Tesoro Gold Locks in 1.28Moz Reserve at Ternera Underpinning 13-Year Mine Life
Key Takeaways
- Tesoro Gold's maiden Ore Reserve at Ternera stands at 42.8Mt at 0.93g/t Au for 1.28Moz of contained gold, converting approximately 87% of the Measured and Indicated resource base — a high-confidence outcome that reflects exceptional mineralisation consistency.
- The pit shell was optimised at US$3,000/oz, roughly 30% below spot gold price at the time, embedding meaningful financial headroom into the reserve design before a single tonne is mined.
- PFS economics at US$3,500/oz gold deliver a post-tax NPV of US$994M, a 57% IRR, and a 17-month payback period, with life-of-mine free cash flow of US$1,510M — though these are ±35% accuracy estimates and should not be the sole basis for investment decisions.
- The DFS is targeted for completion in CY2026, with full EIA and sectorial permit applications to Chilean authorities anticipated in Q1 2027 and already 75% complete, while debt advisor BurnVoir and legal advisor Thomsons are engaged with formal financing discussions underway.
- Metallurgical test work confirmed 94.5% gold recovery at a 125µm grind with no deleterious elements identified, and the project benefits from sealed road access, proximity to the port of Caldera, and active MoUs for grid power and desalination water supply.
Tesoro Gold declares maiden 1.28Moz Ore Reserve at Ternera, underpinning 13+ year mine life
Tesoro Gold has announced a maiden JORC-compliant Ore Reserve of 42.8Mt at 0.93g/t Au for 1.28Moz of contained gold at its Ternera Gold Deposit, part of the 94.5%-owned El Zorro Gold Project in Chile. The announcement, made on 18 September 2026, marks a defining step in the project’s development trajectory.
The Reserve is contained entirely within a single open pit and represents approximately 87% of the 1.47Moz of gold within the Measured and Indicated components of the August 2026 Mineral Resource Estimate, demonstrating a high conversion of the resource base into mineable Ore Reserves. The pit shell was designed at US$3,000/oz, approximately 30% below the spot gold price at the time of optimisation, signalling meaningful financial robustness.
The Reserve supports a production life of more than 13 years at a planned 3.0Mtpa processing rate, with an average head grade of 1.16g/t Au for the first 10 years.
When big ASX news breaks, our subscribers know first
Reserve and resource breakdown at a glance
Ore Reserve summary
The table below presents the Ternera Deposit Ore Reserve as at 16 September 2026, reported in accordance with the JORC Code (2012 Edition).
| Category | Tonnes (Mt) | Grade (g/t Au) | Gold (koz) |
|---|---|---|---|
| Proved | 2.8 | 1.05 | 93 |
| Probable | 40.1 | 0.92 | 1,190 |
| Total | 42.8 | 0.93 | 1,283 |
Resource-to-reserve conversion
The conversion from the August 2026 Mineral Resource Estimate to the maiden Ore Reserve tells a compelling consistency story:
The high-grade gold expansion at Ternera, reported in August 2026, provided the resource base from which this Ore Reserve was ultimately drawn, with the Measured and Indicated categories reflecting drill results that confirmed mineralisation continuity across the deposit envelope.
- Total August 2026 MRE (open pit constrained): 1,822koz at 1.10g/t Au (51.6Mt)
- Measured and Indicated component: 1,466koz
- Ore Reserve conversion: 1,283koz = approximately 87% of Measured and Indicated ounces converted
Managing Director Zeff Reeves
“The Ternera Gold Deposit represents a rare, single open pit development opportunity in a world-class mining friendly country… That is a strong conversion outcome and is reflective of the consistency of mineralisation at Ternera.”
What is an Ore Reserve, and why does this one matter?
A JORC Ore Reserve is the portion of a Mineral Resource that has been demonstrated to be economically mineable, incorporating all Modifying Factors across mining, metallurgy, costs, and environmental considerations. In plain terms, it is the ounces a company can credibly plan to mine and process at a profit.
