Several genetic models have been suggested for Chapada, including: (i) a deformed and metamorphosed porphyry-type copper-gold deposit (Richardson et al., 1986; Oliveira et al., 2015), (ii) a deformed and metamorphosed volcanogenic disseminated sulphide deposit (Silva and Sá, 1986; Kuyumjian, 1989), and (iii) epithermal copper-gold deposit overprinted by metamorphic remobilization (Kuyumjian, 2000).

Currently, the most accepted metallogenetic model for Chapada is a metamorphosed porphyry model associated with skarn system. The magmatic hydrothermal system was generated in island arc stage setting (approximately 884 Ma to 879 Ma) and posteriorly overprinted by remobilization of orogenic fluids during Brasiliano events (ca. 630 Ma).

The porphyry, skarn, and epithermal system can be separated into three distinct mineralization styles, based on hydrothermal alteration and metal association:
- Copper-Gold Porphyry System (Chapada Corpo Principal, Corpo Sul, and Sucupira);
- Gold (Silver-Lead-Zinc) Distal Skarn (Suruca);
- Copper-Gold Proximal Skarn (Suruca SW).

The Chapada and Suruca deposits are located in the metavolcano-sedimentary sub-unit of Mara Rosa Sequence.

MINERALIZATION.
SURUCA.
The Suruca SW mineralization was discovered in 2017 exhibiting similar geological features to the Chapada deposit. The mineralization was delineated along a 2.1 km strike, 650 m width, and average depth of 50 m, and was partially exposed on surface.

The gold at Suruca is related to folded quartz veins/veinlets with sericitic and biotite 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 Suruca SW displays same features as Chapada, with sulphide disseminations and sulphides associated with stockwork quartz veinlets. In general, Suruca SW mineralization is formed predominantly by chalcopyrite and pyrite, with subordinate sphalerite and molybdenite.

Mineralization predominately pre-dates deformation so the gold (Suruca) and copper- gold (Suruca SW) zones are associated with skarn features, however, some structurally controlled features are also observed.

SKARN SYSTEM – SURUCA
The Suruca deposit is host to gold-zinc mineralization associated with sericite- chlorite-epidote carbonate (- biotite) and the argillic to propylitic alteration which corresponds to a skarn system.

According to Sillitoe (2014), the Suruca metal concentrations marked by zinc (sphalerite), lead (galena), and gold associated to epidote/calcite and/or garnet/amphibole rich schists, point to a distal gold (Ag-Zn-Pb) skarn system. These epidote-calcite rich schists are interpreted as skarns, which were subjected to amphibolite and subsequent greenschist facies regional metamorphism. Also, the possible presence of deformed and metamorphosed diorite porphyry in the copper- gold zone suggests that Suruca may be related to a discrete porphyry centre represented by Suruca SW.

At Suruca, pit design parameters are as follows:
For saprolite and oxide material types:
- 5 m bench height,
- 60° bench face angle,
- 4 m to 8 m safety berm,
- 15 m ramp width at maximum 10% gradient.

For sulphide material type:
- 30 m bench height,
- 70° bench face angle,
- 12 m safety berm,
- 25 m ramp width at maximum 10% gradient.

The start date of the Suruca oxide mine is currently under consideration by Yamana. Studies are ongoing to assess the Suruca oxide and sulphide pits as an integrated complex.

Currently, 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 Mtpa. However, alternative scenarios are currently being studied to process Suruca Sulphide with a standalone CIL or CIP plant.

SURUCA SULPHIDE ORE
Suruca sulphide ore is currently being planned to be processed through the existing Chapada plant, with some modifications, at the end of the Chapada mine life.

Existing Chapada plant
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.

SURUCA OXIDE ORE
Processing oxide from the Suruca deposit is planned according to the Suruca FS, prepared by Yamana and SNC Lavalin in February 2018 (Yamana and SNC Lavalin, 2018). Lundin is currently assessing the Project within the context of the Chapada complex.

USE OF EXISTING EQUIPMENT
Second-hand and previously purchased equipment has been specified and obtained by Yamana for the crushing, agglomeration, adsorption, reagents and select other processes, and thus utilization of existing purchased equipment is required as much as possible.

CRUSHING AND AGGLOMERATION
The ore processing route begins with the crushing of the raw ore from the mine, consisting of two in series stages of roller crushers; the first with a single crusher and the second with two crushers in parallel. Cement is added to crushed ore and routed to the agglomeration drum where moisture (sodium cyanide solution) is added to the solids. After the drum, the ore is stacked on a dynamic leach pad.

SURUCA DEPOSIT OXIDE AND SULPHIDE ORES
Run of mine (ROM) material from the Suruca deposit, which consists of oxide and sulphide mineralization, will be processed separately. The oxide ore will be processed using conventional heap leaching technology, and the sulphide ore will be processed in the existing concentrator after some modifications.

SURUCA SULPHIDE ORE
Suruca sulphide ore is currently being planned to be processed through the existing Chapada plant, with some modifications, at the end of the Chapada mine life. There is also an option to construct a standalone CIL or CIP plant for processing the sulphide ore. Conceptual studies are ongoing.

Existing Chapada plant

ROUGHER FLOTATION
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), c ........