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
Aurizona is an open-pit gold with average life-of-mine gold production estimated at 130,000 ounces of gold per year. 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. The Company is exploring along strike of the existing open pit with the objective of mine-life extension, and is completing a prefeasibility study to determine the potential to develop an underground mine that could be operated concurrently with the existing open-pit mine.
Management believes the Aurizona mine life can be 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. The Company is also examining the potential to develop an underground mine at Aurizona.
AURIZONA MINE PLAN ESTIMATES 1
|Mine type||Open pit|
|Current P&P Reserve||958 Koz @ 1.51 g/t Au|
|Current M&I Resource 2||1,793 Koz @ 1.62 g/t Au|
|Initial Mine Life||6.5 years|
|Annual Production (LOM)||Avg. ~130,000 oz gold|
|Total Production (LOM)||885,700 oz gold|
|Strip Ratio / Recovery||5.7:1 / 91%|
|Cash Cost (LOM)||US$691/oz|
- Based on the April 2020 technical report.
- 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 and Boa Esperança pits. Equinox Gold believes the mine life can be extended with exploration success along strike from existing reserves, and is testing high-priority targets that could 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.
Confirming continuity of the mineralized zone
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.
Equinox Gold drilled nearly 20,000 metres at Piaba West in 2017-2018 and intersected broad zones of ore-grade mineralization on strike and to depth, including shallow and higher-grade mineralization both below the pit and more than 350 metres along strike.
These results were incorporated into a resource update in March 2019, increasing the M&I Resource 50%, increasing the underground Inferred Resource 115% and demonstrating the potential to both expand the open-pit resource base and develop an underground mine at Aurizona, which could extend production well beyond the current mine life.
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.
A total of 6,662 m of core (38 holes) was drilled in 2019 in the Tatajuba area bringing the total to 14,072 m (101 holes) in support of a maiden Indicated Mineral Resource estimate for Tatajuba of 2.1 million tonnes grading 1.62 g/t gold for 112,000 oz of contained gold, as announced in a May 12, 2020 resource update for Aurizona. The Company has planned a substantial drill program to expand the resource base along the Piaba Trend and within the near-mine concessions with the objective of extending the open-pit mine life.
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.
Equinox Gold has been studying potential underground mining scenarios and on May 7, 2020 announced the results of a positive preliminary economic assessment (“PEA”) for potential development of an underground mine at Aurizona, demonstrating the substantial opportunity for both mine life extension and increased annual gold production.
The current Aurizona mine plan contemplates mining the open pit to a depth of 220 metres. Drilling below the open pit has intersected mineralization at depths up to 600 metres below surface. The underground mine could be operated concurrently with the existing open-pit mine and has the potential to deliver an additional 740,500 oz of gold, $1 billion in revenue and $204 million in after-tax net cash flow over a ten-year mine life at a base case gold price of $1,350 per oz.
PEA Highlights for the Piaba Underground Mine (at $1,350/oz gold)
- 740,500 oz gold production from the underground mine, in addition to existing open-pit gold production
- 2,800 t/d mill feed at steady state from the underground mine
- PEA mine plan incorporates 2.8 million tonnes of Indicated Resources grading 2.73 g/t gold and 6.2 million tonnes of Inferred Resources grading 2.89 g/t gold
- Mined using low-cost long-hole open stoping method
- Processed using the existing 8,000 t/d plant and other existing surface infrastructure
- Initial capital costs of $69.7 million and sustaining capital of $138.4 million
- $1 billion gross revenue with a post-tax net cashflow of $204 million
- All-in sustaining costs of $925/oz
- $122 million after-tax NPV5% ($228 million at $1,620/oz gold)
- 25% IRR (38% at $1,620/oz gold)
Equinox Gold will continue to advance studies focused on underground development and intends to complete a pre-feasibility study for the Piaba underground mine in 2021. The Company has commenced a 25,000 m drill program aimed primarily at converting underground Inferred Resources to Indicated Resources in support of a prefeasibility study for the underground mine.
The PEA is included in Section 24 of the “Technical Report on the Aurizona Gold Mine, Brazil” dated April 27, 2020. The PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the results contemplated in the PEA will be realized.