VANCOUVER, BC, Sept. 9, 2026 /PRNewswire/ -- OceanaGold Corporation (TSX: OGC, NYSE: OGC) ("OceanaGold" or the "Company") announces that it has lodged its application for approval of the Macraes Phase 4 Project ("MP4") under New Zealand's Fast-track Approvals Act 2024. The MP4 application seeks to extend the mine life at Macraes from the current reserve life of 2032 to the late 2030s, consistent with Macraes' history of mine life extension since it commenced operation in 1990.

The Company also provides details on the technical study work and exploration results which support the potential to extend mine life at Macraes via MP4 and beyond.

Gerard Bond, President and CEO of OceanaGold, said "Submitting the MP4 application is an important step in securing the long-term future of Macraes through permitting of additional open pit cutbacks and a mine life extension to the late 2030s. Recent drilling supports both the extensions included in MP4 and identifies further opportunities to potentially enable meaningful gold production into the 2040s.

For 36 years Macraes has safely and responsibly produced gold, delivering multi-generational benefits to the surrounding communities and to New Zealand through sustaining many hundreds of jobs, socio-economic community contributions, taxes and royalties, and export earnings. Our permit application and exploration results show the potential for Macraes to continue its long history of value creation while generating strong returns for our stakeholders."

For a visual overview of the site, mine life extension opportunities and drill results, please see the accompanying 3D video:

Macraes is located on the South Island of New Zealand, approximately 60 kilometres ("km") northwest of Dunedin. Production at Macraes commenced in 1990, with an initial 7-year mine life. In July of this year, the mine celebrated the production of its 6 millionth ounce of gold over its 36-year operating history. Macraes has a geologically prospective land package of over 14,000 hectares, including a 30 km highly mineralized structure known as the Macraes Shear Zone which hosts multiple gold deposits and exploration targets (Figure 1).

Macraes Mine Life Extension Potential

MP4 Fast-track Application

On September 9, 2026, the Company lodged its Fast-track application for the MP4 project. The MP4 application includes:

permitting for all activities required to complete the current reserve mine plan;

the development of Southern Pit Innes Mills ("SPIM", details below);

extensions of the Golden Point Underground ("GPUG"); and

flexibility to incorporate additional Mineral Resources into the future production profile.

Approval of MP4 will enable the extension of the Macraes operation to the late 2030s. Under the "one-stop shop" process of the New Zealand government, the Company expects MP4 to be fully permitted by mid-2027 (subject to appeals). MP4 permit approval is necessary for mine life extension, subject to achieving other ancillary permits, satisfactory technical and financial reviews, and market and operating conditions.

Approval and subsequent execution of MP4 works will enable the Macraes operation to continue to have a strong positive impact on the Otago region and New Zealand more broadly for many more years, bringing substantial investment, maintaining current and future employment opportunities and continuing to provide meaningful social, environmental and economic benefits.

The Company is familiar with the Fast-track approval process, having successfully permitted the Waihi North Project in 2025.

Mine Life Extension Technical Studies

The approval of MP4 will enable the Company to proceed with extensions to the Innes Mills, Coronation, Coronation North and Golden Bar open pits. A mine life extension of Golden Point Underground is also included in MP4, to provide additional flexibility for future development.

MP4 also includes an extension to the north of the current Innes Mills open pit, referred to as SPIM. Advanced studies are underway to bring SPIM into Mineral Resources by year end 2026, supported by drilling completed in prior years.

The Company believes that SPIM has the capability to contribute meaningful production at Macraes from 2032. Together with the extension of the Golden Point Underground, the Company is targeting to maintain production at Macraes above 100,000 ounces per year into the late 2030s.

Details regarding Macraes' expected production profile, development timeline for SPIM, capital expenditures and overall economics will be included in an updated National Instrument – 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") technical report that is expected to be released in early 2028.

SPIM development capital will include waste stripping, rehandling and relocation of a portion of historic tailings into the current Frasers tailings storage facility, relocation of the open pit workshop, re-routing the public road, and upgrades to site power infrastructure.

Advancing SPIM also has the benefit of enhancing the feasibility of mining the Round Hill deposit which was previously removed from Mineral Resources at year-end 2023. The Round Hill deposit is not included in MP4 and represents a potential opportunity for mine life extension into the 2040s.

