In her presentation to the Mines and Money conference in Hong Kong on Thursday, Harmony Gold Mining investor relations manager Marian van der Walt called the Wafi-Golpu copper-gold project in Papua New Guinea the "find of the century".
The exploration play already hosts 27 million ounces of gold and 9 million tonnes of copper and those numbers are expected to grow before commissioning in 2018.
"We believe Wafi-Golpu is amongst, possibly, the top 10 copper-gold porphyries in the world at this stage," van der Walt said.
"Bougainville, Grasberg are very familiar names but Wafi-Golpu as a combined copper-gold resource currently has more than a billion tonnes of copper of more than one per cent.
"Harmony together with [joint venture partner Newcrest Mining] are currently busy preparing the prefeasibility and we should be done by the end of June."
Regarding growth, van der Walt said Harmony saw its future in PNG, while retaining its flagship South African gold mines as "annuities" to fund exploration.
"We currently have 3000 square kilometres of exploration tenements and the geologists are all telling me the next Wafi-Golpu is awaiting in the future," she said.