Multiple Ore-Grade Intercepts Drilled For Horseshoe Extension At Haile

VANCOUVER - OceanaGold Corporation reported on exploration and resource conversion drilling for Haile and Didipio.

Gerard Bond, President & CEO, said "We are off to an excellent start to the year with our exploration and resource conversion programs with results continuing to reinforce the growth potential we see within our existing mine footprints. Results from the Horseshoe Extension target at Haile, outside of existing resources, reflect the first drilling we have completed into this target from underground. We have encountered similar grades and widths to the Horseshoe orebody, and the Horseshoe Extension target is close to planned future underground development. Results at Didipio continue to extend mineralization at depth and we have now drilled a second hole below the existing resource as a follow-up to last year's drilling. This result extends known mineralization a further ~150 metres at depth into Panel 4, and a total of ~200 metres below the current inferred resource. Lastly, I am delighted we are now drilling at the Napartan regional target, located 9 kilometres northwest of Didipio, with two holes of a 2,500 metre program now completed, awaiting assay results."

Resource conversion and extensional drilling from Horseshoe Underground continues with 2,142 metres completed of a planned 10,605 metres this year. The results from 8 holes drilled at Horseshoe Extension target and lower Horseshoe at the end of 2023 and the beginning of 2024 have been received. Highlights from this drilling include 34.9 m @ 7.60 g/t Au from hole UGD0026 targeting conversion of the lower Horseshoe Inferred resource (result received after data cut-off for 2023 end of year Reserve and Resource model update) and 39.3 m @ 5.8 g/t Au from hole UGD0044, among others, targeting resource growth at Horseshoe Extension. Horseshoe Extension is a zone of mineralization located approximately 200 metres southwest of the Horseshoe orebody with similar plunge on the southern limb of the northeastern striking antiform. Mineralization is of the same character as Horseshoe, occurring along a mineralized metasediment/metavolcanic contact. Continuity of the lower Horseshoe Extension mineralization is confirmed.

Drilling in 2024 will continue to target the Horseshoe Extension as more optimal drill locations become available with more underground development and will also target infill drilling of inferred mineralization at lower Horseshoe. Since the February, 6,763 metres of extensional and resource conversion drilling in twenty-three holes has been completed from Didipio underground. Extensional drilling has been achieved by extending resource conversion drill holes beyond the resource shell to the north, northeast, and at depth to approximately 1,700 mRL; extending mineralisation approximately 750 metres below the bottom of the open pit. Extensional drilling has focused on (a) depth extension of Balut Dyke mineralization on the northern side of the Syenite Porphyry, and (b) depth extension of mineralization within the Monzonite in Panel 4.

Extensional hole RDUG522 was completed to follow up on the previous success of hole RDUG611 (72 m @ 3.40 g/t AuEq) reported in August 2023, which has opened up a lower zone of mineralization to the north and at a depth of ~1,900 mRL and below. An intercept returning 87 m @ 1.43 g/t AuEq (RDUG522) has confirmed mineralization extends for over 150 metres further below RDUG611 down to 1,710mRL, opening up a zone of 200 metres vertical extent below the reported Inferred resource. Further drilling will be undertaken in 2024 to define the extent of this new mineralization zone. 

Hole RDUG523 returned a result of 35 m @ 1.06 g/t AuEq and confirmed a 70 m vertical continuation of the recently identified Balut Dyke on the northern side of the Syenite with similar thickness below previously reported RDUG500 with 45.4 m @ 2.51 g/t AuEq. Mineralization of the Balut on the north remains open along strike and at depth while its analogue defined at a higher elevation on the south also remains open at depth and to be tested to a similar elevation (i.e. 1,900mRL).

In addition, hole RDUG627 has identified an additional zone of mineralization further east intersecting 15 m @ 3.32 g/t AuEq associated with another Feldspar Porphyry. The recent discovery of three new mineralized intrusives in the east highlights the prospectivity that remains for further mineralized areas. Resource Conversion drilling has focused on (i) conversion of the inferred resource within the Monzonite Porphyry directly east of the Syenite Porphyry within Panel 3 (< 2,100 mRL, Figure 4, C-C', D-D'), and (ii) infill drilling of the mineralized Eastern Breccia and Feldspar Porphyry in the east (Figure 4, section E-E' and F-F'). These drill programs broadly confirm and provide improved confidence in the inferred grade estimates as calculated in the end of year 2023 annual resource and reserve model.  Follow-up drilling on two mineralized intrusives discovered in 2022 (Eastern Breccia and Feldspar Porphyry) demonstrates continuity of mineralization with both zones remaining open at depth and potentially expanding the mineralized Feldspar Porphyry.  Hole RDUG625A has confirmed the continuity of mineralization within the Feldspar Porphyry while holes RDUG626 and RDUG623 appear to have closed off this mineralization to the east.

Regional exploration in 2024 includes advancing the Napartan initial drill target, 9 km north-west of the Didipio mine. Surface mapping and sampling has identified a Cu-Au mineralised pegmatite similar in nature to the Balut Dyke and an important ores source at Didipio. Drilling at Napartan began in March with one drill rig mobilized. Two holes have now been completed of a 2,500 m program budgeted for 2024, with assay results pending.