Martha open pit Credit: OceanaGold
NEW ZEALAND – The Waihi District preliminary economic assessment (PEA) from OceanaGold suggests an additional 2.2 million oz. of gold output from the Waihi district between 2021 and 2036.
These additional ounces would be sourced from the Marth and Gladstone open pits as well as from the underground portions of the Martha and Wharekirauponga (WKP) deposits.
Based on a growth capital estimate of US$447 million over eight years for the producing site and life-of-mine all-in sustaining costs at US$627 per oz., the after-tax net present value estimate for this additional development comes in at US$665 million, at a 5% discount rate.
“Using our base-case assumptions, the significant exploration potential recognized at Martha Underground and WKP, combined with the existing infrastructure and skilled workforce, the results of the study give us confidence to move forward in the Waihi District opportunities and as a result, we will continue advancing each forward,” Michael Holmes, the company’s president and CEO, said in a release. “Leveraging exploration potential through aggressive drill campaigns has been the key to our success since acquiring the Waihi asset in late 2015.”
Holmes added that the company continues to see potential for additional resource growth across the existing deposits with a 25,000-metre drill program underway at Martha underground and an additional 5,000 metres of drilling ongoing at WKP. OceanaGold now plans to start the permitting process for the proposed surface mines and an additional tailings facility.
The latest study assumes an expansion of the existing Waihi plant, to 1.6 million tonnes per year, for annual gold production between 35,000 oz. to 45,000 oz. in 2021 and increasing to approximately 300,000 oz. by 2028.
Along with the PEA, OceanaGold released an updated resource for the Martha open pit. Total indicated resources at Waihi stand at 12.2 million tonnes grading 4 g/t gold for 1.6 million gold oz. with a further 11 million inferred tonnes at 4.4 g/t gold, containing an additional 1.6 million oz. of gold.
OceanaGold expects to deliver a feasibility study for Martha underground in the first quarter of next year, which would be followed by a prefeasibility study for WKP in the second half of the year.
The Waihi district is on the North Island of New Zealand, 140 km southeast of Auckland. The Waihi site hosts a producing underground mine, which is expected to generate 18,000 oz. to 20,000 oz. of gold this year at site all-in sustaining costs of US$715 per oz. to US$765 per oz.
OceanaGold’s producing operations are in New Zealand and the U.S. – this year’s total production guidance for the company stands at 360,000 oz. to 380,000 oz. at all-in sustaining costs of US$1,075 to US$1,125 per oz.
For more information, visit www.OceanaGold.com.