Gold mineralization at the Gualcamayo Property occurs in three main areas: Quebrada del Diablo (QDD), Las Vacas (LV), and Salamanca. The QDD area includes the QDD Main, Condor, Potenciales, Amelia Inés and Magdalena (together AIM), Target D, QDD Lower, and Rodado deposits. There are also a number of small satellite deposits not currently included in the mine plan.

Three distinct mineralization types of economic interest occur in the Gualcamayo Property:
• sediment-hosted distal-disseminated gold (QDD)
• sulphide-bearing skarn deposits containing copper zinc and molybdenum with late stage gold-arsenic mineralization (Amelia Inés and Magdalena)
• porphyry style molybdenum mineralization (Quebrada Perdida)

SEDIMENT-HOSTED DISTAL-DISSEMINATED GOLD
The QDD deposit is genetically analogous to Carlin-type sedimentary rock-hosted deposits. Carlin deposits form as structurally and/or stratigraphically controlled replacement bodies consisting of stratabound, tabular, disseminated gold mineralization occurring in carbonate rocks. Deposits are localized at contacts between contrasting lithologies, metamorphosed to varying extents. They can also be discordant or breccia related.

Host rocks are most commonly thinly bedded, silty or argillaceous carbonaceous limestone or dolomite, commonly with carbonaceous shale. Although less mineralized, non-carbonate siliciclastic and rare metavolcanic rocks can locally host gold that reaches economic grades. Felsic plutons and dikes may also be mineralized at some deposits.

The deposits are hydrothermal in origin and are usually structurally controlled. Current models attribute the genesis of the deposits to:
• epizonal plutons that contributed heat and possibly fluids and metals,
• meteoric fluid circulation resulting from crustal extension and widespread magmatism
• metamorphic fluids, possibly with a magmatic contribution, from deep or mid-crustal levels,
• upper crustal orogenic-gold processes within an extensional tectonic regime.

SKARN DEPOSITS
Skarn mineralization is hosted by contact, metasomatic calc-silicate rocks proximal to intrusive rocks. They typically form by contact metamorphism of a carbonate rich rock and as a result are not common in Archean terranes because of the paucity of carbonate units in the Archean geological record. The reader is referred to Meinert (1993), Dawson et al. (1984) and Einaudi et al. (1981) for more detailed descriptions of skarns. The following is taken from Rogers et al. (1995).

Host rocks consist of magnesian skarn and calcic skarn which were formed from the metasomatic replacement of dolomite and limestone, respectively. Metasomatized rocks consist of limestone, dolomite, and calcareous clastic sedimentary rocks. Associated intrusive rocks include gabbro to granite and diorite to syenite for Zn-Pb-Ag and W-Mo skarns and twomica, S-type granite-granodiorite for Sn-W skarns.

Skarn mineralization varies from massive to disseminated and/or interstitial. Irregular, tabular, vein-like, and pene-concordant bodies are possible. Mineralized zones may occur within the causative intrusion (endoskarn) or adjacent to the intrusion (exoskarn) up to several tens to hundreds of metres away if controlled by structural and/or stratigraphic features.

Geological controls on skarn mineralization include relatively tick, pure and impure limey rocks; shallow-dipping pluton/carbonate traps, irregularities in the pluton/carbonate contacts; structural and stratigraphic traps or controls in the host rocks; stockwork fracturing along the pluton/carbonate contacts. Faults, contacts, bedding, breccias, cross-cutting dikes, or structures control the location of the deposits at a distance from the pluton.

Cu +/- gold skarns may be zoned from a Cu-Au-Ag rich inner zone to Au-Ag rich to a Zn-PbAg outer zone. Cu skarn ore mineralogy may consist of chalcopyrite, magnetite, bornite, molybdenite, pyrite and pyrrhotite plus a variety of lesser sulphides

PORPHYRY DEPOSITS
Porphyry deposits are large, low to medium grade deposits in which primary (hypogene) ore minerals are dominantly structurally controlled and which are spatially and genetically related to felsic to intermediate porphyritic intrusions (Kirkham, 1972). The large size and structural control (e.g., veins, vein sets, stockworks, fractures, “crackle zones” and breccia pipes) serve to distinguish porphyry deposits from a variety of deposits that may be peripherally associated, including skarns, high temperature mantos, breccia pipes, peripheral mesothermal veins and epithermal precious metal deposits (Sinclair, 2007).

Porphyry deposits range in age from Archean to Recent, although predominantly associated with Mesozoic to Cenozoic orogenic belts. They occur throughout the world in a series of extensive, relatively narrow, linear metallogenic provinces. Porphyry deposits occur in close association with porphyritic epizonal and mesozonal intrusions, typically in the root zones of andesitic stratovolcanoes. A close temporal relationship between magmatic activity and hydrothermal mineralization in porphyry deposits exists (Kirkham, 1971). Magma composition and petrogenesis of related intrusions exert a fundamental control on the metal content of porphyry deposits. Intrusive rocks associated with porphyry Cu, porphyry Cu-Mo, porphyry Cu-Au and porphyry Au tend to be low-silica, relatively primitive dioritic to granodioritic plutons
whereas porphyry deposits of Mo, W-Mo, W, and Sn typically are associated with high-silica, strongly differentiated granitic plutons.

