Resources and Reserves

Mineral Reserves
The Proven and Probable Mineral Reserves estimates as at December 31, 2024 are presented in Table 1 below.
Table 1: Proven and Probable Reserves as at December 31 , 2024
Gold |
Proven |
Probable |
Proven & Probable |
|||||||
Tonnes |
Au |
Contained |
Tonnes |
Au |
Contained |
Tonnes |
Au |
Contained |
Cut-off grade |
|
Horseshoe underground |
1.12 |
4.72 |
0.17 |
2.66 |
4.49 |
0.38 |
3.78 |
4.56 |
0.55 |
1.79 g/t Au |
Palomino underground |
– |
– |
– |
4.33 |
2.73 |
0.38 |
4.33 |
2.73 |
0.38 |
1.79 g/t Au |
Haile open pits |
4.12 |
1.44 |
0.19 |
30.8 |
1.53 |
1.52 |
34.9 |
1.52 |
1.71 |
0.50 g/t & 0.60 g/t Au |
Haile Total |
5.25 |
2.14 |
0.36 |
37.8 |
1.88 |
2.28 |
43.0 |
1.91 |
2.64 |
|
Didipio underground |
15.0 |
1.40 |
0.67 |
14.8 |
0.85 |
0.40 |
29.8 |
1.12 |
1.08 |
0.76 g/t & 1.16 g/t AuEq |
Didipio open pit stockpile |
15.8 |
0.31 |
0.16 |
– |
– |
– |
15.8 |
0.31 |
0.16 |
0.40 g/t AuEq |
Didipio Total |
30.8 |
0.84 |
0.83 |
14.8 |
0.85 |
0.40 |
45.7 |
0.84 |
1.23 |
|
Macraes underground |
0.16 |
1.86 |
0.01 |
3.81 |
1.79 |
0.22 |
3.96 |
1.79 |
0.23 |
1.20 g/t & 1.01 g/t Au |
Macraes open pits |
11.5 |
0.58 |
0.22 |
8.02 |
0.70 |
0.18 |
19.5 |
0.63 |
0.40 |
0.30 g/t Au |
Macraes Total |
11.6 |
0.60 |
0.22 |
11.8 |
1.05 |
0.40 |
23.5 |
0.83 |
0.62 |
|
Martha underground |
– |
– |
– |
4.13 |
3.80 |
0.50 |
4.13 |
3.80 |
0.50 |
2.60 g/t & 3.10 g/t Au |
Wharekirauponga |
– |
– |
– |
4.10 |
9.20 |
1.21 |
4.10 |
9.20 |
1.21 |
2.40 g/t & 1.40 g/t Au |
Waihi Total |
– |
– |
– |
8.23 |
6.49 |
1.72 |
8.23 |
6.49 |
1.72 |
|
Total Gold |
47.7 |
0.92 |
1.42 |
72.7 |
2.06 |
4.80 |
120 |
1.61 |
6.22 |
Silver |
Proven |
Probable |
Proven & Probable |
||||||
Tonnes |
Ag |
Contained |
Tonnes |
Ag |
Contained |
Tonnes |
Ag |
Contained |
|
Horseshoe underground |
1.12 |
1.8 |
0.1 |
2.66 |
2.0 |
0.2 |
3.78 |
2.0 |
0.2 |
Palomino underground |
– |
– |
– |
4.33 |
2.5 |
0.3 |
4.33 |
2.5 |
0.3 |
Haile open pits |
4.12 |
1.8 |
0.2 |
30.8 |
2.3 |
2.3 |
34.9 |
2.3 |
2.6 |
Haile Total |
5.25 |
1.8 |
0.3 |
37.8 |
2.3 |
2.8 |
43.0 |
2.3 |
3.1 |
Didipio underground |
15.0 |
1.8 |
0.8 |
14.8 |
1.3 |
0.6 |
29.8 |
1.5 |
1.5 |
Didipio open pit stockpile |
15.8 |
2.0 |
1.0 |
– |
– |
– |
15.8 |
2.0 |
1.0 |
Didipio Total |
30.8 |
1.9 |
1.9 |
14.8 |
1.3 |
0.6 |
45.7 |
1.7 |
2.5 |
Martha underground |
– |
– |
– |
4.13 |
16 |
2.2 |
4.13 |
16 |
2.2 |
Wharekirauponga |
– |
– |
– |
4.10 |
16 |
2.1 |
4.10 |
16 |
2.1 |
Waihi Total |
– |
– |
– |
8.23 |
16 |
4.3 |
8.23 |
16 |
4.3 |
Total Silver |
36.1 |
1.9 |
2.2 |
60.8 |
4.0 |
7.8 |
96.9 |
3.2 |
9.9 |
Copper |
Proven |
Probable |
Proven & Probable |
||||||
Tonnes |
Cu |
Contained |
Tonnes |
Cu |
Contained |
Tonnes |
Cu |
Contained |
|
Didipio underground |
15.0 |
0.40 |
0.1 |
14.8 |
0.31 |
0.05 |
29.8 |
0.36 |
0.11 |
Didipio open pit stockpile |
15.8 |
0.29 |
0.0 |
– |
– |
– |
15.8 |
0.29 |
0.05 |
Didipio Total |
30.8 |
0.34 |
0.1 |
14.8 |
0.31 |
0.05 |
45.7 |
0.33 |
0.15 |
Total Copper |
30.8 |
0.34 |
0.1 |
14.8 |
0.31 |
0.05 |
45.7 |
0.33 |
0.15 |
Notes:
- Mineral Reserves estimates have been prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and are shown on a 100% basis. All tonnage, grade and contained metal content estimates have been rounded; rounding may result in apparent summation differences between tonnes, grade, and contained metal content.
