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 the whole unit, between Upper Breccia and Lower Breccia. The contact between the Lithium-rich Tuff and the Lower Breccia is less marked than the Upper Breccia. The Lower Breccia has been identified in outcrop in the Tres Hermanas trenches, and has been interpreted from drilling.

The thickness of the Upper Breccia varies from 10m to 20m, while the thickness of the Lithium-rich Tuff varies in drilling from 50m to 140m. The Lower Breccia unit is variable in thickness, but recent drilling has indicated that the Lower Breccia unit can reach thicknesses of up to 175m and contains large (up to 20m) blocks of Lithium-rich Tuff. The Upper Breccia, Lithium-rich Tuff and Lower Breccia show remarkably consistent vertical zonation of lithium, strontium, cesium and other elements. The highest concentration of lithium is at the top and bottom of the Lithium-rich Tuff.

The Lithium-rich Tuff, and the transitional Upper and Lower Breccias are interpreted to have been deposited in a technically active, crater-lake environment, where the breccias represent the transition from the rhyolitic ash-flows above and below, and the Lithium-rich Tuff, represents a period of sub-aerial deposition. This is supported by the regular layering observed in the tuff, and the angular clasts of the breccia.

The lithium mineralization is interpreted to be primary – related directly to the chemistry of the parent magma, although alteration and enrichment by groundwater or hydrothermal fluids in the interim has not been ruled out. The reason for the elevated lithium concentration, relative to the surrounding acidic tuffs is directly related to the parental magmas resulting from extreme fractionation of peraluminous melts and will be further investigated by Plateau Energy Metals through additional university and internal research.

As with the lithium in the uranium Complexes, typical lithium minerals are not visible in hand specimen, and it is interpreted that the majority of the lithium is located in the glassy, siliceous groundmass of the tuffs.

The SGS Canada work has identified only rare Li-minerals, and the current stage of understanding of the lithium deportment at Falchani is that the bulk of the extractable lithium resides in alumino-silicate volcanic glass.

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 should be optimized to reduce haul distances and environmental impacts.
Consideration should made to ensure the position of the waste dump will not impact further exploration or mineralisation.

Some waste material may be used in the construction for the tailings storage facility (TSF), however this will only be addressed in the next study phase. Waste rock dumps are generally constructed in 5 to 10m lifts to a maximum of 40 to 60m depending on local geotechnical stability and terrain.

Due to the fact that the mining deposits are massive with low strip ratios the following dilution and losses parameters where used:
• Mining losses of only 2% where used due to the limited zones of interaction between waste and mineralised material.
• Geological losses of 5.8% average are derived from the geological resource works which consider the current relatively low drilling density. Mine Sequencing/Scheduling.

The life of mine is estimated to at 33 years, including 6 months pre-production and a relatively slow process plant ramp up to Phase I at 1.5Mtpa. At full steady state an average of 14Mtpa rock movement will be required. The mine is operation is planned on two 10-hour shifts per day, 353 days per year. The mine plan has been developed based on using one or more mining contractors for all planning and operational aspects of the mining operation.

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 ........