A Chinese conglomerate planning to develop the Frieda River copper and gold project in Papua New Guinea has more than doubled the estimated construction cost.
It said to boost production capacity the mine would cost $US 3.6 billion to develop.
State-owned Guangdong Rising Assets Management Co Ltd bought into Frieda River in East Sepik in 2015, in line with moves by Chinese companies to pursue offshore copper mines.
A spokesperson for its subisidiary, PanAust, Joe Walsh, said the project still had to gain formal financing and no date had been set for the start of construction.
The company estimates Frieda River may contain as much as 12 million tons of copper and 19 million ounces of gold.
Copper has been earmarked as one of the few growth markets for mining companies stung by a slowdown in metals directly related to steelmaking, such as iron ore and nickel.
Reuters reports copper is languishing near its lowest price in seven years due to a supply glut but it says with fewer discoveries, however, miners exploiting new lodes hope by the time they are up and running, the market will have turned.