For the first four months of the year, the market was in a 69,000 tonnes surplus compared with a 110,000 tonnes surplus in the same period a year earlier.
The Panguna mine was operated by BCL, majority-owned by Rio Tinto, for 17 years from 1972 until 1989, when operations were suspended due to an uprising against the mine and subsequent civil war.
Brazilian miner Vale said on Monday that it had produced 75.7 million tonnes of iron ore in the second quarter, with output of 41,500 tonnes of nickel.