the first cleaners. The first cleaners will have 20 to 30 minutes of residence time and will be pulled moderately hard to achieve recovery in the cleaner circuit. Cleaner tails will be collected in a launder, sampled, and then piped to the cyanide leach circuit. The cleaner tails after leaching will be deposited below the surface of the water in the tailings pond to prevent acid formation due to oxidation of the sulphide content.

Copper concentrate from the second cleaner columns will collect in a pipe launder and flow by gravity to a 6 m diameter thickener. This thickener is operated without flocculant to avoid compromising the subsequent flotation process.