The Ann Mason deposit has the characteristics of a typical, large copper-molybdenum porphyry system. Projected to the surface, the 0.15% Cu envelope covers an area approximately 2.8 km northwest and up to 1.3 km northeast. At depth, this envelope extends more than 1.2 km below surface. The mineralization remains open in most directions.

The deposit is hosted by several phases of the Jurassic Yerington batholith, including, granodiorite (Jgd), porphyritic quartz monzonite (Jpqm), quartz monzonite (Jqm) and younger quartz monzonite porphyry dykes (Jqmp-a, Jqmp-b and Jqmp-c). Copper mineralization primarily occurs within a broad zone of main-stage potassic alteration containing chalcopyrite and bornite and an assemblage of chalcopyrite-epidote or chalcopyrite-epidote-quartz mineralization that locally overprints main-stage potassic alteration and copper mineralization.

Within the Yerington district, Mesozoic host rocks and copper-molybdenum porphyry deposits have been rotated 60° to 90° westward by Miocene age normal faulting and extension. As a result, mineralized intercepts in vertical drill holes through Ann Mason represent approximately horizontal intervals across the original pre-tilt geometry of the deposit.

Within the 0.15% Cu envelope the highest grades occur within a 200 m to 800 m thick, westplunging zone that surrounds the intrusive contact between granodiorite and porphyritic quartz monzonite. Within this zone, copper grade is dependent on vein density, sulphide species, frequency and relative age of quartz monzonite porphyry dykes and the mafic content of the granodiorite. Mineralization is also closely associated with Qmp-a and Qmp-b quartz monzonite porphyry dykes.

The copper sulphide zoning is that of a typical porphyry copper with an outer pyritic shell, and concentric zones of increasing chalcopyrite and decreasing pyrite progressing inward to a central zone of chalcopyrite-bornite.

Within the northeast, southeast, and southwest quadrants of the deposit, chalcopyrite and chalcopyrite-bornite are the primary sulphide domains. This mineralization is the most dominant in terms of overall deposit tonnage and continues to the drilled depth of the deposit. In the northwest quadrant, the primary sulphide domain is chalcopyrite = pyrite; a domain that forms thick intervals of >0.3% Cu, with only minor bornite present at depth, near the granodiorite- orphyritic quartz monzonite contact. Copper mineralization >0.15% Cu in this northwest portion of the deposit coincides with a pyrite:chalcopyrite ratio of less than 7:1.

Chalcopyrite occurs as individual grains in veins and disseminated in rock, as fillings in brecciated pyrite grains, attached to or included in pyrite grains, and attached to or included in bornite; bornite occurs as separate grains in veins, and disseminated in rock and attached to chalcopyrite. Chalcocite occurs as replacement rims on chalcopyrite, but more commonly as replacement rims or exsolution replacement of bornite.

Molybdenum occurs as molybdenite in quartz and quartz-chalcopyrite veins and on fracture or shear surfaces as molybdenum paint. In the current resource model molybdenum is constrained within a >0.005% Mo grade envelope that occurs almost entirely within the 0.15% Cu envelope and extending further below, where sodic (albite) alteration has removed copper mineralization, leaving molybdenum largely in place. The molybdenum mineralization also remains open towards the north.

Silver =0.6 g/t and gold =0.06 g/t are closely associated with the occurrence of bornite within the chalcopyrite-bornite sulphide domain.

Alteration types include a broad, main-stage zone of potassic alteration (secondary biotite, Kfeldspar), an outer propylitic zone (chlorite±epidote±pyrite) and restricted late-stage overprints of chlorite±oligoclase±epidote, sodic (albite±chlorite) and sericitic alteration.

Late-stage sodic and sericite alteration occur along late, high-angle faults and as local, pervasive alteration of rocks. In areas of strong (>15%) albite or sericite alteration, the copper grades can locally be greatly reduced, resulting in copper grades < 0.2% and in places, < 0.05%. Molybdenum mineralization is not significantly affected by the late sodic alteration, beyond partial remobilization from veins into nearby fractures and shears.

The Blue Hill deposit is about 1.5 km northwest of Ann Mason and occurs in a very similar geologic environment, but in a separate fault block.

Both styles of mineralization are hosted primarily by quartz monzonite with lesser amounts of porphyritic quartz monzonite and quartz monzonite porphyry. The low-angle, southeast dipping Blue Hill Fault strikes northeast through the middle of the target, cutting off a portion of the near-surface oxide mineralization. However, sulphides continue below the fault to the southeast.

