OGC.TO · 2024-12-11 12:00:00

OceanaGold Releases Waihi District Pre-Feasibility Study with Attractive Economics and Initial Wharekirauponga Reserve of 1.2 Million Ounces

Economic Studies

December 11, 2024

News Release

OceanaGold Releases Waihi District Pre-Feasibility Study with Attractive

Economics and Initial Wharekirauponga Reserve of 1.2 Million Ounces

(All financial figures in United States dollars unless otherwise stated)

(VANCOUVER) OceanaGold Corporation (TSX : OGC ; OTCQX: OCANF ) (“OceanaGold” or the

“Company”) is pleased to announce the Waihi District Pre-feasibility Study (“PFS”) results, which includes

the existing Waihi operation and the proposed Wharekirauponga underground mine in New Zealand.

Waihi District PFS Highlights

• I nitial Mineral Reserve for Wharekirauponga Underground of 4.1 Mt at 9.2 g/t for 1.2 Moz of gold

• A fter-tax NPV5% of $621 million at a gold price of $2,400 per ounce, or $138 million at $1,750 per ounce

• IRR of 24% at a gold price of $2,400 per ounce, or 9.2% at $1,750 per ounce

• G old production of 1.6 Moz over a 15-year mine life at a n average All-in Sustaining Cost of $994 per

ounce (or $634 per ounce over the Wharekirauponga-only mine life)

• Significant project upside at Wharekirauponga with ~400 koz of Inferred Resources and recent results

confirming the EG Vein Zone mineralization extends a further 270 metres to the south and remains

open in all directions

• Growth capital of $556 million over an 8-year period, expected to be funded from Free Cash Flow

• First ore from Wharekirauponga Underground expected in 2032

• Early-works 2025 capital budget of $40 to $45 million approved for design and construction activities,

subject to receipt of necessary permits.

Gerard Bond, President & CEO of OceanaGold, said “Th is PFS is a major milestone for OceanaGold and

the Waihi operation. We plan to safely and responsibly develop the Wharekirauponga U nderground mine

which extends the life of the Waihi operation to at least 2038 , while generating strong returns for our

shareholders and wider economic benefits for local communities and New Zealand.

There remains significant exploration upside at Wharekirauponga, as seen in the exploration results we

have released since the June 30, 2024 date of the PFS. The orebody remains open in all directions , with

high-grade mineralization now defined to 270 metres beyond exi sting resources. Drilling is scheduled to

continue on the EG Vein Zone in 2025 with the goal of expanding the orebody, extending the life of the

Waihi operation and improving the economic returns to all stakeholders.”

The technical report is prepared in accordance with National Instrument 43- 101 – Standards of Disclosure

for Mineral Projects ("NI 43-101") with an effective date of June 30, 2024. The technical report is available

under the Company's profile on SEDAR+ at www.sedarplus.com and on our website at

www.oceanagold.com.

Senior management will host a webcast to discuss the results on Thursday, December 12, 2024 at 10:00

am Eastern Time, details of which are provided in this release. See: https://app.webinar.net/DdjR72Pnakx

Overview

The town of Waihi on the North Island of New Zealand is located approximately 140 kilometres southeast

of Auckland and is the location of a significant gold district which has produced an estimated 8 million

ounces of gold to date.

The PFS for the Waihi District includes the Martha Underground mine ("MUG") and the Wharekirauponga

Underground mine ("WUG"). WUG is located approximately 10 kilometres north of Waihi (Figure 1). The

Company owns a property (Willows), adjacent to and outside of the Coromandel Forest Park, that will host

the main access portal to, and service the development of WUG.

For a visual overview of the site and proposed project infrastructure, please see the accompanying VRIFY

media at https://vrify.com/meetings/recordings/7bed3b3f-699c-42e0-b243-f219d70af6fa.

The PFS is based on Mineral Reserves only and operating metrics reflect the inclusion of both MUG and

WUG as they contribute to production. E xisting operations at MUG, which have been in active production

since 2019, are expected to continue until 2033. Production from WUG is expected to begin in 2032, with

first stope ore in 2033 and mining to continue until 2038.

Figure 1: Map Showing Location of WUG and Waihi

Mineral Reserves

Mineral Reserves in the Waihi District comprise underground reserves only. The Mineral Reserves estimate

as of June 30, 2024 is presented in Table 1.

