Overview

Deposit type

• Epithermal

Summary:

The Veladero deposit is a high sulphidation epithermal gold-silver deposit hosted by volcaniclastic sediments, tuffs, and volcanic breccias related to a Miocene diatreme-dome complex. Hydrothermal alteration is typical of high sulphidation gold deposits, with a silicified core grading outward into advanced argillic alteration, then into peripheral argillic and propylitic alteration haloes. Gold occurs as fine native grains, and is dominantly associated with silicification and with iron oxide or iron sulfate fracture coatings. Silver mineralization is distinct from gold, and occurs as a broader, more diffuse envelope, probably representing a separate mineralizing event. Copper and other base metals are insignificant, and sulphide mineralization is negligible. Principal controls on gold mineralization are structures, brecciation, alteration, host rocks, and elevation.

The Veladero deposit forms a broad, disseminated, three kilometre long blanket of mineralization along a N15ºW-striking structural trend. The diatreme-dome complex includes a massive, central, brecciated core of heterolithic, matrix-supported tuffisite that transitions outward through clast-supported breccias into the volcanic country rocks. A bedded tuff unit that represents fragments ejected from the central vent forms a ring that overlies portions of the tuffisite and breccias at the southern end of the deposit. The Veladero deposit comprises three main ore bodies: Amable in the south; Cuatro Esquinas in the center; and Filo Federico in the north. The Argenta ore body is a small satellite deposit located approximately five kilometres to the southeast of the Veladero deposit.

A variety of volcanic explosion breccias and tuffs are the principal host rocks at Cuatro Esquinas and Filo Federico, where alteration consists of intense silicification. The Amable ore body is hosted within bedded pyroclastic breccias and tuffs which are affected by silicification and advanced argillic alteration. Much of the Veladero deposit is covered by approximately 40 m of overburden and the overburden in some areas is up to 170 m thick. The colluvium is generally uncemented.

Precious metal mineralization at Veladero is controlled by stratigraphy, structural trends, and elevation. Disseminated gold mineralization forms a 400 m to 700 m wide by three kilometre long tabular blanket localized between the 3,950 m and 4,400 m elevations. Veladero has been separated into three main sectors, Amable in the south, Cuatro Esquinas in the centre and Filo Federico to the north. All sectors of the deposit are characterized by the same high sulphidation style of mineralization.

The mineralized envelope encompassing greater than 0.2 g/t Au is oriented along a 345°- trending regional structural corridor. The mineralization is dominantly hosted in the diatreme breccias along the fault-bounded northwest trend. Within this trend, higher grade mineralized shoots, averaging approximately 4 g/t Au but with one metre values up to 100 g/t, with lengths of 300 m to 500 m, form along northeast striking structural trends and are surrounded by a halo of lower grade mineralization ranging between 0.1 g/t Au and 1.0 g/t Au.

A mostly barren zone approximately 300 m long occurs between Amable and Cuatro Esquinas. From Cuatro Esquinas north through Filo Federico, the gold mineralization envelope is continuous. The Veladero ore envelope lacks recognized roots or high-grade feeder conduits at depth, and exhibits no evidence for significant supergene enrichment of metals (Barrick, 2005).

Gold mineralization can be hosted by any kind of rock at Veladero, including overburden and steam-heat altered lithologies. Principal host rocks are hydrothermal breccias and felsic tuffs at Filo Federico and Cuatro Esquinas, and pyroclastic breccias and felsic to intermediate tuffs at Amable. Main-stage introduction of gold clearly is younger than diatreme eruption, acid leaching, and major stages of silicification and fracturing. It accompanied or closely followed hypogene deposition of iron oxides and jarosite. Principal controls on localization of gold mineralization are structurally-induced open spaces (fracture zones, structural intersections), favourable host rocks, brecciation, alteration, and elevation.

Gold occurs at Veladero as minute native grains disseminated along fracture surfaces, and usually it is associated with silicification and hematite, goethite, or jarosite. Trace gold telluride minerals have been identified petrographically, but are not significant. Gold grains have been found encapsulated by quartz overgrowths, and also by jarosite. Megascopic gold grains up to one millimetre in size have been recovered from a number of drill holes, but most Veladero gold is less than 50 microns in size. Metallographic studies indicate that the gold contains some silver and that the overall gold purity or millesimal fineness is approximately 800 to 900.

Silver values are consistently anomalous at Veladero. The principal silver-bearing mineral is acanthite (silver sulphide). In addition, grains of native silver, silver chloride, and a silverbearing telluride have been identified in thin sections. Within the ore zone, silver and gold exhibit different distributions: some silver mineralization correlates with gold (Ag:Au ratios generally less 20:1); some silver has no associated gold; and some gold has little to no associated silver. These observations of silver and gold distributions suggest multiple events of precious metal mineralization (Barrick, 2005).

