1. Measured and Indicated Mineral Resources are reported inclusive of Mineral Reserves.
1. Measured and Indicated Mineral Resources are reported inclusive of Mineral Reserves.
www.oceanagold.com 1
NEWS RELEASE
February 18, 2026
OceanaGold Reports Mineral Reserves and Resources
for the Year Ended 2025
VANCOUVER, BC – OceanaGold Corporation (TSX: OGC) (OTCQX: OCANF) (“OceanaGold” or the
“Company”) is pleased to provide its Mineral Reserves and Mineral Resources statement for the year
ended December 31, 2025.
Highlights
• Total Mineral Reserves of 5.83 million ounces of gold (“Moz Au”) across its four operating assets.
• Total Measured and Indicated Resources of 8.63 Moz Au1 and Inferred Resources of 2.5 Moz Au.
• An initial underground Mineral Reserve of 0.44 Moz gold declared for Ledbetter Underground (“LUG”),
Haile has removed lower margin open pit ounces while increasing asset Net Present Value (“NPV”) by
determining that Ledbetter will be best advanced as an underground mine.
• Gold price assumption increased to a prudent $2,200/oz for reserves and $2,450/oz for resources.
• Reserve additions were driven by open pit extensions at Macraes, supported by a higher gold price that
extends mine life to 2032, and increases at the Horseshoe Underground at Haile.
• At Wharekirauponga , 0.16 Moz of Inferred Resources was added , while a significant increase in
resource conversion and growth drilling is planned for 2026.
• NI 43 -101 Technical Reports for Haile and Macraes w ill be released by March 31, 2026 providing
updated life-of mine plans based on Mineral Reserves only. The Didipio NI 43-101 Technical report will
be released in the first half of 2026.
Gerard Bond, President and CEO of OceanaGold, said " Our 2025 Reserves and Resources reflect the
value added through our successful exploration efforts in 2025, particularly at Horseshoe Underground
at Haile and Wharekirauponga Underground at Waihi. The technical work to convert the final open pit
phase at Ledbetter to an underground Reserve at Haile resulted in increasing Haile’s NPV . We are
recognizing the benefits of operating in a higher gold price environment with the addition of 5 years mine
life at Macraes, while maintaining a prudent $2,200 per ounce Reserve gold price assumption to ensure
we produce profitable gold. We have a tremendous track record of organically growing our Reserve and
Resources through exploration and we are increasing our investment in explorat ion by 50%, with a
planned expenditure of $60M in 2026.”
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Updated Mine Plans for Haile and Macraes
The updated Mineral Reserves for Haile reflects a change in mining method for the final Ledbetter open
pit phase ( Phase 4) to an underground mine. This change removes low-margin open pit ounces while
improving the NPV of Haile. Beyond the economic benefits, the transition to underground also provides
operational benefits, including significantly less waste movement, less rehandle, lower greenhouse gas
emissions and lower tailings facility capacity requirements. In the upcoming technical report mine plan,
LUG portal construction commences in 2028, with first development ore expected in 202 9 and steady-
state production expected in 20 30. First ore from the Palomino Underground (“PUG”) remains on
schedule for 2028. Mine life for the site will be extended to 2036.
Haile is expected to produce on average 210,000 ounces of gold per year from 2027 through 2031,
providing the mine a more sustainable, de-risked production profile as compared to the previous
technical report. Notably, open pit mining continues at Haile across the other open pits until 2033, which
remain part of the planned mining sequence in conjunction with the underground operation.
The increased reserves at Macraes reflects the leverage the mine has to a higher gold price , with
previously marginal open pits becoming economic in a rising gold price environment , resulting in the
addition of 5 years of reserve mine life. Applying a $2,200 gold price assumption (compared to $1,750
previously), additional open pit cutbacks were economic at Innes Mills, Coronation, Coronation North
and Golden Bar , which, in conjunction with the Golden Point Underground , extends the mine life at
Macraes to 2032.
Updated National Instrument 43-101 – Standards o f Disclosure for Mineral Projects (“ NI 43 -101”)
technical reports for Haile and Macraes will be filed on SEDAR+ by the end of March 2026 and will include
life-of-mine plans, capital and costs estimates based on Mineral Reserv es only. The Didipio NI 43 -101
Technical report will be released in the first half of 2026.
Mineral Reserves
Mineral Reserves total 5.83 Moz, representing a net decrease of 0.39 Moz from the prior year (see Figure
1). The change was mainly driven by Haile, where reserves declined due to depletion and the change in
mining method at LUG from an open pit to an underground mine , which removes lower margin open pit
inventory while improving overall asset NPV . This was partially offset by additions at depth in the
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Horseshoe Underground. Additionally, higher gold price assumptions allowed for multiple new open pit
phases at Macraes.
