Osisko Development Announces Optimized Feasibility Study for Permitted Cariboo Gold Project with C$943 Million After-Tax NPV5% and 22.1% IRR at US$2,400/oz Base Case Gold Price; at US$3,300/oz Spot Gold C$2.1 Billion After-Tax NPV5% and 38.0% IRR
Press Release
HIGHLIGHTS1
- Robust returns with base case after-tax NPV5% of $943 million, unlevered after-tax IRR of 22.1% and payback2 of 2.8 years at $2,400/oz gold price assumption. Using spot gold price of $3,300/oz, NPV5% improves to $2,066 million, IRR 38.0%, and payback2 of 1.6 years
- Average annual production of ~190,000 ounces of gold over a 10-year mine life (202,000 ounces in the first 5 years) with first gold anticipated in H2 2027, assuming construction commences in Q3 2025, subject to progress on ongoing project financing discussions
- Average TCC of US$947/oz and AISC of US$1,157/oz over the LOM, placing the Cariboo Gold Project within the lower half of the global cost curve for gold mines3
- Average base case LOM annual FCF of $158 million ($296 million per year in the first 5 years)
- Improved single-phase build over 24 months and direct ramp-up to 4,900 tpd with total initial capital cost of $881 million and sustaining capital of $525 million over the LOM
- Streamlined processing facilities into a single location and improved flowsheet design with incorporation of a gravity circuit and production of higher-grade concentrate product
- Strong support for local employment with up to 613 direct jobs created during peak construction and 525 permanent jobs during operations
- Significant opportunities to potentially enhance Project economics and extend mine life through conversion of Mineral Resources adjacent to Mineral Reserves through infill drilling
Montreal, Québec, April 28, 2025 – Osisko Development Corp. (NYSE: ODV, TSXV: ODV) (“Osisko Development” or the “Company”) is pleased to announce the results of a positive optimized Feasibility Study (“2025 FS”) for its permitted, 100%-owned Cariboo Gold Project (“Cariboo Gold” or the “Project”), located in central British Columbia (“BC”), Canada. The 2025 FS was completed by BBA Engineering Ltd. (“BBA”) as lead independent consultant, and supported by other independent engineering firms, in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”). The Company intends to file the technical report in respect of the 2025 FS (the “Technical Report”) on SEDAR+ (www.sedarplus.ca) and on EDGAR (www.sec.gov) under Osisko Development’s issuer profile within 45 days of the date of this news release. The 2025 FS confirms strong economics for a low-impact underground operation using mechanized bulk mining methods, with attractive operating costs, manageable capital requirements, and well-positioned to benefit from favorable macroeconomic and gold price trends. The process facilities have been designed to accommodate potential future throughput expansions.
Sean Roosen, Founder, Chairman and CEO, commented, “The completion of this optimized feasibility study represents a critical milestone for the Cariboo Gold Project, one of the few undeveloped, permitted gold projects in a Tier-1 jurisdiction4. The results reaffirm our view that Cariboo is a high-quality asset with robust returns and significant upside potential within the existing mine plan. Our immediate focus remains on advancing project financing and further de-risking the project toward FID, but, we believe additional work could support potential future production increases within the planned mine footprint. Additionally, our extensive land position around the Project area offers numerous opportunities for new discoveries in this prolific gold belt. With today’s favorable gold price backdrop and positive outlook, we believe this project is well-positioned to deliver substantial value to all stakeholders. We look forward to sharing further updates in the coming months.”
A formal positive final investment decision, along with securing of a project financing package in the coming months would enable certain construction activities to commence in the second half of 2025, with project completion targeted for the end of 2027.
Osisko Development will host a conference call and webinar presentation by management on the 2025 FS results on Monday, April 28, 2025 at 11:00 a.m. ET, followed by a question & answer session. Details for dial-in, webcast access, and replay archive are available at the end of this news release.
OPTIMIZED FEASIBILITY STUDY OVERVIEW
The Cariboo Gold Project is envisioned as a traditional underground operation, employing mechanized long-hole open stoping to extract ore from gold-bearing vein corridors—an intricate network of mineralized quartz veins predominantly hosted within unmineralized sandstone. An improved flowsheet from the 2023 FS (as defined herein5), supported by additional metallurgical testwork, envisions ore beneficiation to be exclusively completed at the Mine Site Complex. This would produce saleable gold doré from a gravity concentrate and ~66 tpd of high-grade flotation concentrate averaging ~133 g/t Au. The flotation concentrate would be transported by truck to the Port of Vancouver for transport and sale to a smelting partner. 2025 FS key summary results and assumptions are outlined in Table 1:
| Table 1: Cariboo Gold 2025 FS – Key Results and Assumptions (after-tax) | |||
| Metric | units | Base Case | Spot Case |
| Gold price | US$/oz | $2,400 | $3,300 |
| Exchange rate | USDCAD | 1.35 | 1.40 |
| Net Present Value at 5% discount | $ mm | 943 | 2,066 |
| Internal Rate of Return (IRR) | % | 22.1% | 38.0% |
| Payback, from commercial production | years | 2.8 | 1.6 |
| Average annual free cash flow1 | $ mm | 158 | 314 |
| Average AISC, LOM1 | US$/oz | 1,157 | 1,167 |
- All-in sustaining costs per ounce and free cash flow are non-IFRS measures or ratios. Refer to “Non-IFRS Financial Measures” at the end of this news release for more information.
- Spot case is based on the LBMA gold price as of the close of business on April 23, 2025, rounded to nearest $100/oz and the USDCAD exchange rate is based on the Bank of Canada daily exchange rate, rounded to nearest five cents.
