OCEANAGOLD REPORTS MINERAL RESOURCES AND RESERVES FOR THE YEAR-ENDED 2021 Significantly Increases Wharekirauponga Resources in New Zealand
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31 March 2022 News Release
OCEANAGOLD REPORTS MINERAL RESOURCES AND RESERVES
FOR THE YEAR-ENDED 2021
Significantly Increases Wharekirauponga Resources in New Zealand
(BRISBANE) OceanaGold Corporation (TSX /ASX: OGC) ( “OceanaGold” or the “Company”) is pleased to
provide its annual Resource and Reserve (“R&R”) statement for the year ended 31 December 2021.
HIGHLIGHTS
• Wharekirauponga (“WKP”) Indicated Resource increased 53% from 1.0 million tonnes (“Mt”) at 13.4
g/t gold for 0.42 million ounces (“Moz”) gold including 0.8 Moz silver to 1.5 Mt at 13.5 g/t gold for
0.64 Moz gold including 1.27 Moz silver . Inferred Resources of 2.3 Mt at 9.4 g/t gold for 0.7 Moz of
gold including 1.6 Moz of silver remain , presenting a signific ant opportunity for future resource
conversion.
• Year-on-year increase of 0.31 Moz Measured and Indicated Resources at Waihi , New Zealand, to
13.9 Mt at 4.81 g/t gold for 2.15 Moz gold, due to the conversion of Inferred Resources at Martha
and WKP underground projects.
• Includes first Indicated Resources for the Palomino underground deposit at Haile , U.S.A; 2.3 Mt at
2.79 g/t gold for 0.20 Moz of gold. Inferred Resources of 3.6 Mt at 2.3 g/t gold for 0.26 Moz remain
to be converted.
• Proven and Probable Reserves stood at 131 Mt at 1.33 g/t gold for 5.63 Moz gold, including 8.02
Moz silver and 0.15 Mt copper, a 0.43 Moz gold decrease year on year mainly due to mining
depletion.
• Measured and Indicated Resources, inclusive of Mineral Reserves stood at 199 Mt at 1.43 g/t gold
for 9.13 Moz gold, including 14.4 Moz silver and 0.17 Mt copper, a 0.92 Moz gold decrease year on
year largely due to mining depletion and a reduction in the Round Hill open pit resource at Macraes,
New Zealand.
Scott Sullivan, Acting President and CEO of OceanaGold said, “The recent resource conversion drill results
and updated Indicated and Inferred Resources highlight WKP has the makings of a quality gold mine. The
2021 drill program at WKP saw a very high conversion rate of Inferred Resources to Indicated Resources
which resulted in the significant increase in Indicated Resources from 1.0 Mt at 13.4 g/t gold for 0.42 Moz
gold to 1.5 Mt at 13.5 g/t gold for 0.64 Moz gold including 1.27 Moz silver. The 2022 drill program is building
on these exceptional results with a focus on delivering 1 Moz in the short-term at WKP in support of the up-
coming pre-feasibility study.”
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“Our Reserves and Resources continue to provide a strong foundation for the Company as we steadily
increase our gold production over the next three years. The underground potential at Haile is growing with
the introduction of the Palomino Indicated Resource and our investment in both exploration and resource
conversion drilling. Once we develop the underground infrastructure at Horseshoe we will also have further
opportunity to convert resources.”
RESERVES
As of 31 December 2021, OceanaGold’s Proven and Probable (“P&P”) Reserves stood at 131 Mt at 1.33 g/t
gold for 5.63 Moz of gold, including 8.02 Moz of silver and 0.15 Mt of copper, representing a 0.43 Moz
decrease in gold Reserves year-on-year (see Table 1) largely due to mining depletion.
Table 1: Updated Mineral Reserves (as of 31 December 2021)
• Mineral Reserves constrained to mine designs based upon US$1,500/oz gold, US$3.00/lb copper and US$17/oz silver. New Zealand
reserves use 0.71 NZD/USD exchange rate.
• Reported estimates of contained metal are not depleted for processing losses. For undergro und reserves, cut-offs applied to diluted
grades.
• For Macraes: Frasers Underground cut-off is 1.61 g/t Au while Golden Point Underground cut-off is 1.44 g/t Au.
• For Waihi Underground, the cut-off for previously unmined stoping areas is 2.2 g/t Au, increasing to 2.9 g/t Au for stoping areas in close
proximity to remnant workings.
