Overview

Deposit type

• Porphyry
• Skarn

Summary:

The Chapada property includes the Chapada Mine, the Saúva Project, and surrounding exploration concessions. The Chapada Mine comprises the Chapada and Suruca deposits, which are located six km apart. The Saúva Project is located 15 km north of the Chapada Mine and includes the Saúva and Formiga deposits.

Deposit Types
The most accepted metallogenetic model for the Chapada Mine and the Saúva project is a metamorphosed porphyry model associated with skarn system.

The porphyry and skarn system can be separated into three distinct mineralization styles, based on hydrothermal alteration and metal association:
• Copper-Gold Porphyry System: Chapada, Corpo Sul, Sucupira, Baru, Saúva; and
• Skarn Systems: copper (gold) Formiga deposit and gold (silver-lead-zinc) Suruca deposit.

Chapada and the Saúva project feature significant alteration types linked to mineralization. At Chapada, copper-gold mineralization occurs in biotite-plagioclase gneiss and biotite schist, characterized by biotitic alteration with A-type quartz veinlets containing magnetite and chalcopyrite. This is overprinted by sericitic alteration with D-type veinlets. At Saúva, potassic alteration with quartz-feldspar veins and an epidote-rich halo correlate with high copper and gold grades. The Formiga deposit exhibits skarn-type alteration with garnet-epidote-amphibole assemblages, hosting semi-massive chalcopyrite, pyrite, and pyrrhotite, divided into garnet-rich and epidote-amphibole-rich facies. The Chapada Mine areas are covered by a 30-m lateritic profile, comprising saprolite and lateritic duricrust, indicative of extensive weathering processes.

Mineralization Chapada Deposit
Copper is primarily present as chalcopyrite, with minor amounts of bornite. Fine-grained gold is closely associated with the sulphide mineralization and is likely contemporaneous with copper.

The mineralization at the Chapada deposit is represented predominantly by sulphide disseminations along foliation plans (or axial surfaces of folds) and, to a lesser extent, in small, massive concentrations in the hinges of folds. Generally, the ore is formed by chalcopyrite, pyrite and magnetite, with chalcopyrite-magnetite (magnetite-rich ore) and chalcopyrite-pyrite (pyrite-rich ore) being the prevailing associations. Pyrite is the most abundant mineral, magnetite (including hematite, ilmenite and rutile) is subordinate, and galena, bornite, sphalerite, and molybdenite are rarely reported.

The copper mineralization and grade at Chapada Mine are somewhat better in the central zone of the deposit along the anticline axis than in the surrounding anticlinal limbs. However, copper mineralization is pervasive over a broad area. The Chapada deposit footprint is approximately 10.5 km in length, up to 1.5 km in width, and 380 m in depth.

Suruca Deposit
The gold at the Suruca deposit is related to folded quartz veins/veinlets with sericitic and biotitic alteration, rather than high sulphide concentrations. The second-generation quartz veins/veinlets with sulphides (sphalerite + galena + pyrite), carbonates, and epidote, also host gold, which is related to zinc. The copper mineralization in the southwest area of Suruca is similar to Chapada, with sulphide disseminations and sulphides associated with stockwork quartz veinlets. Generally, Suruca mineralization occurs primarily by chalcopyrite and pyrite, with subordinate sphalerite and molybdenite.

The Suruca deposit comprises three distinct zones, divided according to the contained metals and oxidation zones: Suruca Oxide (gold-only), Suruca Sulphide (gold-only), and Suruca SW (copper-gold). The gold-only portion of the Suruca deposit is approximately 4.3 km in length, 1.0 km in width, and up to 540 m in depth. The Suruca copper-gold deposit is approximately 4 km in length, 700 m in width, and up to 540 m in depth.

The Suruca Oxide zone is hosted in a thick weathering mantle with an average thickness of 35 m to 40 m, with a well-defined zoning from top to bottom, composed of soil, mottled rock, fine saprolite, coarse saprolite, and altered rock.

