Global mining giant Rio Tinto Ltd won the official approval of the Western Australian government for proceeding on the initial phase of its $3.9 billion iron ore expansion in the Pilbara region.

West Australia Premier Colin Barnett gave the green light on the project that would enable Rio Tinto to lift its current iron ore capacity from 220 million tonnes per annum (MTPA) to 333 MTPA,

Mr Barnett said on Thursday that the expansion approval "marks the beginning of the next stage for the Pilbara region where companies are able to maximise their efficiencies across mines, ports and infrastructure.

In giving its go signal for Rio Tinto to ramp up its iron ore output, the West Australian government is optimistic that the mining expansion would spark further growth in the state's iron ore industry.

Also, the expansion of its Pilbara iron ore mining activities is seen as a springboard for Rio Tinto to take on the most ambitious mining project ever conceived in Australia.

Part of the approved project deals on the structural expansion of Rio Tinto's Cape Lambert port facilities would see the establishment of an additional 1.8 kilometre jetty and a four-berth wharf that would largely support the mining firm's two-phase surges in production capacity.

Once completed, Rio Tinto's iron ore output in the region is expected to spike by at least 50 percent and breach the 300 MTPA mark.

The expansion undertakings were once part of the joint venture plans of BHP Billiton and Rio Tinto in Pilbara, which collapsed this year and left the two leading mining firms to separately conduct their own respective growth projects.

BHP has earlier indicated that its current iron ore capacity of 125 MTPA would soon improved by almost a hundred percent once its expansion plans in the Pilbara region has been realised, possibly reaching a level of up to 240 MTPA.

Immediately following Mr Barnett's approval, Rio Tinto said that construction works would commence, comprising mainly of dredging and marine works, with close to a $1 billion earmarked by the firm to fund the construction activities.