MOSCOW -(Dow Jones)- The board of Russian miner OAO Norilsk Nickel  Wednesday approved the offer to buy a part of United Co. Rusal PLC's  stake in the company for about $8.75 billion.
Norilsk, the world largest nickel and palladium producer, wants to buy 28,594,162 shares--equivalent to about 15% of the company--out of the 25% stake owned by Rusal. The offer, which stipulates the payment of $306 a share, is valid until Sept. 5.
Norilsk said earlier it would announce a share buyback if Rusal rejects the offer.
Rusal, controlled by billionaire Oleg Deripaska, is locked in a conflict with Interros Holding, owner of about 30% in Norilsk, controlled by billionaire Vladimir Potanin.
Interros previously said it considers the Norilsk offer "reasonable."
Rusal said Wednesday its representatives on Norilsk's board voted against the proposal to buy the stake.
In an emailed statement Rusal said that it believes whoever receives the offer--the company itself, or Norilsk's other holders--"buybacks conducted by the company's management through the subsidiaries of [Norilsk], are in the interests of the management itself and of the Interros group and don't meet the interests of all the shareholders of the company."
Rusal previously rejected offers from Norilsk to buy the entire 25% stake for $12 billion in December, and to buy 20% for $12.8 billion in March. The latter offer worked out at $335.70 a share.