The High Court in London is due to start hearing a $1.4bn dispute over rights at Norilsk Nickel between Russian billionaire Vladimir Potanin and Oleg Deripaska, the owner of the world largest aluminum producer Rusal.

­The Russian oligarchs have been at odds since Rusal bought a 25% stake in Norilsk Nickel from Potanin’s former business partner, Mikhail Prokhorov. Rusal claim that Potanin violated its rights to board representation and demand more than $1 billion in compensation from Potanin’s Interros group. After the purchase Rusal controls 28% of Norilsk Nickel.

Last week Potanin and Deripaska were reported to be negotiating the terms of a new shareholder agreement. If the agreement is signed, Rusal could withdraw its claim that the previous accord was broken, Bloomberg reports citing sources close to the matter. However, Rusal, Potanin’s Interros and Norilsk declined to comment on the progress of the talks.

According to Bloomberg, Deripaska and Potanin have already agreed to replace Vladimir Strzhalkovsky the Norilsk CEO. Also Millhouse Capital owned by billionaire Roman Abramovich may become a Norilsk Nickel shareholder through purchase of a 6.9% stake in an effort to reduce tension over owner rights, they said this week

Last week a court in Krasnoyarsk in Russia ruled that the actions of the Norilsk Nickel board allowed Rusal to go to an arbitration court with its $1.4bn claim.