The remaining mineralization is hosted in the Suruca Sulphide zone and the lithologies are grouped into five domains, including:
- ANF: medium grained to finer grained amphibolite to quartz amphibolite, in which epidote and chlorite are common accessory minerals.
- MTS: the metasedimentary layer and upper metavolcano-sedimentary layer (A layer).
- MVI: metavolcano-sedimentary layer (B layer).
- QDP: intrusions of porphyritic metadiorite composed of quartz, biotite, and plagioclase.
- AQS: an interlayering between lithotypes with metasedimentary protoliths (e.g., garnet-biotitequartz schist and garnet-amphibole-quartz schist) and metavolcanic protolith (e.g., biotite-quartz schist).

The main mineralization pre-dates the documented deformation at Suruca. The gold and copper-gold zones are therefore believed to be associated with calcic skarns that were subjected to amphibolite and subsequent greenschist-facies regional metamorphism; however, some structurally controlled features are also observed.

Mineralization Saúva deposit
The Saúva deposit is classified as porphyry copper-gold mineralization hosted by biotitic, quartz-feldspar, and epidote-rich altered rocks. Mineralization is dominantly hosted in intermediate metavolcanic rocks and secondarily in metadiorite. The layers are primarily tabular and elongated, featuring some boudinage, and trend northeast-southwest, dipping northwest and outcropping to the east. The highest-grade portions lie in the southern part of the body. The Saúva deposit is approximately 2.5 km in length, 1.9 km in width, and up to 1.0 km in depth.

The main sulfide phases are pyrite, chalcopyrite, and bornite, with subordinate molybdenite. Oxidation portions with native copper, chalcocite and malachite are observed in parts of the deposit. Saúva displays a well-developed sulfide zoning, which controls the copper and gold grades. The zoning is described as follows, from outer to inner zones:
- Pyrite Zone
- Pyrite and Chalcopyrite Zone
- Chalcopyrite-only Zone
- Chalcopyrite > Bornite Zone
- Bornite > Chalcopyrite Zone

Additionally, there is a MIX Zone within the mineralized layer, present in some portions of the body, believed to be associated with northwest-southeast trending faults.

Mineralization at the Formiga target is mainly hosted by the metasedimentary units and is between 30 to 100 m thick. When affected by an intense garnet-epidote-amphibole-calcite-chlorite-magnetite alteration, the metasedimentary rocks host the semi-massive chalcopyrite-pyrite-pyrrhotite. The metadiorite locally hosts the semi-massive sulfide mineralization at the contact with the metasedimentary unit and where it has been hydrothermally altered.

The Formiga target contains copper-dominant mineralization, with copper grades varying from one to ten percent and gold grades generally less than 0.4 g/t. The mineralization is hosted stratigraphically below Saúva and trends northwest-southeast, plunging approximately 35 degrees to the northwest.

The deposit is interpreted as a skarn domain of a porphyry system. The alteration is best developed in the metasedimentary rocks (exoskarn), although some massive lenses occur in the metadiorite, and are interpreted as endoskarn alteration. The skarn mineralization is restricted in size likely due to deformation, which caused boudinage and dismemberment of the more competent sulphide-rich skarn, with the less competent metasedimentary host. The semi-massive mineralization strikes northwest-southeast, perpendicular to the main foliation, and is probably associated with the fold axis of the Dn+1 phase.

Mining Methods

• Truck & Shovel / Loader

Summary:

The Chapada Mine includes four operational open pits: Central, North, South, and Southwest. In addition, the 2024 LoM plan includes the development of six other pits: Baru, Sucupira, Buriti, North Buriti, Chapada Northeast (NE), and Cava I. The North, Central, SW and Sucupira pits will eventually join into a single pit.

The Chapada open pit has ultimate design dimensions of approximately 8 km along strike, up to 1.5 km wide, and 380 m deep.

The annual production capacity is around 25 Mtpa, with the processing plant located at the northwest end of the Chapada Mine.

