In general, terms, the mineral system could be classified as a porphyry copper deposit. The system has many of the characteristics of a typical porphyry system, including an association with porphyritic phases of dioritic to granodioritic intrusive phases and typical alteration assemblages associated with potassic, phyllic and propylitic altered rocks. However, there are some key differences between Yandera and typical zoned porphyry systems, including strong structural controls on mineralization and an association between phyllic alteration and elevated copper grades.

The porphyry system at Yandera is hosted in late intrusive phases and structures that disrupt the Bismarck granodiorite. Mineralization appears locally controlled by porphyritic dacite and associated intrusive breccia bodies. The occurrence of these intrusive bodies and later alteration appears to be controlled by a strong northwest trend that intersects and/or is intersected by north and northeasterly trends. Higher-grade copper mineralization appears to be concentrated near the intersection of these trends, such as at Imbruminda, within broader zones of potassic and phyllic alteration.

A number of younger igneous units, including a later porphyritic quartz diorite (POK), porphyritic dacite (PDA), andesite (PAN), microdiorite (POM), and some leucocratic quartz diorite (PLQ), intrude the volumetrically larger quartz diorite porphyry (POD) phases at the property. The younger igneous phases are generally tabular in geometry, sub-vertical, and likely reflect structural zones that were important at the time of emplacement of each.

Within and around the large bodies of POD there are domains of porphyry-style alteration. Within a broad envelope of propylitic alteration, there are more limited domains of potassic alteration and phyllic alteration. Domains of phyllic alteration commonly envelope structures as well as some of the younger intrusive units within domains of potassic and even propylitic alteration.

In association with some of these intrusive units, particularly the porphyritic dacite, there are localized hydrothermal or intrusive breccias. These breccias are commonly closely associated with zones of phyllic alteration. Tectonic breccias observed at the property commonly appear very planar, and sometimes have envelopes of phyllic alteration.

While there is a prominent northwest striking structural trend (300°), there are several other important structural trends including a prominent north-north-westerly trend (330° to 360°) and a north-easterly trend (030°). The northwest trend appears to be the oldest of the three, and reflects the regional-scale structural grain. The north-north-westerly trend cuts the northwesterly trend in a number of locations, but there are some instances when the northwest trend offsets the north-north-westerly trend. The northeast trend appears to be one of the youngest trends, and a number of veins and fractures throughout the property, as well as some prominent sub-vertical dikes of PLQ reflect it.

Early in the copper mineralization history, there likely were some more typical porphyry-style mineralization events with better mineralization associated with potassically altered cores. However, younger, structurally controlled mineralizing events cut these older systems with phyllic alteration that enhanced zones of copper mineralization locally.

Mineralization is most commonly hosted in breccias, porphyritic dacite, porphyritic microdiorite, quartz diorite porphyry and, less commonly, the granodiorite host. Recent interpretive geologic work suggests that higher-grade copper mineralization is commonly associated with phyllic alteration in association with breccias likely related to emplacement of porphyritic dacite.

The most common sulphide minerals in mineralized domains are pyrite, chalcopyrite, bornite and molybdenite, with varying abundances between prospect areas. For example, bornite is more prominent in the Imbruminda area while chalcopyrite is by far the dominant copper mineral at Omora. Previous investigations have interpreted these changes as evidence of typical zonation in a porphyry system; however, some of these differences may alternatively be explained as structural blocks that have been up-thrown or down-thrown to expose different portions of the mineralized system.

Recent work suggests that large-scale structure is very important to controls for mineralization. Mineralization at Gremi and Dimbi roughly follow a northwest trend; however, higher-grade copper mineralization at Imbruminda is coincident with the intersection of a mineralized north- north-westerly trend and a mineralized northwesterly trend.

Analysis of structural data from oriented core indicates that the largest population of veins, dominantly mineralized in the resource area strike northeasterly and dip steeply (~70°+) to the south-east or north-west. The orientation of these veins is sub-parallel to the most populous drill azimuth in the property. Locally, such as at Rima, mineralized veins and veinlets strike nearly north north westerly and dip steeply (77°+) to the west.

Most of the known copper mineralization is hypogene, and near-surface sulphides have been oxidized to varying depths and degrees. For example, oxide mineralization at Gremi reaches depths of up to 50m, while oxide mineralization at Dimbi is significantly shallower. To date, no significant supergene enrichment blanket has been identified at the property.

Conventional open pit mining methods consisting of drilling, blasting, loading and hauling will be employed at Yandera Mine. Contractor mining was determined to be more viable than an owner-operated fleet during the financial analysis of the PFS.

The primary mining activities will be supported by ancillary activities including the following:
- bench preparation;
- pit dewatering;
- dust suppression;
- haul road construction and maintenance; and
- General housekeeping.

