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Oceana Gold has already extracted more than $9 million of gold from its $70 million Frasers underground development at its Macraes site in East Otago and is on track for its full commissioning by the end of the year.
Since beginning in mid-April last year, Frasers underground tunnelling has progressed to 3.54km, of which 1.6km is the main tunnel decline and the rest is some of the myriad off-shoot dead-end tunnels where gold-bearing ore is removed.
Oceana Gold's vice-president of New Zealand operations, John Kinyon, said the project was well ahead on many budgets, having extracted 175,000 tonnes of gold-bearing ore compared to expectations of 135,000 tonnes, and having driven 2.2km of tunnelling in recent months, as opposed to a budgeted 1.6km.
However, the grade of gold-bearing ore extracted was down on expectations of 2.5 grams per tonne to 1.8 grams, Kinyon said.
"We've found a lot more tonnes but at a lower grade," he said.
More gold was subsequently mined from ore removed from the main decline than anticipated, which meant less was taken from the trial stope area at the time, he said.
Eventually, the entire Frasers project will have mined a total tunnel system of 21km, of which 3.5km will be a main decline.
Oceana is preparing next month to bore two 430m vertical shafts up from the main decline, respectively 4m and 2m wide, as ventilator and escape tunnels, with the former eventually helping to circulate air throughout the entire labyrinth of tunnels.
- OTAGO DAILY TIMES
