The Josemaria project area is underlain most extensively by Permo-Triassic rocks assigned to the Choiyoi Group, which forms the Andean basement in the region. They include volcaniclastic and ignimbritic rhyolites as well as broadly equivalent granites. Triassic intrusive complexes of tonalite, diorite and granodioritic composition intrude the rhyolites and granite. Swarms of andesite dykes, which are typical of the Permo-Triassic in this region, cut the older Permo- Triassic units.

Porphyry intrusive rocks and associated porphyry and epithermal mineralized systems are largely hosted within basement rocks. Late Oligocene systems form a north-south trend extending from Josemaria to the Sillimanita and Cerro Blanco Cu-Au porphyry prospects formed around similar dacitic intrusions. Middle Miocene systems such as the Filo del Sol porphyry-epithermal Cu-Au-Ag deposit and the Los Helados porphyry Cu-Au deposit occur several kilometres westward.

The Josemaria porphyry copper-gold deposit is centred on a Late Oligocene dacitic porphyry intrusive complex emplaced into Permo-Triassic rhyolite and tonalite. Porphyry ascent and localization appears to have been guided by a pre-existing north-south structural zone.

The Cu–Au mineralization at Josemaria is hosted within a porphyry system that includes two main types of hypogene mineralization. These two types occur in proximity to one another due to a high degree of telescoping of high-sulphidation alteratio ........

Being a large, near-surface ore body, the Josemaria project will be developed as an open pit mining operation. Over 1 billion tonnes of ore will be mined at average diluted head grades of 0.30% Cu, 0.22 g/t Au and a strip ratio of 0.98 over a 19-year mine life. Waste and ore will be drilled and blasted, loaded by hydraulic shovels and loaders, and transported by haul trucks to external waste storage facilities (WSF), long-term stockpiles, or a run-of-mine (ROM) pad where it is fed to a primary crusher for mineral processing.

The pit footprint is on a hillside and the maximum wall heights will range from approximately 800 m in the south to 400 m in the north. Rock mass and strength data were interrogated via histograms and statistics based on lithology, alteration and mineralization properties. Rock mass ratings of the major units were in the ‘fair’ to ‘good’ categories, with the exception of a distinct zone of rock (‘low-RQD’ zone) at depth in the north that was in the ‘poor’ category.

Mining will occur with 15 m benches (often double benching) with average slope angles ranging from 37 to 43 degrees. Shallowest overall slope angles are in the north of the pit where there is a zone of lower rock mass strength at depth, requiring an angle of 34 degrees in that specific zone. Large electrically powered hydraulic shovels will be used in combination with ultra-class 360-tonne haul trucks.

For the FS, it was assumed the former would be accomplish ........

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The Josemaria process facilities are designed for a throughput rate of 150,000 t/d of tonalite
material at the 75th percentile hardness.

The process facilities include the infrastructure, equipment and systems required for crushing, grinding, flotation, concentrate and tailings thickening, concentrate filtration, storage and loadout. Major process unit operations are:
- Primary crushing
- SAG milling and pebble crushing
- Ball milling
- Flotation and regrind
- Copper concentrate thickening
- Tailings thickening and distribution
- Concentrate dewatering, storage and loadout.

Copper Flotation & Regrind
The flotation and regrind facilities will be installed in an enclosed, insulated, clad building. The bulk flotation and regrind circuits consist of three distinct areas: rougher-scavenger flotation, regrind milling and cleaner flotation.

The ball mill cyclone overflow is fed into the rougher flotation feed di ........