Pit Design Parameters:
- Bench height: 10-20 m.
- Berm width: 7.5-8.5 m.
- Batter: 27-80°.
- Inter Ramp Angle: 21-60°.
- Ramp width: 32 m.
- Minimum pushback width: 80 m.
- Ramp gradient (centerline): 8%.
- Minimum mining width: 40 m.

During mine planning, one or more pushbacks may be discarded due to discounted cash flow outcomes. The mine life from the pits is 22 years plus an additional four years at the end for processing the remainder of the stockpiles. The main scheduling targets and constraints are as follows:
- Maximum plant feed throughput of 25 Mtpa (dry).
- Plant feed limit is limited by domain and rock hardness.
- The proportion of stockpile plant feed should be less 33% and will be processed intermittently throughout the mine life.
- The sinking rate is limited to a maximum of 90m vertical m per year.

The Chapada Mine operates with a mix of owner and contractor equipment for its mining processes.

The loading and haulage processes is carried out by the Chapada fleet and complemented by the contractor. The Chapada fleet operates preferably in ore fronts, while contractor is assigned preferably to waste. The loading fleet consists of equipment ranging in capacity from 11 m³ to 34 m³, while the size of the trucks varies from 96 t to 290 t.

The drilling process occurs in a similar way, in which the Chapada fleet is complemented by the contractor. In this fleet, equipment capacity varies between drillhole diameter of 6 3/4 inches to 9 inches.

In addition, blasting process is carried out by the specialized company and supervised by the Chapada team.

The LOM plan forecasted plant feed will come from the main pit combined with a significant blend of old low-grade stockpiled material. The Sucupira pit development will provide plant feed starting in 2035, mainly mixed with low-grade, stockpiled material. As of 2046, only stockpiled material will feed the plant until the end of mine life in 2050.

Comminution

Crushers and Mills

Summary:

Nominal plant capacity is 65,000 tpd (24 Mtpa equivalent) fed by two crushing lines: an IPCC gyratory in parallel with an MMD sizer followed by a jaw crusher. Both products feed the same, 200,000 t live capacity coarse ore stockpile. A portion of this material is secondary crushed through a semi-mobile crushing (SMC) plant.

Primary grinding is an SABC circuit – semi-autogenous grinding (SAG) mill with pebbles crushed and screen undersize reporting to a single ball mill. Both mills have 12.5 MW in installed power with a circuit product 80% passing (P80) size of 250 to 300 µm.

Rougher-scavenger concentrate is reground in a vertical stirred Vertmill to a P80 size of 65µm.

Primary crushing
Ore is delivered from the mine by haul truck to one of two parallel lines of primary crushers. The first line consists of a primary gyratory crusher located adjacent to the pit. Ore is dumped directly into the crusher feed bin. Oversized material is broken using a hydraulic rock breaker. The discharge of the gyratory crusher is then conveyed to the feed bin of an MMD 1000 Sizer (Sizer) for secondary crushing. The ore is transferred from the bin with an apron feeder and passed over a vibrating grizzly feeder which feeds the Sizer. Grizzly undersize bypasses to the Sizer product conveyor and, along with the Sizer product, is conveyed to the crushed ore stockpile. The Sizer limits the production rate as it has a lower capacity than the gyratory crusher. Consideration has been given to bypassing the Sizer to increase production.

The second system consists of a Metso C160 jaw crusher. Ore is dumped directly into the crusher feed bin. The ore is drawn from the bin with an apron feeder to a vibrating grizzly feeder which feeds the jaw crusher. Crusher product and grizzly undersized material are combined on the jaw crusher discharge conveyor and transferred the crushed ore stockpile.

Crushed ore stockpile and reclaim
The crushed ore stockpile is a conical stockpile with three draw points using apron feeders. Ore is drawn from the stockpile by three apron feeders onto the SAG mill feed conveyor, which delivers the ore directly into the SAG mill feed chute.

