The mineralization at the Pilar Mine is hosted by a number of the host rock units including the BIFs along with mafic schists and talc-chlorite schists. Gold mineralization is associated with sulphide mineralization consisting of arsenopyrite and pyrrhotite. Quartz veins and veinlets can also be present, but the presence of quartz is not a prerequisite for higher gold values. The sulphide minerals occur mostly as disseminations in the host rock, but can achieve semimassive to massive concentrations locally over a few tens of centimetres. Quartz veins are typically less than one metre in width and can be observed to be of two generations. The quartz veins of the first generation are typically associated with the gold mineralization and are folded. The quartz veins of the second generation are typically lower grade or barren and not affected by folding.

At Roça Grande, gold mineralization is more commonly associated with BIF horizons. In RG01, RG02, RG03, and RG06 mineralized bodies, the gold mineralization is developed roughly parallel to the primary bedding and is related to centimetre-scale bands of massive to disseminated pyrrhotite and arsenopyrite. In many cases, better gold values are located along the hangingwall contact of the iron formation sequence and is hosted by carbonate-facies iron formation. The grades generally decrease towards the footwall where the iron formation becomes more silica-rich. The thicknesses of the iron formations are observed to be affected by broad-scale boudinaged structures . Better gold grades are found in the thicker portions while the narrower portions of the boudinaged structures have lower grades. Late-stage, barren quartz veins are also ubiquitously present and also display a boudinaged form.

The Caeté Gold Mining Complex has two underground mines (Pilar and Roça Grande). Pilar primarily uses sub-level open stoping with backfill, while Roça Grande (“RG”) exclusively uses the mechanized horizontal cut and fill mining method. The Pilar mine provides 1,000 tonnes per day, or two-thirds of the Caeté complex ore, while the RG mine provides 500 tonnes per day from the underground RG-1 deposit.

The Caeté processing plant has a design capacity of 720,000 tpa of run-of-mine (ROM) ore. In 2015, the plant processed feed from the Pilar and Roça Grande mines.

The process flowsheet primarily consists of the following unit steps:
- Crushing
- Grinding
- Gravity Gold Recovery
- Flotation
- Leaching & Carbon-in-Pulp
- Gold Recovery
- Detoxification
- Tailings.

The ore from the Pilar and Roça Grande Mines is transported by trucks to the crusher circuit and placed in the ROM stockpile. The crushing circuit is made up of a primary jaw crusher in open circuit, and secondary and tertiary cone crushers, operating in closed circuit.

The ROM stockpile ore is fed to the jaw crusher though a grizzly and vibrating feeder. The jaw crusher discharge feeds a multi deck screen, which feeds either the secondary or tertiary crushing circuit or the final product conveyor. The secondary cone crusher operates in closed circuit with a double deck screen. Product from the double deck screen either recirculates back to the secondary crusher, feeds the tertiary crusher, or goes to the final product conveyor. The tertiary cone crusher operates in closed circuit with a single deck scree, with the product recycling to the crusher or going to the final product conveyor, which goes to crushed ore stockpile. The final particle size of the crushing process is 16 mm.

The grinding circuit consists of a horizontal ball mill with a capacity of up to 100 tonnes per hour, operating in closed circuit with a series of hydrocyclones. The overflow from the hydrocyclones (-200 mesh (74µm)) proceeds to the flotation circuit and the underflow (+200 mesh (74µm)) either feeds the gravity concentration circuit (75%) or is recycled to the ball mill feed (25%).

Gravity concentration at the Caeté plant uses a centrifugal gravity concentrator (Knelson) to recover fine particles of free gold. The gravity concentrate proceeds to an intense cyanidation plant (Acacia), from which the gold bearing solution is pumped directly to a dedicated set of electrolytic cells. The precipitate from the cells is sent to a refinery for further processing into doré gold bars.

The flotation circuit consists of a series of twelve (12) 500 cubic foot flotation cells, the first three operating as roughers, three operating as primary scavengers, three operating as secondary scavengers, and the last three operating as tertiary scavenger cells.

The concentrate thickener underflow slurry (40% solids w/w) is pumped to an agitated conditioning tank, where lime and cyanide are added, and then further pumped to a set of three agitated leach tanks operating by gravity, in series.

The four CIP tanks are designed to hold activated carbon in each tank through a designed screen which allows slurry to flow from tank to tank, but retains the carbon in each tank. The carbon interacts with the slurry, adsorbing the gold cyanide complex created in the leach tanks.

The gold loaded carbon is transferred to a desorption column. A hot solution (approx. 98° C) of caustic soda and 1% cyanide concentration is pumped upwardly through the elution column to remove or desorb the gold cyanide complex from the carbon.

After the desorption cycle, the sludge, steel wool, and cathodes are withdrawn and sent to the refinery for production of gold doré containing about 80% gold. The doré gold is then further refined, obtaining pure gold bars (minimum 99.99%).