The mine was designed to produce 30Mt of above cut-off grade sulphide ore per annum. An additional 3Mtpa will be processed from the below cut-off grade sulphide ore stockpile or from the oxide ore stockpile when the sulphide ore sources are insufficient. A total of 533,185,430t ore is produced from the production schedule. A total of 705,286,358t waste rock will be produced over the life of the mine. The tonnage that will be placed in the waste rock dump amounts to 531,364,993t and the remaining tonnages (173,921,366t) will be backfilled into the Gremi and Omora pits.

The following assumptions were made for the proposed slope design:
- Slope design is within FoS guidelines for major structures.
- Pre-spit drilling and buffer blasting will occur along all final pit slopes.
- General good blasting practices will be followed in the pit and especially close to final pit walls.
- Slope stability monitoring systems will be installed.
- Slope management will be conducted and all possible reasonable effort will be made to ensure that geotechnical design criteria are followed; where the layout is changed, proper geotechnical diligence is applied and the loop between short- and long-term mine planning is closed.
- Access to catch benches will be maintained throughout the life of the individual pits.
- The catch benches will be cleaned periodically when material starts to build up on the berm.
- The berm wall as recommended will be constricted on all the safety benches.

The bench height for the client defines the pit and slope design based on its current equipment fleet and is fixed at 10m vertical height. The bench face angle is defined at 84° because pre-split slopes drilled at a 90° slope perform much better than vertical walls where sub-vertical joints are present.

The 3m bench offset defined for the triple bench configuration creates a safe working area at the toe of the slope for the drilling crews drilling the pre-split. The 3m also acts as a buffer to poor blasting results: it sometimes happens that toe positions are not reached and if the crest line of the next bench is too close, the holes cannot be drilled at the designed positions.

The stack slope configuration adopted consists of three 10m benches with a 3m bench offset on the middle two benches, resulting in a stack height of 30m. A catch bench is provided for at the toe of the third bench. This configuration allows for a catch and safety bench that is wide enough both to accommodate the material from a slope failure and to manoeuvre equipment for periodic cleaning.

The slope design for the waste rock dump evolved through a number of iterations into a design that is practical, economical and sufficiently robust to withstand the seismicity and rainfall of the area for the life of the mine and beyond. The design is a benched design with the waste rock being dumped at right angles to the front face in stacks no higher than 50m with the final profile having a 100m-wide safety bench. The stability analysis taking seismicity and a high- water table inside the dump into account had a FoS of 1.5 for the overall slope. Small-localized areas on the individual benches had a FoS of between 1.0 and 1.5.

Drill and blast techniques will be applied to fragment in-situ rock. A combination of buffer blasting and presplitting is recommended to reduce the damaging effect of the shock energy from production blasting on the highwall slopes. A single row of presplit holes will be drilled along the position of the highwall and a minimum of one row of buffer holes will be drilled inbetween the presplit and production holes.

Bulk emulsion is proposed for production and buffer blasting due to its excellent water resistant characteristics. Considering the spacing between buffer holes, waste decking is recommended for buffer blasting to reduce the amount of explosives contained in each hole and to maintain the powder factor required to fragment rock. It is recommended for each buffer hole to have two waste decks, each having a length of 2.4m and three explosive decks each with a length of 0.9m. Packaged emulsion (cartridges) is recommended for presplitting as continuous decoupled charges provide the excellent energy distribution that is required for effective presplitting (Read and Stacey, 2009).

RoM ore is crushed in a single stage gyratory crusher and conveyed to the coarse ore stockpile. Ore from the stockpile is withdrawn by a series of vibrating feeders onto the mill feed conveyor. The grinding circuit consists of a SAG milling, ball milling and pebble crushing (SABC) circuit. The ball mill operates in closed circuit with a classification cyclone cluster. Cyclone overflow is dewatered in a thickener ahead of an overland slurry transfer pipeline.

The flowsheet selected for processing ore at Yandera is a conventional concentrator comprising milling and flotation to produce two concentrate streams, i.e. a copper concentrate and a molybdenum disulphide concentrate.

The major unit operations consist of:
- Crushing.
- Two stage milling (SAG and Ball milling) incorporating pebble crushing.
- Slurry dewatering and overland transfer by pipeline.
- Bulk rougher and scavenger flotation.
- Copper concentrate regrind ahead of two stage cleaning and a cleaner scavenger circuit.
- Molybdenite rougher circuit.
- Seven stage molybdenum disulphide cleaner circuit incorporating concentrate regrind.
- Concentrate dewatering and filtration/drying.
- Tailings dewatering and disposal by DSTP (Deep Sea Tailings Placement).

The process plant is designed for a throughput of 30Mtpa, but is capable of a throughput of 33Mtpa. Treatment of ore arising from the Yandera Project will ........