Earlier this year, Oceana posted an estimated maiden resource of 290,000 ounces of gold at Coronation North, but had since continued more exploration drilling to adjacent areas in the north and northeast of Coronation North, which has extended the known gold mineralisation in the area.
Oceana Gold investor relations analyst Jeff Sansom, contacted in Melbourne yesterday, said while no timetable had been announced, the company expected Coronation North to be operating commercially in 2017.
The estimated stripping ratios for the overburden soil above the ore body were still being finalised, but he understood it would not be onerous to get to the ore body.
He said exploration drilling to date had shown a 25% to 40% increase on the estimated gold resource.
At present, around the existing Coronation open pit, the grams of gold per tonne (g/t) of ore were coming at between 0.9 g/t and 1 g/t, but drilling around Coronation North was in a range of 0.95 g/t to 1.52 g/t.
Oceana had not formally upgraded the earlier 290,000oz resource estimate. This calendar year Oceana forecasts all operations in New Zealand and the Philippines will deliver 385,000oz to 425,000oz.
''We're going to continue [exploration] drilling in the third quarter at Coronation North, while processing the resource consent application,'' Mr Sansom said.
Three ore bodies to the north of Coronation were being test drilled at present, he said.
When asked whether more plant and staff would be required to work on Coronation North, Mr Sansom said at this point there was no need for a plant upgrade or additional staff to the 550-600 already employed at Macraes.
''We'll be moving from one pit to another,'' he said.
Oceana's application, which overlaps with the Otago Regional Council, Waitaki District Council and Dunedin City Council, said a mine life extension could be about three years.
Mr Sansom said Coronation North ''does present an extension to the [commercial] viability of Macraes'', and he hoped a mine life extension would be included when Oceana went public with its 2017 mine plan.
Oceana was still at the point of determining what the extent of a mine life extension might be, he said.
''We have [historically] mined a year and added a year, so as not to be hand-to-mouth,'' Mr Sansom said.
The new Coronation North pit would cover up to 63ha, containing about 9million tonnes of ore.
A new waste rock stack would need to be constructed, northeast of the existing (consented 2013) Coronation stack, handling a volume of 280million tonnes and covering up to 230ha.
The old Coronation stack, consented in 2013 to receive 94million tonnes, would reduce to about 29million tonnes and reduce from 105ha to 41ha.
There is a proposal for a a 27m high dam in the Coal Creek catchment area, to supplement naturally occurring low flows in Coal Creek and Mare Burn, for water quality purposes.
A 2km extension is also being sought to an existing haul road, connecting the Coronation area to the Macraes processing plant. Submissions to the resource consent application close on August 19.
