Four distinct mineralization types occur in the Gualcamayo Project and three of these are of present economic interest. They are:

1. Sediment-hosted distal-disseminated gold (Quebrada Del Diablo deposit);
2. Sulphide-bearing skarn deposits containing copper, zinc and molybdenum with late stage gold-arsenic mineralization (Amelia Inés and Magdalena deposits); and
3. Porphyry style molybdenum mineralization.

Gold mineralization at Quebrada Del Diablo deposit (QDD) occurs in carbonate sediments within conformable and discordant carbonate breccias and fractured limestone. The gold mineralization is related to a hydrothermal event overprinting the proximal skarns and extending into the surrounding marbles and limestones. The QDD canyon itself lies along a fault/dyke system, which is believed to be a reactivated, Ordovician rift structure that acted as the primary conduit for hydrothermal fluids migrating away from the intrusive contacts.

Alteration of the host rocks is minimal and sulphide content is low. Gold, sulphides (arsenopyrite), realgar, orpiment, pyrite, and calcite are deposited along fractures and as matrix fillings. Higher gold values are spatially related to the intrusive breccia (Bx4). The mineralized structures are strongly oxidized throughout the depth of drilling, except for minor unoxidized intervals in which the primary mineralization is preserved.

Higher-grade zones in the QDD deposit (> 2 g/t Au) are common and related to fold hinges, sediment infilled karst cavities, and brecciated intrusive contacts with limestone and marble. Mineralized breccia thicknesses range from 30 m to 150 m thick and extend more than 500 m outboard to the east and NW of the QDD feeder structure. Due to the complex folding along NNW and E-W axes and strong lithological control, the mineralized collapse breccias form an undulatory ore deposit (dome and basin geometry) underlain by the hydrothermally altered dolomite member of the upper San Juan Formation.

Although more confined, gold mineralization remains open down dip along the QDD fault zone cutting the white recessive limestone unit (white marble) of the lower San Juan Formation.

The QDD deposit is silica poor, high-level gold-arsenic system with fine marcasite and trace amounts of realgar and orpiment forming the main sulphide minerals. Silver values generally less than 0.1 ppm. Barium is also elevated (200 ppm to 400 ppm) with higher concentrations localized along brecciated E-W striking dike margins.

Mercury and Antimony are weakly anomalous. Strong clay alteration along brecciated intrusive margins consisting of supergene kaolinite and alunite is also common suggesting a fairly acidic hydrothermal system. Gold occurs mainly as 1 µm to 5 µm inclusions within marcasite that was deposited with calcite along fractures and breccia matrices.

At Amelia Inés and Magdalena, late stage gold-arsenic mineralization overprints skarn zones and extends into the surrounding marbles of the San Juan Formation. Skarn hosted mineralization comprised of chalcopyrite, sphalerite, galena, pyrrhotite and pyrite was deposited as a retrograde event preceding the introduction of the gold-arsenic mineralization.

Gold mineralization is intimately associated with fine grained marcasite that lines late fractures and forms the chief component to marble and skarn breccias matrices Brecciation and higher grade gold mineralization are localized along the W to NW trending marble–skarn contact and cross cutting E-W tensional structures. The rheological contrast between the brittle skarn and ductile marble is believed to have accommodated much of the movement during later wrench fault tectonics, forming localized E-W trending, tensional zones (i.e breccia zones) that extend 10’s of metres outboard into the marble and skarn from the contact.

Silver is anomalous but very sporadic returning greater than 30 gpt within the higher grade >5 gpt Au zones. Silver is localized within retrograde tetrahedrite veinlets and possibly electrum during deposition of the later stage fine grained marcasite.

Negligible gold mineralization extends into the intrusive stock to the north. Narrow 1-3 cm wide sheeted quartzmolybdenite veinlets are generally confined within the skarn at both Magdalena and Amelia Inés and extend outboard into the intrusive stock, localized along EW tension structures.

Areas of high molybdenum content commonly lie peripheral to the gold enriched zones and overlap the intrusive contacts. Molybdenum mineralization is often associated with high manganese levels and occurs mainly in skarn with lesser amounts hosted by marble and intrusive rocks. Drill holes at Magdalena commonly encounter intervals of +1000 ppm Mo over several metres. Core hole 06QD-369 intersected an average Mo grade of 422 ppm over 152.4 metres. Hole 07QD-412 intersected 113.8 m averaging 556 ppm Mo including an interval grading 1014 ppm. RC holes drilled into the intrusive stock more than 50 metres away from the contact intersected anomalous Mo mineralization but the levels were much lower with the best interval averaging 162 ppm over 56 m in hole 06QDR-350.

The Gualcamayo gold mine combines open pit and underground operations.

Open Pit Mine
- Conventional Open Pit Mine
- 660 m high wall
- Overall Slope Angle 48 deg
- 20 m Bench Height
- Real Time Monitoring radar
- In pit Ore Pass to UG Crusher
- 40 Tons Trucks

Underground Mine
The underground mine at Gualcamayo, called Quebrada del Diablo Bajo Oeste (QDD Lower West), currently uses the Sub Level Caving (SLC) system.

The sub level caving system consists in digging parallel tunnels, usually between 9 and 15 meters apart horizontally, known as production drifts. The sub-levels run through the mineral deposit in vertical intervals that are usually between 8 and 13 meters apart. The mine design therefore consists of a symmetrical geometric configuration.

Three-stage crushing circuit:
The product extracted from the mine (Right Of Mine - ROM) is initially crushed in a primary crushing plant to reduce the size of the ore from 650 to 139 mm. After primary crushing, ore even more crushed and sieved in secondary and tertiary crushing circuit to reduce the size of the ore by 80 percent, below 17.6 mm.

The first step is to detach the mineral from the mountain, which is performed by means of controlled explosions. The detached minerals are loaded with mechanical shovels onto trucks that carry them to a transfer hopper (orepass) that carries the ore to the cavern where the primary crusher is installed. There, the ore derived from surface operations is consolidated with ore from the underground mine. The crushed ore is transported through the tunnel to the intermediate ore sink by means of a conveyor belt that is 1647 m long. Once outside the tunnel, the ore is received by a second crushing unit, for secondary and tertiary crushing, which breaks down the rock until reaching the desired size for the next stage of the process. Then a set of conveyor belts carry the crushed ore to a leaching sink. The system used by Gualcamayo is to leach using a cyanide solution in a closed circuit.

The leaching sinks are waterproofed using a high-density polyethylene (HDPE) geo-membrane and a ........