Chinese, Russian-owned companies place binding bids for Serbian copper mine

China's Zijin Mining and Russian-owned U Gold have sent valid bids for a strategic partnership in RTB Bor, Serbia's only copper mine and smelter, Mining and Energy Minister Aleksandar Antic said on Tuesday.

In July, Belgrade invited bids for a partner to invest at least $350-million in debt-laden RTB Bor but did not say how big a stake it would offer in return.