Just two weeks ago the 50:50 joint venture partners released the long-awaited prefeasibility study for the Golpu project.
Golpu has probable reserves of 450 million tonnes at 0.86 grams per tonne gold, 1.2% copper and 1.4gpt silver for 12.4 million ounces of contained gold, 5.4Mt copper and 19.7Moz silver.
"There's more upside to that," Harmony chief executive Graham Briggs told the Denver Gold Forum.
He highlighted three intersections not included in the resource, one of which hit 702m at 1.7% copper and 0.82gpt gold.
The total combined Wafi-Golpu resource is 28.5Moz gold and 9.06Mt copper, but the partners have set an exploration target of 40Moz and 15Mt copper.
"The geos in this part of the world have great fun," Briggs said.
There are five rigs currently on site at the project, focusing on Golpu and the Wafi Transfer Zone, a 25km porphyry corridor.
Newcrest has budgeted $A150 million for exploration in the 2013 financial year, the largest chunk, comprising $35-$40 million, to be spent at Wafi-Golpu.
Meanwhile, the Golpu base case PFS focused on a block cave operation from two lifts, producing an average 400,000ozpa and 250,000tpa copper in the first 15 years of the 26-year mine life, with peak annual production of 550,000ozpa gold and 330,000tpa copper during that time.
The companies' figures on cash costs differed due to assumed metal prices, but both sets of numbers are compelling.
Newcrest used assumed metal prices of $US1250 per ounce of gold and $3.10 per pound of copper, equating to unit cash costs of negative $2150/oz and unit production costs of negative $1200/oz.
Harmony's numbers use a gold price of $1650/oz and a copper price of $3.50/lb to arrive at gold cash costs of negative $2600 - a figure Briggs described as "mouth-watering" - and copper cash costs of 54c/lb, net of by-product credits.
However, both companies were keen to highlight the expanded case which would likely form the basis of the feasibility study.
The PFS envisaged an initial 15Mt per annum plant with the scope to be expanded to 22Mtpa, but if the companies include a third lift, the plant capacity would expand further to 25Mtpa according to Newcrest.
However, Briggs said the addition of Lift 3 would take the plant closer to 30Mtpa.
Including Lift 3 would give the project a mine life in excess of 30 years with production of 580,000ozpa gold and 300,000tpa copper, peaking at 720,000ozpa gold and 380,000tpa copper.
Newcrest chief executive Greg Robinson was a no-show in Denver, leaving presenting duties to finance director and chief financial officer Gerard Bond, who also talked up the prospects of Lift 3, with the deposit remaining open at depth.
Bond also touched on recoveries, which would be a focus of the FS.
The PFS envisaged average recoveries of 61%, but Bond said feasibility work would focus on improving that to around 70%.
"There's a very large prize for us if we're able to optimise those opportunities," he said.
The FS, expected to take two and a half years, would also weigh up infrastructure options.
"We have a number of decisions we need to make in regards to infrastructure," Bond said.
Meanwhile, the 6.9Moz Wafi deposit is still in concept study phase and Bond said Newcrest would place an "overwhelming focus" on Wafi over the coming months.
Briggs said he expected Wafi to "catch up" with Golpu and the deposit would move to
Both companies see Wafi-Golpu as their next major respective developments.
Initial capital costs were estimated at $4.8 billion, and Briggs said he thought Harmony could be in a position to fund its portion internally.