DISTRICT GEOLOGY
The Almas Gold Project is situated in an historical gold mining area with numerous small artisanal mines (garimpos) and the former Vale Paiol Gold operation. Gold occurs in sheared metavolcanic rocks within the greenstone sequence, as well as in sheared felsic intrusive rocks. The rocks are, in general, Paleo-Proterozoic in age (~2.2 billion years old) and have undergone regional metamorphism ranging in intensity from greenschist- to amphibolite-facies. The metamorphism resulted in deep-seated, shearhosted, mesothermal, gold deposits which have more recently been referred to as orogenic gold deposits. The gold-mineralized zone occurs in the core of hydrothermal alteration zones, generally associated with variable amounts of quartz, carbonate, albite, sericite and sulphide minerals.

DISTRICT MINERALIZATION
Gold mineralization is found in three groups of rocks, in metabasalts of the Córrego Paiol Formation, in metasedimentary rocks of the Morro do Carneiro Formation and in granite-gneiss complexes.

Several occurrences of gold are hosted in the metabasalts, mainly south of Almas, the most important being that of the Córrego Paiol mine. The occurrences hosted in metasedimentary rocks are dominant in the southern portion of the terrain, Conceição do Tocantins region, while the occurrences in granite-gneissic rocks are distributed throughout the granite-greenstone terrain.

Gold in the Almas Greenstone Belt occurs in three different associations:
• Gold associated with hydrothermally-altered shear zones in basic to intermediate volcanic rocks; • Gold associated with hydrothermally-altered banded iron formation;
• Gold associated with smoky quartz veins in sheared granite gneiss.

Gold mineralization is closely associated with mylonitic banding in shear zones that cut mafic-to-intermediate volcanic rocks, schists and granite-gneiss, the latter being noted at the Vira Saia deposit. Gold occurs as free gold and as gold inclusions within sulfide minerals. The stronger gold mineralization is associated with faults and shear zones.

DEPOSIT GEOLOGY
The Cata Funda - Paiol Trend is a structural domain within the Almas volcano-sedimentary sequence that contains the primary and secondary gold targets. The Paiol and Cata-Funda deposits have many similarities with respect to mineralization type, geometry and lithologies, although some distinctive characteristics are noted.

The Paiol and Cata Funda deposits are situated on the same trend that generally strikes N10°-20°E at Paiol but rotates to N10°- 20°W at Cata Funda. The dips range from 60° to 80° northwest and 40 to 60 southwest, respectively. Strong gold mineralization is associated with hydrothermal alteration centered on mylonitic bands and sulfide-bearing quartz veins in strongly sheared metavolcanic rocks.

DEPOSIT TYPES
The known gold occurrences in the Almas area are classified as orogenic, shear-hosted mesothermal gold deposits. Minor occurrences of lateritic or even placer gold is also found in the area but are typically small and not the target of current exploration.

Mesothermal gold deposits are a distinctive type of gold deposit which are typified by many consistent features in space and time. Perhaps the single most consistent characteristic of the deposits is their consistent association with deformed metamorphic terranes of all ages. Observations from throughout the World’s preserved Archaean greenstone belts and most recently active Phanerozoic metamorphic belts indicate a strong association of gold and greenschist facies rocks. However, some significant deposits occur in higher metamorphic grade Archaean terranes or in lower metamorphic grade domains within the metamorphic belts of a variety of geological ages. Pre-metamorphic protoliths for the auriferous Archaean greenstone belts are predominantly volcano-plutonic terranes of oceanic back-arc basalt and felsic to mafic arc rocks. Clastic marine sedimentary rock-dominant terranes that were metamorphosed to graywacke, argillite, schist and phyllite host younger mineralization and are important in some Archaean terranes.

These deposits are typified by quartz-dominant vein systems with =3 to 5% sulfide minerals mainly Fe-sulfides and =5 to 15% carbonate minerals. Albite, white mica or fuchsite, chlorite, scheelite and tourmaline are also common gangue phases in veins in greenschist-facies host rocks. Vein systems may be continuous along a vertical extent of 1 to 2 km with little change in mineralogy or gold grade. Mineral zoning does occur, however, in some deposits. Au/Ag ratios range from 10 (normal) to 1 (less common) with ore in places being in the veins and elsewhere in sulfurized wallrocks.

