Rio Tinto is formalising plans for a new massive pit at its Yandicoogina operation in the Pilbara.
The project, which already has environmental applications filed, would be a 70 million tonne a year operation, according to The West.
Rio is carrying out pre-feasibility reports on the new pit as a replacement for other sites that are running out of ore.
The new pit, known as Pocket and Billiard South, would be approximately 7.5 kilometres long and close to a kilometre wide.
At a projected 70 million tonnes it would out-produce the Pilbara region’s current largest mine, BHP Billiton’s Mt Whaleback, which has a production rate of around 55 mtpa.
Rio Tinto has slated production at the new pit to kick off in 2017, at an initial rate of 28 million tonnes per annum.
It comes as the miner ramps up production at its iron ore sites in WA, bringing on an expansion two months ahead of schedule.
The miner announced it had reached the annual run rate milestone of 260 million tonnes from its Pilbara iron ore system of mines, rail and ports.
Rio first announced plans for the $3.1 billion expansion in 2012, with $2 billion going towards extending the life of Nammuldi iron ore mine and $1.1 billion used on works to expand the company's Cape Lambert port and rail facilities.
The company will now focus on the second phase of its expansion which will increase iron ore production to 360 million tonnes per annum by the end of 2015.