OceanaGold Reports Exploration Results at Haile

MEDIA RELEASE

16 August 2018

OCEANAGOLD REPORTS EXPLORATION RESULTS AT HAILE

(MELBOURNE) OceanaGold Corporation (TSX: OGC) (ASX: OGC) (the “Company”) is pleased to announce an update on exploration activity at the Company’s Haile gold mine in South Carolina, U.S.A. This exploration update follows the update provided to the market on 8 November 2017 (“November update”) and results herein reflect activity completed after this date.

Selection of significant drill results within and/or adjacent to pit designs

• 46.6 metres @ 4.93 g/t between Ledbetter and Snake
• 32.3 metres @ 10.14 g/t at Mill Zone
• 77.7 metres @ 4.04 g/t at upper Ledbetter

• 21.3 metres @ 4.51 g/t at Red Hill

• 45.1 metres @ 1.17 g/t between Mill Zone and Mustang

Mick Wilkes, President and CEO of OceanaGold said, “I am very pleased to announce the results of brownfields drilling at Haile over the past nine months that are expected to add more low-cost ounces to our reserves. These results demonstrate the potential for additional mineralisation close to surface between current pit designs and at depth. Comprehensive geological reassessment from mapping and core logging has identified important structural controls that are being applied to our 3D models which will play a critical role in ongoing and future target generation. Haile’s exploration team is also driving innovative modelling for emerging geophysical targets that will be pursued in 2019.”

“Since acquiring the Haile Gold Mine in late 2015, we have delivered a 70% increase in reserves and, through our exploration program, we continue to learn more about the genesis of the mineralisation. Through this greater understanding, we are improving our mine planning and design which fits well with our continued focus on improving productivities and reducing costs.”

“In addition to exploration, the Company continues to advance the expansion of the process plant with the pebble crusher now fully constructed and commissioned. The Tower and Isa Mills, critical processing equipment for the expansion and recovery enhancement, are scheduled for completion in the first quarter of 2019.”

Since the last exploration update on November 8, 2017, the Company has drilled 100 drill holes for a combined 26,149 metres at Haile using four surface diamond drills. Resource infill and extension drilling has targeted low-cost reserve growth areas in and around the Ledbetter, Mustang, Mill Zone, Snake, Red Hill, and Haile deposits (Figure 1).

Favourable extension drill results are expected to add ore-grade mineralisation between pit designs at low strip ratios (Table 1). Pit designs will likely be merged between the Mill Zone/Mustang (e.g. DDH0715: 45.1m @ 1.17 g/t from 91.9m) and Ledbetter/Snake pit designs (e.g. DDH0669: 46.6m @ 4.93 g/t from 243.8m). Drilling below the northwest wall of the Mill Zone Phase 1 pit returned positive results and a Phase 2 layback design is in progress (e.g. DDH0736: 32.3m @ 10.14 g/t from 59.6m).

Infill and delineation drilling continue to support our models and robust mineralisation, notably in the upper Ledbetter area (e.g. DDH0678: 77.7m @ 4.04 g/t from 173.2m and DDH0771: 75.9m @ 1.57 g/t from 203.1m) (Figures 1 & 2). Shallow, medium-grade drill intercepts have been confirmed in diamond holes at Red Hill which is scheduled for mining in 2019 (e.g. DDH0805: 21.3m @ 4.51 g/t from 54.0m) (Figure 1). An 18-hole diamond drill program was conducted outside the reserve pit design at the Snake West extension and returned positive results (e.g. DDH0755: 64.8m @ 0.97 g/t from 198m) (Figures 3 and 4). Further drilling is planned in the second half of 2018 at Ledbetter, Mill Zone and Snake.

Assays received from delineation drilling continue to validate high-grade, continuous mineralisation at the Horseshoe underground deposit (e.g. DDH0609: 233.5m @ 2.87 g/t from 168.6m).

