When Glencore proposed a combination with Rio Tinto Group a decade ago, the larger company turned it down after just a few days. News this week that the two spent several months in negotiations in the second half of last year shows how the sands have shifted,

Glencore approached Rio Tinto late last year about combining the two big copper producers but the discussions are no longer active, a person familiar with the matter said. The talks between Rio, the world's No.

Both Glencore and Rio own some of the best copper mines in the world. However, Rio — like BHP — still depends heavily on iron ore to drive its profits, at a time when China’s decades-long construction boom is drawing to an end and the iron ore market appears headed for an extended period of weakness.