Macraes Exploration Overview

The 2026 exploration program at Macraes is focused on supporting the mine life extensions outlined in MP4 and beyond. Supported by a record expected expenditure of US$13 million in 2026, a total of 60,000 metres ("m") of drilling is being executed at Macraes. The Innes Mills, Coronation and Nunns open pits, together with Golden Point Underground, continue to show significant potential for further resource conversion and growth.

Macraes Drill Results

Innes Mills

Innes Mills has been the main open pit ore source since 2024, accounting for approximately 39% of total Measured and Indicated Mineral Resource ounces for Macraes as at December 31, 2025. Drilling since the last resource estimate has focused on conversion of Inferred Mineral Resources in, and down dip of, the current reserve open pit design, with more than 12,000 m across 48 holes completed (Table 1). Drill hole DDH8224 returned 25.0 m @ 0.8 g/t gold ("Au"), confirming that mineralization continues at least 150 m down dip, towards the east, beyond the Innes Mills current reserve open pit design (Figure 2). This area is a target for additional resource expansion drilling in the remainder of this year to confirm the economic feasibility of additional future open pit cutbacks.

Golden Point Underground (GPUG)

GPUG is located immediately down dip of the historic Golden Point and Round Hill open pits which were mined between 1990 and 2002 and produced approximately 1.3 million ounces of gold. Underground mining at GPUG commenced in 2021.

Since the last resource estimate for the year ended December 31, 2025, more than 13,000 m of drilling across 37 holes has been completed, targeting both conversion and extension opportunities (Table 1).

In the north, DDH8281 stepped out approximately 40 m down dip of the current mine plan, intercepting 12.0 m @ 2.1 g/t Au and confirming the continuation of economic mineralization down-plunge. In the south, a 40 m step-out from the existing mine plan reported 15.0 m @ 1.5 g/t Au (DDH8412). These results are well above the current underground reserve cut-off grade and support the potential for future resource and reserve growth to the east and southeast (Figure 3). Drilling will continue at GPUG for the remainder of the year, targeting extension to mineralization both down dip and to the south along strike, where the deposit remains open, to further grow the resource.

Coronation

The Coronation open pit is located approximately 5 km to the northeast of the processing plant. Since the last resource estimate, more than 6,000 m of drilling across 36 holes has been completed at Coronation, with a focus on the conversion of Inferred Mineral Resources (Table 1).

Notable results included 7.9 m @ 5.4 g/t Au (DDH8286), 12.0 m @ 2.3 g/t Au (DDH8298), 21.0 m @ 1.1 g/t Au (DDH8283) and 6.0 m @ 1.7 g/t Au (DDH8367), which support the emergence of a higher-grade zone plunging to the southeast (Figure 4). This area remains open to the southeast, with further exploration drilling planned to pursue extension of this higher-grade trend beyond the current pit design to support future pit cutbacks.

Nunns

The Nunns prospect, containing a small resource defined in 2017, is located at the northwestern end of the Macraes property, approximately 6 km along strike from Coronation. Following the Company's additional land purchase in early 2026, a drill program focused on converting and growing the existing Mineral Resources, with 4,250 m of drilling across 48 drill holes was completed (Table 1). Notable results included 14.0 m @ 2.5 g/t Au (RCH8374), 8.0 m @ 4.2 g/t Au (RCH8375) and 4.0 m @ 7.9 g/t Au (RCH8344), confirming the extension of mineralization down dip and along strike, outside of the known resource (refer to VRIFY).

The mineralization at Nunns represents a potentially low capital, future open pit ore source for Macraes, that is outside of the MP4 permit application. An updated resource estimate is expected to be included at the end of 2026.

Table 1: Select Macraes significant drill intersections since the 2025 resource estimate[1]

OceanaGold is a global intermediate gold and copper producer committed to safely and responsibly maximizing the generation of Free Cash Flow from our operations and delivering strong returns for our shareholders. We have a portfolio of four operating mines: the wholly-owned Haile Gold Mine in the United States of America; the wholly-owned Macraes and Waihi operations in New Zealand; and the 80%-owned Didipio Mine in the Philippines.