Status In production
Location Northeastern Brazil
Production 130,000-140,000 oz in 2021
Estimated Costs $1,025-$1,075/oz AISC in 2021
Reserves 1,660 Koz @ 1.60 g/t gold
M&I Resources 2,689 koz @ 1.67 g/t gold 1
Inferred Resources 915 koz @ 2.18 g/t gold
Mining Style Open-pit with cip plant
Upside Potential near-mine targets, underground development
COMMERCIAL PRODUCTION ACHIEVED ON JULY 1, 2019
Equinox Gold assumed management of the Aurizona mine in 2016 when it was on care and maintenance. The team completed a feasibility study in 2017, started construction in early 2018 and achieved commercial production in July 2019. As a brownfields past-producing mine, the majority of site infrastructure was already in place, resulting in construction capex of only $160 million.
Aurizona is an open-pit gold with average life-of-mine gold production estimated at 130,000 ounces of gold per year. Mining is performed by a mining contractor with conventional truck and shovel operations. Ore is delivered to an 8,000 tonnes per day crushing and grinding circuit and processed in a carbon-in-pulp plant. For 2021, Equinox Gold expects Aurizona to produce between 130,000-140,000 oz of gold at AISC of $1,025-$1,075 per oz of gold sold.
In September 2021, the Company completed a pre-feasibility study demonstrating that mining the underground deposit and additional open-pit satellite deposits concurrent with the existing open-pit mine will nearly double the mine life and also increase production, with peak annual production estimated at more than 160,000 ounces of gold per year. The results of the pre-feasibility study and next steps are described in Growth Projects.
Management believes the Aurizona mine life can be further extended with exploration success, and drilling is underway to test high-priority drill targets that could extend mineralization up to 4.5 km to the west of the existing pit. There is also significant potential to establishing a mining district by exploring and developing additional mineralized targets on the Company’s more than 1,100 km2 land package.
AURIZONA MINE PLAN ESTIMATES
|Mine type||Open pit|
|Current P&P Reserve||958 Koz @ 1.51 g/t Au|
|Current M&I Resource 1||1,793 Koz @ 1.62 g/t Au|
|Mine Life||6.5 years with expansion potential to 11 years|
|Annual Production||~130,000 oz gold|
|Strip Ratio / Recovery||5.7:1 / 91%|
|AISC||$1,025-$1,075 in 2021|
- Resources are inclusive of Reserves.
Aurizona exploration is a key driver for Equinox Gold’s growth
The approximately 1,100 km2 land package at the Aurizona Project provides an exciting exploration and growth opportunity for Equinox Gold, with both near-mine (pink) and district level (green) exploration potential. Equinox Gold’s current exploration focus is on near-mine targets that could expand the resource base and extend the Aurizona mine life.
Extending the mine life
The current reserve model for Aurizona outlines a 6.5-year mine life based on reserves identified in the Piaba, Tatajuba and Boa Esperança pits, along with some satellite pits to the east of the main Piaba deposit. Equinox Gold believes the mine life can be extended with exploration success along strike from existing reserves, and is testing high-priority targets at Tatajuba that could further extend mineralization to the west of the existing Piaba pit.
Surface exploration, geophysics and drilling at Aurizona have identified a structurally controlled mineralized corridor that includes the Piaba deposit and continues another five km along strike to the west. High-priority drill targets along this mineralized trend include Piaba West and Tatajuba.
The Piaba West target is an approximately 900-metre long extension of the Piaba pit. Previous drilling at Piaba West confirmed extension of the mineralized zone and encountered mineralized intervals similar to those seen in the Piaba deposit.
Gold mineralization at Piaba West is hosted in a northern, hanging wall sequence composed mainly of diorite and quartz diorite intrusives with subordinate dacitic volcanics. The mineralized zone dips steeply (80°) to the north north-west with gold occurring with disseminated sulphide and in several generations of quartz veins within the intrusives and volcanics. Hydrothermal alteration is intense and is dominated by silica-graphite-chlorite-carbonate-sericite-pyrite. Zones (shoots) of high-grade gold mineralization controlled by oblique shear zones occur within the mineralized areas.
The Tatajuba target is situated on the same structure as the Piaba deposit and represents a potential four-km extension of the Piaba Trend. Previous drilling at Tatajuba has encountered mineralization similar to that found in the Piaba pit, but often at higher grades. The Tatajuba target is close enough to the Piaba deposit and Aurizona mine facilities that ore could be trucked to site and processed at the main plant.
Like Piaba, Tatajuba contains gold mineralization associated with a sub-vertical to moderately north-dipping structure. Mineralization is hosted in a mafic to ultramafic volcano-sedimentary sequence and is similar to Piaba. There is a strong weathering overprint to the alteration zones at Tatajuba, in addition to a discrete zone of strong fracturing infilled by graphite, which has been overprinted by a later chlorite-iron carbonate fracture controlled alteration. The background alteration is chlorite and albite with calcite/dolomite.
50km of cumulative strike
The Aurizona Project land package includes 450 km2 of exploration licenses that Equinox Gold refers to as its “brownfields exploration properties”. Limited surface work and drilling on these properties has identified a number of drill targets that will be explored in the second phase of Equinox Gold’s exploration program.
Surface exploration in the brownfields properties has identified more than 50 km cumulative strike of structures, shown as grey lines on the map, with anomalous to high-grade soil and rock geochemistry. Additional surface exploration, coupled with airborne surveys and geophysics data, will allow Equinox Gold to identify drill targets and commence regional exploration in the brownfields properties.
Touro is one of the key brownfields targets. Located approximately 15 km southwest of Piaba, Touro is similar in scale to the Piaba deposit with a footprint of more than 6 km2. While drilling at Touro has been limited to date, the mineralization encountered is similar to that seen in the Piaba deposit, making Touro a high-priority target for Equinox Gold’s second phase of exploration.
The greenfields exploration properties were explored for two years in a joint venture with AngloGold Ashanti Holdings plc. AngloGold spent approximately US$9 million at the greenfields concessions from August 2016 to July 2018, completing more than 43,000 line-kilometres of high-resolution aeromagnetic, radiometric, and electromagnetic surveying over the entire property, approximately 10,000 metres of drilling on eight targets, and extensive soil geochemistry and geologic mapping surveys. AngloGold also applied considerable effort to social engagement, establishing strong communication and relationships with local landowners that Equinox Gold will maintain with the objective of restarting regional exploration efforts in the future.
Equinox Gold has received all data acquired through AngloGold’s exploration activities and retains a 100% interest in the greenfields concession. AngloGold’s exploration programs significantly advanced regional geological models and highlighted several untested targets that warrant further exploration. While Equinox Gold’s current priority in the region is near-mine exploration to expand the reserve and resource base, the Company will continue to review and interpret AngloGold’s exploration data to prioritize regional exploration targets for future drilling, on its own or with a joint venture partner.
The São Luis Craton, which hosts the Piaba Deposit, consists of the Paleoproterozoic Aurizona Group metavolcano-sedimentary succession, volcanics and granitoids of the Tromaí Intrusive Suite covered by Phanerozoic sedimentary basin deposits and recent coastal sediments. Structural trends throughout the São Luis Craton are dominated by north north-east to south south-west and west north-west to east south-east trending structures and there is a strong association between gold occurrences and structural lineaments, which form distinct gold corridors.