Table 1: MUG and WUG combined Mineral Reserves estimate as of June 30, 2024

Mineral Reserve Area Class Tonnes

(Mt) Au (g/t) Ag (g/t) Au (Moz) Ag (Moz)

MUG

Proven - - - - -

Probable 4.4 3.8 16.1 0.5 2.3

Total MUG 4.4 3.8 16.1 0.5 2.3

WUG

Proven - - - - -

Probable 4.1 9.2 16.1 1.2 2.1

Total WUG 4.1 9.2 16.1 1.2 2.1

Total Mineral Reserves 8.5 6.4 16.1 1.7 4.4

Notes:

• The WUG Mineral Reserves estimate was reviewed and approved by, or is based on information prepared by

or under the supervision of, Euan Leslie, MAusIMM CP, the Company’s Group Mining Engineer and a qualified

person under NI 43-101.

• The MUG Mineral Reserves estimate was reviewed and approved by, or is based on information prepared by

or under the supervision of, David Townsend, MAusIMM CP, the Company’s Mining Manager and a qualified

person under NI 43-101.

• Mineral Reserves are reported based on OceanaGold’s mine design, mine plan, mine schedule and cash flow

model at a gold price of $1,750/oz.

• Tonnages include allowances for losses resulting from mining methods. Tonnages are rounded to the nearest

100,000 tonnes.

• Ounces are estimates of metal contained in the Mineral Reserves and do not include allowances for

processing losses. Ounces are rounded to the nearest hundred thousand ounces.

• All figures have been rounded; totals may therefore not sum exactly.

• Tonnage and grade measurements are in metric units. Gold ounces are reported as troy ounces and "g/t"

represents grams per tonne.

• All key assumptions, parameters and methods used to estimate Mineral Reserves and the data verification

procedures followed are set out in the technical report titled “ NI 43-101 Technical Report – Waihi District Pre-

feasibility Study, New Zealand” dated December 11, 2024 with an effective date of June 30, 2024 (the

“Technical Report”), which is available under the Company's profile on SEDAR+ at www.sedarplus.com and

on the Company’s website at www.oceanagold.com.

Mineral Resources

The Mineral Resources estimate at the Waihi District comprise both open pit and underground resources.

The Mineral Resource estimate as of June 30, 2024 for Waihi is presented in Table 2.

Table 2: Summary of Mineral Resources estimate as of June 30, 2024

Area

Indicated Inferred

Tonnes Grade Grade Au Ag Tonnes Grade Grade Au Ag

(Mt) (g/t Au) (g/t Ag) (Moz) (Moz) (Mt) (g/t

Au)

(g/t

Ag) (Moz) (Moz)

MOP 6.50 1.95 13.44 0.41 2.81 2.3 2.1 12.1 0.2 0.9

GOP 3.22 1.44 3.76 0.15 0.39 0.8 1.0 2.6 0.03 0.1

MUG 6.42 5.29 25.51 1.09 5.27 2.7 4.7 27.1 0.4 2.4

WUG 2.39 17.88 28.02 1.37 2.15 1.3 9.6 17.1 0.4 0.7

Total

Mineral

Resources

18.53 5.07 17.82 3.02 10.6 7.1 4.3 17.6 1.0 4.0

Notes:

• Mineral Resources are reported inclusive of Mineral Reserves. Mineral Resources that are not Mineral

Reserves do not have demonstrated economic viability.

• Mineral Resources estimates were prepared by or under the supervision of, Leroy Crawford-Flett, MAusIMM

CP, the Company’s Exploration and Geology Manager and a qualified person under NI 43-101.

• Mineral Resources are reported at a gold price of $1,950/oz.

• Mineral Resources estimate for MUG is reported below the MOP5 design and constrained to within a

conceptual underground design based upon the incremental cut-off grade of 2.15 g/t Au.

• Mineral Resources estimate for WUG is reported within a conceptual underground design at a 2.10 g/t Au cut-

off grade.

• Mineral Resources estimate s for Martha Open Pit ( “MOP”) and Gladstone Open Pit ( “GOP”) are reported

within conceptual pit designs and incremental cut-off grades of 0.50 g/t Au and 0.56g/t Au, respectively. The

MOP conceptual pit design is limited by infrastructural considerations.

• Tonnage and grade measurements are in metric units. Gold ounces are reported as troy ounces and "g/t"

represents grams per tonne.

• No dilution is included in the reported figures and no allowances for processing or mining recoveries have

been made.

• All figures have been rounded; totals may therefore not sum exactly.

• All key assumptions, parameters and methods used to estimate Mineral Resources and the data verification

procedures followed are set out in the Technical Report, which is available under the Company's profile on

SEDAR+ at www.sedarplus.com and on the Company’s website at www.oceanagold.com.

• Mineral Resource close out dates for data used in the estimation are as follows: MUG – June 11, 2024; MOP

– February 1, 2024; WUG – April 24, 2024; GOP – September 1, 2022.