Figure 1 – Selected Drill Holes and Significant Intercepts (November 2017 to July 2018)

Figure 2 – Cross Section A-A’ With Drill Hole and Assay Results

Figure 3 – Map of the 18-Hole Snake West Drill Program

Figure 4 – Cross Section B-B’ With Snake West Drill Hole and Assay Results

Table 1 – Significant Drill Hole Intercepts from November 2017 To July 2018

All drill hole data and additional information in relation to the Haile Gold Mine can be found on the Company’s website at http://www.oceanagold.com/investor-centre/filings/. In line with ASX listing requirements, OceanaGold has appended the information required by JORC Table 1 for Haile Exploration Results to its ASX announcement. JORC Table 1 is not required under National Instrument 43-101. Readers are referred to the ASX website at www.asx.com.au or the OceanaGold website at www.oceanagold.com to view JORC Table 1.

• ENDS -

For further information please contact:

Investor Relations Media Relations

Sam Pazuki Melissa Bowerman Tel: +1 416 915 3123 Tel: +61 405 900 099

Jeffrey Sansom Tel: +61 3 9656 5300

[email protected] [email protected]

www.oceanagold.com | Twitter: @OceanaGold

About OceanaGold

OceanaGold Corporation is a mid-tier, high-margin, multinational gold producer with assets located in the Philippines, New Zealand and the United States. The Company’s assets encompass the Didipio Gold-Copper Mine located on the island of Luzon in the Philippines. On the North Island of New Zealand, the Company operates the high-grade Waihi Gold Mine while on the South Island of New Zealand, the Company operates the largest gold mine in the country at the Macraes Goldfield which is made up of a series of open pit mines and the Frasers underground mine. In the United States, the Company operates the Haile Gold Mine, a toptier, long-life, high-margin asset located in South Carolina. OceanaGold also has a significant pipeline of organic growth and exploration opportunities in the Americas and Asia-Pacific regions.

OceanaGold has operated sustainably over the past 27 years with a proven track-record for environmental management and community and social engagement. The Company has a strong social license to operate and works collaboratively with its valued stakeholders to identify and invest in social programs that are designed to build capacity and not dependency.

In 2018, the Company expects to produce 500,000 to 540,000 ounces of gold and 15,000 to 16,000 tonnes of copper with All-In Sustaining Costs that range from $725 to $775 per ounce sold.

Competent/Qualified Person’s Statement

The exploration results were prepared in accordance with the standards set out in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’ (“JORC Code”) and in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators (“NI 43-101”). The JORC Code is the accepted reporting standard for the Australian Stock Exchange Limited (“ASX”).

Information relating to Haile exploration results in this document has been verified by, is based on and fairly represents information compiled by or prepared under the supervision of John Jory, a Certified Professional Geologist and Member of the American Institute of Professional Geologists and an employee of OceanaGold. Mr Jory has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the JORC Code and is Qualified Persons for the purposes of the NI 43 101. Mr Jory consents to the inclusion in this public report of the matters based on their information in the form and context in which it appears.

Cautionary Statement for Public Release

Certain information contained in this public release may be deemed “forward-looking” within the meaning of applicable securities laws. Forward-looking statements and information relate to future performance and reflect the Company’s expectations regarding the generation of free cash flow, execution of business strategy, future growth, future production, estimated costs, results of operations, business prospects and opportunities of OceanaGold Corporation and its related subsidiaries. Any statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions or future events or performance (often, but not always, using words or phrases such as "expects" or "does not expect", "is expected", "anticipates" or "does not anticipate", "plans", "estimates" or "intends", or stating that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved) are not statements of historical fact and may be forward-looking statements. Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ materially from those expressed in the forward-looking statements and information. They include, among others, the accuracy of mineral reserve and resource estimates and related assumptions, inherent operating risks and those risk factors identified in the Company’s most recent Annual Information Form prepared and filed with securities regulators which is available on SEDAR at www.sedar.com under the Company’s name. There are no assurances the Company can fulfil forward-looking statements and information. Such forward-looking statements and information are only predictions based on current information available to management as of the date that such predictions are made; actual events or results may differ materially as a result of risks facing the Company, some of which are beyond the Company's control. Although the Company believes that any forward-looking statements and information contained in this press release is based on reasonable assumptions, readers cannot be assured that actual outcomes or results will be consistent with such statements. Accordingly, readers should not place undue reliance on forward-looking statements and information. The Company expressly disclaims any intention or obligation to update or revise any forwardlooking statements and information, whether as a result of new information, events or otherwise, except as required by applicable securities laws. The information contained in this release is not investment or financial product advice.

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