When Glencore Plc 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,

A deal aimed at capturing a bigger slice of the metals market, the proposed $160 billion merger of Rio Tinto a Glencore appears doomed to fail

Glencore approached Rio Tinto late last year about combining the two big copper producers but the discussions are no longer active, a person familiar with the matter said.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