The mineralogy of porphyry deposits is highly varied, although pyrite is typically the dominant sulphide mineral in Cu, Cu-Mo, Cu-Au, Au, and Ag deposits. The principal ore and associated minerals in porphyry Cu-Au deposits are chalcopyrite, bornite, chalcocite, tennantite, enargite, other Cu minerals, native Au, electrum, and tellurides. Associated minerals include pyrite, arsenopyrite, magnetite, quartz, biotite, K-feldspar, anhydrite, epidote, chlorite, scapolite, albite, calcite, fluorite, and garnet.

The Gualcamayo Mine consists of three operating open pits, QDD Main, AIM, and Condor, and one operating underground mine, QDD Lower. The operation also includes crushing facilities, an adsorption, desorption and recovery (ADR) plant, heap leach pads; and accommodation camp, maintenance buildings, and office buildings. The Deep Carbonates Project (DCP), which consists of the Santiago, Feeder, and Rodado deposits, is the primary target for future expansion.

The current Life of Mine (LOM) plan is for three years of mining and processing. Mineros intends to expand the current Mineral Reserves and further develop the DCP as an underground mine.

OPEN PIT MINING
Open pit mining takes place in various distinct areas of the Gualcamayo Mine, including a central, large open pit area, and three small satellite workings. As the deposits are located against a mountainside, the open pit operation is a combination of hillside benches and in pit benches. Most of the ore haul is downgrade.

Open pit ore production employs standard drill and blast, load and haul operational procedures. Mining is carried out on 10 m bench heights, with some pit walls left with a double bench.

Material is loaded and transported to an ore pass, on the edge of the QDD Main pit, which delivers the material to an underground primary crusher, where it is combined with underground ore. The ore is then conveyed to a secondary crushing system on surface, after which it is taken to one of two leach pads through a system of grasshopper conveyors.

Production comes from three teams with two excavators each. Eight articulated dump trucks (ADT) with capacities of 36 t are used to haul broken rock. All the equipment is owned and operated by MASA.

Waste dumps are located in the immediate vicinity of each open pit and tend to be dumps on the hillside edge. In some instances, the waste dump is rehandled by being pushed further down the hill as the pit deepens.

UNDERGROUND MINING
Underground production started in March 2013, and the SLC method has been used for the last three years.

Approximately 41% of the mill feed tonnes and 40% of the ounces in the mill feed come from underground sources, the QDDL and Cuerpo Este orebodies, using SLC.

The underground workings are accessed by a conveyor decline and vehicle access ramp. The vehicle access ramp is the primary access for personnel, material, and equipment, as well as the egress for waste rock and the ventilation intake. The conveyor is used to transport ore out of the Gualcamayo Mine and to the heap leaching operation.

Current underground mining in the QDDL ore zone comes from two (1782L and 1798L) of the five existing levels. Current production rates vary between 3,000 tpd and 3,500 tpd.

Stopes are based on development ends in ore with rings sequentially blasted, followed by the drawdown of broken material, assisted by caving. Levels are designed with 14 m to 16 m vertical spacing. The level is accessed off the main ramp with a footwall drift developed 20 m from the planned mining areas. Ore is accessed by cross-cuts which are developed from the footwall drift to the end of the mineralized zone at 15 m spacing. A series of slot raises are blasted out at the end of each cross-cut to provide the required void space for blasting of subsequent stope rings. Production drill holes are fan drilled with a 2.5 m burden and 80° dump angle. The production rings are blasted one at a time and sequentially starting from the end of the cross-cut. Depending on the shape of the stope, each ring delivers approximately 1,500 t to 2,200 t of ore. The blasted material is supplemented by ore that caves into the void, as well as ore from the previously mined stopes above that were not fully loaded out.

Ore is loaded by load-haul-dump (LHD) units and trammed to one of two rehandle points. From the rehandle point it is loaded into trucks and taken to an underground tip, conveyed to an underground crusher, mixed with surface ore received via an ore pass, and then conveyed out of the Gualcamayo Mine to the fine crushing complex. The conveyor has a capacity of 5,000 tpd.

Ore is mined in the open pit and underground mines, with the primary crusher located underground. Open pit ore is dumped from the surface either into an ore pass or an ore chute, both of which deliver the ore to the underground primary crushing and conveying system. The primary crusher reduces the ore to P80 150 mm. Crushed ore is transported via overland conveyor to the crushed ore stockpile. Ore is drawn from the crushed ore stockpile with apron feeders and conveyed to the secondary-tertiary crushing circuit. Ore is screened on the secondary screen, with oversized material fed to the secondary crusher. The secondary crusher product is then conveyed to the tertiary crushers which are closed by the tertiary screens. The screen undersized product, with P80 25 mm from the secondary and tertiary screens is conveyed to the heap leach pad.

The Gualcamayo process facility is designed to treat 25,000 tpd of ore using primary, secondary, and tertiary crushing, heap leaching, carbon adsorption-desorption-regeneration (ADR), for gold recovery, electrowinning of gold from the gold bearing eluant solution and casting of gold doré.

The fines in the ore are agglomerated by adding cement to the ore on the heap leach pad loading conveyor, which mixes as it transfers from one conveyor to the next. The ore is then loaded onto the heap leach pad in lifts with a conveyor stacker. Cyanide leach solution is distributed over the ore with pipelines and drip emitter tubing. The solution percolates through the ore dissolving the gold and is collected on the pad liner and transferred to the pregnant solution pond by gravity in lined channels.

The pregnant gold solution is pumped from the pond through carbon columns in series to adsorb the gold in solution onto the carbon. The barren solution exiting the carbon columns fl ........