The project area is situated in the Borborema Province within the domain of the Seridó Fold Belt in north-eastern Brazil. It is situated in the top of the Seridó Group stratigraphy (the Seridó Formation) within a sequence of banded arkosic metapelitic schists, subjected to upperamphibolite facies regional metamorphism. Gold mineralisation is located within a NNE trending structure which forms part of the northern segment of the Santa Mônica dextral shear zone. The shear zone displays a penetrative NNEtrending fabric, dipping east at around 35 degrees. In the project area the principal mineralised shear zone, termed the Morro Pelado shearis around 30m thick.

The modelled mineralised zone has dimensions of 3,250m (surface trace striking 035) of varying thickness between 30m and 60m, and ranging between 150m and 500m RL (AMSL).

For the statistics and subsequent grade estimation descriptions, the mineralised zone has been arbitrarily subdivided into the Southern (Zone 1), Central (Zone 2) and Northern (Zone 3) domains based on the 20,050mN and 21,300mN northings.

The mine will be an open pit with contractor operated equipment including excavators with 3.5 m 3 buckets and 45 t trucks. The access roads will be 15 m wide with 10% maximum inclination, meeting safety standards and specifications of the mining fleet. The operational slopes will have 5 m benches in ore and 10 m benches in waste, with a total height of 20 m.

It is anticipated that only 70% of mined material will require blasting.

Material storage:

• The ROM (Run of Mine) ore >0.7 g/t Au will be transported by trucks and discharged directly into the ROM receiving hopper at an average feed rate of 330 tph. Oversize will be removed and broken by hydraulic hammer. Three days crusher feed of 18,000 tonnes will be stockpiled for wheel loader recovery and production continuity.
• Medium Grade Ore (0.5g/t Au to 0.7g/t Au) in the first 4 years, will be transported to the allocated NW1 Stockpile close to the plant. From years 5 to 10, this material will be reclaimed to feed the plant.
• Marginal ore with less than 0.5 g/t Au, will be stockpiled in the NW Waste stockpile which will be reserved specifically for low grade or mineralised waste.
• The waste rock will be transported to the NE Waste stockpile where it will be co-disposed with the filtered tailings generated in the Filtration Plant.

The Stage 1 open pit designed by GE21 Consultorio Mineral for the DFS. The portion of the reserves that will be mined in the 10.2 year Life of Mine schedule total 20 Mt grading 1.22 g/t Au containing 784,000 ounces gold.

Comminution Circuit
CPC were commissioned to incorporate changes to the Wave DFS comprising a three stage crushing and ball milling circuit in lieu of primary crushing and SAG/Ball milling (SAGB). In Brazil there are considerable numbers of jaw and cone crushers as well as ball mills and far fewer SAG mills, which are more sophisticated units. All mechanical units in the crushing circuits are manufactured in Brazil.

In 2019, Orway Mineral Consultants Pty Ltd (OMC) reviewed the testwork in the context of a comminution circuit and concluded: the Borborema ore is of low to medium competency, with low abrasion, crusher and rod work indices and above average Bond ball mill work indices. OMC reported there was no major benefit of using either of the two comminution routes considered.

The pricing of the optional 3-stage crush ball mill circuit showed very little difference in capital and operating cost over the SAG/Ball option.

The original recommendation for a Primary Crush/SAGB option over a 3-stage crush/ball mill followed examples in other mining locations where there is considerable advantage in lowering the number of operating units and therefore labour.

However, the 3-stage crush ball mill circuit is favoured over the SAG/Ball option to reduce operational risk, because it:
• Includes multiple plant units available and manufactured in Brazil.
• Provides for a shorter delivery time than for a SAG mill.
• Means only a ball mill is imported. This is a more common occurrence in Brazil with less likely importation difficulties.
• Provides better support, maintenance and availability of spare parts in Brazil than a SAG mill.
• Results in less complicated operations and maintenance.

The metallurgical process proposed is conventional carbon-in-leach (CIL) gold extraction.

Elution and gold room
The elution circuit involves the stripping of gold from the carbon in solution from the CIL tanks. Changes that included the replacement of the proposed AARL elution circuit with a Pressure Zadra (PZ) plant were incorporated into this area. There is no discernible difference in layout of an AARL or a pressure Zadra elution plant in terms of footprint.

AARL elution is more sophisticated and requires more complex valve and piping arrangements than the PZ as well as a high standard control system. The PZ circuit on the other hand requires longer strip times and has less flexibility but this is considered manageable without large operating cost imposts.

However, the decision was taken to go with the PZ circuit because the quality of water required for acceptable AARL elution performance is higher than the PZ circuit which would be better s ........