Figure 1: Changes to Proven and Probable Reserves
Notes:
• "Depletion" refers to 2025 mining depletion.
• "Reserve Model Updates" represent drilling and/or model updates to reserve or initial reserve declarations.
• "Economic Factors" relate to gold price, mining cost and cut-off grade changes.
• "Adjustments" relate to changes not captured in other categories. This includes the LUG mining method change.
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The Proven and Probable Mineral Reserves estimates as at December 31, 2025 are presented in Table 1 below.
Table 1: Proven and Probable Reserves as at December 31, 2025
Proven Probable Proven & Probable
Gold
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Haile
Horseshoe Underground 1.52 4.39 0.21 2.63 4.24 0.36 4.14 4.29 0.57
Palomino Underground - - - 3.62 2.96 0.34 3.62 2.96 0.34
Ledbetter Underground - - - 4.00 3.39 0.44 4.00 3.39 0.44
Open Pits 2.47 1.23 0.10 16.1 1.62 0.84 18.6 1.57 0.94
Haile Total 3.99 2.43 0.31 26.3 2.33 1.98 30.3 2.35 2.29
Didipio
Didipio Underground 13.5 1.39 0.60 14.7 0.85 0.40 28.3 1.11 1.01
Didipio Open Pit Stockpile 13.2 0.30 0.13 - - - 13.2 0.30 0.13
Didipio Total 26.7 0.85 0.73 14.7 0.85 0.40 41.5 0.85 1.13
Macraes
Macraes Underground 0.04 2.01 0.00 2.57 1.90 0.16 2.62 1.90 0.16
Macraes Open Pit 11.5 0.55 0.20 19.7 0.64 0.40 31.2 0.61 0.61
Macraes Total 11.5 0.56 0.21 22.3 0.78 0.56 33.8 0.71 0.77
Waihi
Martha Underground - - - 3.43 3.85 0.42 3.43 3.85 0.42
Wharekirauponga - - - 4.10 9.20 1.21 4.10 9.20 1.21
Waihi Total - - - 7.53 6.76 1.64 7.53 6.76 1.64
Total Gold 42.3 0.92 1.25 70.9 2.01 4.58 113 1.60 5.83
Proven Probable Proven & Probable
Silver
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Haile
Horseshoe Underground 1.52 1.5 0.1 2.63 1.8 0.2 4.14 1.7 0.2
Palomino Underground - - - 3.62 2.7 0.3 3.62 2.7 0.3
Ledbetter Underground - - - 4.00 11 1.3 4.00 11 1.3
Open Pits 2.47 2.1 0.2 16.1 2.3 1.2 18.6 2.2 1.3
Haile Total 3.99 1.9 0.2 26.3 3.5 3.0 30.3 3.3 3.2
Didipio
Didipio Underground 13.5 1.7 0.7 14.7 1.3 0.6 28.3 1.5 1.4
Didipio Open Pit Stockpile 13.2 1.9 0.8 - - - 13.2 1.9 0.8
Didipio Total 26.7 1.8 1.6 14.7 1.3 0.6 41.5 1.7 2.2
Waihi
Martha Underground - - - 3.43 17 1.9 3.43 17 1.9
Wharekirauponga - - - 4.10 16 2.1 4.10 16 2.1
Waihi Total - - - 7.53 17 4.0 7.53 17 4.0
Total Silver 30.7 1.8 1.8 48.6 4.9 7.6 79.3 3.7 9.5
Proven Probable Proven & Probable
Copper
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Didipio
Didipio Underground 13.5 0.38 0.05 14.7 0.31 0.05 28.3 0.35 0.10
Didipio Open Pit Stockpile 13.2 0.28 0.04 - - - 13.2 0.28 0.04
Didipio Total 26.7 0.33 0.09 14.7 0.31 0.05 41.5 0.32 0.13
Total Copper 26.7 0.33 0.09 14.7 0.31 0.05 41.5 0.32 0.13
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Notes:
• Mineral Reserves are defined by mine designs based upon the following assumptions: metal prices of US$ 2,200/oz gold, US$4.00/lb copper
and US$25/oz silver; NZD/USD exchange rate of 0.60.
• Reported estimates of contained metal are not depleted for processing losses.
• For underground reserves, cut-offs applied to diluted grades.
• Mineral Reserves are reported on a 100% basis. OceanaGold holds an 80% attributable interest in the Didipio Mine.
• Haile:
o Open Pit: the primary cut-off grade is 0.5 g/t Au, while oxide material is assigned a cut-off grade of 0.6 g/t Au.
o Underground: the cut-off grade is 1.86 g/t Au.
