Summary

Deposit type

• Paleoplacer
• Conglomerate hosted

Summary:

The Castelo de Sonhos Formation is a small remnant of sedimentary rock caught between continental plates that collided almost two billion years ago. Before the collisions that added crust to what is now the Amazonian plate, sediments ranging in size from sand to large boulders accumulated in an alluvial fan and marine delta near the shoreline of an ancient super-continent now referred to as “Nuna”.

When the continental plates collided, a large granite intrusion formed below the sedimentary rocks, and dykes of molten material intruded into the sediments, metamorphosing them slightly. The sediments were folded into the bowl-shaped structure which eventually became a plateau because its silicified rocks were more resistant to weathering than the surrounding granites.

Deposit types
Castelo de Sonhos is referred to as a “modified paleo-placer”. It is a “placer” because the free gold grains from higher elevations in the hinterland were transported downhill, toward the shore, and accumulated in the bottom gravels of rivers and creeks. It is “paleo” because it was formed two billion years ago, during the Paleoproterozoic Era (2,500 to 1,600 million years ago). It is “modified” because it has been slightly metamorphosed into hard and consolidated rock.

Mineralization
Gold occurs as free grains and flakes of various sizes, from sub-visible (less than 100 microns) to highly visible. In the near-surface workings dug by local artisanal miners, supergene enrichment creates nuggets that can reach a few centimeters in size.

The two predominant styles of mineralization are:
- Paleo-placer: Free grains of gold that were likely deposited along with the quartz-rich sediments. In core these can be seen in the matrix of the conglomerate, sometimes in heavy mineral bands.
- Remobilized: Gold associated with alteration, usually hematitic alteration. Free grains of gold have been observed in hematite-filled fractures, and as thin films plated onto fracture surfaces.

Gold mineralization occurs throughout the conglomeratic band. Although there are many barren samples within the conglomerate, there are gold grades above 0.5g/t in almost every drillhole that penetrates more than half of the stratigraphic thickness of the central conglomeratic band. Gold grades tend to be higher in the central cobble unit, often reaching several grams per tonne. The lowest grade encountered in drilling to date is below the detection limit; the highest grade encountered in drilling to date is a 160g/t assay over a 1m interval. The existence of gold in heavy mineral bands, and its tendency to be more frequent in the proximal rocks are consistent with the view that most of the gold in the conglomerate band was deposited along with the sediments.

Where gold mineralization extends into the upper and lower arenites, such as the interval of 5 – 10g/t mineralization seen at the base of the upper arenite in several Esperança South drillholes, this is understood to be the result of remobilization caused by hydrothermal fluids. This remobilized gold in the arenites, along with direct observations of gold in direct association with hematite-filled fractures in the conglomerates, confirms that some of the gold within the conglomerate band must also be remobilized. The low temperatures of dike emplacement, the low grade of metamorphism, the difficulty of keeping gold in solution, and the proximity of the remobilized gold in the arenites to the conglomerate band all support the view that remobilized gold did not travel far from where it was originally deposited as paleo-placer gold. There is currently no evidence that any of the remobilized gold has migrated more than a few tens of meters.

The strike length of the mineralized conglomerate is approximately 16 km; samples from outcrops and workings along the entire length of this band return both barren samples and well-mineralized samples. The true width of the central conglomerate band is 250-300m. At the surface, the apparent width is close to the true width in Esperança West, where the dip is vertical and is approximately three times the true width in Esperança Center, where the dip can be as low as 20°.

The true depth of mineralization is unknown since the deepest parts of the conglomerate have never been encountered in drilling but are known to be at least 500m from the surface in the center of the plateau. In drillholes, well-mineralized samples (above 4g/t) have been encountered at depths of 300m. The current mineral resource estimate spans the conglomerate band from hanging wall to footwall but is restricted in its strike length by the availability of drilling and by the decision to report resources to a depth of only 150m. Some of the blocks on the edge of the current resource model are well mineralized, leaving the model open in the strike direction and down dip.