PFS Operating Summary

The Waihi District PFS covers the current operating Martha underground mine (“MUG”) and the new

Wharekirauponga underground mine (“WUG”). MUG and WUG are expected to produce a combined 1.6

million ounces of payable gold over a 15 year mine life (2024-2038) with peak production of 253 koz of gold

in 2035 and a life-of-mine average All-In Sustaining Cost (“AISC”) of $994 per ounce (Figure 2).

MUG is expected to be the primary ore source until 2033, when mining transitions to WUG. A mill expansion

to 0.8 Mtpa is also included in the PFS, which begins to process at the increased throughput levels in 2033.

WUG begins commercial production in 2033 with an average AISC of $634 per ounce, demonstrating the

strong margins of this high-grade orebody.

Figure 1: MUG and WUG Gold Production and Combined AISC Profile

182 222

253

187 148

47 52 57 57 57 56 56

101

204

223

253

188

165

$2,571

$2,226

$1,869 $1,712 $1,538 $1,473 $1,349

$686 $758 $655 $495 $606 $574

$1,011

2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038

MUG Au Production (koz) WUG Au Production (koz) AISC ($/oz)

Project Economics

At a Reserve gold price assumption of $1,750 per ounce, the Waihi District generates pre-tax and after-tax

NPV5% values of $259 million and $138 million respectively, and an IRR of 9.2%.

Using a flat $2,400 per ounce gold price over the life of the operation, the project is estimated to produce

pre-tax and after-tax NPV5% values of $902 million and $621 million respectively, and an IRR of 24.0%.

Table 3: PFS economic results

Description Units Reserve Case $2,400 Case

Gold Price $ per ounce 1,750 2,400

Payable Gold 000 ounces 1,593 1,593

Life of Mine Free Cash Flow – Pre-Tax $M 648 1,629

Life of Mine Free Cash Flow – After-Tax $M 431 1,147

NPV @ 5% - Pre-Tax $M 259 902

NPV @ 5% - After-Tax $M 138 621

IRR % 9.2% 24.0%

Capital and Operating Costs

The total non- sustaining capital investment for the Waihi District is estimated to be $ 556 million, spread

over eight years (Table 4) beginning in 2025. Growth capital expenditures include WUG mine development,

surface infrastructure, expansion of the process plant and water treatment plant and construction of a new

tailings storage facility ( “TSF”). WUG is accessed via 6.5 kms of underground development from surface,

with two ventilation shafts to be located in the Coromandel Forest Park.

Table 4: Total capital cost summary ($M)

Description Non-Sustaining

Capex

Sustaining Capex Total

WUG 357.9 62.9 420.9

MUG - 102.1 102.1

Processing and Water Treatment 92.8 8.4 101.2

TSFs 44.4 80.5 124.9

Other Capital 60.6 16.0 76.7

Rehabilitation - 71.6 71.6

Total 555.8 341.6 897.4

Total life of mine operating costs are summarized in Table 5.

Table 5: Operating cost summary ($M & $/t)

Description $M $/t Ore Mined

UG Mining – MUG 488.8 110.8

UG Mining – WUG 264.4 65.2

Life of Mine 753.2 89.0

$M $/t Ore Processed

Processing 222.7 26.3

G&A Costs 191.0 22.6

Refining / Freight Costs 5.6 0.7

Other - Carbon Costs and stockpile movements 28.2 3.3

Total Operating Costs 1,200.8 141.8

Permitting

The New Zealand government Fast -track Approvals Bill (the “Bill”) was formally introduced into the New

Zealand Parliament on March 7, 2024. It has completed the process of parliamentary sub-committee review

and is expected to be enacted by the New Zealand Parliament imminently and become effective in the first

quarter of 2025. In October 2024, the New Zealand Government named the Waihi North Project (“WNP”),

including WUG, as a listed project that will be eligible to apply for approvals through processes under the

Bill once the Bill becomes law.

Key permitting and schedule assumptions included in the PFS are:

 T he Bill will be passed and the fast-track process will be open for applications before the end of

March 2025;

 T he WNP Fast -track application including the supporting Assessment of Environmental Effects

(AEE) will be lodged in March 2025; and

 Fast-track approvals to commence construction will be granted to OceanaGold by the end of

November 2025.

Early-works construction, including infrastructure at Willows (the main underground portal site) , the water

treatment plant and services trench, is expected to begin in the second half of 2025 and enables the decline

and underground development to commence in late 2026.

Development of WUG and the Waihi North Project generally has the potential to create significant socio-

economic contributions for the communities in the Waihi region and for New Zealand. This includes

significant in-country investment and a substantial increase in direct and indirect employment opportunities,

with the project having the potential to extend operation of the Waihi operation to and beyond 2038.

Company tax payments in New Zealand are estimated at $482 million (NZ$790 million) at a $2,400/oz gold

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