- Mineral Reserves are defined by mine designs based upon the following assumptions: metal prices of US$1,750/oz gold, US$3.50/lb copper and US$20/oz silver; NZD/USD exchange rate of 0.61.
- Reported estimates of contained metal are not depleted for processing losses.
- For underground reserves, cut-offs applied to diluted grades.
Haile:
-
- 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. The Mineral Reserves estimate for Haile open pit has been verified and approved by, or is based on information prepared by, or under the supervision of, D. Londoño, our Executive Vice President and Chief Operating Officer Americas and a qualified person for the purposes of NI 43-101.
- Underground: the cut-off grade is 1.79 g/t Au, with adjacent lower grade stopes included in the reserves estimate based on an incremental stope cut-off grade of 1.69 g/t Au. The Mineral Reserves estimate for Haile underground has been verified and approved by, or is based upon information prepared by, or under the supervision of, B. Drury, our Superintendent – Engineering Services (Underground), Haile and a qualified person for the purposes of NI 43-101.
Didipio:
-
- Gold equivalence (AuEq) is based upon the presented gold and copper prices as well as processing recoveries. AuEq = Au g/t + 1.37 x Cu%.
- The 15.8 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.
- Underground: 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.
- The Mineral Reserves estimate for Didipio has been verified and approved by, or is based upon information prepared by, or under the supervision of, P. Jones, our Head of Underground Mining and a qualified person for the purposes of NI 43-101.
Macraes:
-
- The Mineral Reserves estimate for Macraes open pits has been verified and approved by, or is based on information prepared by, or under the supervision of, K. Madambi, our Manager – Technical Services & Projects, Macraes and a qualified person for the purposes of NI 43-101.
- Golden Point underground cut-off grade is 1.20 g/t Au. Stopes for which access already exists are reported to a lower cut-off grade of 1.01 g/t. The Mineral Reserves estimate for Macraes underground has been verified and approved by, or is based upon information prepared by, or under the supervision of, E. Leslie, our Group Mining Engineer and a qualified person for the purposes of NI 43-101.
Waihi:
-
- Martha underground cut-off grade for previously unmined stoping areas is 2.60 g/t Au, increasing to 3.0 g/t Au for stoping areas in close proximity to remnant workings, while development cut-off grade is 0.90 g/t Au. The Mineral Reserves estimate for each of Martha underground and Wharekirauponga underground has been verified and approved by, or is based on information prepared by, or under the supervision of, D. Townsend, our Manager – Mining (Underground), Waihi and a qualified person for the purposes of NI 43-101.
- Wharekirauponga underground cut-off grade for stopes is 2.40 g/t Au, while development cut-off grade is 1.40 g/t Au. The Mineral Reserves estimate for Wharekirauponga underground has been verified and approved by, or is based upon information prepared by, or under the supervision of, E. Leslie a qualified person for the purposes of NI 43-101.
Mineral Resources
The Measured, Indicated and Inferred Mineral Resource estimates (inclusive of Mineral Reserves) as at December 31, 2024 are presented in Table 2 below.
