BC Iron and equal joint venture partner Fortescue Metals Group have extended the life of their Nullagine iron ore mine in the Pilbara by 18 months.

The extension follows a recent increase in defined ore reserves at the project.

Managing director Mike Young said the company was aggressively trying to increase its inventory of mineable ore and expected positive results.

"We expect that during the next financial year, we will have a complete assessment of every tonne of extractable ore at Nullagine with a commensurate increase in mine life," Mr Young said.

Nullagine is currently producing iron ore at a rate of three million tonnes per annum and the joint venture plans to increase output to 5Mtpa by the end of June.