Silver is present as sub five micron size mineralization most typically as silver sulphide, silver chloride (cerargyrite), and native silver with all forms present with varying levels of silica encapsulation.

Mining Methods

• Truck & Shovel / Loader

Summary:

The Veladero Mine is a traditional open pit truck and shovel operation that has been in continuous operation since 2005.

The Veladero area consists of two major pit areas, Amable and Filo Federico, while there is a single pit at Argenta. Current operations are exclusively from the Filo Federico pit of Veladero. Mineral Reserves at Amable were exhausted in 2013, with no future plans to recommence
mining operations in this pit (waste backfilling began in 2014).

Mine operations are exclusively by open pit method, with a fleet of primarily 218-tonne rigid frame haul trucks combined with a variety of diesel powered hydraulic shovels and front end loaders as the primary loading equipment. The haul trucks are also utilized to transport ore to the Valley
Leach Facility (VLF) for placement. Blasting is required other than for the occasional unconsolidated material at the surface when starting a new pushback. A fleet of large diesel-powered blast hole rigs are employed for the production drilling.

The following description of the mining methods refers to the Filo Federico pit and associated infrastructure.

Open pit mining operations are located on steep mountain side slopes in rugged terrain with the majority of planned mining occurring between elevations of 3,900 MASL and 4,600 MASL.

The Filo Federico final pit will measure approximately two kilometers along strike, typically one kilometre across, and have a maximum depth of approximately 750 m. For comparison, the exhausted Amable final pit footprint is circular and measures approximately one kilometre in diameter with a maximum depth of approximately 530 m. The Argenta final pit footprint is approximately one kilometre along strike, typically half a kilometre across, with a maximum depth of approximately 300 m.

The final arrangement of the Veladero Waste Rock Facilities (WRF) is for the continued development of surface dumps along contour to either side of the Filo Federico pit and backfilling of the exhausted Amable pit. Backfilling of the Amable pit began in October 2014.

MINE DESIGN PARAMETERS:
- Haul Road Width - 32 m;
- Haul Road Gradient, Maximum - 10%;
- Mining Bench Height - 15 m;
- Safety Berm Width - from 7.1 to 19.6 m;
- Bench Face Angle - from 67 to 80 degrees;
- Inter-ramp Slope Angle - from 30 to 54 degrees.

The majority of remaining Mineral Reserves are scheduled for crushing prior to placement on the VLF as this typically offers a higher profit margin than ROM placement. ROM ore is hauled directly from the pit to the VLF and direct dumped. The crushing facilities are located approximately 1.5 km east of the final pit rim. After crushing, the ore is transported by mine truck direct to the Valley Leach Facility (VLF).

Comminution

Crushers and Mills

Summary:

The crushing plant capacity is approximately 83,000 tonnes per operating day. The technical limit of the plant is 100,000 tonnes per operating day, which may be achievable through optimum operational and mechanical availability.

Haul trucks dump directly into the primary 1,270 mm by 1,650 mm gyratory crushers. After crushing, the ore from line one is discharged into a surge pocket and transferred to a 2,000 t live capacity covered stockpile via an apron feeder and a belt conveyor. The primary crushed ore from line two is reclaimed from the surge pocket and placed on a belt conveyor. From the belt conveyor the ore can either go directly to a secondary crusher surge bin or be transferred to the covered stockpile.

The primary crushed ore is reclaimed from the stockpile and conveyed to a splitter chute to feed two scalping screens that operate in parallel in line one to remove the material that meets the required size criteria. The oversize from the screens discharges to two MP800 standard cone crushers, after which lime is added to the recombined undersize and crusher product. Line two is similar to line one except it has only one scalping screen and one secondary cone crusher. The secondary crushers operate in open circuit so the crushed ore and the undersize from the scalping screens are fed to the crushed ore bin.

An overland conveyor that previously transported crushed ore from Ore Bin #1 to Ore Bin #2 has been out of service since February 2015, and subsequently decommissioned due to excessive maintenance and mechanical issues in this area. The crushed ore is hauled by a fleet of 11 trucks from the crushing plant to the Valley Leach Facility (VLF), a distance of approximately 4.2 km.

Processing

• Smelting
• Heap leach
• ROM/dump leach
• Merrill–Crowe
• Filter press
• Cyanide (reagent)

Summary:

Gold is recovered from ore at Veladero using ROM and crushed ore cyanide heap leaching, and a Merrill-Crowe zinc cementation gold recovery plant. The lower gold grade ore, i.e., above the cut-off grades (COG) for ROM ore and below the COG for crushed ore, is mined and trucked to the Valley Leach Facility (VLF) and co-mingled with crushed ore (in the past, ROM ore was stacked in a separate area from crushed ore). Final delivery to the pad for ROM and crushed ore is by haul truck and spreading is by track-mounted dozer.