Table 2: Measured and Indicated Resources as at December 31 , 2024
Measured |
Indicated |
Measured & Indicated |
Inferred |
Cut-off grade |
|||||||||
Gold |
Tonnes |
Au |
Contained |
Tonnes |
Au |
Contained |
Tonnes |
Au |
Contained |
Tonnes |
Au |
Contained |
|
Horseshoe underground |
1.47 |
4.90 |
0.23 |
3.93 |
4.53 |
0.57 |
5.40 |
4.63 |
0.80 |
0.8 |
3.7 |
0.09 |
1.50 g/t Au |
Palomino underground |
– |
– |
– |
4.72 |
3.18 |
0.48 |
4.72 |
3.18 |
0.48 |
1.1 |
2.3 |
0.08 |
1.50 g/t Au |
Haile open pits |
4.14 |
1.44 |
0.19 |
30.8 |
1.53 |
1.52 |
34.9 |
1.52 |
1.71 |
2.2 |
0.8 |
0.06 |
0.50 g/t & 0.60 g/t Au |
Haile Total |
5.61 |
2.35 |
0.42 |
39.4 |
2.03 |
2.57 |
45.1 |
2.07 |
2.99 |
4.1 |
1.7 |
0.2 |
|
Didipio underground |
15.6 |
1.57 |
0.79 |
17.6 |
0.88 |
0.50 |
33.2 |
1.20 |
1.28 |
6.4 |
0.8 |
0.2 |
0.67 g/t AuEq |
Didipio open pit stockpile |
15.8 |
0.31 |
0.16 |
– |
– |
– |
15.8 |
0.31 |
0.16 |
– |
– |
– |
0.27 g/t AuEq |
Didipio Total |
31.4 |
0.93 |
0.94 |
17.6 |
0.88 |
0.50 |
49.0 |
0.92 |
1.44 |
6.4 |
0.8 |
0.2 |
|
Macraes underground |
0.30 |
2.34 |
0.02 |
7.91 |
2.23 |
0.57 |
8.22 |
2.23 |
0.59 |
3.0 |
1.7 |
0.2 |
0.90 g/t Au |
Macraes open pits |
13.7 |
0.66 |
0.29 |
25.1 |
0.69 |
0.56 |
38.8 |
0.68 |
0.85 |
23 |
0.7 |
0.5 |
0.30 g/t Au |
Macraes Total |
14.0 |
0.69 |
0.31 |
33.1 |
1.06 |
1.12 |
47.1 |
0.95 |
1.44 |
26 |
0.8 |
0.7 |
|
Martha underground |
– |
– |
– |
6.71 |
5.18 |
1.12 |
6.71 |
5.18 |
1.12 |
2.4 |
4.5 |
0.4 |
2.15 g/t Au |
Wharekirauponga |
– |
– |
– |
2.42 |
17.9 |
1.40 |
2.42 |
17.9 |
1.40 |
1.9 |
9.8 |
0.6 |
2.10 g/t Au |
Waihi open pits |
– |
– |
– |
9.72 |
1.76 |
0.55 |
9.72 |
1.76 |
0.55 |
3.1 |
1.8 |
0.2 |
0.50 g/t & 0.56 g/t Au |
Waihi Total |
– |
– |
– |
18.9 |
5.06 |
3.06 |
18.9 |
5.06 |
3.06 |
7.4 |
4.7 |
1.1 |
|
Total Gold |
51.0 |
1.02 |
1.68 |
109 |
2.07 |
7.26 |
160 |
1.74 |
8.94 |
44 |
1.6 |
2.2 |
Measured |
Indicated |
Measured & Indicated |
Inferred |
|||||||||
Silver |
Tonnes |
Ag |
Contained |
Tonnes |
Ag |
Contained |
Tonnes |
Ag |
Contained |
Tonnes |
Ag |
Contained |
Horseshoe underground |
1.47 |
1.9 |
0.09 |
3.93 |
2.1 |
0.3 |
5.4 |
2.1 |
0.4 |
0.8 |
2.0 |
0.05 |
Palomino underground |
– |
– |
– |
4.72 |
2.7 |
0.4 |
4.7 |
2.7 |
0.4 |
1.1 |
2.0 |
0.07 |
Haile open pits |
4.14 |
1.4 |
0.18 |
30.8 |
2.3 |
2.3 |
35 |
2.2 |
2.5 |
2.2 |
2.2 |
0.2 |
Haile Total |
5.61 |
1.5 |
0.27 |
39.4 |
2.4 |
3.0 |
45 |
2.3 |
3.3 |
4.1 |
2.1 |
0.3 |
Didipio underground |
15.6 |
1.9 |
1.0 |
17.6 |
1.4 |
0.8 |
33.2 |
1.6 |
1.7 |
6.4 |
1.1 |
0.2 |
Didipio open pit stockpile |
15.8 |
2.0 |
1.0 |
– |
– |
– |
15.8 |
2.0 |
1.0 |
– |
– |
– |
Didipio Total |
31.4 |
2.0 |
2.0 |
17.6 |
1.4 |
0.8 |
49.0 |
1.7 |
2.7 |
6.4 |
1.1 |
0.2 |
Martha underground |
– |
– |
– |
6.71 |
21 |
4.4 |
6.7 |
21 |
4.4 |
2.4 |
22 |
1.7 |
Wharekirauponga |
– |
– |
– |
2.42 |
28 |
2.2 |
2.4 |
28 |
2.2 |
1.9 |
15 |
0.9 |
Waihi open pits |
– |
– |
– |
9.72 |
10 |
3.2 |
9.7 |
10 |
3.2 |
3.1 |
9.6 |
1.0 |
Waihi Total |
– |
– |
– |
18.9 |
16 |
9.8 |
19 |
16 |
9.8 |
7.4 |
15 |
3.6 |
Total Silver |
37.0 |
1.88 |
2.2 |
75.9 |
5.6 |
14 |
113 |
4.4 |
16 |
18 |
7.1 |
4.1 |
Measured |
Indicated |
Measured & Indicated |
Inferred |
|||||||||
Copper |
Tonnes |
Cu |
Contained |
Tonnes |
Cu |
Contained |
Tonnes |
Cu |
Contained |
Tonnes |
Cu |
Contained |
Didipio underground |
15.6 |
0.44 |
0.07 |
17.6 |
0.32 |
0.056 |
33.2 |
0.38 |
0.12 |
6.4 |
0.3 |
0.02 |
Didipio open pit stockpile |
15.8 |
0.29 |
0.05 |
– |
– |
– |
15.8 |
0.29 |
0.046 |
– |
– |
– |
Didipio Total |
31.4 |
0.36 |
0.11 |
17.6 |
0.32 |
0.056 |
49.0 |
0.35 |
0.17 |
6.4 |
0.3 |
0.02 |
Total Copper |