• For Didipio: old equivalence is based upon the presented gold and copper prices as well as processing recoveries. Gold Equivalent
(AuEq) = Au g/t + 1.37 x Cu%. The 22.2 Mt open pi t stockpile inventory includes 5.3 Mt of low -grade stocks mined at an approximate
0.27 g/t AuEq cut-off. The UG, incremental stopes proximal to development already planned to access main stoping areas are reported
to a lower cut-off of 0.76 g/t AuEq.
• For Haile: Open Pit, the primary cut -off grade is 0.5 g/t Au while oxide material is assigned a 0.6 g/t Au cut-off grade. Horseshoe
Underground, the cut-off is 1.53 g/t Au, with adjacent lower grade stopes included in the reserves based on an incremental stope cut-off
grade of 1.37 g/t Au.
PROJECT
AREA Cut-Off Mt Au g/t Ag g/t Cu % Mt Au g/t Ag g/t Cu % Mt Au g/t Ag g/t Cu % Au Moz Ag Moz Cu Mt
MACRAES Open Pit 0.40 g/t Au 15.6 0.87 . . 19.9 0.85 . . 35.5 0.86 . . 0.98 . .
MACRAES Underground 1.44g/t & 1.61g/t Au 0.33 2.23 . . 3.21 1.88 . . 3.54 1.91 . . 0.22 . .
BLACKWATER
WAIHI Open Pit . . . . . . . . . . . . . . .
WAIHI Underground 2.20 g/t & 2.90 g/t Au 0.00 4.50 14.5 . 4.77 4.20 14.53 . 4.77 4.20 14.5 . 0.64 2.23 .
NEW ZEALAND 15.9 0.90 27.9 1.54 43.8 1.31 1.84 2.23 .
DIDIPIO Open Pit 0.40 g/t AuEq 22.2 0.34 1.99 0.29 . . . . 22.2 0.34 1.99 0.29 0.24 1.42 0.07
DIDIPIO Underground 0.76 g/t & 1.16 g/t AuEq 12.7 1.83 1.98 0.46 7.33 1.03 1.44 0.34 20.0 1.54 1.79 0.42 0.99 1.15 0.08
PHILIPPINES 34.9 0.88 7.3 1.03 42.2 0.91 1.23 2.57 0.15
HAILE Open Pit 0.50 g/t & 0.60 g/t Au 4.4 1.26 1.98 . 37.6 1.62 2.44 . 42.0 1.58 2.39 . 2.14 3.23 .
Haile Underground 1.53 g/t Au . . . . 3.4 3.78 . . 3.4 3.78 . . 0.42 . .
USA 4.4 1.26 41.0 1.80 45.4 1.75 2.55 3.23 .
TOTAL 55.2 0.92 76.2 1.63 131 1.33 5.63 8.02 0.15
PROVEN PROBABLE PROVEN & PROBABLE
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Figure 1: Changes to Proven & Probable Mineral Reserves
Note: “Depletions” refer to 2021 mining depletion, “Reserve Model Updates” represent drilling -related changes to reserve changes (growth or
reductions) or initial reserve declarations, “Economic Factors” relate to mining cost and cut-off grade changes, “Adjustments” relate to changes
in mining method assumptions (e.g. open pit versus underground).
RESOURCES
As of 31 December 2021, OceanaGold’s Measured and Indicated (“M&I”) Resources stood at 199 Mt at 1.43
g/t gold for 9.13 Moz of gold, including 14 Moz of silver and 0.17 Mt of copper (Table 2). Mineral Resources
are reported inclusive of Mineral Reserves.
Table 2: Updated Mineral Resources – Measured and Indicated (as of 31 December 2021)
• Mineral Resources include Mineral Reserves. There is no certainty that Mineral Resources, not included as Mineral Reserves, will convert
to Mineral Reserves. All resources based upon US$1,700/oz gold, US$3.50/lb copper and US$17/oz silver and a 0.71 NZD/USD exchange
rate for New Zealand resources.
• Open pit resources constrained to shells based upon economic assumptions above. Waihi open pit resources reported within a pit design
limited by infrastructural considerations. Underground resources for Didipio, Horseshoe at Haile, and Frasers and Golden Point at Macraes,
are reported within volumes guided by optimised stope designs . Underground resources for Palomino at Haile and Martha and WKP at
Waihi are reported within optimised stope designs based upon economic assumptions above.
• For Macraes: Frasers Underground at a 1.25 g/t Au cut-off and Golden Point Underground at a 1.34 g/t Au cut-off.
• For Waihi: Martha Underground at a 2.15 g/t Au cut-off, WKP at a 2.5 g/t Au cut-off, Martha open pit at a 0.5 g/t Au cut-off and Gladstone
open pit at a 0.56 g/t Au cut -off. Martha Underground M&I Resources 5.8 Mt at 5.93 g/t Au for 1.11 Moz. WKP M&I resources 1.5 Mt at
13.5 g/t Au for 0.64 Moz.