The garimpeiros followed high-grade reefs very closely, with their hand-dug trenches stepping over wherever faults disrupt the continuity of the reefs they were mining. The hand-dug garimpos show that the continuity of mineralization is very strong at the surface and to depths of several tens of meters where the garimpeiros dug tunnels to follow gold reefs at the base of their trenches. Between offsetting faults, many of the individual garimpos are several hundred meters in length.

Mineralization Thicknesses and Orientation
Esperança South
The mineralization in Esperança South is hosted in a series of stacked metaconglomerate beds striking north-south or northeast-southwest and dipping west, or northwest, at 30° to 35°, with thicknesses of individual mineralized reefs ranging from 2 m to 20 m. The mineralized reefs in Esperança South are thinner than in Esperança Center but have higher gold grades. This is consistent with the interpretation that the proximal (land) side of the Gilbert fan-delta system lay in what is now Esperança Center and the distal (sea) side lay in what is now Esperança South.

Esperança Center
The mineralization is hosted in a series of beds, striking north-south and dipping 20° to 30° west. Thicknesses of individual mineralized reefs range from 1m to 20m. Although the highest grades in Esperança South are higher than in Esperança Center, it is Esperança Center that has the higher average grade because it has far fewer very low-grade intervals. With more of the grade distribution lying close to an average of 0.2g/t, the thickness of mineralized horizons in Esperança Center increases as the cut-off used to define a significant interval is lowered. At cut-offs near 0.2g/t, Esperança Center has many thick intervals, some exceeding 50m.

Esperança East
Esperança East is more structurally complex than Esperança Center and Esperança South, with bedding directions often changing quickly between the available outcrops. Generally, the mineralization dips to the west, consistent with the view that the Esperança East block is the bridge between Esperança Center and Esperança South.

True Thickness
Almost all diamond holes were drilled to intercept the mineralized beds at right angles, or as close as practically possible, in Esperança South, Center and East. As a result, the core axis angle of bedding is often very high (70-90°), making the apparent thickness of most intervals from diamond drillholes very close to true thicknesses. In RC holes, which were drilled vertically, the apparent thickness of an interval observed in the hole is about 15% longer than the true thickness, due to a bedding dip that averages 25° to 35°.

Mining Methods

• Truck & Shovel / Loader

Summary:

Mining will be carried out using conventional open-pit methods (drill, blast, load, and haul), which are well-suited to the Project´s location, orebody geometry, and site conditions.

Open-pit operations are expected to continue for 11 years, including Phase 1 (Esperança South) during the first six years of operation, and Phase 2 (Esperança East and Esperança Center) during the years 7 through 11. The anticipated production rate is 3.6 million tonnes of ore per year, with a life-of-mine strip ratio of 9:1.

Mining and fleet maintenance will be owner-operated, running 365 days per year with three 8-hour shifts per day, organized into four operating teams. Initial mining operations will use bucket hydraulic excavators and haul trucks, with blasting applied to both ore and waste materials.

Waste rock will be disposed of in designated areas near the pits. These waste dumps will be properly prepared to include drainage systems at the base and surface water diversion channels, aiming to enhance geotechnical stability and reduce erosion of the stockpiled material. Waste placement will follow an ascending method, beginning with the construction of the initial lift at the base of the dump area. Trucks will deposit the material, which will be spread and leveled by a dozer operator. This process will be repeated to build successive lifts above the previous ones, maintaining a haul ramp for truck access as the dump elevation increases.

Pit Design Parameters:
- Inter-ramp Slope Angle: 55°.
- Face Angle: 75°.
- Bench Height ROM: 8 m.
- Bench Height Waste: 10 m.
- Berm Width: 5 m.
- Minimum Bottom Area: 30 m².
- Road Ramp Width: 12 m.

Mine Schedule
The production schedule was developed using the following key assumptions:
- Production rate: 3.65 Mtpa.
- Target gold production: ~ 150 koz per year during the first five years.
- Modifying factors: Mass dilution of 3.9% and grade dilution of 4.5%.

The scheduling defines the annual Run-of-Mine (ROM) and waste movement volumes, as well as the geometrical evolution of the pits throughout the 11-year Life of Mine (LOM).