• Didipio:
o Gold equivalence (AuEq) is based upon the presented gold and copper prices as well as processing recoveries. AuEq = Au g/t + 1.27 x Cu%.
o The 13.2 Mt surface stockpile inventory includes 5.3 Mt of low-grade stocks mined at an approximate cut-off grade of 0.27 g/t AuEq.
o Underground: cut-off grade of 1.16 g/t AuEq is used. Incremental stopes proximal to development already planned to access main stoping
areas are reported to a lower cut-off grade of 0.76 g/t AuEq
• Macraes:
o Open Pit: Primary cut-off grade is 0.25 g/t while Golden Bar is 0.30 g/t
o Underground: Golden Point cut-off grade is 1.08 g/t Au. Stopes for which access already exists are reported to a lower cut-off grade of 0.94
g/t.
• Waihi:
o Martha Underground cut-off grade for previously unmined stoping areas is 2. 60 g/t Au, increasing to 3. 2 g/t Au for stoping areas in close
proximity to remnant workings.
o Wharekirauponga Underground cut-off grade for stopes is 2.40 g/t Au.
Mineral Resources
Measured and Indicated Resources (inclusive of reserves) total 8.63 Moz, a net decrease of 0.31 Moz from
the prior year (Figure 2). The change was mainly driven by mining depletion at all operations, and at Haile,
resources decreased due to the change in mining method of Ledbetter to an underground mine. This was
partially offset by growth at Macraes, where resources increased as higher gold price assumptions
allowed for multiple open pit expansions , with increases from model updates at Innes Mills and
Coronation particularly contributing to growth. Additional increases came from the Horseshoe
Underground at Haile and from Waihi, with increases at Wharekirauponga.
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Figure 2: Changes to Measured and Indicated Resources
Notes:
• "Depletion" refers to 2025 mining depletion.
• "Resource Model Updates" represent drilling and/or model updates to reserve or initial reserve declarations
• "Economic Factors" relate to gold price, mining cost and cut-off grade changes.
• "Adjustments" relate to changes not captured in other categories.
Inferred Resources total 2.5 Moz, a net increase of 0.3 Moz from the prior year (Figure 3). The increase was
largely driven by additions at Wharekirauponga Underground at Waihi, gold price -related open pit
expansions at Macraes and additions at depth at Didipio, offsetting the decreases from Inferred
Resources conversion.
Figure 3: Changes to Inferred Resources
Notes: See notes for figure 1.
The Measured, Indicated and Inferred Mineral Resource estimates (inclusive of Mineral Reserves) as of
December 31, 2025 are presented in Table 2 below.
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Table 2: Measured, Indicated and Inferred Resources as of December 31, 2025
Gold
Measured Indicated Measured & Indicated Inferred
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Au
(g/t)
Contained
Ozs (Moz)
Tonne
s (Mt)
Au
(g/t)
Contained
Ozs (Moz)
Haile
Horseshoe
Underground 1.98 5.11 0.33 2.76 5.11 0.45 4.74 5.11 0.78 0.5 2.7 0.0
Palomino
Underground . . . 4.19 3.38 0.45 4.19 3.38 0.45 0.8 2.5 0.1
Ledbetter
Underground . . . 4.07 4.12 0.54 4.07 4.12 0.54 1.2 2.9 0.1
Open Pits 2.58 1.21 0.10 16.1 1.64 0.85 18.7 1.58 0.95 0.6 0.9 0.0
Haile Total 4.56 2.91 0.43 27.1 2.63 2.30 31.7 2.67 2.72 3.1 2.4 0.2
Didipio
Didipio
Underground 14.3 1.53 0.71 17.7 0.89 0.51 32.0 1.18 1.21 9.2 0.9 0.3
Open Pit
Stockpiles 13.2 0.29 0.12 . . . 13.2 0.29 0.12
Didipio Total 27.5 0.94 0.83 17.7 0.89 0.51 45.2 0.92 1.34 9.2 0.9 0.3
Macraes
Macraes
Underground 0.08 3.02 0.01 6.37 2.28 0.47 6.45 2.29 0.47 2.4 1.8 0.1
Open Pits 12.6 0.62 0.25 35.7 0.67 0.76 48.3 0.65 1.01 25 0.7 0.5
