(bloomberg) The billionaire owners of Russia’s biggest mining company have revived a years-old quarrel. Oleg Deripaska, one of the top shareholders of MMC Norilsk Nickel PJSC, wants to stop Roman Abramovich from selling a stake in the company that may be 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. „Investors are worried about the new feud in the company,“ Oleg Petropavlovskiy, an analyst at BCS Global Markets, said by phone. Norilsk Nickel shares fell as much 2.8 percent in Moscow. United Co. Rusal, which is owned by Deripaska, is seeking an injunction in a London court on Friday against Vladimir Potanin’s Whiteleave Holdings Ltd. and Abramovich’s Crispian Investment Ltd. The judge will hear the case at 11:30 a.m. London time. The move signals the return of a conflict between Potanin and Deripaska over who should control Norilsk Nickel, a $33 billion mining giant. The dispute ended in 2012 after Russian President Vladimir Putin intervened to broker an agreement. The deal involved a group led by Abramovich taking a stake in the company with the promise to resolve conflicts between the other owners. Rusal controls about 28 percent of the company and Interros Holding Co., a holding company owned by Potanin, has about 30 percent. Abramovich’s Crispian owned about 5 percent in Norilsk Nickel at the start of 2017, which is currently worth more than $1.5 billion. As part of the shareholder agreement, there was a five-year lock up period that prevented Abramovich from selling shares. That expired in December, Rusal documents show. Rusal declined to comment before the court hearing. Abramovich’s spokesman John Mann declined to comment on a possible share sale or the court case. Interros confirmed to Bloomberg News that it had offered to buy Crispian’s Norilsk Nickel shares. Crispian has made a counteroffer, according to the press service, which called Rusal’s claim unjustified. Interros acted in accordance with the shareholder agreement, it said.