Crucially, Oceana has not changed its forecast all in sustaining cost of production, maintaining a range of between $US725 and $US775 per ounce sold, which is markedly up on calendar 2017's cost of $US617 per oz.
Last year's gold production of 574,606oz was a record for the 28-year-old company.
Its chief executive, Mick Wilkes, announced yesterday guidance was changed from an expected 480,000oz to 530,000oz of gold, up to 500,000oz to 540,000oz.
Guidance for the copper by-product from its northern Philippine mine, Didipio, remained unchanged, within a production range of 15,000 tonnes to 16,000 tonnes.
Mr Wilkes said first-half trading had delivered a strong operating and financial performance, while Oceana's four mining operations in New Zealand, the US and Philippines had been achieving better than expected results.
At Didipio, improvements were made to the mine plan and it had continued to "outperform". There were opportunities for further optimisation and the ramp-up of the underground mine was "progressing nicely", he said.
Haile, in North Carolina, which had been dogged by equipment commissioning issues a year ago, had more recently seen a "strong" operating performance alongside "solid" plant performance, while mining activities were gradually improving, Mr Wilkes said.
In New Zealand, after a slow start to the year, Oceana's Waihi mine in Coromandel was "back on track".
At its Macraes operation in East Otago, which for 27 years to 2017 was the main annual gold producer, Mr Wilkes said operations were "slightly exceeding expectations" with improved plant performance and a steady supply of higher grade ore from its Coronation North open pit operation.
Just last week, Mr Wilkes released a market update from Waihi, highlighting "high mineralisation" gold test drilling results, from beneath the historical Martha pit.
He said the test drilling was designed to unlock a million ounces of gold resource-target, which could extend Waihi's mine life, at the current production levels, as far as 2030.
Last month, Oceana lodged resource consent applications to develop another underground mine adjacent to the Martha pit, and also to resume open pit operations. The permitting process was expected to be complete by the end of next year.
Mr Wilkes said, "With the increase to our production guidance and strong financial performance, we fully expect to maintain our standing as one of the most profitable gold companies globally."