• For Didipio open pit, only stockpiles remain. These include 5.3 Mt of low grade at 0.27 g/t AuEq. Underground resources reported between
the 2,460mRL and 1,980mRL with AuEq cut-off based on presented gold and copper prices. AuEq = Au g/t + 1.39 x Cu %.
• For Haile OP primary cut-off 0.45 g/t Au, oxide cut-off 0.55 g/t Au. Palomino Resources at a 1.39 g/t Au cut-off and Horseshoe Resources
at a 1.35 g/t Au cut-off, the difference due to slightly lower metallurgical recovery at Palomino.
PROJECT
AREA Cut-Off Mt Au g/t Ag g/t Cu % Mt Au g/t Ag g/t Cu % Mt Au g/t Ag g/t Cu % Au Moz Ag Moz Cu Mt
MACRAES Open Pit 0.30 g/t Au 21.7 0.88 . . 56.0 0.75 . . 77.7 0.79 . . 1.96 . .
MACRAES Underground 1.25 g/t / 1.34 g/t Au 0.7 2.98 . . 6.1 2.48 . . 6.9 2.53 . . 0.56 . .
BLACKWATER
WAIHI Open Pit 0.5 g/t / 0.56 g/t Au . . . . 6.6 1.86 13.6 . 6.6 1.86 13.6 . 0.40 2.89 .
WAIHI Underground 2.15 g/t / 2.50 g/t Au 0.00 4.50 15.3 . 7.3 7.45 21.1 . 7.3 7.45 21.1 . 1.76 4.99 .
NEW ZEALAND 22.4 0.95 76.1 1.63 98.5 1.48 4.68 7.87 .
DIDIPIO Open Pit 0.40 g/t AuEq 22.9 0.33 1.98 0.29 . . . . 22.9 0.33 1.98 0.29 0.25 1.46 0.07
DIDIPIO Underground 0.67 g/t AuEq 12.6 1.94 2.09 0.49 12.3 0.95 1.46 0.35 24.9 1.45 1.78 0.42 1.16 1.42 0.10
PHILIPPINES 35.5 0.90 12.3 0.95 47.8 0.92 1.41 2.88 0.17
HAILE Open Pit 0.45 g/t / 0.55 g/t Au 4.5 1.22 1.96 . 43.0 1.55 2.41 . 47.5 1.52 2.37 . 2.32 3.61 .
Haile Underground 1.35 g/t & 1.39 g/t Au . . . . 5.5 4.12 . . 5.5 4.12 . . 0.73 . .
USA 4.5 1.22 48.4 1.84 52.9 1.79 3.04 3.61 .
TOTAL 62.4 0.94 137 1.65 199 1.43 9.13 14.4 0.17
MEASURED INDICATED MEASURED & INDICATED
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On a consolidated basis, OceanaGold’s M&I Resources decreased by 0.92 Moz (Figure 2). Decreases were
mainly due to mining depletion across the Company’s operations as well as the reduction in the reportable
Round Hill Open Pit Resource at Macraes following the completion of an internal prefeasibility -level study
(see section on Macraes). The decreases were partially offset by gains due to resource conversion drilling -
related resource updates for Palomino at Haile, WKP and Martha at Waihi, and Golden Point at Macraes.
Figure 2: Changes to Measured & Indicated Mineral Resources
Note: “Depletions” refer to 2021 mining depletion, “Resource Model Updates” represent drilling-related resource changes (growth or reductions)
or initial resource declarations, “Economic Factors” relate to mining cost and cut-off grade changes, “Adjustments” relate to changes in mining
method assumptions (e.g. open pit versus underground).
As of 31 December 2021, OceanaGold’s Inferred Resources stood at 62 Mt at 1. 9 g/t gold for 3.9 Moz of
gold, including 7.5 Moz of silver and 0.04 Mt of copper ( Table 3). Year on year this represents a 0.5 Moz
decrease mainly due to the conversion of Inferred Resources at Waihi, Macraes and Haile.
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Table 3: Updated Mineral Resources – Inferred Resource Statement (as of 31 December 2021)
See footnotes for Table 2.
Figure 3: Changes to Inferred Resources
NEW ZEALAND
Waihi
Underground P&P Reserves at Waihi stood at 4.77 Mt at 4.2 g/t gold for 0.64 Moz gold including 2.23 Moz
silver with reserve growth at Martha offsetting mining depletion (Figure 4). No open pit reserves are reported.
