After previously refusing to comment, FMG confirmed it had made an expression of interest, joining a list which reportedly includes seasoned coal producers Peabody Energy, Xstrata, Vale and Arcelor Mittal.

“In Mongolia, we responded to an expression of interest so we’re one of a large number of people so we’ll just see what happens with that one,” FMG executive director Russell Scrimshaw told journalists on Friday.

“We will always look at good opportunities if they’re there and if we choose to pursue them, we’ll let the market know.”

FMG has previously hinted that coal is an area of interest, but said its iron ore operations in the Pilbara, including the $US8.4 billion ($A8.3 billion) expansion project, were still the focus.

“That’s our principal organisation focus in the months and years ahead,” Scrimshaw said.

“The Pilbara has proven to be a wonderful home for us and we’ll continue to grow that opportunity.

“Iron ore is the game for us. We are a pure iron ore play and we are continuing to be very successful in that, but where appropriate investment opportunities come up around the resources sector, we’ll always look at them and judge them on their merits.

“Being a big and successful company that we now are, we regularly see new opportunities presented to us from all over the world.

Mongolian government-owned Erdenes MGL holds the Tavan Tolgoi licence.

The mine could produce more than 15Mtpa and hosts a deposit of about 1.8 billion tonnes of coking coal and 4.6Bt of thermal coal in the South Gobi desert.

There is also proposed railway to allow the coal to be hauled through Russia for export off the east coast.

FMG shares closed 1c higher to $6.88 on Friday.