31.4 |
0.36 |
0.11 |
17.6 |
0.32 |
0.056 |
49.0 |
0.35 |
0.17 |
6.4 |
0.3 |
0.02 |
Notes:
- Mineral Resources estimates have been prepared in accordance with NI 43-101 and are shown on a 100% basis. All tonnage, grade and contained metal content estimates have been rounded; rounding may result in apparent summation differences between tonnes, grade, and contained metal content.
- Mineral Resources are reported inclusive of Mineral Reserves. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. It is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration, however, there is no guarantee that all or any part of an Inferred Mineral Resource will ever be upgraded to a higher category.
- All resources are based on the following assumptions: metal prices of US$1,950/oz gold, US$4.0/lb copper and US$23/oz silver; and NZD/USD exchange rate of 0.61.
- Open pit resources are constrained by shells based upon economic assumptions above.
- Underground resources are reported within volumes guided by optimized stope designs based upon economic assumptions above and exclude dilution.
Haile:
- Open pit resources reported within reserve design pit.
- Open pit primary cut-off grade is 0.50 g/t Au, while oxide cut-off grade is 0.60 g/t Au. Palomino resources and Horseshoe resources cut-off grade is 1.50 g/t Au.
- The Mineral Resources estimates for each of Haile open pit and Haile underground have been verified and approved by, or are based on information prepared by, or under the supervision of, J. Moore, our Head of Resource Development and a qualified person for the purposes of NI 43-101.
Didipio:
- The 15.8 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.
- Underground resources reported at a cut-off grade of 0.67 g/t AuEq between the 2,460mRL and 1,965mRL with AuEq cut-off grade based on presented gold and copper prices. AuEq = Au g/t + 1.39 x Cu %.
- The Mineral Resources estimate for Didipio has been verified and approved by, or is based on information prepared by, or under the supervision of, J. Moore, our Head of Resource Development and a qualified person for the purposes of NI 43-101.
Macraes:
- Open pits cut-off grade is 0.3 g/t Au. The Mineral Resources estimate for Macraes open pits has been verified and approved by, or is based on information prepared by, or under the supervision of, J. Moore, our Head of Resource Development and a qualified person for the purposes of NI 43-101.
- Golden Point underground cut-off grade is 0.9 g/t Au. The Mineral Resources estimate for Macraes underground has been verified and approved by, or is based on information prepared by, or under the supervision of, M. Grant, our Senior Geologist – Resource Development, Macraes and a qualified person for the purposes of NI 43-101.
Waihi:
- Waihi open pit resources reported within a pit design limited by infrastructure considerations.
- Martha underground cut-off grade is 2.15 g/t Au, Wharekirauponga cut-off grade is 2.10 g/t Au, 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.
- The Mineral Resources estimate for each of Wharekirauponga underground, Martha underground, Gladstone Open Pit and Martha Open Pit has been verified and approved by, or is based on information prepared by, or under the supervision of, L. Crawford-Flett, our Manager – Exploration and Geology, Waihi and a qualified person for the purposes of NI 43-101.
For more information and cautionary notes regarding Mineral Reserves and Mineral Resources estimates, please see OceanaGold news release titled “OceanaGold Reports Mineral Reserves and Resources for the Year Ended 2024”, dated February 19, 2025.