The key setting for all the nickel that has been mined historically at Kambalda district is at a contact zone between two rock types, with a younger overlaying volcanic rock.[2019 AR, p.15]

MNO is expected to consist of Cassini and the Northern Operations (Long and Durkin North) at commencement, with the Miitel mine contributing in the back half of the project life.

Cassini
Cassini is located on the southern section of the Widgiemooltha Dome. The geology of the Widgiemooltha Dome and the area to the south consists of a thrust repeated sequence of basic ultramafic extrusive and intrusives, with intercalated sediments and acid volcanics with nickel sulphide orebodies found at the base of the ultramafic sequence.

The Cassini orebody as interpreted in the Mineral Resource is split into eight lodes, labelled CS2-CS9. From a mining perspective, the Mineral Resource has been delineated into two main areas based on spatial characteristics. These mining areas have been named by the dominant lode (CS2 or CS4). The CS2 Area (CS2, CS3, CS6, CS7 and portion of CS5 lodes) consists of east-west trending parallel lodes, mainly offset, dipping at ~45° to the south with thickness from ~1m to ~7m, averaging 3m.

The CS2 Area extends from ~260mRL (approx. 50mbs) to ~-240mRL (480m vertical extent). Grades and orebody thickness are inconsistent above ~75mRL.

The CS4 Area (CS4, CS8, CS9 and portion of CS5 Lodes) consists of parallel lodes striking northwest/southeast at ~125° and dipping at ~75-80° to the southwest. Average widths for the CS4, upper CS5 and CS9 lodes are 2-3m, with the CS5 lode thickening to 5-7m and up to 11m in parts below ~-250mRL (grades in this area also increase). The area extends from ~100mRL to -380mRL. Grades and thickness are inconsistent above ~10mRL.

Northern Operations
The Durkin North orebody (“Durkin North”) is an unmined nickel deposit located beneath and to the north of the historical Durkin mine workings, part of the Otter Juan (“Otter”) mine.

There are two mining areas in the Durkin North mine plan, being the D1/D2 area and the D3/D5 area. The D1/D2 area strikes predominantly east-west with a strike length of ~550m, extending from ~-85mRL (~420 mbs) to -260mRL (175m extent). This area gently plunges to the north resulting in a long strike over a relatively small vertical extent. The orebody in D1/D2 is generally narrow (1-3m), with one main lode and a small hangingwall splay in the southern area. The orebody dips to the north, with dips ranging from relatively shallow dipping (down to 45° in parts) up to 75°. The D3/D5 area strikes southeast/northwest with a strike length of ~380 m, extending from -270mRL to -450mRL (180 m extent). The plunge in this area tends to vertical. Dips are generally steeper than D1/D2, ranging from 65-80° to the north-east. The D3/D5 area contains several closely spaced economically extractable lodes in parallel, with widths 1-3m.

The Long Mineral Resource generally strikes northwest-southeast. The Mineral Resource is spread out over an extensive area. Ore pod strike lengths are variable, ranging from 20-30m to ~500m. Some areas dip steeply and continuously to the north-east at approximately 70-80°, while other ore pods are flat dipping at 15-25°. The orebody is generally less than 2m thick.

Miitel
In general, ore at Miitel is located at the steeply dipping contact between footwall basalt and a less competent hanging wall ultramafic unit.

The majority of the Miitel area consists of the N30 and N31 lodes as shown in Figure 8. Both areas strike roughly north-south. The N31 has a strike length of ~180m, extending from ~-400m RL (~705mbs) to -300m RL (100m extent). The N30 has a strike length of ~450m, extending from ~-580m RL (~885mbs) to -430m RL (150m extent) and plunging gently to the south. Both areas consist of single lodes dipping sub-vertically (60-70°) to the east, with widths from 1-8m (N31) and 2-10m (N30).

There are two mining areas in the Burnett mine plan, being the B01 and B02 areas. Both areas strike at ~330-340°. The B01 has a strike length of ~260m, extending from ~-415m RL (~725mbs) to -290m RL (125m extent). The B02 has a strike length of ~340m, extending from ~-460m RL (~420mbs) to -310m RL (150m extent). Both areas consist of single lodes dipping sub-vertically (>80°) to the north-east, with widths ranging from 1-5m.

The Definitive Feasibility Study has adopted an underground contractor model for mining costs.

The primary mining method proposed is bottom-up longitudinal longhole stoping (LHS) with modified Avoca assuming cemented rockfill (CRF).

Cassini
The Cassini mine will be accessed via a new box-cut and portal. Capital works for the box-cut, commenced in February 2020 and are expected to be completed by April 2020. The stope optimisation process showed that the economic portion of the Cassini orebody (commences from 250m below surface). Based on geotechnical analysis and the results of geotechnical drilling, the box-cut has been located ~700m to the south of the orebody where near-surface ground conditions are more favourable.