Deposits exhibit strong lateral zonation of alteration phases from proximal to distal assemblages on scales of meters. Mineralogical assemblages within the alteration zones and the width of these zones generally vary with wallrock type and crustal level. Most commonly, carbonates include ankerite, dolomite or calcite; sulfides include pyrite, pyrrhotite or arsenopyrite; alkali metasomatism involves sericitization or, less commonly, formation of fuchsite, biotite or K-feldspar and albitization and mafic minerals are highly chloritized. Amphibole or diopside occur at progressively deeper crustal levels and carbonate minerals are less abundant. Sulfidation is extreme in banded iron formation (BIF) and Fe-rich mafic host rocks.

The orogenic gold deposits targeted in current exploration in the Almas Gold Project are hosted in Paleoproterozoic rocks, typically metabasalts and metasediments (commonly called greenstones). Exploration has also identified gold mineralization in granitic intrusives or granitoids, as in the case of the Vira Saia deposit. In all cases, the rocks have been metamorphosed to greenschist or lower amphibolite facies. Mineralization invariably forms along faults or shear zones; typically, the larger mineralized areas correlate with the larger shear zones. As well, flexures and intersection zones, where faults or shears cross, generally correspond to prime sites for these deposits.

MINE OPERATION
The mining operation concept for the Almas Gold Project is conventional open pit mining with production schedule that provides an initial 0.6 Mt stock of ROM with 0.92 g/t Au content, equivalent to six months. Commercial operation is scheduled to start up in July, 2022 with a ramping up until October, 2022.

The mine development is planned to allow access to those grade levels to maximize gold production and provide operational flexibility by mining several benches simultaneously. The number of pits mined simultaneously will be no more than two pits.

The waste rock comprises soil, saprolite, weathered and fresh rock. The excavation of these deposits requires the use of drill and blast.30% of saprolite will require explosives. Load and haulage will be performed by a combination of front-end loaders, hydraulic excavators, and on-road trucks.

Benches will be configured as follows:
• A minimum mining width of 30 m on a 10 m-high bench has been maintained for Cata Funda, but Vira Saia and Paiol include a final bench access incorporating an operational mining width of 15 m to maximize access to the mineralized zone.
• The waste and ore benches will be mined as 5 m thick layers, leaving a designed 10 m maximum bench height.
• The ore and waste zones have been analysed and it is possible to operate with a proper berm width and in-pit dumping operational space.
• The benches will have a slight decline from crest to the toe of the upper bench face slope, in the direction of the open side to drain rainfall and to maintain designed slope angles. A good drainage design inside the pit and in rainwater collection contribution areas around the pit allow for the minimization of operational disturbances during heavy rain.

The ultimate Paiol pit will fully overlap the existing pit from the old Vale operation.

The processing plant is located at 0.7 km from the final Paiol pit. The tailings dam already exists from Vale’s operation. It is located about 2.0 km from the plant.

The mining faces will be accessed by 15-m wide double lane roads with 10% gradient. All roads will have 2.0 cm/m transversal gradient, from the Centre to the lateral edge of the road, with drainage ditches along the roads. Road conditions must be compatible with good practices for the operation of mining equipment.

The Almas Gold Project’s gold mining concept is based on the application of conventional techniques for surface rock mass excavation with a maximum level of mechanization:

• Grade control with dedicated drilling: sample collecting to provide good support to the grade control engineering and short-term mine plan. The technology being considered is Down the Hole hammer with reverse circulation.
• Blastholes: the holes are going to be drilled, most probably by an hydraulic Top Hammer drilling rig.
• Primary rock blasting: most of the rock, ore and waste, will be fragmented by using explosives. The ore fragmentation has special requirements, specifically for the ore we are considering the use of electronic caps.
• Rock mechanical excavation: must be made by bulldozers or directly by hydraulic excavators. • Loading operation will be done, preferentially, by retro bucket profile hydraulic excavator, and complemented by front end loaders (FEL).
• Rock transport will be done by conventional on-road trucks, 8 x 4 PBT (Total Gross Weight) bigger than 48 tons.
• Mine development and preparation will be undertaken by bulldozers, motor grader, road roller, water tank truck. As important as the production equipment are the ancillary equipment for the preparation and development of the mine: crawler tractor, motor graders, water tank trucks. Without proper mine development / preparation the production, and/or costs/t, would increase significantly.
• Bulldozer selection must be done considering activities on blasted rocks fronts and spreading blasted rock in waste dump piles.

