The Jacobina gold district is defined by a 40-km long belt that extends from Campo Limpo, in the south, to Santa Cruz do Coqueiro, in the north. The vast majority of significant gold mineralization occurs within the matrix of the conglomerates; these include the Canavieiras, Morro do Vento, João Belo, Serra Branca deposits as well as other minor occurrences.

The gold mineralization found at Jacobina occurs as two styles of mineralization (Texeira et al, 2001):
• Conglomerate-hosted placer gold mineralization (the most important mineralization type in the Jacobina district)
• Post-depositional gold-bearing stockwork, shear zones, and associated extensional quartz veins. These styles of mineralization are relatively minor and do not contribute to the established resources at Jacobina.

CONGLOMERATE-HOSTED PLACER GOLD MINERALIZATION
Conglomerate-hosted deposits contain very fine grains of native gold, typically 20 to 50 µm in size, hosted in the matrix of the conglomerate. Gold may also be associated with rounded pyritic aggregates believed to be of sedimentary origin. There are no other significant elements present, with detailed studies of the reef chemistry showing only very minor enrichment in iron, titanium and uranium in some reefs associated with rounded grans of uraninite, ilmenite and rutile. Mineralization is typically hosted by well sorted, clast-supported conglomerate and may comprise micro-fractured, gold-bearing, recrystallized, silicified, and pyritic conglomerate units of the Serra do Córrego Formation, with a greenish fuchsite matrix and common hematite coatings along shear planes, joints, and fracture surfaces. Gold mineralization does not display a correlation with the pyrite or fuchsite content of the rock, although well-mineralized reefs are typically enriched in hematite and may contain red colored, oxidized pebbles.

POST-DEPOSITIONAL GOLD-BEARING STOCKWORK, SHEAR ZONES AND EXTENSIONAL QUARTZ VEINS
This group encompasses gold-bearing extensional quartz veins and veinlets related to semiconcordant shear zones hosted by quartzites, andalusite-graphite-quartz schists, and local conglomerates of the Rio do Ouro Formation (e.g., Goela da Ema, Biquinha, Cercadinho and Guardanapo gold workings). This style of gold mineralization is a very minor volumetric component at Jacobina and does not contribute significantly to the mineral resource. The main hydrothermal alterations associated with this style of mineralization are silicification, sericitization, chloritization, and pyritization (locally with chalcopyrite), and local tourmalinization.

The ultramafic and mafic rocks also host mineralization as narrow shear zones up to 4 m- thick in north-south oriented ultramafic sills and dikes, close to their footwall and hangingwall contacts with the hosting quartzite and conglomerate units of the Serra do Córrego, Rio do Ouro, and Serra da Paciência Formations. The mineralized shear zones are characterized by the development of gold-bearing quartz veins and/or stockwork. The main hydrothermal alteration types are silicification, fuchsitization, pyritization, and sericitization, with local tourmalinization. A number of examples of this group are known at the mine sites and surrounding areas (Canavieiras, Itapicurú, Serra do Córrego, Morro do Vento, and João Belo), and at Serra da Paciência (Mina Velha, Várzea Comprida, Ciquenta e Um, Cabeça de Nego and Milagres gold workings), in the north. This style of mineralization does not contribute significantly to the mineral resource at Jacobina.

ALTERATION
The overprinting hydrothermal alteration event at the Jacobina deposit consists of pyrite, pyrrhotite, quartz, chrome-sericite (fuchsite), chrome-rutile and chrome-tourmaline. The chromium-rich nature of this alteration assemblage is attributed to leaching of the maficultramafic intrusive rock by circulating hydrothermal fluids.

Jacobina utilizes the sublevel longhole stoping (SLS) method without backfill to achieve an average production rate of approximately 6,500 tpd from the ramp-accessed underground mines; these include João Belo, Canavieiras, Serra do Córrego, Morro do Cuscuz, and Morro do Vento.

Production drill holes vary from 76 to 112.5 mm in diameter and are drilled using three types of fan drills; these include the Solo 5 7F, the Solo DL 420, and the Solo DL 421. For the most part, drill holes are no longer than 25 m, which helps control deviation. Backfill is not required for the SLS mining method as the stopes are supported by pillars left in place. However, development waste is increasingly being deposited in underground voids.

The Phase 2 expansion is planned for completion in mid-2022 and will increase throughput to 8,500 tpd, raising annual production to 230,000 ounces by 2023. Beyond Phase 2, the Company plans to implement a Phase 3 expansion which, for a modest cost, would increase throughput to 10,000 tpd and raise annual production to 270,000 ounces.

