The Finniss Lithium Project (Grants and BP33 Lithium Deposits) is hosted within a rare element pegmatite that is a member of the Bynoe Pegmatite Field. The Bynoe Pegmatite Field is situated 15km south of Darwin and extends for up to 70km in length and 15 km in width. Over 100 pegmatites are known within clustered groups or as single bodies. Individual pegmatites vary in size from a few metres wide and tens of metres long up to larger bodies tens of metres wide and hundreds of metres long.

The pegmatites are predominantly hosted within the early Proterozoic metasedimentary lithologies of the Burrell Creek Formation and are usually conformable to the regional schistosity. The Bynoe pegmatites are classified as LCT (Lithium-Caesium-Tantalum) type and are believed to have been derived from the ~ 1845 Ma S-Type Two Sisters Granite which outcrops to the west.

Fresh pegmatite is composed of coarse spodumene, quartz, albite, microcline and muscovite (in decreasing order of abundance). Spodumene, a lithium-bearing pyroxene (LiAl(SiO3)2), is the predominant lithium- bearing phase and displays a diagnostic red- pink UV fluorescence. The pegmatite is not strongly zoned, apart from a thin (1-2m) quartz-mica-albitewall facies and some barren internal quartz veins.

The geological interpretation is considered robust due to the nature of the mineralisation. The mineralisation is hosted within the pegmatite. The locations of the hangingwall and footwall of the pegmatite intrusion are well understood with drilling which penetrates both contacts.

The Finniss pegmatites have intruded early Proterozoic shales, siltstones and schists of the Burrell Creek Formation which lies on the northwest margin of the Pine Creek Geosyncline. To the south and west are the granitoid plutons and pegmatitic granite stocks of the Litchfield Complex. The source of the fluids that have formed the intruding pegmatites is generally accepted as being the Two Sisters Granite to the west of the belt, and which probably underlies the entire area at depths of 5-10 km.

The pegmatite is considered to be continuous over the length of the deposit. It thins and pinches out to the north and south. The mineralisation terminates approximately 40 m from the northern extent of the modelled pegmatite. A non-mineralised wall rock phase of 1-2m thickness is often present. A single grade domain has been identified and estimated using a hard boundary.

The lithium is hosted within a 170m long section of mineralised pegmatite which strikes NE and averages 20-30m in true width.

The pegmatite is sub-vertical to steeply east dipping and has been intersected at a depth of approximately 240m below surface.

Whilst continuous, the pegmatite body does appear to narrow to the north but remains open to the south. The pegmatite is deeply weathered to depths of approximately 50m below surface.

Stage 1 mine plan comprises open pit production from Grants and Hang Gong and underground at Grants, BP33 and Carlton prospects.

Grants Open Pit
Mining of Grants will be undertaken by a Mining Contractor using conventional open pit mining methods.

The pit will be mined in two stages; Stage 1 will target early ore by reducing the volume of pre-strip waste to be mined with Stage 2 a cutback out to the final pit limits.

Mining will predominately occur concurrently within both stages over a 9-month period to ensure continuity of ore supply to the crusher with Stage 1 anticipated to start only 2 months before Stage 2. First ore will be mined in Month 6 of the mine schedule, with mining activities continuing in Grants until Month 31.

Hang Gong Open Pit
The Hang Gong pit design was completed using the same design parameters as Grants with a combination of dual lane and single lane ramps utilised. The pit will be mined as a single phase.

Combined with Grants, the two open pits only contain 5% Inferred Resources & together they support 3 years and 45% of the contained metal of life of mine processing requirements.

Hang Gong Pre-strip commences in Month 60 (Year 5, Month 12) for 10 months before ore is exposed. Mining continues for an additional 19 months until mineral inventory is exhausted, with mining activities ceasing in Month 88.

