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 ........

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 b ........

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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 ........