Key Improvements and Optimizations vs. 2023 FS
The 2025 FS incorporates several important improvements and de-risking initiatives over the 2023 Feasibility Study that better position the Project from an execution, financing, and operational perspective. Notable changes include:
- Accelerated Development Sequence: Single-phase construction and ramp up directly to nameplate capacity of 4,900 tpd, which increases the LOM average gold production profile by 16% to 190,000 oz per year, and 202,000 oz per year in the first five years.
- Streamlined Processing: A single milling facility at the mine site removes the need (as had been previously contemplated) to transport flotation concentrate 116 km to the QR Mill. This reduces capital and operating costs by consolidating operations into one location.
- Improved Flowsheet Design: Updated metallurgical studies and testing has resulted in the addition of a gravity circuit which, combined with a rougher and cleaner flotation circuit, resulted in overall project gold recovery of 92.6% and the production of ~66 tpd higher-grade concentrate product (reduction from 590 tpd in 2023 FS Phase II) averaging ~133 g/t Au (vs. 28 g/t Au in 2023 FS Phase II). Approximately 46% of gold is expected to be recovered by gravity.
- Underground Mine Design: Increased average stope size by ~60% compared to the 2023 FS, significantly reducing the total number of stopes required to achieve average daily throughput. Optimization of the geotechnical design of the mined stopes, supported by recent trial mining, allows for more operational flexibility of underground operations.
- Mineral Reserves: Probable Mineral Reserves remained largely unchanged, increasing slightly to 2.071 million ounces Au (17.8 Mt grading 3.62 g/t Au).
- Permitted: Project design and sequencing contemplated in the 2025 FS is aligned with the BC Mines Act and Environmental Management Act permits obtained in Q4 2024.
| Table 2: Cariboo Gold 2025 FS vs. 2023 FS – Project Operating and Financial Metrics | |||
| Assumptions | units | 2023 FS | 2025 FS |
| Gold price | US$/oz | 1,700 | 2,400 |
| Exchange rate | USDCAD | 1.30 | 1.35 |
| Discount rate | % | 5.0% | 5.0% |
| Production | |||
| Mine life | yrs | 12.0 | 10.0 |
| Total ore mined | kt | 16,703 | 17,815 |
| Peak annual throughput | tpd | 4,900 | 4,900 |
| Average gold head grade | g/t Au | 3.78 | 3.62 |
| Total contained gold | koz | 2,031 | 2,071 |
| Avg. gold recovery | % | 92.0% | 92.6% |
| Total recovered gold, payable | koz | 1,869 | 1,894 |
| Avg. gold production, LOM | koz/yr | 164 | 190 |
| Avg. gold production, first 5 yrs | koz/yr | 96 | 202 |
| Operating Unit Costs | |||
| Underground mining | $/t mined | 53.6 | 62.3 |
| Processing | $/t mined | 31.2 | 23.2 |
| Water and waste management | $/t mined | 7.2 | 5.0 |
| Electrical transmission line | $/t mined | — | 4.9 |
| General and administrative | $/t mined | 10.7 | 15.4 |
| Total unit operating costs | $/t mined | 102.6 | 110.7 |
| Total operating costs | $ mm | 1,714 | 1,921 |
| Royalty payments | $ mm | 206 | 292 |
| Offsite charges | $ mm | 5 | 143 |
| Operating Costs | |||
| Total cash costs2 | US$/oz | $792 | $947 |
| AISC2 | US$/oz | $968 | $1,157 |
| Capital Expenditures | |||
| Initial costs | $ mm | 137.3 | 881 |
| Expansion costs | $ mm | 451.1 | — |
| Sustaining costs | $ mm | 466.6 | 426 |
| Closure costs, net3 | $ mm | (38.9) | 99 |
| Total capex | $ mm | 1,016 | 1,406 |
| Economics (after-tax) | |||
| Total free cash flow, LOM2 | $ mm | 901 | 1,577 |
| Net Present Value (NPV5%) | $ mm | 502 | 943 |
| Internal Rate of Return (IRR) | % | 20.7% | 22.1% |
| Payback, from commercial production | yrs | 5.9 | 2.8 |
| Average free cash flow, first 5 yrs2 | $ mm | (63) | 296 |
| Average free cash flow, LOM2 | $ mm | 75 | 158 |
- Total may not add up due to rounding.
- Cash costs, all-in sustaining costs per ounce and free cash flow are non-IFRS measures or ratios. Refer to “Non-IFRS Financial Measures” at the end of this news release for more information. Total cash costs are presented on a per ounce payable basis inclusive of total operating costs mining costs, processing costs, site G&A costs, royalties, smelting, refining, and transports costs. AISC are presented on a per ounce payable basis and include cash costs plus sustaining and closure costs.
- Closure costs are shown net of salvage value.
- Pre-final investment decision capital costs total $38.6 million.
Figure 1: Payable Gold Production and AISC1 Profile by Year
- All-in sustaining costs per ounce is a non-IFRS ratio. Refer to “Non-IFRS Financial Measures” at the end of this news release for more information.
Figure 2: Free Cash Flow1 by Year
- Free cash flow is a non-IFRS measure. Refer to “Non-IFRS Financial Measures” at the end of this news release for more information.
ECONOMIC SENSITIVITY ANALYSIS
The Company used a base case gold price assumption of US$2,400/oz and a USDCAD exchange rate of 1.35 in its analysis and incorporated only Probable Mineral Reserves (as defined herein). Based on these assumptions, the Project generates an after-tax NPV5% of $943 million, an after-tax unlevered IRR of 22.1% and a payback of 2.8 years (from commercial production). The 2025 FS economics are most sensitive to fluctuations in the following inputs (in order of magnitude of impact): gold price, foreign exchange, operating costs, and capital costs.
IBF4