Open pit operations are structured into two phases:
- Phase 1 (Esperança South): Years 1–6.
- Phase 2 (Esperança East and Center): Years 7–11 (East in Years 7–8, Center in Years 8–11).

No pre-stripping is planned.

Production Plan
Based on the annual production schedule for ore and waste, along with average yearly haulage distances, a fully owned and operated mining fleet has been estimated for the Castelo de Sonhos Project.

Mining operations will include:
- Drilling and blasting using explosives;
- Loading and haulage of ROM and waste;
- Discharge of ROM at the primary crusher feed hopper;
- Disposal of waste at designated waste dumps;
- Operation of mine infrastructure and supporting ancillary equipment.

ROM material will be mined, transported by haul trucks, and discharged directly into the crusher feed hopper. A ROM pad will be constructed near the crushing area, providing a buffer stockpile of approximately 20,000 tonnes, equivalent to two days of plant feed. This stockpile will be managed and reclaimed using wheel loaders, ensuring continuous and stable feed to the processing plant in the event of temporary production interruptions.

Drilling and Blasting
The drilling and blasting plan was developed using GE21’s internal database and benchmark parameters from projects with geomechanical conditions comparable to those at Castelo de Sonhos. It is estimated that approximately 90% of both ore and waste consists of hard rock and will require blasting.

To ensure operational selectivity:
- Ore benches: 5 meters high.
- Waste benches: 10 meters high.

During early operations, drilling performance, rock hardness, and fragmentation will be monitored to allow adjustments to blast designs and patterns.

Secondary blasting, when required, will be carried out using either conventional explosives, hydraulic hammers mounted on excavators, or bulldozers for block reduction.

Regarding explosive management, two alternatives were considered:
1. Explosives Magazine: A designated area for secure storage of ready-to-use explosives, as defined in the general site layout.
2. On-site Explosives Mixing Plant: A modern and increasingly adopted solution in Brazil. This facility would mix only the required volume of explosives for same-day use, reducing the need for storage and associated security costs.

Ore and Waste Rock Excavation and Loading
Excavation and loading of ore and waste rock will be performed using hydraulic excavators in backhoe configuration. Due to the need for ore blending, at least two mining fronts will be operated simultaneously. Additionally, for mine development purposes and to ensure the release of ore with the planned qualities, waste removal will also be carried out concurrently in at least two active fronts.

Backhoe-configured excavators allow excavation from the upper bench level, with the haul trucks positioned on the lower bench. This setup significantly improves overall productivity, as the truck is typically positioned at an angle of approximately 30° to the excavator’s longitudinal axis, resulting in reduced swing time during excavation and loading operations. Operating from the upper bench also enhances the excavator operator's field of vision, which improves safety, load positioning, and productivity. Most importantly, it enables better selectivity during ore extraction.

Comminution

Crushers and Mills

Summary:

Primary Crusher
10,000 dry metric tonnes per day. Twelve hours per day, seven days per week, 85% availability equals 980 dry metric tonnes per hour. Moisture content 2.5%.

Primary Stockpile
Nominally 40,000 tonnes total, with 10,000 tonnes effective capacity. Feed size 100% passing 300 mm 80% passing 150 mm.

Grinding
Final product to leaching P80 = 105 microns. Ball mill sized on testwork results (McClelland Laboratories, Sparks, Nevada USA). Bond Index (metric) 13.62, SAG mill sized on in-house data at 8 kWh per tonne.

Selected SAG mill 28ft (8.5 meters) diameter, 12 ft (3.6 meters) long, ball mill 18ft (5.5 meters) diameter, 25ft (7.5 meters) long, both with 3,750 kW motors (fixed speed drives) for common spare purposes.

Subsequent testing and analysis (Hazen Labs Golden, Colorado, USA 6 JK Simmet Red Bluff California USA) to produce P80 = 150 microns.

Suggests SAG mill 26ft (7.9 meters) diameter, 12 ft (3.7 meters) long 4,300 kW motor, ball mill 16ft (4.9 meters) diameter, 26ft (7.9 meters) long with 2,900 kW motor.

Trade off will be needed in detail design to compare P80 =105 µm vs P80 = 150 µm and evaluate savings in grinding to coarser size against increased costs due to longer retention time in leach.

