Resource & Technical Disclosure

Lundberg Deposit · Effective September 2, 2026

The estimate comprises 26.08 Mt Indicated at 0.87% CuEq and 0.87 Mt Inferred at 1.54% CuEq, constrained within an optimized pit shell at a US$20.40/t NSR cut-off. Resource categories are presented separately.

Contained metal is in situ and does not represent recovered metal. Contained metal and CuEq grades are calculated from unrounded tonnes and grades before rounding for presentation. Mt = million tonnes; kt = thousand tonnes; Moz = million ounces; koz = thousand ounces.

Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. The pit shell is a resource reporting constraint, not a proposed mine plan. It was not constrained by surface infrastructure.

Assumptions and supporting disclosure

Complete resource notes

1. Mineral Resources are defined within an optimized pit shell using pit slope angles between 33° and 50°, based on a pit slope stability study by The Mines Group Inc. (2013). The optimized pit shell has an overall strip ratio of 3.16:1 (waste to mineralized material).
2. Pit optimization costs include mineralized material mining costs of US$3.60/t, waste mining costs of US$3.00/t, processing costs of US$18.00/t, general and administrative costs of US$2.40/t, and an exchange rate of C$1.37 per US$1.00.
3. Metal price assumptions are US$4.97/lb Cu, US$1.35/lb Zn, US$0.95/lb Pb, US$42.30/oz Ag and US$3,285.90/oz Au.
4. Metallurgical recoveries to concentrates are based on the “Centralized Milling of Newfoundland Base Metal Deposits - Bench Scale DMS and Flotation Test Program” (Thibault & Associates Inc., 2017). Metal recoveries are 83.0% Cu, 13.3% Au, and 7.84% Ag in the copper concentrate, 84.31% Pb, 10.54% Au, and 50.26% Ag in the lead concentrate, and 87.20% Zn, 8.28% Au, and 14.77% Ag in the zinc concentrate.
5. Net Smelter Return (“NSR”) US$/t values were determined for each resource model block using an NSR calculator. The NSR calculator incorporates the stated metal prices, metallurgical recoveries to concentrates, concentrate payable factors, and current shipping and smelting terms for similar concentrates.
6. The NSR calculator’s payable assumptions for each metal in each concentrate result in overall recovery and payability factors (payable factor × metal recovery) of 80.18% Cu, 80.09% Pb, 74.12% Zn, 65.69% Ag and 23.05% Au.
7. Copper equivalent (CuEq) grades were calculated using the stated metal prices, metallurgical recoveries to concentrates and concentrate payable factors: CuEq (%) = Cu (%) + (Pb (%) × 0.1909) + (Zn (%) × 0.2511) + (Ag (g/t) × 0.0102) + (Au (g/t) × 0.2772).
8. Mineral Resources are reported at a cut-off of US$20.40/t NSR within the optimized pit shell and are considered to reflect reasonable prospects for eventual economic extraction by open pit mining methods.
9. Mineral Resources were interpolated using inverse distance squared methods applied to 1.5 m downhole assay composites constrained within three-dimensional solid models representing stockwork and massive sulphide mineralization. No grade capping was applied.
10. An interpolated inverse distance squared bulk density model (g/cm³) was applied.
11. The block model uses blocks measuring 5 m (x) by 5 m (y) by 5 m (z), with a minimum block size of 0.625 m (x) by 0.625 m (y) by 0.625 m (z).
12. Mineral Resources were depleted for the Buchans Lucky Strike glory hole and historical mining. Historical stopes are assumed to be sand-filled with a density of 1.92 g/cm³, and historical development workings are assumed to be open void space.
13. The classification of the current Mineral Resource Estimate into Indicated and Inferred is consistent with the Canadian Institute of Mining, Metallurgy, and Petroleum (“CIM”) Definition Standards for Mineral Resources and Mineral Reserves, May 10, 2014 (“CIM Definition Standards”).
14. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the estimated Mineral Resources will be converted into Mineral Reserves. An Inferred Mineral Resource has a lower level of confidence than a Measured or Indicated Mineral Resource. It is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.
15. Mineral Resource tonnages have been rounded to the nearest 10,000 tonnes. Totals may vary due to rounding.
16. The MRE was completed in consideration of the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines (November 29, 2019).
17. The technical report in support of the 2026 MRE will be filed by the Company within 45 days of this news release.

