OceanaGold prepares to ramp up Didipio as new Sandvik fleet starts arriving
The OceanaGold Didipio gold-copper mine in the Philippines has confirmed a new Sandvik equipment order as the site ramps up underground production from 1.7 Mt/y to 2.5 Mt/y. The package includes two LH621i loaders, three TH663i trucks, and 1 rebuilt TH663 truck. These units support Didipio’s goals for operational excellence, sustainability, and lower cost per tonne. The underground mining fleet is owned by OceanaGold (Philippines), Inc (OGPI), with the majority of the equipment acquired from Sandvik. OGPI has a contract with Sandvik for the provision of supplies and services.
As outlined in the updated Technical Report for Didipio filed March 27, 2026, the long hole open stoping method (LHOS) is employed underground at the Didipio mine for the extraction of underground ore. LHOS allows for a high degree of mechanisation and good mining selectivity, high mining recovery and scheduling flexibility. A primary/secondary stoping sequence is utilised where primary stopes are separated by a secondary stope. Extraction of the secondary stope can only occur after the two immediately filled adjacent primary stopes have been mined, backfilled and have time to cure.
Stope dimensions vary depending on their location within the orebody. On the eastern side of the orebody in the monzonite zone, stopes are up to 60 m high whereas in the breccia zone on the western side of the orebody, more conservative stope dimensions are adopted due to poorer ground conditions. These include, where required, significant stope crown support to prevent unravelling. Paste backfill is utilised for backfilling of all stope voids. A top-down sequence beneath paste fill is employed.
The Western Breccia zone has been subjected to recent studies and optimization due to poor ground conditions. A small section of bottom-up mining and smaller stope sizes planned to mitigate any potential unravelling due to these conditions has been trialled with good success. The extraction sequence in the Western Breccia is geotechnically constrained and planned to be mined slower than previous versions of the mining schedule resulting in a diversion of a portion of ounces from this zone to later years of the Life of Mine (LoM). This strategy strives to provide a safe and sustainable production sequence that maximizes metal recovery.
The current decline face has advanced to the 2133 mRL. Approximately 47 km of lateral development is required in the mining schedule which includes capital development in the lower part of the mine to establish production levels down to the 1980 mRL and associated active dewatering and critical pumping infrastructure including Capital Pump Station 1 (CPS1).
Each underground level at Didipio is designed to have its own ventilation circuit and ventilated through the overall pull exhausting type ventilation system. Fresh air enters production levels via the decline and internal FAR’s. This air is exhausted to the surface via two dedicated RAR’s on the east and west side of each level.
Lateral development rates of just under 8 km a year are required from 2027 to 2029 before tailing off once capital development is complete at depth in 2030 per the current schedule. Additional capital development will be required if drill conversion programs in Panel 3 and 4 are successful, however are not considered in current mine schedules or capital cost estimates for this current report.
Historic haulage rates from the Didipio underground has achieved annual rates exceeding 1.6 Mt/y and instantaneous rates in excess of 2.5 Mt/y but these have not been sustained due to various interruptions to production, including poor performance of Breccia stopes on the western side of the orebody and inundation of the lower levels of the mine following typhoons in 2024, with the lower levels of the mine remediated in late 2025.
A Pre-Feasibility Study (PFS) has been undertaken to assess increased mining rates from the underground mine. Results from the study show that rates in excess of 2.5 Mt/y can be achieved when additional mining fronts at depth are available and supported by upgrades to existing pumping, electrical and paste fill infrastructure.
Planned production rates from the underground in 2026 is 1.9 Mt/y, increasing to 2.1 Mt/y in 2027, 2.2 Mt/y in 2028, and 2.6 Mt/y in 2029, in line
with the commissioning of planned dewatering and primary ventilation infrastructure to support the increased mining rates. Annual underground gold mined ranges from 82,000 oz to 99,000 oz from 2026 to 2036, before tailing off in 2037 (19,000 oz). Annual copper mined ranges from 8,000 t to 10,000 t before similarly tailing off in 2037 (2,000 t).
From 2028 onwards the mine will utilise 11 underground mining trucks and seven LHDs along with three production drills. The largest development fleet will be required from 2026 to 2029 including five twin boom development jumbo drills and 14 ancillary equipment units. The mine will also use a cable bolter and Rhino raiseborer. Anticipated daily bogging rates will be 1,500 t per LHD with haulage of 1,200,000 TKM/year/truck.
The Didipio underground schedule is based on productivity assumptions using a combination of historical rates achieved at Didipio and first principles based on expansion of the mine at depth and associated infrastructure that will facilitate an increase in throughput. The schedule was completed using Deswik mine planning software and is based on operations occurring 365 days/year, seven days/week, with two 12-hour shifts each day.
Average lateral development rates of 615 m/month in 2026, and 660 m/month in 2027, 2028 and 2029 are required to open additional stoping fronts at depth in Panels 2 and 3. Increased lateral development rates will be achieved through several initiatives including an additional jumbo drill being mobilised to the fleet in 2026, an increase in equipment availability through a targeted fleet management strategy, quality control to maximize advance per cut, and an increase in available
headings.
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