This is the fourth time since 2017 the copper giant issues long-term debt to refinance its short- and medium-term debt.

State-owned copper giant plans to spend $3 billion this year to contain a wave of nationwide protests.

The move adds a potential barrier to any takeover proposal at a time analysts, bankers and miners expect to see more deals in copper.

Gold miners storm the ranking as the value of the 50 biggest mining companies approaches $1 trillion after a stellar year.

What has ailed copper for most of the year largely dissipated last month as the US and China closed in on an interim trade deal.