Macraes Total 12.7 0.63 0.26 42.1 0.91 1.23 54.8 0.85 1.49 27 0.8 0.7
Waihi
Martha
Underground 6.33 5.24 1.07 6.33 5.24 1.07 2.2 4.6 0.3
Wharekirauponga 2.63 17.3 1.46 2.63 17.3 1.46 2.9 8.5 0.8
Open Pits 9.72 1.78 0.56 9.72 1.78 0.56 3.2 1.8 0.2
Waihi Total 18.7 5.13 3.08 18.7 5.13 3.08 8.3 4.9 1.3
Total Gold 44.8 1.05 1.51 106 2.10 7.11 150 1.78 8.63 48 1.6 2.5
Silver
Measured Indicated Measured & Indicated Inferred
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Tonnes
(Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Tonne
s (Mt)
Ag
(g/t)
Contained
Ozs (Moz)
Haile
Horseshoe
Underground 1.98 1.9 0.1 2.76 2.1 0.2 4.74 2.0 0.3 0.5 1.0 0.0
Palomino
Underground . . . 4.19 2.8 0.4 4.19 2.8 0.4 0.8 2.1 0.1
Ledbetter
Underground . . . 4.07 12 1.6 4.07 12 1.6 1.2 7.5 0.3
Open Pits 2.58 2.5 0.2 16 .1 2.5 1.3 18.7 2.5 1.5 0.6 2.4 0.0
Haile Total 4.56 2.2 0.3 27.1 4.0 3.5 31.7 3.7 3.8 3.1 4.0 0.4
Didipio
Didipio
Underground 14 .3 1.8 0.8 17.7 1.4 0.8 32.0 1.6 1.6 9.2 1.2 0.4
Open Pit
Stockpiles 13 .2 1.9 0.8 . . . 13.2 1.9 0.8
Didipio Total 27.5 1.8 1.6 17.7 1.4 0.8 45.2 1.7 2.4 9.2 1.2 0.4
Waihi
Martha
Underground 6.33 20 4.1 6.33 20 4.1 2.2 24 1.7
Wharekirauponga 2.63 27 2.3 2.63 27 2.3 2.9 13 1.2
Open Pits 9.72 10 3.2 9.7 10 3.2 3.2 9.6 1.0
Waihi Total 18.7 16 9.6 18.7 16 9.6 8.3 15 3.9
Total Silver 32 .1 1.9 1.9 63.5 6.8 14 95.6 5.1 16 21 7.1 4.7
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Copper
Measured Indicated Measured & Indicated Inferred
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Tonnes
(Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Tonne
s (Mt)
Cu
(%)
Contained
Tonnes
(Mt)
Didipio
Didipio
Underground 14.3 0.43 0.06 17.7 0.33 0.06 32.0 0.37 0.12 9.2 0.3 0.02
Open Pit
Stockpiles 13.2 0.28 0.04 . . . 13.2 0.28 0.04
Didipio Total 27.5 0.36 0.10 17.7 0.33 0.06 45.2 0.35 0.16 9.2 0.3 0.02
Total Copper 27.5 0.36 0.10 17.7 0.33 0.06 45.2 0.35 0.16 9.2 0.3 0.02
Notes:
• Mineral Resources are reported inclusive of Mineral Reserves. Mineral Resources that are not Mineral Reserves do not have dem onstrated
economic viability.
• All resources are based on the following assumptions: metal prices of US$2,450/oz gold, US$4.50/lb copper and US$28.50/oz silver; NZD/USD
exchange rate of 0.60.
• Macraes Open Pit resources are constrained by optimised shells based upon economic assumptions above. Waihi Open Pit resources reported
within a pit design limited by infrastructural considerations. Haile Open Pit resources reported within the reserve design pit.
• Underground resources are reported within volumes guided by conceptual stope designs which are based upon economic assumptions above
and exclude dilution.
• Mineral Resources are reported on a 100% basis. OceanaGold holds an 80% attributable interest in the Didipio Mine.
• Haile
o Open Pit primary cut -off grade is 0.50 g/t Au, while oxide cut -off grade is 0.60 g/t Au. Horseshoe, Ledbetter and Palomino underground
resources at 1.70 g/t Au cut-off.
• Didipio
o 13.2 Mt surface stockpile inventory based on mining cut-off grades at the time ranging from 0.27 g/t to 0.40 AuEq.
o Underground resources reported at a cut-off grade of 0.67 g/t AuEq between the 2,460mRL and 1,800mRL with AuEq cut-off grade based
on presented gold and copper prices. AuEq = Au g/t + 1.27 x Cu %.
• Macraes
o Open Pits cut-off grades between 0.25 g/t Au and 0.40 g/t Au.
o Golden Point underground cut-off grade is 0.97 g/t Au.
• Waihi
o Martha underground cut-off grade is 2.15 g/t Au, Wharekirauponga cut-off grade is 1.70 g/t Au.
o Martha Open Pit cut-off grade is 0.5 g/t Au and Gladstone Open Pit cut-off grade is 0.56 g/t Au.