The oxide zone is exposed on surface and has been traced by drilling as a relatively flat-lying zone covering an area of about 900 m x 450 m, and continuing for several hundred metres further to the west in narrow intervals. Significant copper oxides, encountered in both RC and core drill holes extends from surface to an average depth of 124 m. Oxide copper mineralization consists of malachite, chrysocolla, rare azurite, black copper-manganese oxides, copper sulphates, and copper-bearing limonites. Mineralization occurs primarily on fracture surfaces and in oxidized veins or veinlets. A zone of mixed oxide/sulphide mineralization with minor chalcocite is present below the oxide mineralization up to depths of 185 m. The copper oxide zone remains open to the northwest and southeast.

Oxide copper mineralization at Blue Hill is interpreted to be the result of in-place oxidation of copper sulphides with only minor transport of copper into vugs, fractures, and faults or shear zones. No significant zones of secondary enrichment have been observed.

The copper-mineralized sulphide zone underlies the southern half of the oxide mineralization and continues to depth towards the southeast below the Blue Hill Fault. Mineralization consists of varying quantities of pyrite, chalcopyrite, and molybdenite. Local, higher-grade sulphide mineralization commonly occurs within zones of sheeted veins containing chalcopyrite, magnetite, and secondary biotite. Significant amounts of disseminated molybdenum mineralization have been observed locally, often in contact with dykes. To the northwest, below the oxides only a few holes have tested the sulphide potential, however in this direction the sulphides appear to be increasingly pyritic with only minor amounts of copper.

Alteration assemblages are similar to the Ann Mason deposit except that original zoning is difficult to discern in areas of pervasive oxidation. Within zones of sulphide mineralization, propylitic alteration is more widespread and potassic alteration is more restricted to quartz monzonite porphyry dykes and immediately adjacent rocks of the Yerington batholith. Late stage sodic alteration locally reduces copper grades, similar to what has been observed at the Ann Mason deposit.

The sulphide mineralization remains open is several directions, most importantly, to the southeast, towards the Ann Mason deposit.

Ann Mason is envisioned as a large-scale conventional open pit mine, involving the development of a single pit with five pit phases.

Mining will use conventional rotary drilling, blasting, and loading with large 56 m3 cable shovels and 360-tonne trucks working on 15 m benches.

The proposed method of copper and molybdenum recovery from the Ann Mason deposit
consists of conventional crushing and milling, followed by rougher and cleaner froth
flotation. A copper-molybdenum separation step generates final product copper and
molybdenum concentrate products. This section describes the flowsheet, design criteria, and
process description for a 100,000 t/d processing plant.

The Ann Mason concentrator is designed as a nominal 3,000,000 tonne per month plant. Mine haul trucks will tip into twin primary gyratory crusher stations that are designed for 86% availability. Surge capacity between the mill and crusher stations is handled by two ~40,000 tonne stockpiles.

Material is drawn off the stockpiles using apron feeders. SAG mill feed control would consist of variable speed feeders plus mill feed size distribution measurement. The SAG mill discharge classification is achieved as follows:
• Trommel screen (40 mm) directs oversize to a series of recycle conveyors and allows undersize to gravitate to the SAG mill discharge sump.
• Trommel screen undersize material is further classified by a vibrating, multi-angle scalping screen which cuts at 1.5 mm, oversize recycling back to the SAG mill, undersize feeding forward to the ball mill circuit.

Scalping screen undersize flows by gravity to the ball milling circuit. The ball mill operates in closed circuit with cyclones. The cyclone pack cuts at a P80 of ~155 µm, providing the required liberation for good flotation.

The cyclone overflow reports to the feed box of the rougher flotation circuit. The rougher/scavenger flotation plant consists of nine tank cells in series. Each cell would have independent air flow control.

Rougher flotation concentrate is reground in a ball mill to an 80% passing size of 45 µm. The ball mill operates in closed circuit with a cyclone cluster. Cyclone overflow reports to the 1st Cleaner feed box.

The 1st Cleaner/Scavenger circuit consists of eight tank cells in series. 1st Cleaner Scavenger tailings are fed by gravity into the rougher scavenger concentrate pump box. The 2nd and 3rd Cleaner circuits consist of five and four tank cells in series, respectively.

The third cleaner concentrate is pumped to the conditioning tank in the copper-molybdenum separation circuit. The molybdenum roughers consist of six tank cells in series. The molybdenum rougher concentrate proceeds through five stages of cleaning, with the last two stages in column cells. The tailings are fed counter- currently to the feed box of the previous stage.

Molybdenum concentrate product from the fifth cleaner stage of separation circuit, and copper concentrate (molybdenum rougher tailings) are thickened and press filtered. The copper concentrate is loaded onto trucks and/or stockpiled, while the molybdenum concentrate is rotary dried and loaded into drums.

Flotation tailings from the rougher-scavenger circuit are thickened and pumped to the TMF.

Reagents are stored, mixed and distributed from a central reagents area. Frother, collector, and depressant are pumped from the reagents area to head tanks in the flotation section from where peristaltic reagent pumps accurately dose to the process.