Ramp access to the mineralized zones allows for a high degree of flexibility.

Yamana is reviewing alternative mining methods and testing the suitability of the Jacobina tailings for paste fill or hydraulic fill applications. The results will be considered in a conceptual study that will evaluate the potential for constructing a fill plant at Jacobina. The use of cemented rock fill is also being evaluated. Alternative mining methods and the use of backfill is likely to increase mining extraction and has the potential to increase conversion of measured and indicated mineral resources to mineral reserves.

Stope stability is typically controlled through modification of the stope length as a way to manage the hydraulic radius of the hangingwall. For long-term planning, a hydraulic radius of approximately 13 is typically used, resulting in stope dilution estimates of 10% to 20%. Shortterm planning dilution estimates are supported by the actual results of the reconciliation process.

The selection of ground support for temporary and permanent excavations depends on the class of the rock mass (geomechanical domain) in which they are located. Bolts; bolts and steel screen; or a combination of bolts, steel screen, and shotcrete are used. The bolts are the primary support element. They can be fixed with resin or cement cartridges and their spatial distribution varies in spacing and quantity according to the quality of the rock mass. Steel screens are installed in regions or areas of very fractured rocks to hold the rock blocks that form between the risers. Shotcrete is used in areas of extremely fractured rock, subject to popping or immediate rupture; its thickness can vary between 60 mm and 90 mm.

CRUSHING CIRCUIT
Several options were considered to increase secondary crushing capacity and provide the greater operational flexibility needed for the Phase 2 Expansion:
• Option 1: Operate the crushing circuit at an increased availability.
• Option 2: Include a third HP500 crusher.
• Option 3: Replace the two existing HP500 crushers with two HP6 crushers.
• Option 4: Replace an existing HP500 crusher with one HP800 crusher.
Option 1, while not requiring capital investment, would limit the crushing circuit’s catch-up capacity, and would therefore present a risk to reaching the required production rate. Option 2 would require a third HP500 crusher which is of a similar size as the existing crushers. Yamana indicated that the inclusion of a third crusher would require major changes in the secondary and tertiary crushing areas such as new conveyor belts, new belt feeder, modification of the crusher feed silo, relocation of the hydraulic units for all crushers (to allow for expansion of existing buildings) and structural works (concrete and steel structures). These changes were deemed complex, expensive, time consuming, and would impact the existing operation during construction and commissioning. Option 3 considers the replacement of both HP500 secondary crushers with two HP6 crushers; the HP6 is slightly larger than the HP500. Option 4 requires the replacement of one existing HP500 with a larger and heavier HP800. Both options 3 and 4 can achieve the required throughput rates for the crushing circuit. Yamana has selected to proceed with option 4, in which the new crusher can be installed in the location of the existing HP500, offering the least impact on the operation.

GRINDING CIRCUIT
The Phase 2 Expansion project includes the following additional grinding equipment:
• A third ball mill (15’ x 30’). The new ball mill is identical in size to the existing ball mill 2, which will enable synergies in maintenance and supply of spare parts.
• A 6,000 t capacity silo for additional storage of crushed ore to feed the third ball mill circuit.
• A new cyclone feed hopper and duty/standby pumping arrangement.
• A new cyclone cluster, screen, and gravity concentrator associated with the third ball mill.
• A new cyclone feed distribution box associated with ball mill 1 and ball mill 2 to split feed to an existing gravity concentrator as well as to a new gravity concentrator.
• A new Acacia intensive leach reactor to work in parallel with an existing Acacia intensive leach reactor.

The Jacobina mineral processing plant uses conventional gold processing methodologies to treat run-of-mine (ROM) material from the underground mines. Comminution comprises three stages of crushing followed by wet grinding. Within the grinding circuit, gravity concentration of gold is performed on a bleed stream of classification cyclone underflow.

Rejects from the gravity circuit are returned to the grinding circuit. The cyclone overflow is sent to leaching in a conventional cyanide leaching process, and gold extraction from the leach solution is performed by carbon adsorption in the CIP tanks. Gold is stripped in an elution circuit and final gold recovery is performed in an electrowinning circuit. The sludge and solids from electrowinning are dried and smelted in an induction furnace to produce doré bars. The overall gold recovery in 2019 was 96.7%.

The mineral processing plant at Jacobina is currently being optimized to support a daily production throughput of ........