Oceana Gold has delivered "strong exploration results'' from more than $US30million ($NZ43.1million) of drilling programmes in New Zealand, the Philippines and the United States.
During calendar 2016, Oceana is spending more than $US30million in more than 100 lineal kilometres of drilling, at Macraes in East Otago, Waihi in the central North Island, Didipio in the northern Philippine Luzon Island and its development mine Haile, in South Carolina, in the US.
Its is understood to be the largest annual exploration spend by 26-year-old Oceana, which started life with its Macraes mine.
Earlier this year Oceana said it expected to spend up to $US3million each at both Macraes and Didipio, up to $US12million at Waihi and up to $US15million at Haile.
In a market update yesterday, chief executive Mick Wilkes said he was "greatly encouraged'' by first-quarter drilling results, across all mines.
"I'm pleased to report strong ongoing results which further demonstrate the significant resource potential that exists in our assets,'' he said in a statement.
The results from Haile were demonstrating a "high grade resource'', citing drilling intersections at 17.5 grams of gold per tonne (g/t) along 50 metres and 18.7g/t along 61m, within the Horseshoe deposit.
"I'm comfortable these [overall] studies will demonstrate considerable additional value, given the success of the exploration programme to date,'' Mr Wilkes said.
Oceana is yet to announce intentions to reopen its Waihi open pit, the historic Martha Mine, which is closed following two cumulative slips, but underground drilling had continued.
Some "significant intersections'' from underground Waihi included 17.5g/t over 4.8m, 35.7g/t over 3m and two other results over 20g/t, also over 3m each.
Mr Wilkes said at Haile the primary focus was a study to optimise the design of an open-pit operation, and how that could work with a potential underground operation.
"Drilling to date supports the current resource estimate and will feed into an updated resource estimate, scheduled for the second half of 2016,'' Mr Wilkes said.
The company was also investigating development of an exploration tunnel, to further define underground gold reserves.
At Macraes, Oceana had so far drilled more than 14km this year, focusing on the deposits of Coronation North, Coronation open pit, Coronation South, Horse Flat and Frasers underground.
Exploration in the 3A Panel area of Frasers underground had discovered a "sheeted vein system'', which could be "amenable to bulk underground mining''.
At Waihi, 16km of drilling had been completed and a further 20km was scheduled for the rest of the year. Mr Wilkes said of underground deposit Correnso Deeps and Daybreak, mine design and planning in preparation for development had been completed and development was expected to start in the third quarter of this year.