Limited mineralogical work has been undertaken by SGS Canada on samples from the Falchani Project, and the understanding of the stratigraphy has evolved through exploration mapping and drilling programmes. In the immediate vicinity of the boreholes drilled at Falchani, the youngest rocks would appear to be these described in the field by Plateau Energy Metals as the Upper Rhyolite. The Upper Rhyolite forms prominent outcrops, and demonstrates a crude bedding, and appears to have a shallow dip to the north-northeast. Outcrops of the Upper Rhyolite have a similar appearance to the acidic tuffs of the Yapamayo and Sapanuta Members of the Quenamari Formation, which host the uranium mineralization.

This together with the fact that the Falchani Project is mapped as being underlain by the Sapanuta Member of the Quenamari Formation, support the interpretation. Below the Upper Rhyolite is the Upper Breccia, which separates the Upper Rhyolite from the Lithium-rich Tuff. The Upper Breccia is not well defined in outcrop but is very distinctive in core. The Upper Breccia contains angular clasts of volcanic material, in a very fine groundmas. The Lithium-rich Tuff is a light grey to white, very fine grained rock, with prominent layering.

Although the Lithium-rich Tuff has been further sub-divided, on the basis of its chemistry (Section 14.2.1), these subdivisions are not immediately recognizable in outcrop or in core, and the term Lithium-rich Tuff is used to describe ........

Open pit mining is planned to use conventional truck and shovel mining methods with drill and blasting to break the rock mass into manageable particle sizes. Mining operations are planned to be undertaken by a contractor operated fleet, which is the cost basis for this preliminary economic assessment.

The following design parameters where used for the PEA study revision:
• Fully mobile production equipment, consisting of medium sized hydraulic shovels and 90 tonne rigid dump trucks has been planned
• Total mining costs of $2.40/t of material moved at altitude is the basis for the Project economics
• Support equipment will be Front End Loaders, tracked dozers, graders, and water trucks
• The run-of-mine (RoM) pad at near the Process Plants primary crusher will be the mining and process battery limit
• Benchmarked operation elevation of 4,700masl was used
• Optimisation of mining sequencing to minimise the waste stripping costs in phase I of the production ramp up
• 10m waste benches, with stacking of 2 benches was basis of the design used to access mineralized material to a maximum depth of 200m
• Geotechnically designed slope are applied to relevant pit areas.

Waste dump will be planned in accordance with environmental constraints and located around the pit edges once it has been confirmed that there are no additional mineral resources in these areas.

Backfilling of waste into mined out pit areas shoul ........

Mined lithium-bearing tuff mineralised material is stockpiled on the run-of-mine (RoM) pad. The mineralised material is first deposited in the mineralised material feed hopper using a Front End Loader (FEL). From there, the pre-crushed mineralised material passes over a scalping screen where the undersized particles fall through via a chute on to the fresh mineralised material feed conveyor. The scalping screen oversize is fed to the first stage jaw crusher where it is crushed. Both the crushed product and scalping screen undersize is conveyed to the mineralised material feed conveyor where it is combined with the secondary and tertiary cone crusher product to form a vibrating screen feed.

The vibrating screen feed is fed to a double deck screen with the oversize and middling being separately conveyed to the secondary and tertiary cone crusher respectively. Discharge from both the secondary and tertiary crushers reports back to the mineralised material feed conveyor for further screening. The double deck screen undersize falls through a chute and onto the crushed product conveyor where it is conveyed to the crushed mineralised material bin.

A substantial body of metallurgical testwork has been carried out on the Falchani lithium-bearing tuff material. The testwork referenced in this report was carried out by Tecmmine in Peru (prior to 2018) and testwork carried out in 2018 and 2019 was carried out by Techmine and ANSTO Minerals in Australia. Both the Tecmmine and ANSTO testwork was carried out on the lithium rich tuff obtained from a trench on site.

The testwork supports a number of technically viable process flowsheet routes (hydrochloric acid leaching, salt roast, sulfation baking, pressure leaching, purification processes) but for the purpose of this PEA a flowsheet using atmospheric leaching in a sulfuric acid medium, followed by downstream purification processes, was selected for the production of battery grade lithium carbonate. The early focus of the acid leach process was on maximizing the extraction of lithium using aggressive leach conditions and the later work focused on optimizing the leach paramete ........