Primary and secondary grinding
The grinding circuit consists of a primary 10.4 m x 5.8 m long EGL SAG mill with a dual pinion 12,500 kW drive (2 x 6,250 kW) for primary grinding. The SAG mill discharges onto a horizontal double deck vibrating screen. The top deck has 12 mm openings and the bottom has six millimetres openings. The screen oversize pebble is conveyed to two HP800 pebble crushers with 600 kW drives. The pebble is reduced from the typical critical size of 38 mm x 75 mm, to approximately 12 mm and then returned by conveyor to the SAG mill feed conveyor. The screen undersize slurry reports to the primary cyclone feed pumpbox. The slurry is then pumped to a cyclopac consisting of six 813 mm diameter hydrocyclones (five operating). The cyclone underflow slurry flows by gravity to the 7.3 m x 12.2 m long EGL ball mill with a dual pinion 12,500 kW drive (2 x 6,250 kW) drive, while the cyclone overflow flows to the rougher flotation feed distribution tank. The primary cyclone underflow can be routed to either the ball mill or SAG mill, allowing the SAG mill to be operated in either open or closed circuit as required. The ball mill discharges into the secondary cyclone feed pumpbox from which it is pumped to the ball mill cyclopac consisting of nine 813 mm diameter cyclones (seven operating). The cyclone underflow reports to the ball mill feed chute and the cyclone overflow flows by gravity to the rougher flotation feed distribution tank.

Processing

• Crush & Screen plant
• Flotation
• Dewatering
• Filter press

Summary:

The Chapada concentrator is designed to treat copper sulphide ore at a nominal rate of 65,000 tpd for a total of 24.0 Mtpa.

The process flowsheet for Chapada is a conventional crush, grind and flotation circuit, producing a single copper concentrate with payable gold and silver values. Copper concentrate is considered clean with any impurities managed by blending lead, zinc and iron (pyrite) levels before shipping from the Port of Açu, some 1,630 km from site. Final concentrate undergoes thickening and pressure filtration to achieve a final moisture content of around 8% w/w (weight per weight). Copper concentrate is transported to the Port of Açu for storage, blending and shipping to smelters in Europe and Asia.

Rougher flotation
Flotation consists of conventional rougher cells followed by Woodgrove Direct Flotation Reactor (DFR) cells in re-scavenger duty.

Chapada Mine has undergone a number of flotation capacity expansion projects, focused on the implementation of Woodgrove Technologies flotation cells.

The rougher flotation circuit consists of two lines of rougher-scavenger flotation cells. Each line has a bank of five 160 m3 Dorr-Oliver Eimco tank flotation cells that have been retrofitted with Outotec mechanisms (Outotec TankCell and FloatForce), consisting of two rougher cells, one middling cell and two scavenger cells in series.
- The concentrate from the rougher cells flows to the concentrate regrind feed pumpbox.
- The cyclone underflow feeds the vertical regrind ball mill.
- The concentrate from the middling cell can either report the concentrate regrind or to the primary cyclone feed pumpbox in the grinding circuit.
- The concentrate from the scavenger cells is pumped back to the primary cyclone feed sump in the grinding circuit.
- The scavenger tailings are pumped to the TSF.

Rougher-scavenger concentrate is reground in a vertical stirred Vertmill to a P80 size of 65µm.

Cleaner flotation
- The cyclone overflow from the concentrate regrind circuit flows to the new SFR cleaner scalper cells.
- The concentrate from the SFR scalper cells is final concentrate grade and is pumped to the concentrate thickener.
- The cleaner scalper tailings are pumped to a bank of six 21.5 m3 conventional cleaner flotation cells.
- The cleaner tailings are pumped to a new bank of four Staged Flotation Reactor (SFR) cleaner scavenger flotation cells.
- There is an existing bank of two 160 m3 Wemco tank cells that currently operate as cleaner scavenger cells or pyrite cells in parallel with the new SFR cleaner scavengers.
- The concentrate from the cells is pumped to the feed of the cleaner flotation cells. The tailings from both banks of cells are pumped the final tailings pumpbox and then to the TSF.
- The cleaner concentrate is pumped to a final cleaner column flotation cell. The tailings from the column cell are pumped to the concentrate regrind circuit and the concentrate is pumped to the final concentrate thickener.

