The San Jose Deposit was formed by an amalgamation of quartz and quartzpegmatite veins, which formed a stockwork hosted by metasediments. The mineralisation is disseminated in both the host as lithium micas and the veins hosting tin as cassiterite, lithium as amblygonite-montebrasite and minor tungsten as wolframite. The lithium is found mainly in the micas of muscovite-fengite type in the host rock and in lesser proportion in the amblygonite-montebrasite of the veins.

Primary mineral occurrences in the area appear to be of 3 types, lodes, stratabound or stratiform. The lode deposits are essentially quartz vein or stringer systems that fill late- Variscan Orogeny fractures and carry tin and/or tungsten minerals. Most of these occurrences, even if they are hosted by meta-sediments are regarded as being related to the ubiquitous lateVariscan granitic intrusions.

The drilling at the deposit extends over a strike distance of 420m and includes a 480m vertical interval from 530m to 50m.

Mineralisation is hosted within the slate (bearing 220°) the quartzite (bearing 300°) and the quartz veins (bearing 220°).

Mining is expected to use conventional drilling and blasting, truck and shovel open pit mining. All material is to be drilled and blasted and loaded by an excavator in backhoe configuration onto articulated dump trucks. The trucks will haul high grade ore via an appropriately constructed haul road to the onsite process facility. Lower grade ore will be hauled to an ore stockpile and stored for processing once all the higher grade ore has been depleted. Waste rock will be directly hauled by the same trucks to an appropriately constructed waste dump.

San Jose combines a long life, low cost open pit or quarry operation with a processing plant located on-site and within 2 kilometres of the resource. The work envisages a process flowsheet whereby ore containing an average of 0.82% Li2O over the first 10 years is mined and delivered to the ROM. The lithium bearing mica ore is separated from quartz and tourmaline through a crush, grind and froth flotation beneficiation process. The mica concentrate will then be treated via a sulphate roast using water leach with crystallisation and precipitation.

Stage 1:
Comminution and Beneficiation.
The ROM grade for the first 10 years of mine life is approximately 0.82% Li2O. It is stored on the ROM stockpile and subsequently crushed and milled. Beneficiation of mined ore is envisaged using froth flotation to upgrade to on average 1.36% Li2O over the first 10 years with retention of ~42% of mass. The residual ~58% reject will be stored in separate dumps.

Stage 2:
Sulphate Roast, Water Leach and Purification.
The process flowsheet envisages the conversion of refectory lithium host mica minerals into a soluble sulphate compound that can be water leached. The beneficiated filtered mica concentrate is added to a mixture of potassium sulphate to form small agglomerates, where they are then fed into a kiln and roasted for 20 minutes at a temperature of approximately 840°C. The roasting component of the process is made possible on site due to the availability of natural gas (required to power the kiln) from a gas pipeline adjacent to the San Jose/ Valdeflorez area.

The product is cooled and transferred to the water leach circuit where potable water is used to leach the lithium where recovery into solution is in excess of 90%. The lithium sulphates present in the roasted cake material are dissolved allowing for the leached slurry to be filtered for the removal of solid impurities such as silica.

The environmental credentials of San José remain a priority and Stage 2 provides advantageous components on two fronts. It is envisaged utilisation of a Stage 2 sulphate roast and water leach process mitigates the requirement to introduce large volumes of sulphuric acid as commonly used in hard rock lithium conversion plants. This is a clear positive differentiation and improvement for the environmental profile of San José when compared to a tradition non-sulphate roast and sulphuric acid leach pathway.

Stage 3:
Crystallisation, Purification and Production of Lithium Hydroxide.
The leachate material is neutralised and then treated in a press filter to remove solid particles. The lithium is in solution and then treated with addition of sodium carbonate (purification). This purified liquor is then transferred to a sulphate recovery stage (crystallisation), then cooled and with the use of alunite, sulphate (potassium and sodium if used) is recovered and can be recycled.

The resultant liquor is then enriched through evaporation and the addition of caustic soda (sodium hydroxide) is made in the reactor producing lithium hydroxide. Key reagents such as potassium sulphate are recycled and reused in Stage 2.