That requires tractors of greater weight than soil-cutting tractors only. Soft rock will be excavated and loaded directly onto the trucks by hydraulic back-hoe excavators. Where the layers of altered rock are thicker, track dozers can be used to the complement excavation work.

PRIMARY CRUSHING & STOCKPILING
The crushing circuit is designed for an annual operating time of 6,130 h/or 70% availability at the capacity of 3,560 t/d.

Material is hauled from the mine or stockpiles and fed by front-end loader into the mobile crushing system. This system is composed of the run-of-mine run-of-mine (ROM) hopper, a vibrating grizzly feeder, a primary crusher and a discharge conveyor, along with some auxiliary equipment. As part of the mobile system, the ROM is dumped into the ROM hopper, equipped with a static grizzly. Provision for dumping on the ROM pad for blending and re-handling into the ROM hopper is provided. Material from the ROM hopper is crushed by a primary jaw crusher. ROM hopper material is reclaimed by a vibrating grizzly at 212 t/h to feed the jaw crusher.

A mobile rock breaker is utilized to break oversize rocks at the feed to the jaw crusher. The crushed material is conveyed to a surge bin that provides approximately 3 hours of live storage at the nominal processing rate. The bin has an overflow system, which forms an emergency stockpile next to the bin. Given the milling operation is designed for an annual operating time of 8,059 h/or 92% availability, this will result in excess crushed material production when the crusher is operational. The excess crushed material will allow routine crusher maintenance to be carried out without interrupting feed to the mill.

The mill feed surge bin is equipped with two vibrating feeders to regulate feed at 161 t/h into the SAG mill. When the surge bin has material, crushed material is drawn from the surge bin by the vibrating feeders and feeds the SAG mill circuit via the SAG mill feed conveyor. When operating using the bin overflow stockpile, front-end loaders (FELs) reclaim the material to a reclaim bin equipped with a vibrating feeder that also feeds the SAG mill circuit. Pebbles from the SAG mill are fed to a recycle circuit via conveyor and discharged on the SAG mill feed conveyor to recycle to the SAG mill. The transfer point of the pebble recycle conveyor has a chute that allows purging of the pebbles as required.

GRINDING CIRCUIT
The grinding circuit consists of a low-aspect single stage SAG mill in closed circuit with hydrocyclones. The SAG mill is an adaptation of an existing ball mill, already purchased by Aura Minerals. The mill size and design were reviewed, and it is suitable for this new application. The circuit is sized based on a SAG F80 of 85 mm and product P80 of 75 µm. The SAG mill slurry discharges through a trommel screen where the pebbles are screened and recycled back to the SAG mill via a conveyor, with the ability to purge the pebbles at the conveyor transfer point. Trommel undersize discharges into the cyclone feed pumpbox.

Water is added to the cyclone feed pumpbox to obtain the appropriate density prior to pumping to the cyclones. Cyclone underflow is split and part feeds the gravity circuit scalping screen and the rest recycles back to the SAG mill. Cyclone overflow gravitates to the pre-leach thickener via a trash screen.

OVERALL PROCESS DESIGN
The process design is based on the results of several testwork programs. This includes testwork completed for the feasibility study and historical testing. Historical testing evaluated different flowsheet options.

The flowsheet selected for the feasibility study is based on typical industry unit operations for gold processing plants. The flowsheet includes primary crushing followed by grinding to achieve a particle size distribution of 80% passing 75 µm. Part of the cyclone underflow will be processed in a gravity circuit and the cyclone product (overflow) will feed a pre-leach thickener, with the underflow processed through a leach/carbon in leach (CIL) circuit. CIL tailings will be treated for cyanide destruction. The carbon from CIL will go to elution, regeneration and the final solution will go to electrowinning and the gold room.

Key process design criteria are listed below:
• Nominal throughput of 3,560 t/d or 1. ........