Deposit Types
According to classical classifications of magmatic nickel-copper-PGE sulphide deposits, the Samapleu deposits are interpreted to occur as sulphides concentration within a differentiated, ultramafic and mafic feeder dykes system of the layered Yacouba complex. These rare intrusion types are host to the largest Ni-Cu deposits in the world, such as Jinchuan or Kalatongke (China), Voisey's Bay or Eagles Nest (Canada), Kabanga (Tanzania), Eagle (USA) and N'komati (South Africa).

The Samapleu mineralization is part of an ultramafic sequence part of the Yacouba complex, rather than of the type associated with a gabbro assemblage.

Geological Setting and Mineralization
The project area is located in the eastern portion of the Archean West-African Craton (WAC) that is represented by two shields: Reguibat to the north and Man to the south. The Man shield is subdivided into a western domain, predominantly of Archean age (Kénéma-Man), and an east-central domain (Baoulé-Mossi) composed of Paleoproterozoic rocks.

The Project lies within the Kénéma-Man domain, which consists chiefly of Archean granulitic and migmatitic gneiss and relic supracrustal belts with mafic to ultramafic rocks and iron formation. In turn, the Kénéma-Man domain is separated in two, and the project is located in the granulitic and migmatitic rocks of the southern domain.

The Yacouba mafic and ultramafic Layered Complex of Eburnean age has intruded the older gneissic assemblage of the WAC. The Complex that was recently discovered by Sama can be traced discontinuously over 60 km along a NE-SW corridor. The Yacouba Complex is characterised by magmatic intrusions, prompting assimilation of the country rock creating a large complex predominantly composed of the resultant migmatite material with well-preserved pyroxenite, gabbro and anorthosite members (Figure 7.1). At the Samapleu deposit, the intrusive members appear as possible feeder dyke that vertically crosscuts the Archaean gneiss and granulite sequence.

The Yacouba complex was recognised by drill holes at the Samapleu Main, Samapleu Extension and Yorodougou locations. The Samapleu intrusion is interpreted to represent a magmatic conduit of the Yacouba complex.

The layered successions are the host of Ni-Cu sulphides (mainly pyrrhotite-pentlandite and chalcopyrite), disseminated Pt and Pd minerals and massive chromite layers. The mineralization is preferably hosted in pyroxenite, although local zones rich in sulphides were identified within the peridotite units. In addition, strong sulphide mineralization also occurs at the gabbro-norite contact of the main zone of Samapleu.

The mining method selected for the Project is a conventional open pit operation with off-highway haul trucks, hydraulic excavators, and wheel loaders.

The Project consists of three (3) separate pits (Pit A, Pit B, and Pit C) with one (1)waste dump designed close by to reduce haulage distance.

The mineralised material and waste rock will be loaded into off-highway haul trucks with excavators and/or wheel loader.

To properly manage water infiltration into the pits, sumps will be established at the lowest point of each pit floor. Water collected in the sumps will be pumped to a collection point at surface.

Samapleu mineralised material, contained into three (3) pits, are intended to be mined by surface operations. It is estimated that approximately 44.42Mt of mineralised material is extractable over a 20-year mine life.

The mine will operate year-round, seven (7) days per week, twenty-four (24) hours per day (2 shifts, 12 hours each). Since the mill will operate seven (7) days per week, a run of mine stockpile will be maintained to provide a constant supply of feed to the crusher with a minimum of one (1)month of production capacity. During the days when the mine is not operating (for technical or weather reasons), the crusher will be fed by the front-end loader from the stockpile or with a production truck. The mine fleet requirements and manpower are based on this work schedule.

Mine Design Engineering (MDEng) issued a scoping level review summarised in the Report #18022-104 Feasibility level site characterisation, Geotechnical Scoping Study for Samapleu Ni-Cu-PGE project, dated March 21, 2019.

Based on MDEng's recommendations for bench slopes, DRA/Met-Chem used a high wall slope within the unweather rock of 55° for the final pit walls. The recommended bench heights of 8m and a bench face angle (BFA) of 65°.

The ramps and haul roads were designed with an overall width of 21.7 m. For double lane traffic, industry practice indicates the running surface width to be a minimum of 2.5 times the width of the largest truck. The overall width of a 55-tonne off-highway haul truck is 5.39 m which results in a running surface of 12.22 m. The allowance for berms and ditches increases the overall haul road width to 21.7 m. A maximum ramp grade of ten (10) % was used.

CRUSHING AND STORAGE
The Run-of-Mine (“ROM”) mineralised material will be deposited into a grizzly feeder using a front-end loader, at a maximum size of 600 mm, that will be assisted by a rock breaker. The -90mm undersized material from the grizzly feeder will discharge onto a conveyor and transported to a crushed ore pile. The +90 mm oversized material will feed a jaw crusher and then discharge onto the conveyor to the crushed ore pile. 80% of the ore in the stockpile will be -112 mm.

To lower the Capex, the crusher material from the stockpile will not be reclaimed by feeders and a main conveyor located under the stockpile in a concrete reclaim tunnel, which would also require the emergency escape tunnel. The crusher material will be reclaimed from the stockpile and deposited directly into a crushed ore hopper using a front-end loader. A feeder, located under the hopper, will feed the crushed material onto belt conveyors to feed the SAG mill in the concentrator.

PRIMARY GRINDING CIRCUIT
The primary grinding circuit includes a SAG mill that will be operated in a closed circuit with a double-deck vibrating screen. The -3 mm screen undersize material is directed to the cyclone feed. The +3mm oversized material reports back to the SAG mill feed. The SAG mill will have a diameter of 7.3m and a length of 3.8m, with a power draw of 3,100kW.

SECONDARY GRINDING CIRCUIT
The secondary grinding circuit includes a ball mill and fifteen (15) 510 mm diameter cyclones. The circuit is fed in a feed forward configuration: from the SAG mill vibrating screen undersized discharge and ball mill discharge. The oversized material in the cyclone underflow flows into a ball mill. The ball mill operates in a closed circuit with the cyclones to obtain a grind size of 0.065 mm at the cyclone overflow, which feeds the flotation circuit. The ball mill will have a diameter of 6.1m and a length of 9.4m, with a power draw of 6,100kW.

The processing plant includes the following major areas:
• A crusher and crushed material storage that will provide crushed material to the downstream concentrator;
• A concentrator that will include grinding, conventional rougher and cleaner flotation for the production of concentrates, and conventional rougher and scavenger flotation for the desulphurisation of tailings;
• A concentrate dewatering area that will consist of thickening, filtration, handling, and loading;
• A tailings dewatering area that will consist of thickening, and filtration, and handling.

BULK FLOTATION
The overflow from the cyclones, at 0.18% Cu grade and 0.24% Ni grade, passes through a conditioning tank before being pumped to the Cu/Ni rougher flotation circuit. To aid the flotation process, the reagents used in the bulk flotation circuit are:lime as a pH modifier, diethyl triamine (“DETA”), sodium metabisulfite (“SMBS”), and carboxymethylcellulose (“CMC”) as depressants, so ........