Ore that has a gold grade above the cut-off grade for crushed ore is trucked from the mine or stockpiles and crushed in one of two two-stage crushing circuits to a nominal size of 80% passing (P80) 40 mm.

The crushed ore is hauled by a fleet of 11 trucks from the crushing plant to the Valley Leach Facility (VLF), a distance of approximately 4.2 km.

The Valley Leach Facility (VLF)
A single VLF is located south of the Amable pit and South WRF. The final proposed VLF design is approximately five kilometres east to west by one kilometre north to south, with a footprint of approximately 270 ha. Elevations of the footprint range between 4,000 MASL and 4,300 MASL, with a maximum bench elevation of approximately 4,375 MASL. The maximum vertical height within the VLF is constrained to 150 m above the primary liner at nominal 13 m stack heights.

To date, the Phase 6 leach pad expansion was successfully commissioned in the second quarter of 2021, in line with guidance. The Phase 7 construction is under way.

At the VLF, ore is stacked as cells in 13 m lifts. Cells are typically 200 m to 250 m by 80 m to 100 m in size, or approximately 20,000 m2, and contain approximately 450,000 t to 500,000 t of ore. The maximum height of the leach pad is constrained to an overall stack height of 150 m above the primary liner, but is typically 100 m or less stack height.

Approximately 230,000 m2 to 260,000 m2 of surface area in the VLF is actively under leach at any given time with dilute cyanide leach solution applied using drip emitters. The drip emitters are buried approximately 60 cm to 65 cm to maximize distribution of solution and minimize freezing risk and evaporation. The nominal capacity of the Barren Solution pumping system is 2,900 m3/h. Pregnant solution is collected by the dam, at the toe of the leach pad, and pumped to the Merrill-Crowe recovery plant. An additional 0-2,700 m3/h is provided by a PLS Recycle system which provides an ability to control the Pregnant Solution Storage Area (PSSA) solution level and pursue solution enrichment with lower grade ore.

The pregnant solution is clarified in pressure leaf filters and stored in a clarified solution tank. From the tank, solution is pumped to a vacuum de-aeration tower which removes the dissolved oxygen from the precious metal bearing solution. Zinc dust is fed to the solution as it exits the de-aeration tower and the precious metals are removed from the solution as solid precipitate. Plate and frame filter presses are used to separate the precipitate from the solution. The barren solution is collected in a barren solution tank, cyanide and make-up water are added to the solution, and it is re-circulated to the VLF for reuse.

The zinc precipitate is collected from the filter presses and processed in retorts designed to recover mercury vapours from the precipitate as it is heated under vacuum. By-product mercury is collected and stored on site.

The dried precipitate is mixed with flux and smelted in electric induction furnaces. Gold doré that is produced by the refining process is shipped off site for further refining to produce fine gold and silver.

In November 2021, the board of Minera Andina del Sol approved the Phase 7A leach pad construction project. Phase 7B was subsequently approved by the board in the third quarter of 2022. Construction on both phases will include sub-drainage and monitoring, leak collection and recirculation, impermeabilization, and pregnant leaching solution collection. Additionally, the north channel (noncontacted water management) will be extended along the leach pad facility.

Construction of Phase 7A was completed on budget at a cost of $81 million (100% basis). Construction of Phase 7B began during the third quarter of 2023 and is scheduled for completion in 2024. Overall for Phase 7, as at December 31, 2023, project spend was $112 million (including $10 million in the fourth quarter of 2023) out of an estimated capital cost of $160 million (100% basis).

Construction of Phase 7A and 7B combined with upcoming leach pad expansion in Phases 8 and 9 will allow the extension of the life of mine to 10 years at an average production rate of approximately 400,000oz p.a.

Water Supply

Summary:

The water supply for industrial usage (i.e., process and dust control) is secured from the Rio de las Taguas. Potable water is provided by two water wells. The water is treated using reverse osmosis.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Chief Operating Officer	Mark Hil		May 21, 2024
General Manager	Yuri Damián Sáenz More		May 21, 2024
Health & Safety Superintendent	Fuad Omar Teme		May 21, 2024
Materials & Logistics Superintendent	Pablo Pugliese		May 21, 2024
Mine Maintenance Manager	Damián Chiquette		May 21, 2024
Mine Operations Manager	Javier Eduardo Cristiani		May 21, 2024
Operations Superintendent	Juan Emanuel Rodriguez		May 21, 2024
Planning Manager	Andres Claudio Stefan		May 21, 2024
Plant Maintenance Manager	Herman Bofinger		May 21, 2024
Process Manager	Marco Antonio Nuñez D'Amico		May 21, 2024
Process Superintendent	Mathias Gustavo Agüero		May 21, 2024
Project Manager	Diana Nuñez		May 21, 2024
Supply Chain Manager	Patricia Higueras		May 21, 2024
Supply Chain Superintendent	Ramiro German Cortes		May 21, 2024