A twin decline system will be developed from the box-cut zone to the production zone, with access and return air declines excavated in parallel, allowing primary ventilation to be established early in the mine life. Ventilation and secondary egress will be via a raise system developed from the ventilation decline to the box-cut.

Vertical sub-level intervals are 15m floor-to-floor, allowing good drill and blast control. Areas with no top access (i.e. crown stopes or levels directly beneath sill pillars) will be mined using conventional longhole open stoping, retaining in-situ pillars for support. Maximum open stope strike lengths of 30m have been applied based on geotechnical studies. Slots to open stoping spans have been designed assuming handheld development methods. Subsequently mined stopes in filled levels will be fired against fresh CRF without the requirement for additional slotting.

Stopes will be mined from the ends of the orebody retreating towards central level accesses from the decline, with each stoping level to be completed before stoping in the level above commences. The stoping block will be split into independent panels of several levels to allow concurrent mining, with each panel separated by a 1.5m thick high strength (8% cement) CRF sill pillar.

Northern Operations
The Durkin North mine is planned to be accessed both through the existing Long mine and the existing Otter mine. Both mines are accessible and require minimal rehabilitation. The Durkin North access decline will be developed from both sides and will connect Long and Otter when broken through. The Long designs are all located within the existing Long capital development. Long orebodies will initially be accessed through the Long-Victor portal. Once the Durkin decline has broken through, all access will be via the Otter portal, as this provides a shorter haul distance than the Long-Victor portal with additional ventilation benefits.

Vertical sub-level intervals are 14-16m floor-to-floor, allowing good drill and blast control. Areas without top access (i.e. crown stopes or levels directly beneath sill pillars) will be mined using conventional longhole open stoping, retaining in-situ pillars for support. Maximum open stope strike lengths of 20m have been applied based on geotechnical studies. Slots to open stoping spans have been designed assuming handheld development methods. Subsequently mined stopes in filled levels will be fired against fresh CRF without the requirement for additional slotting.

Stopes will be mined from the ends of the orebody retreating towards central level accesses from the decline, with each stoping level to be completed before stoping in the level above commences. The Durkin North stoping blocks will be split into independent panels of several levels to allow concurrent mining, with each panel separated by a 1.5m thick high strength (8% cement) CRF sill pillar. The Long stoping blocks are sufficiently spatially separated to allow independent mining without sill pillars.

Miitel
Historical production for Miitel between 2000 and 2016 totalled 2.5Mt @ 2.9% Ni for 72,000t of contained nickel.

The orebodies are planned to be accessed through the existing Miitel portal and decline. The Miitel decline will require dewatering and rehabilitation of ground support and services prior to the commencement of development.

Currently the mining schedule allows for the mining fleet (including personnel) at Miitel to be sourced from the Northern Operations. This will be dependent on whether mine life can be extended at the Northern Operations.

Vertical sub-level intervals are 15-20m floor-to-floor. Areas without top access (i.e. crown stopes or levels directly beneath sill pillars) will be mined using conventional longhole open stoping, retaining in-situ pillars for support. Maximum open stope strike lengths of 12m have been applied based on geotechnical advice. Slots to open stoping spans have been designed assuming handheld development methods. Subsequently mined stopes in filled levels will be fired against fresh CRF without the requirement for additional slotting. Some areas will be mined using overhand cut-and-fill methods or airleg stoping, dependent on orebody geometry. All these methods were previously successfully applied at Miitel by MCR.

Waste for fill will be backhauled from surface and mixed with cement delivered by agitator trucks to the fill location. Loaders will deliver the CRF (3% cement) to the stoping voids. Specialist underground contractors will provide equipment, personnel and consumables required for the works. Mincor will supply technical support, environment health and safety (EHS) support, site management and diesel.

Under the Ore Tolling and Offtake Purchase Agreement, Mincor has the right to process a minimum of 200ktpa and up to a maximum of 600ktpa of nickel sulphide ore at the Kambalda Nickel Concentrator (KNC), which is owned and operated by BHP Nickel West.

Each of the mines has been scheduled separately, but with the overall objective for the Project to deliver between 500ktpa – 600ktpa of ore (on average) to the KNC.

Mincor plans to blend nickel sulphide ore from the three mining centres over a five-year period. Ore from each mine has been approved by BHP Nickel West for processing at the KNC.

The KNC design was based on a conventional sulphide processing route using traditional grinding and flotation technology to produce saleable nickel-copper-cobalt concentrate.

Ore will be delivered by the haulage contractor from each site ROM to the KNC ROM. On delivery and exit to the Kambalda ROM pad, each truck will be weighed over a certified weighbrid ........