Russia's mining billionaires are back to fighting over Nornickel

The billionaire owners of Russia’s biggest mining company have revived a years-old feud. Oleg Deripaska, one of the top shareholders of MMC Norilsk Nickel, wants to stop Roman Abramovich from selling a stake in the company that may worth $1.5-billion, according to three people familiar with matter, who asked not to be identified as the information hadn’t been made public.