Concentrate thickening, filtration, and storage
The final concentrate is thickened to approximately 60% solids in a 13 m diameter x 3 m high Dorr Oliver Eimco thickener. The thickened concentrate is then pumped from the thickener underflow to an 11 m diameter x 11 m high concentrate storage tank. The concentrate is then pumped to a Larox PF60/72 M145 filter press, with a capacity of approximately 45 tph, located in the concentrate storage building above the concentrate stockpile. The pressure filter reduces the concentrate moisture to approximately 8% before discharging it onto the stockpile below. The concentrate is then loaded onto trucks and transported to the Port of Vitoria for shipping.

An expansion study, completed by Ausenco Engineering Canada Inc. (Ausenco) and AtkinsRéalis (formerly SNC-Lavalin Group Inc.) in 2022, looked at options to achieve 32 Mtpa (or 3,900 tph equivalent). This prefeasibility study was referred to as Chapada Brownfield Expansion (CBFE). The CBFE expansion study, completed by Ausenco in 2021, investigated a range of scenarios to either debottleneck the existing plant flowsheet or add a second processing line. Based on hardness estimates of future ore sources, it was expected the current plant capacity would drop to 18 Mtpa with a second processing line increasing capacity back to between 26 Mtpa and 32 Mtpa.

Suruca Sulphide
Suruca Sulphide reserves are planned to be mined at the end of the Chapada mine life and ore from Suruca Sulphide will be fed into a modified Chapada processing plant at a rate of 8.0 Mtpa.

Water Supply

Summary:

Water is reclaimed from the TSF via the process water reservoir while fresh water is sourced from the Rio dos Bois pump station and the Cava Central mine. Additional fresh water supplies for processing can be drawn from the nearby Rio dos Bois river, if required.

Process water is pumped from a water pumping station located in the water reservoir adjacent to Dike II in the TSF area to the process water reservoir at the process plant. A booster pump station is located outside of the TSF in the reclaim water pipeline. Each station is equipped with a set of three submersible centrifugal pumps operating in parallel for a combined capacity of 7,600 m3/h.

The Rio dos Bois pump station consists of two parallel pipelines fed by six submersible pumps connected to the water lines by a valved header which allows each pump to supply either pipeline. A submersible pump is connected to each of the headers by a flexible hose.

The Cava mine pits are the primary source of fresh/process water and have been used exclusively for the past several years. Surface and ground water drains into and collects in the bottom of the pit. Water is pumped from the pit using submersible pumps and a booster pump station to transfer the water to the water reservoir in the tailings dam. From there it is pumped to the process water reservoir at the process plant.

The water storage capacity in the bottom of the mine pits is used to maintain the overall site water balance. Water can be pumped from one pit to the other and to the TSF and process plant, providing flexibility in controlling the site water balance.

Water Balance
• approximately 1,500 mm of rainfall per year;
• annual consumption is 3.4M m³/year and with contemplated expansions could increase to 7.0M m³/year, which is within the permitted level;
• recycled water constitutes roughly 86% of process requirements;
• the open pits are the primary source of make-up water. Storage capacity in the bottom of the mine pits is used to maintain the overall site water balance;
• process water is pumped from the water reservoir in the Tailings Storage Facility (TSF) area to the reservoir at the plant;
• permitted to withdrawal up to 10.3M m3 /yr from local Bois river though not typically required.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Director of Environment & Sustainability	Marcos Lewin		Feb 26, 2025
Mine Operations Manager	Igor Alberto Melo Souza		Feb 26, 2025
Plant Maintenance Manager	Lucas Paes		Feb 26, 2025
Plant Operations Manager	Alderney Moreira		Feb 26, 2025
Supply Chain Manager	Artur Fabrini Costa		Feb 26, 2025