Processing Plant Operations
A run of mine (“ROM”) stockpile area and the primary crusher dump hopper will be located adjacent to the Esperança South pit rim close to the centroid of the deposit. ROM ore will be hauled from the pit and either stockpiled for blending and/or subsequent reclamation by front end loader or direct dumped over a 400mm square opening stationary grizzly into the primary dump hopper, nominal capacity 150 tonnes. Sonic fogger dust suppression will be provided above the hopper. A rock pick mounted on the hopper will handle grizzly oversize. Ore will be withdrawn from the dump hopper with a vibrating grizzly feeder (1.6 x 3.7m with 150mm grizzly bar openings). Grizzly undersize will bypass the primary crusher, oversize feeds the primary crusher (1.25 x 0.95m jaw, set at 150mm).

Combined grizzly undersize and crusher discharge will be conveyed to a conical, uncovered, 40,000 tonnes total capacity coarse ore pile (live capacity nominally 10,000 tonnes, one day’s production). Ore will be reclaimed by two vibrating grizzly feeders (1.6 x 3.7m with 150mm grizzly bar openings) located in a tunnel beneath the pile.

The grinding circuit consists of an 8.5m diameter, 3.65m long (28 x 12 ft) fixed speed, 3,750 kilowatt semi autogenous (SAG) mill operating in closed circuit with a 200-kilowatt pebble crusher and (primary) cyclones followed by a 5.5m diameter, 7.5m long (18 x 25ft) fixed speed, 3,750 kilowatt, ball mill operating in closed circuit with (secondary) cyclones. Lime and sodium cyanide will be added to the SAG mill feed belt.

Processing

• Smelting
• Carbon re-activation kiln
• Crush & Screen plant
• Agitated tank (VAT) leaching
• Carbon in leach (CIL)
• Elution
• Carbon adsorption-desorption-recovery (ADR)
• Solvent Extraction & Electrowinning
• Cyanide (reagent)

Summary:

The CDS processing plant will be designed to treat 3.65 million tonnes of run-of-mine (ROM) ore per year using a whole-ore agitation leaching process. This circuit is expected to achieve a gold recovery rate of 98%. Projected gold production is approximately 146,000 troy-ounces per year during Phase 1 (Years 1 to 6) and 91,000 troy-ounces per year during Phase 2 (Years 7 to 11).

Whole-ore agitation leaching has been selected as the preferred process flowsheet for the Project development. The plant will be designed to process 10,000 tonnes per day, incorporating crushing, grinding, and carbon-in-leach (CIL), carbon acid wash, pressure stripping, and thermal regeneration. Gold will be recovered from the loaded eluate via electrowinning. Metal deposited on stainless steel wool cathodes will be rinsed, decanted, and collected as "sludge," which will then be dried and smelted to produce doré bars for shipment to third-party refiners.

Processing Plant Operations
Combined primary and secondary cyclone overflows with P80 of 105 microns (150 mesh) in a slurry containing 40% w/w solids, pass through vibrating trash screens which discharge to the first of ten, 15.9m diameter x 16.8m high (52 x 55ft) cyanidation/CIL tanks operating in series for a total retention time of 36 hours. Air is injected into the first three leach tanks to promote gold dissolution and sodium cyanide solution is added to maintain a concentration of 1 g/l in leaching. The last five (CIL) tanks contain 10 g/t activated carbon. Intertank screens retain carbon in the CIL tanks, carbon is advanced through the circuit periodically by pumping slurry countercurrent to the normal slurry flow. Carbon remains in the recipient tank and slurry flows back downstream.

Loaded carbon containing nominally 2,000 g (65oz) of gold per tonne will be pumped out of the first CIL tank, discharged over a wash screen and advanced at the rate of eight tonnes per day to acid washing followed by elution in a pressure stripping system. Stripped carbon will be thermally regenerated in a gas fired rotary kiln operating at 1,200°F and returned to the fifth CIL tank.

Gold and will be electrowon from loaded eluate in three, 750amp cells operating in parallel. Metal deposited on stainless steel wool cathodes will be rinsed off decanted and collected as “sludge” which will be dried and smelted to produce doré bars for shipment to third party refiners.