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Figure 4: Changes to Waihi Proven & Probable Mineral Reserves
The Waihi underground M&I Resources stood at 7.3 Mt at 7.45 g/t gold for 1.76 Moz gold, including 4.99
Moz silver and open pit M&I Resources stood at 6.6 Mt at 1.86 g/t gold for 0.40 Moz gold, including 2.89
Moz silver (Figure 5). Combined underground and open pit M&I Resources totalled 13.9 Mt at 4.81 g/t gold
for 2.15 Moz gold, including 7.87 Moz silver, representing a year -on-year increase of 0.31 Moz due to the
conversion of Inferred Resources at WKP and Martha, respectively:
• Martha Indicated Resources 5.8 Mt at 5.93 g/t gold for 1.11 Moz gold including 3.71 Moz silver.
• Martha Inferred Resources 2.9 Mt at 5.1 g/t gold for 0.47 Moz gold including 2.0 Moz silver.
• WKP Indicated Resources 1.5 Mt at 13.5 g/t gold for 0.64 Moz gold including 1.27 Moz silver.
• WKP Inferred Resources of 2.3 Mt at 9.4 g/t gold for 0.7 Moz gold including 1.6 Moz silver.
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Figure 5: Changes to Waihi Measured & Indicated Mineral Resources
Underground Resources at Waihi
During 2022, the Company expects to drill 21,235 metres at Martha Underground (“MUG”) with a focus on
resource conversion (11,875 metres) and resource extension (9,360 metres). This programme is designed
to improve resource confidence and to test opportunities proximal to mine design.
WKP is located in the upper North Island of New Zealand, approximately 10 kilometers north of the Martha
Underground and existing Waihi facilities. WKP is a rhyolite-hosted, low sulphidation epithermal quartz vein
system. The rhyolites have undergone pervasive hydrothermal alteration, often with complete replacement
by quartz and adularia with minor illite and/or smectite clay. Gold mineralisation occurs in association with
quartz veining developed along two types of s tructurally controlled vein arrays. The principal veins occupy
laterally continuous, NE trending (025 -47°), moderately dipping (60 -65°) district-scale graben step faults,
reaching up to 10 metres in width. Subsidiary, extensional veins (1 -100 centimetres wide) are developed
between or adjacent to the principal fault hosted veins.
The Company expects to drill 16,775 metres at WKP primarily on resource conversion in 2022 to increase
the Indicated Resources in support of the prefeasibility study scheduled for release in 2023.
The Waihi Inferred Resources stood at 1.5 Moz gold, a small decrease year on year (Figure 6). The Inferred
Resources at Waihi present a significant opportunity for future conversion.
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Figure 6: Changes to Waihi Inferred Resources
Resource Model Performance
Table 4 summarizes the Waihi underground resource model reconciliations for 2018 to 2021. Reserve
modifying factors have been applied for ore loss and dilution. The resource model to mill -adjusted mine
reconciliation data from various ore sources for the four years to 2021 show variable performance from year
to year with a reasonable long -term average performance; +8% for tonnes, -2% for grade and +7% for
contained gold.
Table 4: Waihi Underground Model to Mill-Adjusted Mine Reconciliation
Year Resource Model (1), (2) Mine (Mill-Reconciled) Reconciliation Ratios
Mt grade Moz Mt grade Moz Mt grade Moz
2021(3) 0.22 4.19 0.030 0.29 3.24 0.030 1.31 0.77 1.01
2020 0.13 5.80 0.024 0.13 5.30 0.022 1.01 0.91 0.92
2019 0.43 5.52 0.077 0.43 5.60 0.078 1.00 1.01 1.01
2018 0.40 6.20 0.08 0.43 6.80 0.095 1.07 1.10 1.18
Total 1.19 5.53 0.211 1.29 5.44 0.225 1.08 0.98 1.07
1. Underground models include reserve modifying factors for ore loss and dilution
2. Current resource models used
3. 2021 mining included Inferred Resources of 0.063 Mt at 3.23 g/t for 7 koz. These Inferred Resources are not included in the reconciliation
as they are not considered to have sufficient geological confidence for detailed mine planning.
Mining during 2018, 2019 and 2020 was largely on the Correnso vein for which reconciliation was in line with
expectations. The reconciliatio n for 2021 largely represents mining at MUG and shows greater variance.
However, the mined MUG tonnage to -date is not considered to be large or geologically representative,
reflecting less than 5% of the total MUG reserve. The majority of ore mined at MUG to-date has been
development ore rather than stoping ore, and with limited grade control coverage. That said, the greater
variance in reconciliation performance is in areas with higher geological and grade complexity, particularly