The Authier project hosts two separate mineralised spodumene-bearing pegmatite systems including, Authier and Authier North. Authier is 1,100m long, striking east-west, with an average thickness of 25m, ranging from 4m to 55m, dipping at 40° to 50° to the north. The deposit outcrops in the central-eastern sector and then extends under up to 10m of cover in the western and eastern sectors.

Authier North, located 400m north of the main Authier pegmatite, is approximately 500m in strike length, 7m average width, dipping 15° to 20° to the north. The Authier and Authier North pegmatite dykesremain open in all directions. A magnetic geophysical survey has demonstrated that the Authier mineralisation is hosted within a strong east-west trending magnetic low anomaly. Future exploration will focus on identifying extensions of know mineralisation within this structural feature.

The lithium mineralisation at Authier is related to multiple pulses of spodumene-bearing quartz-feldspar pegmatite. Higher lithium grades are related with high concentrations of fine and mid-to-coarse spodumene crystals (up to 4cm long axis) in a mid-to-coarse grained pegmatite facies.

Mining will be undertaken using drill and blast, and conventional bulk mining methods utilising hydraulic excavators and dump trucks delivering ore to the primary jaw crusher or to the ROM stockpile.

Multiple mining phases were developed for the UDFS. The LOM was developed based on a range of constraints and results in a mine life of 14 years.

During the lifespan of the open pit mine, a total of 35.9 Mm3 of waste rocks and 4.38 Mm3 of tailings will be generated for a total of 40.28 Mm3. Sayona Québec has opted for a co-disposal method to store tailings produced at the concentrator and waste rocks from the mine.

The co-disposal strategy consists of using waste rocks to construct peripheral berms and peripheral roads and confining filtered tailings into waste rock cells. This method has the advantage of increasing the stockpile’s global stability and the water drainage efficiency while ensuring long-term physical and geochemical stability. Furthermore, the co-disposal method reduces the site’s footprint.

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BBA designed a concentrator to process roughly 883,000 tpa of ore using conventional flotation technology suitable for a pegmatite orebody that will be located near the open-pit.

The ground ore will be passed through a magnetic separation circuit to remove iron-bearing silicate minerals and then de-slimed prior to mica flotation. Following mica flotation, the slurry will flow to an attrition scrubber and hydrocyclones for de-sliming prior to spodumene flotation. The plant will produce 6.0% Li2O concentrate with 78% lithium recovery.

Magnetic and mica concentrates, slimes, and spodumene flotation tailings will be thickened and filtered prior to co-disposal with mine waste (dry stacking). Truck and loading units will be used to dispatch tailings to the waste rock facility. The spodumene concentrate will be filtered to roughly 6% moisture. The dried spodumene concentrate will be stored in a covered storage area prior to bulk shipment to a port and/or other Canadian offtaker.

Update 2022: Following the acquisition of the NAL mine and concentrator in August 2021, the Authier project’s operating strategy was revised to include only mining operations and waste and water management on-site.