SYDNEY--Rio Tinto Ltd. /quotes/zigman/182541/quotes/nls/rio RIO +2.59% said Thursday it has agreed to sell its Eagle nickel and copper project in the U.S. to Lundin Mining Corp. The miner continues to offload assets in a drive to cut costs and boost shareholder returns.

Construction on the Eagle project in Michigan, which includes an underground mine and mill, started in 2010 and the development is about 55% complete, Rio Tinto said.

"We are making good progress on a number of other potential divestments as part of our goal to achieve substantial proceeds from divesting non-core assets," Chris Lynch, Rio Tinto's chief financial officer, said in a statement.