LIMA, Jan 5 - Antamina, a leading copper-zinc mine in Peru, said on Tuesday shareholders have formally approved its $1.2 billion expansion.

Antamina -- a joint venture between BHP Billiton Ltd (BHP.AX) (BLT.L), Xstrata (XTA.L), Teck Cominco Ltd (TCKb.TO) and Mitsubishi Corp (8058.T) -- said the expansion would lift the volume of ore moving through its mills by 38 percent.

It produced 358,179 tonnes of copper and 382,842 tonnes of zinc in 2008, according to Peru's mining ministry.

(Reporting by Patricia Velez, Marco Aquino and Terry Wade)