Leached slurry discharged from the last CIL tank passes through safety screens to recover carbon fines and flows by gravity to the leach discharge thickener where it is diluted with water reclaimed from the tailings pond. Thickener overflow containing approximately 60% of the sodium cyanide in thickener feed is returned to the grinding circuit. Thickener underflow is pumped to cyanide destruction where will be diluted to 40% w/w solids with reclaim water, mixed with sodium metabisulfite, copper sulfate and lime and subjected to intense agitation with low pressure air to destroy residual cyanide down to approximately 1ppm weak acid dissociable (“WAD”) cyanide.

Cyanide destruction circuit effluent will be pumped to the tailings dam constructed approximately 6km from the plant. Process water will be reclaimed with barge mounted pumps in the pond and returned to the process water storage tank at the plant site.

Acid Washing and Carbon Regeneration
The loaded carbon stored in a bin is pumped to the acid washing, recovery of adsorbed gold and subsequent regeneration of the carbon and gold recovery by electrowinning.

Carbon Regeneration and Gold Smelting
The stripped carbon goes to the regeneration furnace and the cathodes containing the gold are washed under high-pressure water and then the sludge with the gold is filtered and smelted to produce doré bars for shipment.

For the purposes of this study, it has been assumed that freshwater will be sourced from a well field close to the plant site. It may be necessary to change to a catchment dam across one of the drainages on site to store precipitation run-off for this purpose.

Pipelines and Water Supply

Summary:

Potable water will be sourced from wells drilled to support plant operations. Water quality will be verified through regular monitoring conducted by accredited laboratories.

A site-wide probabilistic water balance model has been developed for Castelo de Sonhos using the industry-standard software GoldSim. The results of model simulations confirm that the water balance will be net-positive. However, a source of fresh-water supply for the process and/or ancillary uses (e.g., fire, dust suppression, potable supply) must still be established as a contingency, or for those uses requiring a strictly prescribed chemical quality.

The water balance for the process and tailings storage facility (TSF) has been simulated for the projected LOM mill feed rate of 4 Mtpa and a discharged tailings slurry of 50% solids by mass. The total process plant water requirement is estimated to be around 463 m³/h based on this scenario. At mine start-up, a raw water supply to cover all demand, minus a small volume of water held as ore moisture, will be required. This demand will decrease rapidly (within a few months) as the TSF supernatant pond becomes established. Subsequently, process demand for raw water will be reduced to a nominal 14 l/s (50 m³/h), which corresponds to the fresh water strictly required for reagent preparation and gland seals. All other process demand is expected to be met through TSF reclaim, as predicted by the GoldSim model.

Probabilistic simulations, conducted with 100 x LOM daily resolution realizations, produced only one instance where TSF reclaim would be insufficient to meet this demand, resulting in a temporary increase in raw water intake of approximately 40 l/s.

Regardless of the use of TSF reclaim as process supply, a significant year-on-year build-up of water inventory will occur on the TSF in the absence of a pathway for the release of excess water. The facility is predicted to experience a net-positive balance of approximately 3 to 4 Mm³/yr., which will require management through controlled abstraction of between 100 and 150 l/s via a barge pump. This water will be discharged to the natural surface drainage system, subject to compliance with all applicable water quality criteria.

Potable Water
In addition to the process water, a potable water requirement of 10 m³/d is estimated. The supply for this water can also be sourced from the storage water pond and would be subject to testing and appropriate treatment (chlorination).

Freshwater Catchment and Distribution System
The freshwater is pumped from wells to the potable water and fire suppression systems. This system consists of sulphate of the following procedure.

The process water is recovered from the tailings dam, where pumps installed in a barge, reclaim the supernatant clean water, pumping it back to the plant. The freshwater system equipment was estimated based on the consumption and recoveries indicated in the following and recoveries.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Consultant - Mining & Costs	Guilherme Gomides		May 5, 2025
Consultant - Recovery Methods & Costs	Porfirio Cabaleiro Rodriguez		May 5, 2025
VP Operations	Fernanda Bretas		Jul 23, 2025