The agreement foresees Areva holding a 66.65 percent stake in the company operating the mine, with the Niger state holding the remainder.

Production is set to begin in 2012 and will enable Niger to "double its current production and become the second biggest producer of uranium in the world," a statement from Areva said.

Output is forecast to reach 5,000 tonnes per year at full capacity and continue for more than 35 years. Initial investment will total 1.2 billion euros (1.6 billion dollars), Areva said.

The biggest uranium mine in the world is in Canada, called McArthur River.