All material (ore and waste) will require drill and blast, except the oxidised pegmatite and phyllite waste which varies in depth between 30 and 50m from surface, which is based on previous mining activities in the Burrell Creek Formation is assumed to be predominately free dig. The Mining Contractor will also be responsible for pit dewatering, pit surface water management, heavy and light vehicle maintenance, and day to day responsibility for the mining operation. Core will undertake the overall site management, administration, and processing functions.

Grants Underground
The Grants underground is planned as a transition from Grants open pit to underground, access to the Grants underground deposit is via a portal in the Grants open pit and a total decline length of 1,365 m.

The mining method selected for the Grants underground deposit is up-hole retreat mining. The ore body is 5–25 m wide, vertical orientation, and competent host rock ground conditions allows for up-hole retreat mining without back fill to be utilised as a viable low-cost mining method.

The Grants underground is mined without leaving stability rock pillars and is planned to break into the bottom of the open Pit. The Geotechnical assessment of the ground conditions and proposed mine design at Grants underground is to be further assessed.

Mining from Grants underground will be done using underground production loaders. The up-hole retreat mining method selected requires remote loaders as it retreats along the ore drive. Material is to be stockpiled on the production level or loaded directly into underground mining trucks with a 45 t capacity. The haulage path will consist of the stope access development on the production level, the Grants decline, the Grants open pit haul road to the Grants Processing facility.

BP33 Underground
The BP33 deposit is located approximately 6 km south of the proposed Grants open pit. Access to the BP33 underground deposit is via a 340 m decline from the surface box-cut to a decline connecting the lower levels.

The mining method selected for the BP33 deposit is sublevel open stope mining. Internal pillars are utilised for overall stability. The narrow (5–25 m) ore body width, vertical orientation, and competent host rock ground conditions and internal rock pillars allows for sublevel open stoping mining without back fill to be utilised as a viable low-cost mining method.

Mining from BP33 will be done using underground production loaders. The majority of the sublevel retreat mining will be done using remote loaders. It has been assumed that the same mining contractor would carry out mining at all the deposits. The costs for BP33 were prepared in the same way as for Grants underground.

Material is to be stockpiled on the production level or loaded directly into underground mining trucks with a 45 t capacity.

The haulage path will consist of the stope access development on the production level, the BP33 decline, and haul road (6 km) to the Grants Processing facility.

Carlton Underground
The Carlton deposit is south of the planned Grants open pit. Access to the Carlton underground deposit is via a portal in the Grants open pit and a 1,200 m decline. The 6.0 m x 6.0 m decline will also act as the primary ventilation intake into the mine with the exhaust to surface via a return a raise bored Return Air Raise.

The mining method selected for the Carlton deposit is sublevel open stope mining. Internal pillars are utilised for overall stability. The narrow (5–15 m) ore body width, vertical orientation, and competent host rock ground conditions and internal rock pillars allows for sublevel open stoping mining without back fill to be utilised as a viable low-cost mining method.

Mining from Carlton will be done using underground production loaders. The sublevel open stoping method selected requires remote loaders as it retreats along the ore drive. Material is to be stockpiled on the production level or loaded directly into underground mining trucks with a 45 t capacity. The haulage path will consist of the stope access development on the production level, the Carlton decline, the Grants open pit haul road to the Grants Processing facility.

The proposed Finniss Lithium Project Gravity Plant has been designed to treat a nominal 1.0 million tonnes of spodumene bearing pegmatite at a head grade of between 1.4% & 1.5% Li2O and targeting production of a spodumene concentrate containing an average 5.8% Li2O. Once operational, at Grants, the Finniss processing plant will operate 24 hours per day. Operation and maintenance of the plant will be completed by Primero Group.

Following the four generations of metallurgical test work the processing flowsheet will have the following characteristics:
• The crushing circuit is designed to crush to P100 of 6.3mm. This is a four stage crushing circuit;
• The DMS circuit is configured with a coarse and fines circuit with a secondary DMS on the coarse;
• A re-crush facility on DMS middlings consistently aids the production of grades of 5.5% Li2O or better at acceptable recoveries of over 70%;
• A primary and secondary DMS circuit is used to manage the coarser +2 ........