Qualified Persons

Matthew Harrington, P.Geo., of Mercator, is an independent Qualified Person as defined under National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and is responsible for the technical disclosure regarding the 2026 MRE contained in this news release.

Paul Moore, MSc., P.Geo. (NL), Vice President of Exploration, is the Qualified Person for the Company and has reviewed and approved the other scientific and technical information in this news release.

The statements above describe the Qualified Persons’ responsibilities for the supplied news release. This page summarizes that disclosure; refer to the complete news release for the full technical information.

Exploration beyond Lundberg

Follow-up work will focus on Two Level, deposit extensions and the Buchans Mine Trend. Further metallurgical testing is intended to assess processing options. A potential shared-processing or district development concept remains subject to further technical and economic evaluation.

Exploration targets outside the reported Lundberg Mineral Resource are conceptual and include historical mineral resource estimates. A QP has not done sufficient work to classify the historical estimates as current Mineral Resources or Mineral Reserves, and Canterra is not treating historical estimates related to the satellite deposits as current Mineral Resources or Mineral Reserves. Further exploration is required to determine whether they can support Mineral Resources, there is no certainty that new resources will be defined, and references to satellite deposits do not imply that their resources have been incorporated into the 2026 MRE.

Other deposits in the portfolio

The following estimates are identified as historical on the project pages. They have different estimate dates, technical sources and cut-offs and should be read separately from the current Lundberg resource.

How to read these figures

• Resource categories. Measured, Indicated and Inferred resources have different levels of geological confidence. Inferred quantities are reported separately.
• Current and historical information. Historical estimates are not included in the current Lundberg resource and should not be combined into a current portfolio resource total.
• Metal equivalents. ZnEq and CuEq figures depend on metal prices, recoveries, payability and calculation methods stated in the relevant source.
• Rounding. Reported figures may be rounded and may not sum precisely.

Reports and filings

Source: Canterra’s supplied news release dated October 6, 2026, “Canterra Expands Lundberg Indicated Mineral Resource by 55% to 26.1 Mt at the Buchans Project in Newfoundland.” Read the complete October 6 news release or download the release PDF.

The supporting technical report is to be filed within 45 days of the news release. Existing reports in the Investor Centre predate this estimate.

Forward-looking information — supplied release wording

This press release contains forward-looking information within the meaning of applicable Canadian securities legislation, including statements concerning the estimated mineral resources, exploration potential, planned drilling and metallurgical work, potential district development strategies, further technical evaluation, the timing of the supporting technical report and anticipated exploration assistance funding. All statements, other than statements of historical fact, are forward-looking statements and are based on expectations, estimates and projections as at the date of this news release. Any statements that discuss predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as “expects”, or “does not expect”, “is expected”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” occur or be achieved) are not statements of historical fact and may be forward-looking statements. Consequently, there can be no assurances that such statements will prove to be accurate and actual results and future events could differ materially from those anticipated in such statements. Factors that could cause future results to differ materially from those anticipated in these forward-looking statements include risks associated with possible accidents and other risks associated with mineral exploration operations, the risk that assay, geophysical or metallurgical results will not support the Company’s interpretations or continued exploration, the risk that further technical work results in revisions to the mineral resource estimate, volatility in copper, zinc, lead, silver and gold prices, the risk that the Company will encounter unanticipated geological factors, the possibility that the Company may not be able to secure permitting and other governmental clearances necessary to carry out the Company’s exploration plans, the risk that the Company will not be able to raise sufficient funds to carry out its business plans, and the risk of political uncertainties and regulatory or legal changes that might interfere with the Company’s business and prospects, as well as those risks and uncertainties identified and reported in the Company’s public filings under its SEDAR+ profile at www.sedarplus.ca. Accordingly, readers should not place undue reliance on the forward-looking statements and information contained in this press release. Except as required by law, the Company disclaims any intention and assumes no obligation to update or revise any forward-looking statements to reflect actual results, whether as a result of new information, future events, changes in assumptions, changes in factors affecting such forward-looking statements or otherwise.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.