Within the Reserve, Proved ounces carry the highest confidence (derived from Measured Resources with the tightest drill spacing), while Probable ounces carry a slightly lower but still bankable level of confidence (derived from Indicated Resources). Critically, no Inferred Resources were included in this Reserve, meaning every ounce is drawn from the highest-confidence material in the resource base.
A maiden Ore Reserve is a pivotal development milestone. It is the threshold required before a Definitive Feasibility Study (DFS) can be completed and formal financing discussions can begin in earnest. The approximately 87% conversion rate is a strong outcome, reflecting the high degree of mineralisation consistency at Ternera and its amenability to conventional open pit mining.
Strong project economics reinforce the investment case
The following financial outcomes are derived from a Pre-Feasibility Study (PFS) and are stated at an accuracy of approximately ±35%. These are PFS-level estimates and, as the company’s Cautionary Statement makes clear, there is no certainty that the production target or financial forecasts will be achieved. Investors should not make investment decisions based solely on PFS results.
PFS financial highlights
- Gold price assumption: US$3,500/oz
- Pre-production capital: US$276.5M (with approximately US$52.2M expected to be funded via a 7-year vendor lease)
- Life-of-mine AISC: US$1,572/oz
- Post-tax NPV (5% discount rate): US$994M
- Post-tax IRR: 57%
- Payback period: 17 months
- Life-of-mine post-tax free cash flow: US$1,510M
A sensitivity analysis shows that at a gold price movement of ±20%, the post-tax NPV ranges from US$557M on the low side to US$1,427M on the high side, demonstrating the project’s resilience across a range of price scenarios.
Operating cost structure
| Area | US$/t processed | US$/oz produced |
|---|---|---|
| Mining | 23.11 | 831 |
| Processing | 13.73 | 494 |
| General and administration | 4.28 | 154 |
| Capital Lease Items | 1.63 | 59 |
| Total | 42.77 | 1,538 |
The path to the DFS
With the Ore Reserve now established, the project’s development sequence is clearly defined:
- DFS targeted for completion during CY2026, refining project design, economics, and assumptions.
- Full EIA application and all Sectorial permits anticipated to be submitted to Chilean authorities in Q1 2027 (currently approximately 75% complete).
- Debt advisor BurnVoir Corporate Finance and legal advisor Thomsons are already engaged; formal financing discussions with Australian and international financial institutions have commenced.
- Drilling continues across Ternera extensions and broader El Zorro Gold District priority targets.
The next major ASX story will hit our subscribers first
Why Ternera stands out: location, metallurgy, and infrastructure
El Zorro covers approximately 570km² within Chile’s Atacama Region, with Ternera situated 13km inland from the Pacific Ocean and 57km by road from the port of Caldera. The low-altitude coastal setting provides sealed road access and proximity to established regional infrastructure. Tesoro has entered into a Memorandum of Understanding (MoU) with TECNOCAP S.A. to investigate grid power connection, and a separate MoU with AguasCap to investigate the provision of desalination brine from the Totoralillo plant as process water.
Metallurgical test work across three phases, completed at ALS Perth under GR Engineering Services (GRES) supervision, has delivered strong and consistent results:
- 94.5% gold recovery at a 125µm grind size, used as the basis for Ore Reserve calculation
- Conventional 3.0Mtpa crush-grind-gravity-CIP processing flowsheet
- No deleterious elements identified across any phase of test work
On the mining contractor side, Tesoro and STRACON Chile SpA signed a non-binding Letter of Intent on 1 July 2026 to establish an alliance-style mining contractor framework for the project.
The project’s growth story extends beyond the existing Reserve. Ongoing drilling is targeting extensions to the Ternera resource and multiple high-priority discovery targets across the broader El Zorro Gold District, keeping the resource upside narrative firmly open.
The La Brea system discovery, which identified a major new zone within the broader El Zorro Gold District, forms part of the ongoing exploration program that Tesoro is pursuing in parallel with the Ternera development pathway.
Don’t Miss the Next ASX Gold Breakthrough
Get FREE breaking ASX gold news delivered to your inbox within minutes of release, complete with in-depth analysis already done for you. Join 30,000+ subscribers who stay ahead of the market the moment announcements hit. Click the “Free Alerts” button at Discovery Alert to start receiving real-time gold sector alerts today.